I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Basically, you'd put a resistor across the higher-resistance lamp. If you
know the voltage across each lamp, and the current through them, you know
their resistances -- so this should be easy to compute.

Of course, since the filament's resistance varies with the current through
it, "deflecting" some of that current will lower its resistance. You're
probably going to have to experiment a bit.

On 1/4/2011 11:08 AM, klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Is the *battery* on said vehicle a *single* "24V" battery?
I.e., if, instead, it is two 12V batteries in series
(which is what the 24V battery would look like internally),
then why not run another conductor to each "lamp assembly"
(3 wires instead of 2) and run each filament off of its
intended 12V?

On Tue, 04 Jan 2011 12:09:44 -0700, D Yuniskis
wrote:

On 1/4/2011 11:08 AM, klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Is the *battery* on said vehicle a *single* "24V" battery?
I.e., if, instead, it is two 12V batteries in series
(which is what the 24V battery would look like internally),
then why not run another conductor to each "lamp assembly"
(3 wires instead of 2) and run each filament off of its
intended 12V?

One should never tap off the bottom battery in a two battery 24V
system, it will result in improper charging of the batteries.

Two solutions are either do what the OP does (two in series) or use a
voltage regulator capable of handling the current (not an efficient
solution). You can get 24 volt headlights on eBay if you want them, as
well... There are other solutions too, such as getting housings that
handle replaceable bulbs, which may be available cheaper as a 24 volt
unit. (Not sure on costs there).

Just go series, don't worry about minor light output differences, but
realize that if one goes out, both will go dark! Always carry two
spares with you.

klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

On 1/4/2011 1:09 PM, PeterD wrote:
On Tue, 04 Jan 2011 12:09:44 -0700, D Yuniskis
wrote:

On 1/4/2011 11:08 AM, klem kedidelhopper wrote:
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Is the *battery* on said vehicle a *single* "24V" battery?
I.e., if, instead, it is two 12V batteries in series
(which is what the 24V battery would look like internally),
then why not run another conductor to each "lamp assembly"
(3 wires instead of 2) and run each filament off of its
intended 12V?

One should never tap off the bottom battery in a two battery 24V
system, it will result in improper charging of the batteries.

That depends on the actual charger configuration -- hence my
asking if it was a 24V monoblock or a pair of 12V monoblocks.

Given that this is the *military*, I am assuming that they
have deep enough pockets to create their own standards
(e.g., 400Hz power). As such, if they opted for two 12V
monoblocks in the vehicle, I would assume they would have
also designed a charging system that *treated* them as
two 12V monoblocks and not a "24V battery" -- since the
added cost of charging them as two monoblocks would easily
be outweighed by the increased "battery" life that obtains
from that since imbalances between cells are a (the?) primary
cause of battery failure (presumably the military wouldn't
want to have to lug around spare batteries if they could make
the ones they had last longer -- esp. in a war zone). Cells
will *try* to equalize with overcharging in short strings
but, as the string gets longer, battery life goes to hell
(since the "good" cells get overstressed trying to "coax"
the bad ones back in line; and, as a cell gets bad, it gets
bad-er!)

But, I've never peeked under the hood of a military vehicle
so can't tell if:
- 1 monoblock or two
- three terminals to the battery or just two
- is the *entire* system running at 24V (or just parts that
draw higher currents)

Two solutions are either do what the OP does (two in series) or use a
voltage regulator capable of handling the current (not an efficient
solution). You can get 24 volt headlights on eBay if you want them, as
well... There are other solutions too, such as getting housings that
handle replaceable bulbs, which may be available cheaper as a 24 volt
unit. (Not sure on costs there).

Just go series, don't worry about minor light output differences, but
realize that if one goes out, both will go dark! Always carry two
spares with you.

"klem kedidelhopper" wrote in message
...
I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Nothing to do with the post Lenny - just a casual question about your nic !
:-)

I never knew who or what Klem Kedidlehopper was, until I was in a movie
memorabilia shop in Vegas last week. There was a suit on display that
claimed to have been worn by this guy on his TV show (I'm assuming he is a
left-pondian comedian. Me being right-pondian, he's not one that I know).
But anyway, here's the thing. They had his name spelled with a "C" as in
Clem Kedidelhopper. Is that wrong of them, or is your spelling with a "K"
some comedic twist that I'm missing ?

