BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel shelf and one in the lid. No sign of water ingress. Very strange. Any bright ideas out there (excuse the pun)

On 22/10/2019 13:22, wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel shelf and one in the lid. No sign of water ingress. Very strange. Any bright ideas out there (excuse the pun)


Check for broken insulation in the wiring, particularly where it comes
into contact with a metal edge/corner.

In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

--
*OK, who stopped payment on my reality check?

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

On Tuesday, 22 October 2019 13:22:55 UTC+1, wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel shelf and one in the lid. No sign of water ingress. Very strange. Any bright ideas out there (excuse the pun)

If it's blowing a fuse there's a short somewhere. No mystery about that. You just gotta find it. And that's no fun. I'd start by removing the lamps so there's zero load, then replacing the fuse with a resistor, and monitoring the voltage on its output. Disconnecting bits where accessible will show you when the short goes away.


NT

In article ,
wrote:
On Tuesday, 22 October 2019 13:22:55 UTC+1, wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very
strange. Any bright ideas out there (excuse the pun)

If it's blowing a fuse there's a short somewhere. No mystery about that.
You just gotta find it. And that's no fun. I'd start by removing the
lamps so there's zero load, then replacing the fuse with a resistor, and
monitoring the voltage on its output. Disconnecting bits where accessible
will show you when the short goes away.

It might even be one of lamps (bulbs)

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

wrote

BMW 7 Series 3 years old. Has tw lights in the
boot. One under the parcel shelf and one in
the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)

Most likely a pinched wire that blows the fuse occasionally.

On Wed, 23 Oct 2019 05:06:47 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

wrote

BMW 7 Series 3 years old. Has tw lights in the
boot. One under the parcel shelf and one in
the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)

Most likely a pinched wire that blows the fuse occasionally.

Someone suggested that already, senile pest! Just what in hell makes you
believe that anyone's answer only becomes valid when you senile cretin
confirm it?

--
Website (from 2007) dedicated to the 85-year-old trolling senile
cretin from Oz:
https://www.pcreview.co.uk/threads/r...d-faq.2973853/

On 22/10/2019 18:19, wrote:
On Tuesday, 22 October 2019 13:22:55 UTC+1, wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel shelf and one in the lid. No sign of water ingress. Very strange. Any bright ideas out there (excuse the pun)

If it's blowing a fuse there's a short somewhere. No mystery about that. You just gotta find it. And that's no fun. I'd start by removing the lamps so there's zero load, then replacing the fuse with a resistor, and monitoring the voltage on its output. Disconnecting bits where accessible will show you when the short goes away.


If one of the lights in in the boot lid there must be a connection at
the edge of the moving part of the boot to the main body of the car.
Usually wires running in some black corrugated trunking. As the
trunking, and the wires inside, are flexing every time the boot is
opened or closed this would be my first place to look for damaged
wiring. You may have two wires where the insulation has failed and are
shorting together.

See the Youtube video related to a boot lid wiring breakage

https://www.youtube.com/watch?v=o_iI37G9k48


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 22/10/2019 19:39, alan_m wrote:

If one of the lights in in the boot lid there must be a connection at
the edge of the moving part of the boot to the main body of the car.
Usually wires running in some black corrugated trunking. As the
trunking, and the wires inside, are flexing every time the boot is
opened or closed this would be my first place to look for damaged
wiring. You may have two wires where the insulation has failed and are
shorting together.

See the Youtube video related to a boot lid wiring breakage

https://www.youtube.com/watch?v=o_iI37G9k48


Before dismantling anything just turn on the boot lights and pull and
waggle the flexi trunking to see if you can get the fuse to blow (as
indicated by the lights going out)


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

3 years old? I'd be harassing the dealer. If it isn't covered by warranty it darned well ought to be!

Frayed or shorting connections are possible for sure, but shouldn't be happening on such a young car.

Tim

wrote on 22/10/2019 :
I'd start by removing the lamps so there's zero load, then replacing the fuse
with a resistor, and monitoring the voltage on its output. Disconnecting bits
where accessible will show you when the short goes away.

