Originally Posted by FlyingScot
Nothing is stopping someone from adding protections to their AGM banks. Except the cost/benefit ratio doesn't usually justify it, unlike Lithium where the bank is so costly and the risk so great that it usually does warrant built in protections and redundancies.
I think if I were going to stay with lead batteries, I would add a BMS with HV and LV cutoffs just like for lithium. It just makes so much sense compared to going naked the way we do. That's one reason why lithium became much less intimidating, the more I learned about it -- BMS just makes sense -- you are preventing the same kind of accidents we have with lead batteries.
Why do people still think lithium is "so costly"? I don't think that's true any more at all. I think the cost of LiFePo4
cells is already comparable to premium AGM when measured by USABLE energy storage
capacity, and when you factor in cycle life, it's much cheaper. In Europe
, they cost about €1.10 per amp/hour at 3.2v; equivalent to €4.40 at 12v. So €440 for a 12v battery
with usable capacity of about 90 amp/hours.
Compare with for example Trojan 12 AGMs -- €419 for 140 amp/hours -- so 70 amp/hours usable. Or Rolls Series 2 -- €219 for 100 amp/hours or 50 amp/hours usable.
It's a mistake to factor in the cost of the BMS and other elements of the installation
-- first of all, these are not consumables. Second, their existence represents a significant improvement in functionality and reliability
of the battery
system, and once you know about them, you would want them with lead, too.