So would I, but as of now I'm going AGM for everything. Weight isn't an issue but simplicity is. I like being able to charge everything from the engine without any fancy converters involved.
Lithium based chemistry for starting batteries
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So would I, but as of now I'm going AGM for everything. Weight isn't an issue but simplicity is. I like being able to charge everything from the engine without any fancy converters involved.
shade
Well-known member
A flooded lead acid battery might serve you better than an AGM battery at a lower cost.
Charging an LFP battery doesn't require anything too fancy, but maintaining control of other parameters can complicate things.
dreadlocks
Well-known member
LFP's struggles are charging it quickly, but not too quickly.. the'll suck up more current than is safe for em unlike lead acid batteries.. and it would be better to let it cycle over and over than hold it at high charge rate all the time.. everything right now just wants to keep you at 100% all the time like a lead bank would desire.. and if you really want those decades of life out of LFP your trying to keep out the knees.. so like saying within a window of 20-90% SOC the vast majority of the time.
If you have a charging system w/adjustable setpoints, your most of the way there as long as it can handle the constant output for so long.. you can put float at like 13.3v and it'll act less as a float charge and more of a load/storage charge and keep battery ~90%.. but you need a load on system to pull it back down after its done charging and balancing or it'll just sit there full.
If you have a charging system w/adjustable setpoints, your most of the way there as long as it can handle the constant output for so long.. you can put float at like 13.3v and it'll act less as a float charge and more of a load/storage charge and keep battery ~90%.. but you need a load on system to pull it back down after its done charging and balancing or it'll just sit there full.
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LFP will always be **lots** more than lead. And even if it **might** last much longer, that alone does not compensate.
So unless its advantages
high C-rates
no need to get to Full, PSOC no worries
lighter weight, less space, more portable
are critical for your use case, it will never make sense purely economically.
Some just want the status, or a new hobby, I guess that's fine too.
shade
Well-known member
I thought I covered that with "no real benefit". I meant any battery used to replace a traditional flooded lead battery for a starting battery will have a hard time providing any real benefit.
Plenty of people buy AGMs for that purpose, but never see any actual benefit from the increased cost. I upgraded to a store brand Group 31 AGM for the increased capacity over the stock battery size, but if I'd known better, I would've saved a little money and stuck with a flooded lead battery. I doubt I'm really getting any value out of the AGM battery's resistance to vibration damage, but at least I'm only out tens of dollars with the store brand purchase.
The only advantage I can see with LFP for my use as a starting battery would be weight savings. All of the negatives (cost, environmental concerns, durability, complexity of control systems required for good results) far outweigh that single advantage. Maybe if the battery was remotely located outside the engine bay, and it was also used as a house battery where the benefits of an LFP battery are more apparent (as dreadlocks suggested), it would make a little more sense, but I'm not a fan of combining the starting & house power like that, either.