A small 12v lamp would be even easier to use, instead of a resistor.
Lit would suggest the fault is still there, unlit that there is no
short.

Harry Bloomfield wrote:

wrote on 22/10/2019 :
I'd start by removing the lamps so there's zero load, then replacing the fuse
with a resistor, and monitoring the voltage on its output. Disconnecting bits
where accessible will show you when the short goes away.

A small 12v lamp would be even easier to use, instead of a resistor.
Lit would suggest the fault is still there, unlit that there is no
short.

+1 Just the method I used to find an intermittent short which
turned out to be in the feed to a seatbelt clip illumination
bulb. Very much not essential.

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.

On Tuesday, October 22, 2019 at 2:44:33 PM UTC+1, Dave Plowman (News) wrote:
In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

--
*OK, who stopped payment on my reality check?

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

About 40 years ago my mother bought a Fiat 124 which was the first car I ever saw with a boot light. I was demonstrating this to my future father-in-law when we discovered it had no switch but was permanently on

On Tuesday, October 22, 2019 at 8:51:59 PM UTC+1, wrote:
wrote on 22/10/2019 :
I'd start by removing the lamps so there's zero load, then replacing the fuse
with a resistor, and monitoring the voltage on its output. Disconnecting bits
where accessible will show you when the short goes away.

A small 12v lamp would be even easier to use, instead of a resistor.
Lit would suggest the fault is still there, unlit that there is no
short.

Thanks to all for all the suggestions. I'll have a root around on Saturday. I did get tail ended twice last year.One was just a new bumper the other was severe enough to set off the protection system. Seat belts tightened, head restraint snapped vertical (triggered by a small explosive charge apparently). That may have some bearing though all the damage was repaired last year

wrote:
On Tuesday, October 22, 2019 at 2:44:33 PM UTC+1, Dave Plowman (News) wrote:
In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

--
*OK, who stopped payment on my reality check?

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

About 40 years ago my mother bought a Fiat 124 which was the first car I
ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently on


Um, sounds like ******** to me. So the battery was running flat every day?

Tim

--
Please don't feed the trolls

Tim+ formulated the question :
Um, sounds like ******** to me. So the battery was running flat every day?

+1

On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car I
ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently on


Um, sounds like ******** to me. So the battery was running flat every day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them.
If yours do then buy a working one.

In article , dennis@home
wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car
I ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently
on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them. If yours do then buy a working one.

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

dennis@home wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car I
ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently on


Um, sounds like ******** to me. So the battery was running flat every day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them.
If yours do then buy a working one.



True, I hadnt done the sums. You still wouldnt want one on all the time
though. Wouldnt take many days of non-use to flatten the battery.

Tim

--
Please don't feed the trolls

Yes disconnect lights one at a time as close to bulb as possible ran till a
fuse blows, if it does not with eater only on, then you have an over
current situation or maybe a very low tolerance fuse. If either fixes it and
you can pin it down by swapping, the junk the doff one and get another, if
it still trips with no bulbs the short is in the wiring, probably where its
bent or trapped somewhere by the boot lid.
Its not rocket science.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
wrote in message
...
BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel
shelf and one in the lid. No sign of water ingress. Very strange. Any
bright ideas out there (excuse the pun)

Truth probably was just a sticky switch or one timed to go off after a set
period, some switches were damped by some device to do that, Maybe they did
it for a reason but it eludes me.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
Harry Bloomfield; "Esq." wrote in
message ...
Tim+ formulated the question :
Um, sounds like ******** to me. So the battery was running flat every
day?

+1

On Wed, 23 Oct 2019 09:59:20 +0100, "dennis@home"
wrote:

On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car I
ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently on


Um, sounds like ******** to me. So the battery was running flat every day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them.

What about the sort of capacity battery that would have been found on
something like that in 1979 in the middle of the winter?

Say it was a 40Ah new, down to 30Ah because of it's age and now 15Ah
because of the cold ... and it will only restart the engine when the
battery is greater than 50% charged, then it can only take a (say) .5A
parasitic load for 14 hours?

