Lithium-ion 12v Battery Replacement

[Daox]

If you go to their actual site it says they are from the Fit EV.

https://greentecauto.com/hybrid-batt...te-li-ion-scib

They seem to have battery cells / packs from a bunch of different EVs.

[Tahoe_Hybrid]

you will save 1/500th of a gallon of gas

[redpoint5]

and many lead acid batteries.

... some people spend a few hundred bucks on a carbon fiber hood so they can reduce the weight of their car by 5 lbs. This has a lot more bang for the buck.

Who knows how much fuel can be saved over the life of the vehicle. We do know that lead acid batteries are extremely inefficient at accepting a charge when they are near full, which is all the time. Perhaps they are 50% or less efficient, and we know the alternator is extremely inefficient.

Lithium ion batteries are very efficient accepting a charge even when nearly full.

[Daox]

Those packs do look very nice. They apparently use "Toshiba SCiB" cells which are pretty nice.

https://www.scib.jp/en/product/cell.htm

However, I did notice a negative now that I'm home (not looking on my phone). They packs have welded connections between cells. That will make them a bit harder to reconfigure into different series/parallel strings.

[redpoint5]

I've seen some DIY spot welders using capacitors online. I wouldn't let welded terminals slow me down, and simply hacking off some cells should be straightforward.

[serialk11r]

Originally Posted by Tahoe_Hybrid

you will save 1/500th of a gallon of gas

lol this is obviously not about gas, it's about making the car lighter and faster, and saving money on replacement batteries if you abuse your battery by leaving the car sitting around for long periods.

Porsche will charge you >1k for a lithium battery as an option. For a number of years now, there have been manganese doped LiFePO4 batteries that are up to the task, but only in warm weather.

Now that LTO is commonplace, even people in freezing cold areas can have a lightweight battery.

[mpg_numbers_guy]

$/kwh is still a lot higher for lithium than for lead acid, so lithium 12Vs aren't really a practical idea unless you have a hybrid battery that most of the accessories run off of.

Therefore for the same price the lithium battery will have a lower capacity than the lead acid battery, which will mean less ability to engine off coast in your manual transmission econobox, which will handicap maximim MPG.

[redpoint5]

Except that discharging a Pb battery is much more damaging than a lithium ion, and therefore a larger percentage of the battery is usable in a lithium with hardly any consequence to longevity. I've got a 20 Ah LiFePO4 in the Prius, which is probably less than half the OEM battery.

If I were doing EOC, I'd be using a lithium ion battery.

[serialk11r]

You can deep cycle any lithium chemistry much more than lead acid. The lead acid will die and you'll have to buy another one. Once you've paid for several of them, the cost advantage disappears.

[mpg_numbers_guy]

This is true, and if one is looking long term then lithium would potentially be the better option. Its increased efficiency and more compact energy makes it good for those who want the last little bit of efficiency...at a higher initial cost. Most people do not keep their cars long enough to cycle through the lifespan of a lithium 12V, so the cost savings that might've occurred are merely passed to the next owner, leaving the original owner with a net loss.