OK here goes for the umteenth time...
Its a
65Ah battery. So SMALLER at the 24 hour rate than the typical 70 to 80Ah GRP24 so most of the RANGE ADVANTAGE lithium can give is simply lost.
So you spend a lot of money for very little gain, then overwork the cells so they dont last long... To give you an idea, shirley is using 200 plus Ah, my chairs are 120 Ah or bigger, and about to be 160Ah in the salsa. Expresso is using 135Ah (90 plus addon) and snaker is using 160Ah.
- Continuous discharge current: 65AIn a R-Net chair for eg, we often need 120A PER MOTOR while turning. So its internal BMS will cut off power instantly. You stop.
- Maximum continuous discharge current: 100A (<3s)As above, the R-Net can do 2x 120A per motor (240A total) 10 seconds as you climb a steep ramp or turn on grass.
Whats more taking this many amps from a small 65Ah pack means you will have a very short service life ... Even if it could do it. Losing out on the lifespan advantages. But it will chop off the power to save itself...
The technology of this battery differs to that of your original battery (lead acid battery) but it is completely compatible with your device. It can therefore be installed without needing any further modifications. Your original battery charger which was designed for use with lead acid batteries will also be 100% compatible with this new lithium iron phosphate (LiFePO4) battery.
This battery is equipped with a BMS protection circuit which protects the battery from short circuits, overcharge and deep discharge. This BMS also balances the cells to guarantee better battery life.If the pack was large enough all the protection circuitry that causes the problems would not be required. So no cutting power off, no failures, no fires. And the BMS charging is a huge problem as it does a terrible job compared to the PL8 and so you will never get that 2000 cycle servivce life. Or half of it, in practice. Yes it allows a dumb charger. Thats its only advantage.
- Performance: Twice as powerful as a lead acid battery even at high discharge.Define powerful? 65A???
My lithium BM2 pack is 10C peak and 5C continuous and 120Ah so 600A continuous and 1200A peak. My LEAD PC1500 can do 1500 Amps pulse (10 secs) and has 1000 cranking amps!
SUMMARY.
It will repeatedly cut out and stop your chair as you load it.
You will not get more range, unless you discharge it fully, and then you will get a much shorter lifespan.
It isnt cheap, and will likely have BMS reliability and cell failure issues as the Ah isnt up to the job.
Bigger lithium packs will fit in the same space if you do it yourself. And instead of 1C cells you can use higher rated cells. And so you will be treating the cells gently, and charging properly. And so it will last 7 to 10 years, and give 4 or 5 thousand cycles used in this way. With no cutting out, no fires, no reliability issues.
. I'll be able to squeeze maximum use out of my lead-acids with the reassurance of the lithium add-on to get me home, I like that! Plus as you also say it's a good learning project.
.
) and wouldn't go to the trouble of building a lithium battery and buying a dedicated charger, if you can buy an off-the-shelf 12v lifePo4 and use a lead-acid charger? 
