1 big battery or 2 small ones?????

[Grider]

1) 72v 20s6p (120 cells)......OR
2) 2 x 72v 20s4p (2 smaller batteries with 80 cells each)

I know it's a matter of personal preference but Is it better to have one big battery? Or to have 2 smaller ones? I'm about to build one (or two). They will be used for a daily commute.

 

[Tommm]

1) 72v 20s6p (120 cells)......OR
2) 2 x 72v 20s4p (2 smaller batteries with 80 cells each)

I know it's a matter of personal preference but Is it better to have one big battery? Or to have 2 smaller ones? I'm about to build one (or two). They will be used for a daily commute.

You will be able to get much less amps using a small one. Size your pack planning on using 25-75% only.

 

[ScooterMan101]

Grider,

What motor do you have ?

What controller do you have and what is the max amperage it can draw from the battery pack ?

When you ride what is the highest amount of amps you draw from the pack consistently ?

How long is the commute ?

For a general answer , depending on what motor you have ...
If you regularly operate at 20 amps or below consistently I would build 2 packs.
If you regularly operate at 25 amps , 30 amps consistently I would build 1 large pack.

 

[Voltron]

Are you going to parallel them up? That is, use them at the same time, or swapping a fresh one in?

 

[markz]

All depends on how far you ride in a day before you want to charge. Some people charge up all the time, others every now and then.

Keep in mind of the discharge rates for the packs. The easier you are on the packs the longer they last, its always a give and take. Less discharge amps, lasts longer. Fewer charges, lasts longer. Shallower use of packs, lasts longer.

 

[dogman dan]

Based on my own experience with 72v, you intend to haul ass a lot. So the solution with 8p cells beats the one with 6p. And even 8p may still whack those cells with a lot more discharge rate than they like.


Also, just carrying the damn thing. Two motorcycle saddlebags slung as low as you can may be the only way to carry that much battery, and still have a stable enough ride to avoid speed wobble when you do haul ass. Both these bikes I built with that in mind, to be able to carry 40 ah of 48v on one, 80 on the other. Carry your battery wrong, and your 40 mph bike will be unable to go faster than 25 mph without going tank slapper.

One big battery is hell to carry. Its not usually going to fit in just any bikes triangle. Carry what you can there is good, then add more elsewhere on the bike. So its two batteries, maybe one that is 6p in the triangle if it fits, then more in panniers. Maybe you carry 48v in the triangle, and then series in 24v you carry someplace else on the bike.