Arfa

On Jan 4, 8:39*pm, "Arfa Daily" wrote:
"klem kedidelhopper" wrote in message

...





I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. * Thanks for any suggestions. Lenny

Nothing to do with the post Lenny - just a casual question about your nic !
:-)

I never knew who or what Klem Kedidlehopper was, until I was in a movie
memorabilia shop in Vegas last week. There was a suit on display that
claimed to have been worn by this guy on his TV show (I'm assuming he is a
left-pondian comedian. Me being right-pondian, he's not one that I know).
But anyway, here's the thing. They had his name spelled with a "C" as in
Clem Kedidelhopper. Is that wrong of them, or is your spelling with a "K"
some comedic twist that I'm missing ?

Arfa- Hide quoted text -

- Show quoted text -

The military battery system consists of two 12volt batteries in
series..Every load in the vehicle is connected between 24 volts and
ground. There is no 12 volt load connected "halfway" between
batteries. Electrically the charging system treats the two separate
batteries as though they were one 24 volt battery. I like the idea of
connecting each lamp to each battery, ( a three wire circuit), however
in the event that a cell in either battery goes dead, the imbalance in
voltage across the two batteries would be far greater than that
created by a weak filament.

Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny
..

klem kedidelhopper wrote:

On Jan 4, 8:39 pm, "Arfa Daily" wrote:
"klem kedidelhopper" wrote in message

...





I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny

Nothing to do with the post Lenny - just a casual question about your nic !
:-)

I never knew who or what Klem Kedidlehopper was, until I was in a movie
memorabilia shop in Vegas last week. There was a suit on display that
claimed to have been worn by this guy on his TV show (I'm assuming he is a
left-pondian comedian. Me being right-pondian, he's not one that I know).
But anyway, here's the thing. They had his name spelled with a "C" as in
Clem Kedidelhopper. Is that wrong of them, or is your spelling with a "K"
some comedic twist that I'm missing ?

Arfa- Hide quoted text -

- Show quoted text -

The military battery system consists of two 12volt batteries in
series..Every load in the vehicle is connected between 24 volts and
ground. There is no 12 volt load connected "halfway" between
batteries. Electrically the charging system treats the two separate
batteries as though they were one 24 volt battery. I like the idea of
connecting each lamp to each battery, ( a three wire circuit), however
in the event that a cell in either battery goes dead, the imbalance in
voltage across the two batteries would be far greater than that
created by a weak filament.

Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny.


He was a 'County Bumpkin' character perfomed by Red Skelton on his TV
variety show. Along with 'The mean widdle Kid', a bum named 'Freddy the
Freeloader' and other characters.

http://en.wikipedia.org/wiki/Red_Skelton


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

On 1/5/2011 12:20 AM, Michael A. Terrell wrote:
Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny.

Not *the* Lenny Bruce?? ;-)

He was a 'County Bumpkin' character perfomed by Red Skelton on his TV
variety show. Along with 'The mean widdle Kid', a bum named 'Freddy the
Freeloader' and other characters.

Gertrude and Heathcliff

On Tue, 04 Jan 2011 17:14:44 -0700, D Yuniskis
wrote:

...

That depends on the actual charger configuration -- hence my
asking if it was a 24V monoblock or a pair of 12V monoblocks.


With the exception of a few vehicles, all military vehicles use a
standardized 24V alternator to charge two 12V batteries connected in
series. The exceptions are some new HMMWVs with the 4L80E transmission
which have a combination 24/12 volt alternator (which is really
expensive, a couple of thousand dollars), needed because the
transmission controller requires 12Volts, and some older military
pickup trucks (based on commercial pickups) that used two 12V
alternators to minimize the modifications needed to the electrical
system to convert them to military voltage standards.

Given that this is the *military*, I am assuming that they
have deep enough pockets to create their own standards
(e.g., 400Hz power).

The military didn't create 400Hz power, IIRC, it is a standard for
aircraft electronics. It is used to keep transformer weights down in
an environment where weight is critical. The military uses 400 Hz for
some ground equipment, but often this equipment is based on airborn
electronics.

As such, if they opted for two 12V
monoblocks in the vehicle, I would assume they would have
also designed a charging system that *treated* them as
two 12V monoblocks and not a "24V battery"

Not sure what you are saying when you use the term 'monoblocks', all
military vehicles use 12V batteries in series. There is never
(excluding the exceptions noted above) a connection to the lower
battery except to the upper battery.

