Dual battery addition, plz help me...!!

[lucky8csl]

Is it possible to connect dual 48v batteries on my e-bike, which has a 24/36/48v controller? & what do i need to buy to do it the safest & best way? I don't know much about e-bikes, I have an Ecotric Rocket, & I am trying 2 get more speed & power out of it...

 

[RunForTheHills]

You can connect two 48V batteries in parallel, but that will extend the range of the bike and not give you additional speed and power. If you connect two 48V batteries in series, that will give you 96V, which your controller is not designed for.

 

[lucky8csl]

Alright, well I got these extra batteries I paid almost $750 for, two extra 48v batteries. So I don't want 2 just take it as a loss, I want 2 use them, so would my next move be upgrade my motor & controller, then, so I can use the batteries?

 

[RunForTheHills]

Did the seller advise you to buy the extra batteries for added power and speed? If so, perhaps you can return them for a refund because they misled you. You can use the extra batteries to extend the range (distance) that you can ride the bike. Batteries also have a finite number of recharge cycles, so by alternating batteries you can extend the life of the batteries.

If you have the technical knowledge and tools, you can take the batteries apart and use the cells to build a bigger, higher voltage battery. Higher voltage and more current capacity will give you more speed and power with an appropriate controller. Depending on the quality and specs of the cells, this may or may not be a good idea. You would also need to replace the controller if you did that. You probably wouldn't need to replace the motor, but you haven't given any details about the bike or it's components.

 

[Chalo]

If you were using less than 48 volts before, then your bike will be faster with 48V. If you had a smaller 48V battery before, then you'll have about the same performance but more range. If you install a speed controller that can use the extra amps available from your new batteries, then it will accelerate and climb better than before.

Before you get a new controller, know how much current your new batteries can supply, and don't exceed that amount.

 

[docw009]

Did you buy the same type of battery that fits exactly on the existing downtube cradle of the Rocket? It was originally sold as a 36V ebike, and I believe it still is, but some of the later models have an LCD screen that lets you adjust for 48V and the controller may be able to take 48V too, You're getting plenty of power increase going from 36V to 48V,

You cannot combine these batteries in series, as the battery protection circuits will blow up, and leave you vulnerable to fires. There's really no point in putting them in parallel either. Too much work and risk for someone that doesn't understand batteries.

Just carry the second as a spare on the rear rack. You could bolt on a battery cradle to make it more secure. A few minutes to swap batteries when you need to do so.

 

[lucky8csl]

I do have 1 of the newer ones, cuz yes I can change the controller to 24v, 36v, or 48v, but when I changed it to 48v, & tried running 1 of the new batteries that I bought, it gave me an Error 9, I believe that is too much voltage, correct? So I haven't been able 2 use either new battery yet... so just cuz I can't really do anything else, I was gonna pull the controller out, & do that shunt mod, or whatever, 2 c if that does anything 4 me...

 

[99t4]

Did u measure the voltage of the battery before u connected it 2 the bike? How many volts? Did u try it with the other new battery 2? What makes u think Error 9 means 2 much voltage? I don't c how the shunt mod would help u with this problem?

 

[docw009]

You're going to have to find the manual for the display and see what error 09 means. The controller may be hardwired to run on 36V, no matter what the display says. I used to have a 36V Ecotric 20" model, but I changed the controller/display for higher voltage,