2x 1000 watt hub on lead acid

Sm00th

10 mW
Joined
Aug 15, 2017
Messages
28
Hello,

I have two 1000 watt hub motors on four 12v 12ah SLA lead acid batteriets. Can this limit the torque somehow? Their good but I need all torque i can get.
 
torque is a factor of howmany amps you can cram into the motor bascially. but you also need volts in order to get actual power.
so winding count (rpm-per-volt) and amp limits of the motor and controller decide on the turques you are eventually get.
 
The voltage on the lead-acid batteries will sag quite a bit under load. It might sag so much it triggers the low voltage cutoff.
You will probably want batteries that can supply more current without sagging too much.
 
If you want to stick to lead, highly recommend

Odyssey PC-2150 G-31's

for such a stressful use case.

Much higher current discharge rate, excellent longevity (for lead) while deep cycling if cared for properly.
 
It's not rating of the motors that determines the amount of amperage drawn from the batteries, it's the controllers.

I've seen 1000W rated motors connected to controllers as high as 60A, with 40A being pretty common on scooters.

If you're running a pair of 40A controllers pulling a combined 80A from 12Ah of lead acid, I'd expect serious voltage sag, quite possibly to the point of hitting LVC even with a near full charge. Even at 50A (pair of 25A) you're going to be in for a pretty short ride.

So in short yes, expect the batteries to be a fairly serious limitation.
 
I guess I cant change the amps without new controller and then there is risk of broken motor?

Im considering batteries like
Two 48v10ah litium. One for each motor.
Or
One 48v litium for both. Not sure on how much ah I need and if I should look for anything more in the specification.
Or
Four new lead acid either 20ah motorcycle batteries or car batteries with more AH but heavier.
 
Search for "shunt mod" on this forum. By adding a little solder to the shunt in the controller you can raise the current sent to the motor.
 
Ok thanks!

Reason why I need torque at lower speed is that I travel short but have very steep hills. Its a cargo bike with hub in each front wheel. I prefer climbing the hills slow. I normally use little throttle. More throttle doesnt help. I have to assist a little on the pedal when unloaded but loaded I need to push it hard.
 
If more throttle (=more amps) doesn't help then the motors will only heat up with more amps. And not give more torque. It's better to have the motors in a higher rpm range as that is more efficient (less amps turned into heat).
 
Note having a bigger bank (higher capacity in Ah) is priority #1, the amps rate set by the controller is irrelevant if the batteries can't supply it for as long as needed.

LI energy density is 2-3x higher than lead, lots more power for the same weight.

But very expensive.

Putting in enough Ah may cost as much as the rest of the drivetrain put together.

New of course less risky than a scrap EV pack.

If you want to stick with lead, and the Enersys AGM I recommend above is too pricey,

the best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.
 
Update. Bought two 13S4P = 48V13.5Ah (650Wh) = ca 2900 gram = ca 70*300*90 mm. Works Great. Thanks all. I now have some extra power in my steep hills

IMG_20210412_183452.jpg
 
I literally just read up on this. The Odyssey battery is a great alternative to the Optima batteries. I did read that Sears has a similar product, but since Sears is gone in Canada I did not read the 2009 post in Pirate4x4 forum. I noted the Optima batteries are $240cdn (www.4wheelparts.ca, Costco requires account # to view prices), and Odyssey was $150cdn (same 4wp.ca website), and I remember reading that Optima batteries from Costco arent the same as the regular ones sold.

john61ct said:
Mon Sep 02, 2019 11:05 am
If you want to stick to lead, highly recommend
Odyssey PC-2150 G-31's
for such a stressful use case.
Much higher current discharge rate, excellent longevity (for lead) while deep cycling if cared for properly.

Is 650Wh enough for your needs?

Sm00th said:
Update. Bought two 13S4P = 48V13.5Ah (650Wh) = ca 2900 gram = ca 70*300*90 mm. Works Great. Thanks all. I now have some extra power in my steep hills
 
markz said:
I literally just read up on this. The Odyssey battery is a great alternative to the Optima batteries. I did read that Sears has a similar product, but since Sears is gone in Canada I did not read the 2009 post in Pirate4x4 forum. I noted the Optima batteries are $240cdn (www.4wheelparts.ca, Costco requires account # to view prices), and Odyssey was $150cdn (same 4wp.ca website), and I remember reading that Optima batteries from Costco arent the same as the regular ones sold.

Yeah, I used NorthStar AGMs, which is part of the EnerSys AGM family with Odyssey. Arguably the best lead batteries.
Optima are really just heavily promoted in motorsports -- nothing magical.
 
I was considering more AH but the retailer specify all their 48V Batteripack on max 35A/1500W. I usually dont ride too far.
 
How is my current setup compared to if I would buy another battery, 26 amp hour. Bms rated 35 amps 1500 watt. Could I connect my 13.5 in parallell each with same bms 35 amps 1500 watts. This would mean two bms on one motor and one bms on the other. Anyone elaborate on this?

I usually ride short with about 4 very steep hills each about 10 second.
 
Back
Top