Quote:
Originally Posted by serialk11r
Lithium titanate is nowhere close to lead acid. It's the same as lithium iron phosphate per Ah just lower voltage. 6 in series will be 50% heavier. 14.4V on a 6S pack is 80% charge which is not that bad.
I know because I run a lithium titanate starter battery. It's 15lbs 5S 40Ah. The voltage curve is steeper than some images on the internet suggest.
I still think you can use a lithium polymer battery if temperature isn't a problem (I assume it's not if it sits in the back of the car). It will only cycle in a narrow range and will probably never be depleted.
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Ok, so LTO's are better than LA's. But they are still less energy dense than LFP's by quite a bit. Running 80% would be even less energy dense. But a lot comes down to price per Wh too, and the kind of temperatures you'll be in.
According to Wikipedia:
- LA 35-40 Wh/kg 80-90 Wh/L
- LTO 60-110 Wh/kg 177 Wh/L
- LFP 90-160 Wh/Kg 325 Wh/L
I've been very interested in LTO's for two reasons. One is for ham radio power. I live where it gets cold, and LFP's don't do well in the freezing weather. But the voltages aren't ideal as ham radios like to stay around 13.5V and can't be used much over 14V. So a 6S LTO battery could work, but would not even make it to 80% charge. I don't know, maybe I'll at least try a LTO 6S if it isn't too expensive.
The other reason is for a hybrid battery replacement for the NiMH battery in the Prius and eventually Avalon, but again, keeping it within the voltage tolerances of the BMS of 12S NiMH cell blocks running at around 14.4V to 18.5 per block is also hard to fit a block of LTO's into. A 5S LFP block would work and has been demonstrated to work very well actually as a NiMH replacemnt for Prius HV batteries.