I still don't believe a boot light wouldn't have a switch of some sort
though, possibly a gravity one or a micro switch up in the hinges
somewhere?

Cheers, T i m

On Wed, 23 Oct 2019 10:38:54 +0100, Brian Gaff wrote:

Truth probably was just a sticky switch or one timed to go off after a
set period,

In a 40 year old Fiat 124? Delayed off/fading courtesy lights are now
common but not back then.

Maybe they did it for a reason but it eludes me.

If it was delayed off, just one circuit ofr all interior courtesy
lights.

I agree on *all* the time must be wrong. It might not flatten the
battery in a day but two or three easy. On with the iginition switch
in the "accessory" or "run" position is much more likely.

--
Cheers
Dave.

On 23/10/2019 11:52, Dave Liquorice wrote:
On Wed, 23 Oct 2019 10:38:54 +0100, Brian Gaff wrote:

Truth probably was just a sticky switch or one timed to go off after a
set period,

In a 40 year old Fiat 124? Delayed off/fading courtesy lights are now
common but not back then.

Maybe they did it for a reason but it eludes me.

If it was delayed off, just one circuit ofr all interior courtesy
lights.

I agree on *all* the time must be wrong. It might not flatten the
battery in a day but two or three easy. On with the iginition switch
in the "accessory" or "run" position is much more likely.

No, Boot lights generally are on the same ciruits as interior lamps.
They go on when things are opened irrespective of keys in ignition

The only way you could tell if they were on all the time was by being in
the closed boot.

In practice there is a door type switch somewhere.

--
€œIt is dangerous to be right in matters on which the established
authorities are wrong.€�

ۥ Voltaire, The Age of Louis XIV

On 22/10/2019 13:22, wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the parcel shelf and one in the lid. No sign of water ingress. Very strange. Any bright ideas out there (excuse the pun)


Are they original type of bulb? Or has someone replaced them with LEDs
or some other spec?

--
Cheers, Rob

On 23/10/2019 10:14, charles wrote:
In article , dennis@home
wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car
I ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently
on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them. If yours do then buy a working one.

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?
Even the cheap nasty ones you used to get would be around 80AHr for that
small a load.
An "80AHr" one in a modern car would probably be 160AHr for such a small
load.
The capacity is usually stated for a much higher drain.

Most batteries now have capacity in how many amps you can draw while
starting.

dennis@home wrote:
On 23/10/2019 10:14, charles wrote:
In article , dennis@home
wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car
I ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently
on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them. If yours do then buy a working one.

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?
Even the cheap nasty ones you used to get would be around 80AHr for that
small a load.
An "80AHr" one in a modern car would probably be 160AHr for such a small
load.
The capacity is usually stated for a much higher drain.

Most batteries now have capacity in how many amps you can draw while
starting.



How about between 1966 and 74? Batteries have changed a lot over the years.
Its by no means uncommon for a boot light to flatten a battery, how long
itll take will obviously depend of the state/quality/capacity of he
battery.

All this is beside the point that no manufacturer would design a boot light
to be €œpermanently on€�. As TNP suggested, it was probably just linked to
the door switches instead of having its own boot light switch (as an
economy measure), or the OP is just wrong about it having no switch.

Tim

--
Please don't feed the trolls

On Wed, 23 Oct 2019 13:32:48 +0100, "dennis@home"
wrote:

snip

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?

Erm, roughly the rated value at that load, given it's normally the C20
one.

Even the cheap nasty ones you used to get would be around 80AHr for that
small a load.

Nope.

An "80AHr" one in a modern car would probably be 160AHr for such a small
load.

Whilst it might be more if the load isn't on the C20 rating for that
capacity, it's unlikely to be double for 'that' (~.4A) load.

The capacity is usually stated for a much higher drain.

Nope, it's stated at the C20 rate and they are the sorts of numbers we
are talking about here.

https://d3i71xaburhd42.cloudfront.ne...-Figure1-1.png

Most batteries now have capacity in how many amps you can draw while
starting.

Yes, Cold Cranking Amps or Marine Cranking Amps. Not the same as their
std C20 rating.

