48V battery on a 36V motor?

Sorry for the Noob question here. I didn't pay enough attention in my Electricity & Magnetism class in college many years ago.

I have two e-drive systems. One is a 48V 500W system from em3ev. The other is a 36V 500W system from a lesser known company.

I'd like to be able to use both battery packs on one motor for longer distance. Is that possible? What would happen if I connected the 36V battery to the 48V motor? Or the 48V battery to the 36V motor? Would something catastrophic happen, or would I need a regulator/transformer for that?

Thanks in advance for your help and advice.

What controller do you have on each?

On the 48V system that came from EM3EV, I got the Mac kit, and it looks like the controller (IRFB3077) can handle 36-52V . Does that give me the green light to hook up the 36V battery to the 48V system?

I'll have to look up the controller for the mystery brand system. Not home now.

SesameCrunch said:

On the 48V system that came from EM3EV, I got the Mac kit, and it looks like the controller (IRFB3077) can handle 36-52V . Does that give me the green light to hook up the 36V battery to the 48V system?

I'll have to look up the controller for the mystery brand system. Not home now.

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Yes you can use the 36v on the MAC but you might have to reprogram the controller for a lower cut off voltage. It won't hurt it to try it. All the will happen is that the controller will shut down earlier if the cut off voltage is set for the 48v which might be right at 42v which would be peak on the 36v.
TRY IT it won't hurt thr controller.

Dan

It won't hurt the motor to put in less voltage, but you will have 3/4 the rpm.

Someone else will have to answer if you can put 48v into that specific 36v motor.

Thanks much for the assistance. I'll give the 36V on the 48V system a shot. I don't mind the slower speed.

The actual motors don't care about the voltage, but the controllers do. If you hook a 36V battery pack to a 48V controller, it likely won't function at all because of the 42V LVC of the 48V controller. It might twitch when you move the throttle, but that's probably all it will do since the load would probably cause the voltage to sag below LVC immediately.

I think a few of you overlooked that the spec on his EM3ev controller is 36-52v. So no problem there. And very likely that controller could be reprogrammed for a different LVC if it was set to 42v.

On the 36v controller, chances are very good it can handle 48v with no problem. To be sure, peek inside. If capacitors that look like little cans say 60 or 63v, go for 48v.

Thanks Dogman. I now have the confidence to experiment with the two systems.

Rather than start a new thread I thought I'd revive this one with a similar question.

I have a Bafang BBS01B 36V 250W motor, with a 36V 13ah battery, from here https://pirez.com.au/bbs01b-36v250w-bafang-mid-drive-kit/

I'm replacing bikes and building a long-distance tourer with the kit, and I was thinking two 36V 20ah batteries, when I saw teh same seller has this https://pirez.com.au/48v26-4ah-lithium-ion-triangle/ In terms of watt hours that's 1267, which combined with my current battery should give me the range I want and also physically fit together more nicely as a set on the bike.

Is there a problem with running that 48V battery on the 36V 250W motor, the BBS01B?

The answer above "On the 36v controller, chances are very good it can handle 48v with no problem. To be sure, peek inside. If capacitors that look like little cans say 60 or 63v, go for 48v" suggests I have found my answer - that I need to pull out the screwdriver? I'm asking just in case there's something I'm missing....

What controller do you have?, you may be able to id the controller and what it's setup for by model number without taking apart for a look.. I have what i gather is an earlier version of the one above and it's capable of 72v by removing an external wire.

BBS01 mid-drive is different from other systems. I don't think it will work with it's existing controller. See
https://em3ev.com/shop/bafang-36v-250-500w-bbs02-kit/

Ok, so I've got a 36V controller (kt36zwsr-gp1f5) and I was hoping to be able to overdrive my 36V motor with a 48V battery. I presume this means I need to get another controller. Can you swap them like this? will the connections work?

Thanks

terra-ist said:

Ok, so I've got a 36V controller (kt36zwsr-gp1f5) and I was hoping to be able to overdrive my 36V motor with a 48V battery. I presume this means I need to get another controller. Can you swap them like this? will the connections work?

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Your 36V controller might not work with a 48V battery. It might be programmed to fault out and quit when voltage exceeds a preset level. Low voltage cutoff will be set for a 36V battery, not 48V, so it will not protect your 48V battery. It’s worth trying the higher voltage battery before you add different components, because it’s very unlikely that a 36V controller will be damaged by being connected to a 48V battery, even if it does not work.

if you switch to a different controller that isn’t from the same supplier, probably the phase and Hall sensor wires won’t correspond to those on your motor. Even if the plug is the same, which it may or may not be, you likely will have to do some trial and error to assign the right controller wires to their corresponding motor wires.

Additionally, for the same throttle amount, the motor will try to spin faster. The exact consequences of this depend on your riding situation and style, and the system itself.