There were two primary concerns that I heard with respect to using Lithium drop in batteries in cars or boats as replacements for traditional lead acid or AGM batteries:
1) If the BMS detects that the battery charging is complete (or that the alternator is attempting to overcharge), the BMS will electrically disconnect the battery. If there is no load on the alternator when the engine is running, you will typically fry the diodes in the alternator.
2) Lithium batteries can take sink high amounts of current, and can easily overwhelm a traditional alternator, leading to the alternator being burned out if the battery is deeply discharged when the engine is started.
Both of the above two issues can be resolved with smart enough BMS configurations and/or alternators. The second problem (limiting the charge current pulled by the battery) can be managed with a DC2DC charger. I've heard there are also "black boxes" that one can get to serve as a load for the alternator if the BMS hits 'full' and disconnects the battery.
How would one know if the specific BMS of the battery one is buying (i.e. from Amazon, from China, with little to no documentation - especially no documentation about the BMS...) is set up to allow use in a car application? Are current "drop in replacement" 12V Lithium batteries set up to handle the above two cases?
For my trawler, the best solution seems to be to use conventional AGM batteries as the starting batteries, but have a significant LFP (lithium iron phosphate) bank for the house bank. I'm planning to use a Renogy 30A DC-2-DC charger that can supplement charging of the house bank when I'm under way.
On Wednesday, November 30, 2022 at 09:41:42 AM CST, Daniel Wolf <danielhwolf@gmail.com> wrote:
I should have mentioned, for those who are not familiar with Quora, that if you click on the name of the person posting the answer you get all of his or her other answers. There are many more answers and discussions of lithium battery technology there.
Lurker here who enjoys all the informative info you all post.This came down my Quora feed, I thought it might be of interest to you. It's by a Li-ion battery designer and he provides a lot of practical knowledge.Best regards,Dan
Karl Young, Li-ion, supercapacitors, EVs, HEVs, BEVs • Updated November 24
Act always as if the future of the universe depends on what you do, while laughing at yourself for thinking that anything you do makes any difference.
A Buddhist saying
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