-- since the
added cost of charging them as two monoblocks would easily
be outweighed by the increased "battery" life that obtains
from that since imbalances between cells are a (the?) primary
cause of battery failure (presumably the military wouldn't
want to have to lug around spare batteries if they could make
the ones they had last longer -- esp. in a war zone). Cells
will *try* to equalize with overcharging in short strings
but, as the string gets longer, battery life goes to hell
(since the "good" cells get overstressed trying to "coax"
the bad ones back in line; and, as a cell gets bad, it gets
bad-er!)

Generally speaking you try to keep the battery pairs as matched as
possible, and occasionally you check the charge for each one. If one
is not being charged properly, replace them.


But, I've never peeked under the hood of a military vehicle
so can't tell if:
- 1 monoblock or two

Again, what's a monoblock? A battery? Then yes, all have two 12volt
batteries. Yes, I have a number of military vehicles. And yes, I'm
well famiiliar with the electrical configurations for these setups.

- three terminals to the battery or just two

Standard batteries. In fact, I often use batteries I buy from TSC in
my equipment--they are cheaper and usually have a compatible form
factor. Big trucks (like the 2 1/2 ton truck) use big truck batteries,
but they are still standard batteries.

- is the *entire* system running at 24V (or just parts that
draw higher currents)

Generally everything that can be run on 24 volts runs on 24volts. The
transmission controller on HMMWVs can't, so it runs on 12volts from
the dual voltage system. It is an exception! But all lights,
electronics, etc., are 24 volts on military vehicles--the military
doens't like multiple standards...

On Tue, 04 Jan 2011 17:22:27 -0500, "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

Would this 'simple switcher' handle the 5 amps that a headlamp draws?
If so then it would be a really interesting solution. (A typical
halogen headlight draws 4.5 to 5 amps.)

I suppose if you didn't care about efficiency a series regulator might
work, but it would sure generate a lot of heat! Course in the winter,
when it is cold out, that heat might be less of a problem. But your
suggestion of a switcher (which is much more efficient) is good.

On Jan 5, 8:57*am, PeterD wrote:
On Tue, 04 Jan 2011 17:22:27 -0500, "Michael A. Terrell"





wrote:

klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. * Thanks for any suggestions. Lenny

* How about a 24 V to 12 V converter to power the headlamps? *National
Semiconductor makes the 'Simple Switcher' series of regulators.

Would this 'simple switcher' handle the 5 amps that a headlamp draws?
If so then it would be a really interesting solution. (A typical
halogen headlight draws 4.5 to 5 amps.)

I suppose if you didn't care about efficiency a series regulator might
work, but it would sure generate a lot of heat! Course in the winter,
when it is cold out, that heat might be less of a problem. But your
suggestion of a switcher (which is much more efficient) is good.- Hide quoted text -

- Show quoted text -

Last night I put two 12 volt sealed beam lamps that I got from a
vehicle in the junk yard on the bench and tested each one at 13V .They
were both halogen but appeared to be not from the same lot. Each lamp
drew almost 5.0A. The power supply showed a difference of about .125A
between lamps. I then wired the high beams in series and ran 28 volts,
(theoretical worst case charging voltage) across them. Then I measured
the voltage across each lamp. There was difference of about .450Volt
between each lamp. Probably not enough to worry about. I have more
lamps in the basement. I could possibly find a closer match if I
really look I suppose however .450V doesn't seem like an awful lot to
get upset about. Too bad I just couldn't employ a 10 amp zener diode,
if such a thing existed. Imagine the size of the series
resistor...What a seat warmer that would make on a cold Winter's
night.
Peter, I'd like to talk to you further about your military vehicles if
you'd like to .It seems that we share the same hobby. Please email me
privately at: Lenny

On Jan 5, 10:57*am, klem kedidelhopper
wrote:
On Jan 5, 8:57*am, PeterD wrote:





On Tue, 04 Jan 2011 17:22:27 -0500, "Michael A. Terrell"

wrote:

klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years..
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. * Thanks for any suggestions. Lenny

* How about a 24 V to 12 V converter to power the headlamps? *National
Semiconductor makes the 'Simple Switcher' series of regulators.

