3 or 4 wheel ebike

[Mike J]

12 hours ago, Snowy79 said:

It's pretty much plug and play, watch a few videos on You Tube and away you go. You've just got to take your time as there is serious power in the batteries.

You can hold the positive and negative on a 12v and not feel anything, I've had a few small zaps just touching two terminals on the Lifepo4 batteries whilst tightening the nuts just down to sweat.  

Are these the batteries that are about the size of a soda can?

[Snowy79]

3 hours ago, Imaginos said:

Insightful. I'll probably do that when the original batteries wear out on the Kuda. How does cost compare to the gel ones? Where did you source the lifepo4 batteries?

I used Shopee, worked out about 14k pesos all in for the batteries with a battery management system. 48v 22aH. 

[Snowy79]

3 hours ago, Mike J said:

Are these the batteries that are about the size of a soda can?

Yes. 

[Imaginos]

On 8/16/2024 at 1:40 PM, Snowy79 said:

I used Shopee, worked out about 14k pesos all in for the batteries with a battery management system. 48v 22aH. 

My kuda has 60v 32ah lead acid, probably gel. It would probably be around 20k pesos. It looks like prices are dropping on the lifepo4 batteries so by the time I get around to it in 2025 hopefully it will be less. 

Did you purchase a preassembled set or individual batteries that you assembled yourself? I'm assuming the battery management system you refer to is the charger to match the higher ah ratings on the new batteries. Please correct me if I'm wrong. Hopefully you didn't need to modify any of the electrics on the bike.

Sorry for all the questions. I'm still early in the learning curve. If you could point out a couple of informative youtube videos you mentioned. There's a lot of noise out there.

Thanks.

[Snowy79]

8 hours ago, Imaginos said:

My kuda has 60v 32ah lead acid, probably gel. It would probably be around 20k pesos. It looks like prices are dropping on the lifepo4 batteries so by the time I get around to it in 2025 hopefully it will be less. 

Did you purchase a preassembled set or individual batteries that you assembled yourself? I'm assuming the battery management system you refer to is the charger to match the higher ah ratings on the new batteries. Please correct me if I'm wrong. Hopefully you didn't need to modify any of the electrics on the bike.

Sorry for all the questions. I'm still early in the learning curve. If you could point out a couple of informative youtube videos you mentioned. There's a lot of noise out there.

Thanks.

I bought the individual components. It all boils down to battery space. 

In the last one I did it was 48V, 20aH lead acid batteries ( 4 x 12v in series) The electronic motorcycle had a 30aH controller fitted. This limits the draw from the batteries to power the motorcycle. 

I upped it to 48v, 22aH lifepo4 batteries which took up half the space. In theory I could have fitted up to 44aH and got 30aH out of the batteries meaning way more power. 

I fitted a BMS which is basically a miniature computer what monitors each battery cell to ensure they all charge equally. With 48v I used 16 cells to allow a little extra power. Realistically each cell is 3.2v so giving just over 51v which is fine. 

Edited August 19 by Snowy79

[Imaginos]

23 hours ago, Snowy79 said:

I bought the individual components. It all boils down to battery space. 

In the last one I did it was 48V, 20aH lead acid batteries ( 4 x 12v in series) The electronic motorcycle had a 30aH controller fitted. This limits the draw from the batteries to power the motorcycle. 

I upped it to 48v, 22aH lifepo4 batteries which took up half the space. In theory I could have fitted up to 44aH and got 30aH out of the batteries meaning way more power. 

I fitted a BMS which is basically a miniature computer what monitors each battery cell to ensure they all charge equally. With 48v I used 16 cells to allow a little extra power. Realistically each cell is 3.2v so giving just over 51v which is fine. 

I definitely don't have a space problem.

With 5x12v in series there's currently 60v. With the lifepo4's I can go with 19x3.2 for 60.8v or 20x3.2 for 64v. Do you think 64v would be too much? Does a higher voltage give higher top speed, or is it related to the amp hours? 

With the lifepo4's do i need a new charger or would the one that charges the lead acid batteries suffice? I think a BMS would be necessary.

Thanks for all your insights.

Edited August 20 by Imaginos

[Snowy79]

18 hours ago, Imaginos said:

I definitely don't have a space problem.

With 5x12v in series there's currently 60v. With the lifepo4's I can go with 19x3.2 for 60.8v or 20x3.2 for 64v. Do you think 64v would be too much? Does a higher voltage give higher top speed, or is it related to the amp hours? 

With the lifepo4's do i need a new charger or would the one that charges the lead acid batteries suffice? I think a BMS would be necessary.

Thanks for all your insights.

The batteries are usually rated 3.2v to 3.7v. The thing that relates to the power available is the controller ( mini processor) which limits the output to the bike's motors. The motors are rated in Watts, the higher the watts the more power you will get to the wheels if the controller sends it. 

To simplify it you can have 100aH batteries but your controller may still limit it to a 30aH output, you'll just benefit from a massively extended range. 

You can upgrade the controller to allow extra amperage but be aware that the bike wiring has to be the correct gauge to handle the increased current. 

Simple electric conversion Watts, the power at the wheels = volts X amps. Under the seat you will usually see a silver box about 5 inches x 3 inches x 2 inches. That will have the max current written on it plus voltage. Do the maths and that will show your maximum output. Most decent bikes can have a 1500w rated motor but are actually capable of accepting more, the controller limits the power to say 1,440w before losses, it's common to fit a controller with a greater output. 

Edited August 21 by Snowy79