When I was racing EV's, because the race I entered lasted one hour and
the average draw 25A, the 'Reserve Capacity' of the batteries was of
interest to me and I built a discharge jig to test batteries for just
that. Fully charge all the batteries to be tested, put them on the jig
one at a time and select the best 2 that had the same characteristics
(then took the rest back, after fully recharging them of course). ;-)

Cheers, T i m

On 23/10/2019 14:18, T i m wrote:
On Wed, 23 Oct 2019 13:32:48 +0100, "dennis@home"
wrote:

snip

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?

Erm, roughly the rated value at that load, given it's normally the C20
one.

Rubbish.. a 40AHr batter C20 rate is 24W not 5W.
One fifth the discharge rate will nearly double the capacity of a lead
acid battery.

In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very
strange. Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

Sorry - missed the bit about it blowing the fuse. ;-)

If it's anything like my E39, a fractured wire or two where the loom goes
into the boot lid isn't unknown. Because of constant flexing.

--
*A cartoonist was found dead in his home. Details are sketchy.*

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

In article ,
dennis@home wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first
car I ever saw with a boot light. I was demonstrating this to my
future father-in-law when we discovered it had no switch but was
permanently on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them.
If yours do then buy a working one.

Some of us remember the days of parking lights. No street lighting, so had
to be on all the hours of dark. And with a weedy dynamo.

--
*It was all so different before everything changed.

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

On 23/10/2019 16:00, Dave Plowman (News) wrote:
In article ,
dennis@home wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first
car I ever saw with a boot light. I was demonstrating this to my
future father-in-law when we discovered it had no switch but was
permanently on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them.
If yours do then buy a working one.

Some of us remember the days of parking lights. No street lighting, so had
to be on all the hours of dark. And with a weedy dynamo.


and some of us remember paraffin parking lights 'cos the battery
wouldn't start the old bus the next morning with electric ones

--
Robin
reply-to address is (intended to be) valid

On Wednesday, October 23, 2019 at 8:30:08 AM UTC+1, Tim+ wrote:
wrote:
On Tuesday, October 22, 2019 at 2:44:33 PM UTC+1, Dave Plowman (News) wrote:
In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very strange.
Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

--
*OK, who stopped payment on my reality check?

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

About 40 years ago my mother bought a Fiat 124 which was the first car I
ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently on


Um, sounds like ******** to me. So the battery was running flat every day?

Tim

--
Please don't feed the trolls

No as it probably came on only when the driving lights were on

On 23/10/2019 15:58, Dave Plowman (News) wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
BMW 7 Series 3 years old. Has tw lights in the boot. One under the
parcel shelf and one in the lid. No sign of water ingress. Very
strange. Any bright ideas out there (excuse the pun)


Are you certain they are properly switched off when the boot is closed?
Not flickering etc with movement? Some use a switch which works on the
lid angle, rather than the sort operated by the doors for the interior
lights. And that could be faulty.

Light fittings designed for only short term use may well allow the bulb to
get too hot if left on for long periods.

Sorry - missed the bit about it blowing the fuse. ;-)

If it's anything like my E39, a fractured wire or two where the loom goes
into the boot lid isn't unknown. Because of constant flexing.


On a 3 year old 7 series? Standards have slipped since my day ;-)

--
Cheers, Rob

On Wednesday, 23 October 2019 13:48:43 UTC+1, Tim+ wrote:
dennis@home wrote:
On 23/10/2019 10:14, charles wrote:
In article , dennis@home
wrote:
On 23/10/2019 08:30, Tim+ wrote:

About 40 years ago my mother bought a Fiat 124 which was the first car
I ever saw with a boot light. I was demonstrating this to my future
father-in-law when we discovered it had no switch but was permanently
on


Um, sounds like ******** to me. So the battery was running flat every
day?

Tim


Car batteries don't run flat every day just because there is a 5W load
on them. If yours do then buy a working one.

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?
Even the cheap nasty ones you used to get would be around 80AHr for that
small a load.
An "80AHr" one in a modern car would probably be 160AHr for such a small
load.
The capacity is usually stated for a much higher drain.

