Under Bonnet Lithium Batteries

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Originally Posted by Captain_Rightfoot

That''s horrible! :(

Custom lithium made a battery for my camper. When asked they said "if there is an internal short the mosfets blow and that isolates the cells". Some must be made differently.

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Nah, they're all the same. A fault in the BMS is different to a fault in the cells. You might get lucky with a BMS fault and it blows a MOSFET, but once a cell is going there's no stopping it.

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Originally Posted by BradC

Nah, they're all the same. A fault in the BMS is different to a fault in the cells. You might get lucky with a BMS fault and it blows a MOSFET, but once a cell is going there's no stopping it.

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Are the pouch cell lithiums mentioned for cranking the same? I've only heard of them in ev applications. I thought all the LIFEP04 batteries were quite different. Pouch cells AFAIK are not LIFPO4

A123 Systems cells use what they describe as UltraPhosphate Lithium Ion. I believe still LiFePO4 but uses a patented process to manipulate the particle structure.

Invicta say they use the A123 pouch cells, whilst SSB describe them just as LiFePO4 prismatic cells (which could be pouch or cylindrical), but some vendors state they are pouch cells.

One note from my first post. The new Optima OrangeTop lithium whilst it is a cranking battery is not for under-bonnet use.

I had a lithium cranking battery in my 2003 RR TD6. Bought I think in 2019. Was made by iTech(WA).
Never had any problems with it. Car was written off in July this year (other driver smashed into the front R/H side- took out R/headlight,destroyed suspension and R fender [bawl]). Battery was still going strong.
Dont know whether they still make that battery or not.
cheers DG

Quote:

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Originally Posted by Captain_Rightfoot

Are the pouch cell lithiums mentioned for cranking the same? I've only heard of them in ev applications. I thought all the LIFEP04 batteries were quite different. Pouch cells AFAIK are not LIFPO4

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Yes. The major difference is when they thermally runaway they don't burst directly into flames, they just vent hydrogen. Provided there's no ignition source they don't burn. Of course if there is an ignition source then all bets are off, and it's not particularly difficult to ignite hydrogen.

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Originally Posted by BradC

Yes. The major difference is when they thermally runaway they don't burst directly into flames, they just vent hydrogen. Provided there's no ignition source they don't burn. Of course if there is an ignition source then all bets are off, and it's not particularly difficult to ignite hydrogen.

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My dad was a chemistry lecturer. For some reason he taught me how to make hydrogen balloons. Next thing tie a string on and douse it in metho. Stuff we did. Man they used to go with a bang.

Hi,
Especially if you pre-load the balloon with a little Oxy from the welding bottles. Or at least, so I am told.
Cheers