4 20amp 12v batteries to lithium advice plz

If i need 4 x20amp 12v to move my mobility scooter and it was not new so seems mad to replace 4 lead acid what can i use to get same or more range.
Its a zt15 say 20 mile but was flagging after 10 top speed 25km 15mph i do need the range speed increase woyld be nice but not important
i can manage 12 24v electrics
as rebuild cars etc
thankyou
Mike

shoney said:

If i need 4 x20amp 12v to move my mobility scooter and it was not new so seems mad to replace 4 lead acid what can i use to get same or more range.
Its a zt15 say 20 mile but was flagging after 10 top speed 25km 15mph i do need the range speed increase woyld be nice but not important
i can manage 12 24v electrics
as rebuild cars etc
thankyou
Mike

Click to expand...

If those 12V x4 are in series then your scooter runs on 48V.

16S LFP or 13S li-ion chemistry, might be able to go higher voltage but those would be certain without more research.

If you mean 20 Ah not amp, then going to 40-60Ah would be about the same size & weight but give a **lot** more range.


If those 12V x4 are in parallel (unlikely) then 4S LFP, and 20Ah is each battery total of 80 Ah, you could go to likely 150-250Ah in the same space.

Yes sorry 20ah x4 =80 ah in series at the moment 10 to 12 easy but my market town is 10

shoney said:

Yes sorry 20ah x4 =80 ah in series at the moment 10 to 12 easy but my market town is 10

Click to expand...

Batteries in series add voltage, not capacity (Ah).
4x 20Ah batteries in series is still 20Ah for the pack.

FWIW, most of the mobility scooters are 24v (around 28-29v full charge, around 20v empty). You'd need to check yours to be sure, before you go any farther with your battery search.

Those that use four 12v SLA usually wire them as 2S2P, so if you have four 12v 20Ah SLAs they are probably wired up as 24v 40Ah total.


Additionally, many of them use the lead as ballast to prevent the scooter from tipping over in turns. If you replace the lead with something lighter, you may have to slow way way down for any kind of turn and avoid riding sideways across tilted surfaces to prevent tipping over on your side. (or add ballast weight as low down as possible to compensate, like lead plates bolted under the deck.)

So if your system is 24V, and the batteries are currently 20Ah each at 12V

which are tiny capacity

take the above as questions, the most basic information you should know before thinking about making changes!

Then you will be putting eight LFP chemistry cells in to get to 24V,

best to get the largest size Ah cap per cell that fit in the space, only one string of 8

rather than a total if 16 or 24 or 36 smaller-capacity cells.

Whatever the voltage (and thus xPyS layout) you will get 2-3 times longer range by going to LFP rather than lead.

But the bank will cost maybe 10-20 times more, depending on what region of the world you live in and to what degree you are DIYing the support infrastructure like compression enclosures, wiring, BMS, charger etc.