I have a couple of dashcams, both of which have internal batteries. Both
have worked well and neither has, as predicted online, exploded in the
sun.

Both vehicles have permanently on cigar lighter sockets, and I used to
leave the cams to fall into parking mode - 1 frame per second.

This year both internal batteries have failed, and I'm now feeding each
via usb adapters that measure the current taken, voltages etc. This has
slightly alarmed me with the ddPai cam, which is taking 0.6A at 5 volts
in either mode in a car that I'm using less, and is pulling the main
battery voltage down to about 11.5 volts or less at the end of a few
days of little use. The cheaper cam takes 0.2A.

The question isn't that, though. As summer may be coming, I'm thinking
again about the dangers of leaving these things powered up in hot sun.

Is the thermal runaway that causes these lithium batteries to swell and
burn not likely to occur in an electrically dead battery or is it a
chemical effect that occurs with or without volts present?


--
Bill

Well, the small ones are pretty bomb proof. Normally they need a direct
short to burst into flames, as in the famous video where a nail gun is used
to do the deed. Just heating, unless its really far too much for the rest of
the device is unlikely to do it as many do run hot if charged quickly. Can
you not replace the batteries. I know that they do not last for ever, as
they put the same ones in some mp3 players as well.
Brian

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

Blind user, so no pictures please!
"Bill" wrote in message
...
I have a couple of dashcams, both of which have internal batteries. Both
have worked well and neither has, as predicted online, exploded in the sun.

Both vehicles have permanently on cigar lighter sockets, and I used to
leave the cams to fall into parking mode - 1 frame per second.

This year both internal batteries have failed, and I'm now feeding each
via usb adapters that measure the current taken, voltages etc. This has
slightly alarmed me with the ddPai cam, which is taking 0.6A at 5 volts in
either mode in a car that I'm using less, and is pulling the main battery
voltage down to about 11.5 volts or less at the end of a few days of
little use. The cheaper cam takes 0.2A.

The question isn't that, though. As summer may be coming, I'm thinking
again about the dangers of leaving these things powered up in hot sun.

Is the thermal runaway that causes these lithium batteries to swell and
burn not likely to occur in an electrically dead battery or is it a
chemical effect that occurs with or without volts present?


--
Bill

In message , Brian Gaff
writes
Well, the small ones are pretty bomb proof. Normally they need a direct
short to burst into flames, as in the famous video where a nail gun is used
to do the deed. Just heating, unless its really far too much for the rest of
the device is unlikely to do it as many do run hot if charged quickly. Can
you not replace the batteries. I know that they do not last for ever, as
they put the same ones in some mp3 players as well.
Brian

Brian, There are pictures of the type I have at

http://tinyurl.com/y9wmcd74

They show a camera whose battery has left this earth.

This cam looks difficult to get into, and, behind the windscreen in the
sun, it gets too hot to touch. It is said to have a battery which shuts
down at over 70 degrees C, but looks standard. However, there are
warnings about cheap copies of these batteries, and the ones on ebay and
elsewhere would all have to have the connector from the old batt
swapped.

The camera seems to work OK with bad battery, soit is really a question
of whether it would be safer to try to crack the thing open and pull the
battery completely or not to bother.
--
Bill

In message , Bill
writes
There are pictures of the type I have at

http://tinyurl.com/y9wmcd74

They show a camera whose battery has left this earth.

This cam looks difficult to get into, and, behind the windscreen in the
sun, it gets too hot to touch. It is said to have a battery which shuts
down at over 70 degrees C, but looks standard. However, there are
warnings about cheap copies of these batteries, and the ones on ebay
and elsewhere would all have to have the connector from the old batt
swapped.

The camera seems to work OK with bad battery, soit is really a question
of whether it would be safer to try to crack the thing open and pull
the battery completely or not to bother.

Since writing this, I noticed that the current the ddPai M6+ camera was
taking increased from the steady 0.5 amps to 0.8 amps, and the camera
was getting fairly hot even on a cool evening.

I cracked the camera open and took the battery out. It looked slightly
swollen.

The camera, back together, seems to work OK, although I know it won't
save the last short recording if it loses power. It is cooler and down
to 0.5 amps.

If anyone has one of these cameras I really recommend investing in a usb
supply device that displays the current the camera is taking.
--
Bill

Brian Gaff wrote

Well, the small ones are pretty bomb proof.

Tell that to Samsung. Don’t be too surprised if they laugh in your face.

Normally they need a direct short to burst into flames

Tell that to Samsung. Don’t be too surprised if they laugh in your face.

as in the famous video where a nail gun is used to do the deed.

Tell that to Samsung. Don’t be too surprised if they laugh in your face.

Just heating, unless its really far too much for the rest of the device is
unlikely to do it as many do run hot if charged quickly.

Tell that to Samsung. Don’t be too surprised if they laugh in your face.

I wouldn’t want to have one catch fire in the car with that
much internal plastic, the car wouldn’t be any use after that.

Can you not replace the batteries. I know that they do not last for ever,
as they put the same ones in some mp3 players as well.

"Bill" wrote in message
...
I have a couple of dashcams, both of which have internal batteries. Both
have worked well and neither has, as predicted online, exploded in the
sun.

Both vehicles have permanently on cigar lighter sockets, and I used to
leave the cams to fall into parking mode - 1 frame per second.

This year both internal batteries have failed, and I'm now feeding each
via usb adapters that measure the current taken, voltages etc. This has
slightly alarmed me with the ddPai cam, which is taking 0.6A at 5 volts
in either mode in a car that I'm using less, and is pulling the main
battery voltage down to about 11.5 volts or less at the end of a few days
of little use. The cheaper cam takes 0.2A.

The question isn't that, though. As summer may be coming, I'm thinking
again about the dangers of leaving these things powered up in hot sun.

Is the thermal runaway that causes these lithium batteries to swell and
burn not likely to occur in an electrically dead battery or is it a
chemical effect that occurs with or without volts present?


--
Bill

On 18/05/18 18:42, Bill wrote:
is it a chemical effect that occurs with or without volts present?

Yes.


--
Any fool can believe in principles - and most of them do!