Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

Thank you for any views.

Lem

-------------------

BACKGROUND ...

A thread last September in the uk.rec.cars groups called "Need to
disconnect battery before charging?" http://snipurl.com/chww seemed
to generally conclude that it is alright to charge a car battery
without disconnecting it first.

My battery charger is rated, by the manufacturer, at 11 Amps. It is
probably not 11 Amps but it is bigger than I need for my old
Mazda 1400cc car. It cuts out automatically when the battery is
charged and the cutout has an selector for sealed batteries and non-
sealed batteries. I think (not sure) it works at no more than 14.4
volts. This is it http://snipurl.com/chwx.

Is it ok to leave this charger connected until it trips out or will
the trip point be delayed by the presence of the car's elctrics in
the circuit?

On Thu, 03 Feb 2005 01:03:03 GMT, Lem wrote:

Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

Thank you for any views.

Lem

-------------------

BACKGROUND ...

A thread last September in the uk.rec.cars groups called "Need to
disconnect battery before charging?" http://snipurl.com/chww seemed
to generally conclude that it is alright to charge a car battery
without disconnecting it first.

My battery charger is rated, by the manufacturer, at 11 Amps. It is
probably not 11 Amps but it is bigger than I need for my old
Mazda 1400cc car. It cuts out automatically when the battery is
charged and the cutout has an selector for sealed batteries and non-
sealed batteries. I think (not sure) it works at no more than 14.4
volts. This is it http://snipurl.com/chwx.

Is it ok to leave this charger connected until it trips out or will
the trip point be delayed by the presence of the car's elctrics in
the circuit?


The electrics shouldn't make a big difference but if you need to keep
recharging it that regularly then it's not going to last long regardless.

"Lem" wrote in message ...
Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

Thank you for any views.

Lem

-------------------

BACKGROUND ...

A thread last September in the uk.rec.cars groups called "Need to
disconnect battery before charging?" http://snipurl.com/chww seemed
to generally conclude that it is alright to charge a car battery
without disconnecting it first.

My battery charger is rated, by the manufacturer, at 11 Amps. It is
probably not 11 Amps but it is bigger than I need for my old
Mazda 1400cc car. It cuts out automatically when the battery is
charged and the cutout has an selector for sealed batteries and non-
sealed batteries. I think (not sure) it works at no more than 14.4
volts. This is it http://snipurl.com/chwx.

Is it ok to leave this charger connected until it trips out or will
the trip point be delayed by the presence of the car's elctrics in
the circuit?

My charger drops to a trickle mode. Very low amps to maintain the charge if
I am absent.

"Lem" wrote in message ...
Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

Thank you for any views.


If your battery is good, it should be OK
If your battery develops a short, it could blow the top of the battery off.
Cheaper batteries do this sometimes, they keep sucking the amps + never
charge up.
If your battery voltage is less than 10.5 volts, it probably will never
charge

"mugwomp" wrote:
"Lem" wrote in message ...
Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

If the charger works correctly with the battery out of the car,
it will work equally well with it in the car. The only thing
left electrically connected to the battery is the clock in your
radio! So there is no significant difference, in or out.

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

That is *extremely* unlikely. However, what you don't want to
do is connect too large a charger. They virtually all adjust
down to some minimal charge, but generally the higher the
maximum charge the higher the minimum charge too. For example,
any charger from 1 to 10 amps is probably absolutely safe. At
about 10 amps, it starts getting iffy. I'm not sure I'd want to
leave a 15 amp charger connected too long. I certainly would
not leave anything connected that can put out 20 amps or more.

(Note that I've lived in the, ahh, cooler parts of Alaska for a
few decades, and I rather like the idea of hardwiring a 1A
charger into the system, along with a block heater and an oil
pan heater, for winter use. Lots of people put a heat blanket
around the battery, or put a heat pad under it; but that just
keeps it warm and doesn't top off the charge. A 1A trickle
charger keeps it warm and charges it, and doesn't use nearly as
much electricity.

Thank you for any views.