Would this 'simple switcher' handle the 5 amps that a headlamp draws?
If so then it would be a really interesting solution. (A typical
halogen headlight draws 4.5 to 5 amps.)

I suppose if you didn't care about efficiency a series regulator might
work, but it would sure generate a lot of heat! Course in the winter,
when it is cold out, that heat might be less of a problem. But your
suggestion of a switcher (which is much more efficient) is good.- Hide quoted text -

- Show quoted text -

Last night I put two 12 volt sealed beam lamps that I got from a
vehicle in the junk yard on the bench and tested each one at 13V .They
were both halogen but appeared to be not from the same lot. *Each lamp
drew almost 5.0A. The power supply showed a difference of about .125A
between lamps. I then wired the high beams in series and ran 28 volts,
(theoretical worst case charging voltage) across them. Then I measured
the voltage across each lamp. There was difference of about .450Volt
between each lamp. Probably not enough to worry about. I have more
lamps in the basement. I could possibly find a closer match if I
really look I suppose however .450V doesn't seem like an awful lot to
get upset about. Too bad I just couldn't employ a 10 amp zener diode,
if such a thing existed. Imagine the size of the series
resistor...What a seat warmer that would make on a cold Winter's
night.
Peter, I'd like to talk to you further about your military vehicles if
you'd like to .It seems that we share the same hobby. Please email me
privately at: *Lenny- Hide quoted text -

- Show quoted text -

I just noticed that the full number on my email address did not come
through. The full number is 462002

PeterD wrote:

On Tue, 04 Jan 2011 17:22:27 -0500, "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

Would this 'simple switcher' handle the 5 amps that a headlamp draws?
If so then it would be a really interesting solution. (A typical
halogen headlight draws 4.5 to 5 amps.)

I suppose if you didn't care about efficiency a series regulator might
work, but it would sure generate a lot of heat! Course in the winter,
when it is cold out, that heat might be less of a problem. But your
suggestion of a switcher (which is much more efficient) is good.


They have free software to design the switcher. Since you can use an
external pass transistor, you can handle whatever current you need.
Keep in mind that the lamps draw more than 5 A when they are cold, so
you want to double the capacity, or more. If you do, you could also
power a radio or other 12 V items from one switcher.


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

D Yuniskis wrote:

On 1/5/2011 12:20 AM, Michael A. Terrell wrote:
Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny.

Not *the* Lenny Bruce?? ;-)

He was a 'County Bumpkin' character perfomed by Red Skelton on his TV
variety show. Along with 'The mean widdle Kid', a bum named 'Freddy the
Freeloader' and other characters.

Gertrude and Heathcliff


The silly seagulls..


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

On Jan 5, 1:30*pm, "Michael A. Terrell"
wrote:
D Yuniskis wrote:

On 1/5/2011 12:20 AM, Michael A. Terrell wrote:
Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny.

Not *the* Lenny Bruce?? *;-)

* * He was a 'County Bumpkin' character perfomed by Red Skelton on his TV
variety show. *Along with 'The mean widdle Kid', a bum named 'Freddy the
Freeloader' and other characters.

Gertrude and Heathcliff

* *The silly seagulls..

--
For the last time: *I am not a mad scientist, I'm just a very ticked off
scientist!!!- Hide quoted text -

- Show quoted text -

Wasn't he also on the Jackie Gleason show?

On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.

http://www.meanwell.com/search/SD-200/SD-200-spec.pdf

Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.

There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Spehro Pefhany wrote:

On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.

http://www.meanwell.com/search/SD-200/SD-200-spec.pdf

Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.

There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).


Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

klem kedidelhopper wrote:

On Jan 5, 1:30 pm, "Michael A. Terrell"
wrote:
D Yuniskis wrote:

On 1/5/2011 12:20 AM, Michael A. Terrell wrote:
Klem Kedidelhopper was a comediene of 1950's vintage I think.that he
was the brain child of Red Skelton. When my son persuaded me to open
an email account many years ago after I repeatedly told him that I
would never have any use for one I had to pick a screen name.
Never really thinking that this would ever even go anywhere and not
fully taking this whole computer thing seriously at the time anyway, I
chose the name of one of my favorite TV characters. Well these days I
use email a lot, Klem is still on the job, I still think computers are
a royal pain in the ass, and surprisingly most people have no idea as
to who he was. Lenny.

