Can a 48V battery 24Ah with a 40A or a 50A BMS handle a 1500w motor hub?

[Albertosca]

Hi everyone, I want to utilise the entire power of my 1500W motor, do you think a 48V battery 24Ah with a 40A or a 50A BMS can deliver enough power to utilise at max my motor?

I even see batteries that are 48V 15Ah and say that can deliver 1500w. If I do the calculation, to handle at least 1500w Motor, needs a 30Ah battery minimum. Is it correct? Or the BMS can help to deliver more wattage for the motor? Thank you in advance.

 

[E-HP]

No, you are mixing up amp hours with amps. Amps (and volts) will determine how much power the battery can provide. Ah will determine for how long.

 

[lnanek]

Yeah, Ah ( Amp hour ) is irrelevant here. That's just how long the battery will last. Ah is unit for the capacity. How many hours it will last if you drain it at 1A discharge.

The max current is measured in A. So a 40A max discharge BMS attached to a fully charged 48V 13S Lithium ion battery at 54.6V (13 cells * 4.2V) can handle 54.6V * 40A = 2,184 watts.

 

[E-HP]

The max current is measured in A. So a 40A max discharge BMS attached to a fully charged 48V 13S Lithium ion battery at 54.6V (13 cells * 4.2V) can handle 54.6V * 40A = 2,184 watts.

Except it would be optimistic to think those generic cell can output 40A continuous. Maybe peak, but it will kill the pack attempting 40A continuous.

 

[lnanek]

Let's see. Second picture says 5P, LG 21700 4.8Ah. If that's this cell:

Unused LG INR2170 Li-ion 21700 Cells 3.6v, 4800mAh | JAG35.com Jehu Garcia's DIY Shop | Powerwalls, Lithium Batteries, EVs, eScooters, eBikes, Emergency Backup

Please read the description carefully. Shipping via Fedex Ground only. No international shipping (including Hawaii, Guam, Puerto Rico). Non-USA customers click here. UNUSED CELLS in factory packaging. Unused LG INR21700-M50L 3.6v 4800mAh 21700 li-ion cells give you very large capacity at an...

jag35.com

They can handle 9.3A each. So 5 * 9.3A = 46.5A for the pack. Assuming they aren't counterfeit. Yeah, those cells can barely cope. Agreed.

I think even worse is that it's a UPP pack, though. They are famous for being so cheap their BMS can't even top balance. Saves them like 50 cents to not populate those resistors to drain the topmost p-groups when charging, probably.

Given they probably didn't test the cells thoroughly and capacity match them when pack building, just take all cells from the same batch, the battery will probably always be somewhat out of balance and some p-group is going to be weakest and always drag it down.

 

[amberwolf]

If that cell is tested over at lgyte-info.dk or here on ES by pajda or one of the others doing real testing of cells, you can see what it can *really* do at various currents; as it will show voltage drop, and even info about cell heating, resistance, etc.

Gives a better idea of what a pack made from them can do...but:

I wouldn't trust that UPP actually used that cell (or any "real" or even new cell) in any particular pack, no matter what they tell you, nor would I trust that they built the pack well, or in a safe way.

If the last available battery on earth was a UPP, and they were paying me to take it, I'd go get some hamsters and stick a tiny generator on their wheel to power my trike before the UPP would get anywhere near it.

(there are plenty of others that I'd class the same...in fact, most of them)

 

[E-HP]

Let's see. Second picture says 5P, LG 21700 4.8Ah. If that's this cell:

Unused LG INR2170 Li-ion 21700 Cells 3.6v, 4800mAh | JAG35.com Jehu Garcia's DIY Shop | Powerwalls, Lithium Batteries, EVs, eScooters, eBikes, Emergency Backup

Please read the description carefully. Shipping via Fedex Ground only. No international shipping (including Hawaii, Guam, Puerto Rico). Non-USA customers click here. UNUSED CELLS in factory packaging. Unused LG INR21700-M50L 3.6v 4800mAh 21700 li-ion cells give you very large capacity at an...

jag35.com

They can handle 9.3A each. So 5 * 9.3A = 46.5A for the pack. Assuming they aren't counterfeit. Yeah, those cells can barely cope. Agreed.

I think even worse is that it's a UPP pack, though. They are famous for being so cheap their BMS can't even top balance. Saves them like 50 cents to not populate those resistors to drain the topmost p-groups when charging, probably.

Given they probably didn't test the cells thoroughly and capacity match them when pack building, just take all cells from the same batch, the battery will probably always be somewhat out of balance and some p-group is going to be weakest and always drag it down.

Hard to tell what you get since the chart and the circled option all use 2500mAh cells.