If your battery is good, it should be OK
If your battery develops a short, it could blow the top of the battery off.

That might indeed be true, but if so it has absolutely nothing
to do with whether the battery left connect to the car or not.

And... I haven't heard of anything like that in at least 30
years or so.

Cheaper batteries do this sometimes, they keep sucking the amps + never
charge up.

Dead batteries do that, cheap or otherwise.

If your battery voltage is less than 10.5 volts, it probably will never
charge

Not true. But, if you put a charge on it for hours, and
immediately after it is removed the voltage goes to 10.5 volts,
the battery is a gonner.

Heck, I just left a dome light on in my truck the other day and
ran the battery down so low that the clock in the radio actually
stopped. (That must be down about 5 volts or less.) I'm not saying
that is good for the battery (and trying to rapid charge it would
certainly be worse than not), but a nice slow 5A charge for a couple
hours put it right back where it was.

--
Floyd L. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

On Wed, 02 Feb 2005 21:49:25 -0900, Floyd L. Davidson wrote:

If the charger works correctly with the battery out of the car,
it will work equally well with it in the car. The only thing
left electrically connected to the battery is the clock in your
radio!

cough might be true for a 20 year old banger but prettty much
anything younger will have the computer(s) connected, alarm etc. OK
all in various states of "standby" depending on how long the car has
been switched "off" but all still there. Some vehicles have a
deliberate "sleep" mode so that the battery isn't flattened by all
these devices before delivery or other known periods inactivity.

As for the OPs question, the battery will be fine so should all the,
permenantly connected electronics. Indeed disconnecting the permenant
12v may well cause more problems as the computers may "forget" their
settings or reset to basic defaults. Not to mention having to reset
the time on your clock and enter the anti theft code into the radio...

--
Cheers
Dave. pam is missing e-mail

In article ,
Lem wrote:
Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

Yes.

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

However, if a battery is always needing charged and the car charging
system is ok, the battery might well be on its last legs, and never reach
a high enough voltage to cut out the charger.

--
*It's o.k. to laugh during sexŒ.Œ.just don't point!

Dave Plowman London SW
To e-mail, change noise into sound.

"Lem" wrote in message ...
Will an automatic car battery charger trip out at the correct point
if the battery is left connected to the car?

I don't want my charger to keep pumping current into my battery if it
is fully charged in case my battery suffers some sort of damage!

Thank you for any views.

Lem

-------------------

BACKGROUND ...

A thread last September in the uk.rec.cars groups called "Need to
disconnect battery before charging?" http://snipurl.com/chww seemed
to generally conclude that it is alright to charge a car battery
without disconnecting it first.

My battery charger is rated, by the manufacturer, at 11 Amps. It is
probably not 11 Amps but it is bigger than I need for my old
Mazda 1400cc car. It cuts out automatically when the battery is
charged and the cutout has an selector for sealed batteries and non-
sealed batteries. I think (not sure) it works at no more than 14.4
volts. This is it http://snipurl.com/chwx.

Is it ok to leave this charger connected until it trips out or will
the trip point be delayed by the presence of the car's elctrics in
the circuit?

The few times I've had to charge my car battery I've done so in-situ with no
problems. HOWEVER most el-cheapo car battery chargers are NOT regulated and
could seriously over-charge the battery if left connected for too long (they
may well taper off the current but still end up over-charging the battery).

If you want to be sure, you can buy an external battery charging regulator
that you connect between the charger and the battery. This not only
prevents over-charging but some also have indications on them to indicate
how flat the battery is and how the charge is progressing.

In article ,
Miles wrote:
HOWEVER most el-cheapo car battery chargers are NOT regulated and could
seriously over-charge the battery if left connected for too long (they
may well taper off the current but still end up over-charging the
battery).

Most el cheapo chargers are also of low output, so if charging a well
discharged battery will take a long time anyway. Most would simply use an
overnight charge - not leave it on for days.

--
*We have enough youth, how about a fountain of Smart?

Dave Plowman London SW
To e-mail, change noise into sound.