Most batteries now have capacity in how many amps you can draw while
starting.



How about between 1966 and 74? Batteries have changed a lot over the years.
Its by no means uncommon for a boot light to flatten a battery, how long
itll take will obviously depend of the state/quality/capacity of he
battery.

All this is beside the point that no manufacturer would design a boot light
to be €œpermanently on€�. As TNP suggested, it was probably just linked to
the door switches instead of having its own boot light switch (as an
economy measure), or the OP is just wrong about it having no switch.

Tim

On a 1960s Fiat 124 I'd expect about 30Ah. It could be less.


NT

On Wed, 23 Oct 2019 15:37:02 +0100, "dennis@home"
wrote:

On 23/10/2019 14:18, T i m wrote:
On Wed, 23 Oct 2019 13:32:48 +0100, "dennis@home"
wrote:

snip

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?

Erm, roughly the rated value at that load, given it's normally the C20
one.

Rubbish.. a 40AHr batter C20 rate is 24W not 5W.

Possibly, when new and when at 20 DegC and down to 100% discharge.

One fifth the discharge rate will nearly double the capacity of a lead
acid battery.

Agreed, but see above (and depending on what capacity rate you are
referencing).

The point being is that it's quite easy to flatten the battery of an
old vehicle in the cold with just a boot / interior light, overnight.

A mate did exactly that with a Rover SDi and that wasn't that old.

Cheers, T i m

In article ,
T i m wrote:
The point being is that it's quite easy to flatten the battery of an
old vehicle in the cold with just a boot / interior light, overnight.

A mate did exactly that with a Rover SDi and that wasn't that old.

Boot light in an SD1 is 6 watts. Interior lights 2x6 watt. Mine has a 70
amp.hr battery. 1 amp for 12 hours would barely make a dent in it.

I once left the lights on at work on a winter morning. Was told about it
lunch time, and it started OK. Ran it for about 15 minutes to charge the
battery and then had lunch. Started OK at night.

--
*Don't squat with your spurs on *

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

In article ,
T i m wrote:
On Wed, 23 Oct 2019 15:37:02 +0100, "dennis@home"
wrote:

On 23/10/2019 14:18, T i m wrote:
On Wed, 23 Oct 2019 13:32:48 +0100, "dennis@home"
wrote:

snip

5W for 24 hours would be 120 watt hours; at 12v = 10 AH - quite a drain on
a small battery,


What do you think the capacity is for a car battery under a very small
load like that?

Erm, roughly the rated value at that load, given it's normally the C20
one.

Rubbish.. a 40AHr batter C20 rate is 24W not 5W.

Possibly, when new and when at 20 DegC and down to 100% discharge.

One fifth the discharge rate will nearly double the capacity of a lead
acid battery.

Agreed, but see above (and depending on what capacity rate you are
referencing).

The point being is that it's quite easy to flatten the battery of an
old vehicle in the cold with just a boot / interior light, overnight.

A mate did exactly that with a Rover SDi and that wasn't that old.

even a modern car left for 10 days in an airport car park can have very low
battery. The alarm system is quite thirsty.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

In article ,
charles wrote:
even a modern car left for 10 days in an airport car park can have very
low battery. The alarm system is quite thirsty.

Most are meant to be able to be left for 3 weeks - assuming a decent fully
charged battery.

--
*Beware - animal lover - brakes for pussy*

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

On Wed, 23 Oct 2019 18:33:18 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
The point being is that it's quite easy to flatten the battery of an
old vehicle in the cold with just a boot / interior light, overnight.

A mate did exactly that with a Rover SDi and that wasn't that old.

Boot light in an SD1 is 6 watts. Interior lights 2x6 watt. Mine has a 70
amp.hr battery. 1 amp for 12 hours would barely make a dent in it.

Yours had a *good* 70Ah battery in it. ;-)

I once left the lights on at work on a winter morning. Was told about it
lunch time, and it started OK. Ran it for about 15 minutes to charge the
battery and then had lunch. Started OK at night.

(Side lights ...) Yup, that's what I would have expected (hoped for)
on a good battery (and 'these days').

Cheers, T i m