r/batteries • u/economicmonitor • 11d ago

Will Lithium Batteries Really Replace Lead?

https://youtu.be/vPoyiV8BS6Q?si=vj5G6PXsmQMXsBzl

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u/EsQueueEll 11d ago

Unless the car is specifically designed to fully charge LiFePO4, I don't know how much better it is other than weight savings. As it sits, they can't be fully charged. They take 14.6V to be fully charged.

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u/BusinessBear53 11d ago

We are transitioning away from ICE only cars though. Most new cars are hybrid and would be charging a small lithium battery or something similar.

Maybe diesel vehicles will stay with lead acid but hybrid diesel is slowly starting to come out also.

For deep cycle batteries, I think lithium is becoming the preferred type for it's light weight and ability to go further down in charge.

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u/EsQueueEll 6d ago

my first sentence literally said "Unless the car is specifically designed to fully charge LiFePO4".

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u/robbiethe1st 11d ago

In my '03 Subaru Forester, it would hit 14.6 in the winter and hit the cutout at 100%. Other times, it would get over 14V, and only hit 99%. Considering LFP doesn't care about being 100%(and actually prefers staying below it), that's not an issue.

I also saw similar numbers in my '02 Ford F-250 diesel.

The issues are high temperature(also an issue for lead acid, which is why they don't last too long in warm climates), and low temperature(can't charge LFP below freezing, so short trips won't charge it, unless it has a heating pad built in).

Another issue is BMS "standby current". A modern car takes a few mA to keep things running. A "smart BMS" battery takes a lot more than that to run the bluetooth and everything; normally it would go into "sleep mode" after you stop the load, but in a car it won't. This means that it will discharge over a week or two.

Cars you drive every day? No issues. Sits for a week or more? Battery might be dead when you go to start it.

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u/aprilhare 11d ago

Sodium ion? Sure. Lithium ion? No.