Not *the* Lenny Bruce?? ;-)

He was a 'County Bumpkin' character perfomed by Red Skelton on his TV
variety show. Along with 'The mean widdle Kid', a bum named 'Freddy the
Freeloader' and other characters.

Gertrude and Heathcliff

The silly seagulls..

Wasn't he also on the Jackie Gleason show?


As a guest? Probably.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

On Mon, 10 Jan 2011 00:54:59 -0500, the renowned "Michael A. Terrell"
wrote:


Spehro Pefhany wrote:

On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.

http://www.meanwell.com/search/SD-200/SD-200-spec.pdf

Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.

There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).


Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.

Okay, then, if $170 is too much, how about $7.56 including shipping?

http://www.dealextreme.com/details.dx/sku.36230

They also have 15A/20A for 14.89/16.42 including shipping.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Tue, 11 Jan 2011 22:01:33 -0500, Spehro Pefhany
wrote:

On Mon, 10 Jan 2011 00:54:59 -0500, the renowned "Michael A. Terrell"
wrote:


Spehro Pefhany wrote:

On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.

http://www.meanwell.com/search/SD-200/SD-200-spec.pdf

Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.

There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).


Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.

Okay, then, if $170 is too much, how about $7.56 including shipping?

http://www.dealextreme.com/details.dx/sku.36230

They also have 15A/20A for 14.89/16.42 including shipping.

Or this one for $11.72 shipped which is claimed to be 20A

http://www.goodluckbuy.com/dc-24-inp...-inverter.html


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"Spehro Pefhany" wrote in message
...

Or this one for $11.72 shipped which is claimed to be 20A

http://www.goodluckbuy.com/dc-24-inp...-inverter.html

I'd go for that in a heart beat. you could set it in series with the
fuse feeding the head lights.

I'd get two; one as a spare since you have NO idea of its practical
service life in a road truck and you'd like to have a spare along.

Later, if #1 proves flawless, use #2 for the tail lights and swap them
out too when called for...

Ange

Spehro Pefhany wrote:

On Mon, 10 Jan 2011 00:54:59 -0500, the renowned "Michael A. Terrell"
wrote:


Spehro Pefhany wrote:

On Tue, 04 Jan 2011 17:22:27 -0500, the renowned "Michael A. Terrell"
wrote:


klem kedidelhopper wrote:

I have a 24 volt military truck that I use for snow plowing. In the
past I've had trouble finding 6000 series 24 volt sealed beam lamps
for the plow frame.. And when I did I have found them to be very
expensive. So I came up with a circuit using a DPDT switch in which
both the high and low circuit lamp filaments are wired in series when
power is applied. I was very careful to initially select two lamps
that drew exactly the same current when tested on my bench power
supply. The arrangement has worked flawlessly for the past few years.
The other night I had occaision to look at the lights from outside the
truck while it was running. Charging voltage on a 24 volt system can
run as high as 28 volts on a typical 24 volt system. Although I didn't
try to measure the voltage accross each lamp, I noticed that one lamp
is slightly brighter than the other on the low circuit. I'm assuming
that filament is getting weaker and thinner and will likely fail
shortly. And of course when that happens I'll lose the low circuit. I
can rematch two more lamps but before I do the thought occurred to me
if there was any practical easy way the equalise the voltage accross
both lamps in order to compensate for any minute differences in
filament resistance. I think that the total current, (two lamps in
series) is about 5.0 amps. Thanks for any suggestions. Lenny


How about a 24 V to 12 V converter to power the headlamps? National
Semiconductor makes the 'Simple Switcher' series of regulators.

You could also just buy a DC-DC converter.. 24:12 at 200W will run
around $170, in stock at Mouser.

http://www.meanwell.com/search/SD-200/SD-200-spec.pdf

Looks expensive compared to the raw components, perhaps, but I'll bet
most parts for your truck cost more than that.

There's enough adjustment range that you can set it to 13.8VDC or
whatever you think should be nominal. It will also run the lights at
full brightness with the motor off (at the expense of some battery
life, of course).


Probably, but it's 14 years old and I've not spent more than $100 in
repairs in the 3 years I've owned it.

Okay, then, if $170 is too much, how about $7.56 including shipping?

http://www.dealextreme.com/details.dx/sku.36230

They also have 15A/20A for 14.89/16.42 including shipping.


That would be good for people wanting a car radio on a 24 v golf
cart.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.