Jump Starter security for powering Dash Cam

tonecas

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I am thinking on buying two BlackVue 750 2ch for my car and planning on using a jump starter for powering them (mainly in parking mode).

My issue is, most jump starters I see are made in China and are made with Li-Ion/Li-Po batteries that can enter in thermal runaway above 140ºF/60ºC, which in my country can be reached in the summer with outside temperatures at 40ºC.

I don't think the probability of this happening is high since the car's internal temperature would have to built up above 60ºC but nonetheless I really do not want to take a chance, particularly with all these products being made in China. It would be a nightmare having the car catching fire because of this.

Has anyone though of this or use a jump starter or power bank to feed the dash cams?

Would it work buying a LiPo safe bag?

I would be placing the jump starter under the passenger front seat.

Thanks!
 

Nigel

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The starter power banks are almost certainly LiFePO 4, whatever the Chinese translation to English says, otherwise they would be the wrong voltage for starting a car.

LiPo batteries don't enter thermal runaway at 60C, more like 150C, and if your car ever gets that hot then you have much bigger problems since that is above destruction temperature for everything from the cooling system hoses to your aluminium cylinder head.

A decent LiPo bag is a good way to contain the flames and prevent a fire spreading, putting it under the car seat is not a good idea since car seats are flammable and not self-extinguishing like house seats, same goes for the carpets.

The big worry for me is that many of these cheaper powerbanks may not have low temperature cutoffs in which case charging one below freezing point is likely to result in an internal short circuit which can then cause a fire during a subsequent charge. This applies to LiPo, LiIon and LiFePO 4.
 
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tonecas

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you're right Nigel: 150º is more likely to be the lowest trigger point for Li-Ion:
http://batteryuniversity.com/index.php/learn/article/types_of_lithium_ion

I was under the impression that most Li-Iion batteries are of type LCO ( LiCoO2 ) and that LFP ( LiFePO4 ) are expensive and rare to be found for portable power banks/jump starters.
where did you get that info that they should mostly be LFP?

i guess i'm stressing myself with the possibility of thermal runaway. in hottest summer days the temperature inside the car will probably be not far from 60/70ºC.
but i don't now how about the built quality of these jump starters as they suggest an operating range of -20ºC to 60ºC. an individual cell may swell and break the separator above 60º and cause a thermal runaway...

your worry for low temperature and charging leading to a short-circuit is not such a problem to me. i do not get temperatures bellow -5ºC in winter and my main issue is at (low current) discharging the battery when using it rather than when charging it.

bellow the front seat is the easiest place to store the jump starter and get all the cables fed and easy access to charge the jump starter. don't see other better place to put it :/
and staying below the seat will rest at a slightly lower temperature.
 

Nigel

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you're right Nigel: 150º is more likely to be the lowest trigger point for Li-Ion:
http://batteryuniversity.com/index.php/learn/article/types_of_lithium_ion

I was under the impression that most Li-Iion batteries are of type LCO ( LiCoO2 ) and that LFP ( LiFePO4 ) are expensive and rare to be found for portable power banks/jump starters.
where did you get that info that they should mostly be LFP?

i guess i'm stressing myself with the possibility of thermal runaway. in hottest summer days the temperature inside the car will probably be not far from 60/70ºC.
but i don't now how about the built quality of these jump starters as they suggest an operating range of -20ºC to 60ºC. an individual cell may swell and break the separator above 60º and cause a thermal runaway...

your worry for low temperature and charging leading to a short-circuit is not such a problem to me. i do not get temperatures bellow -5ºC in winter and my main issue is at (low current) discharging the battery when using it rather than when charging it.

bellow the front seat is the easiest place to store the jump starter and get all the cables fed and easy access to charge the jump starter. don't see other better place to put it :/
and staying below the seat will rest at a slightly lower temperature.
I think most Li-Ion batteries are LiMn2O4, because 18650 cells are supposed to be reliable and safe, they don't use space efficiently since you can't pack cylindrical cells without leaving empty spaces! You use LiCoO2 when you want to fit maximum power into the smallest space, such as in a phone battery. However it is hard to tell, certainly some LiPo flat cells are LiMn2O4 and probably some 18650 cells are LiCoO2 and there are mixtures. Very hard to find the information in most cases.

However all these batteries are very safe if operated within their safety limits. Remember that Lead Acid batteries do cause explosions and occasionally kill people, you don't want a standard Lead Acid cell under your seat! LiPo batteries don't actually explode, don't have metallic lithium to burn and are normally safe, if mistreated, either by physical damage or charging outside the correct temperature/current/voltage ranges then they can cause a lot of smoke, and occasionally flames for a short period, a LiPo charging bag should contain the flames and prevent other combustible materials catching fire.

Your worry about 60 degrees should only be for charging, charging should be disabled outside the range 0C to 40C, discharge is fine from -40C to 60C and even 80C is not a disaster, just a reduction in lifespan. All types of lithium batteries have the same charging range.
 
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Deleted member 37895

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I tried to use one of those jump starters sold by Lowes Hardware. It shuts off after a few hours even though it has plenty of capacity
 
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