Yamaha e-bike battery for my e-surfboard project

Hi!

Last summer I did build a electric surfboard with 24V DC trolling motor and Lead-acid batteries. This was good fun and now I would like to build something with a little more power, range and lower weight. So LiIon e-bike battery and brushless motor coming up.

Now; I have some questions that I very much would like to have your thoughts on.

1. I have a Yamaha 36V e-bike battery and it has three connectors. One of them is ground, obviuosly. Measuring on the second connector gives me 41.2V stable voltage (when the battery is fully charged) and the third fluctuates between like 39.5 - 41.5 V. Tryilng to connect this battery to my DC-trolling motor results in that nothing happens So, what are these connectors different properties? I am not very familiar with LiIon e-bike batteries.

2. What are your thoughts on how powerful motor this battery could support. I would like to install a 2-3 kW motor on the board. What do you think? Is that to much for this battery?

3. I have still not purchased a motor for my board. As above. I would like to install something that packs around 2-3 kW power. Propably brushless. Do you have any thoughts on what brand and model on a motor I should choose? Given that I would like to use the battery mentioned above.

Thank you

I think 1Kw would be too much for that BMS. If you would be willing to open the battery casing, to show us the cell brand and model number we could figure out how much that pack can really take with a new BMS.

Thank you. The pack is sealed and tinkering to much with it would end the warranty. However I guess you are right. The bms will propably not supply a continuous discharge current around 60-90 Amps (3kW at 48 or 36 V)

Maybe I have to approach the problem from the other end. If I would like to have 3kW power motor working near max load for the total discharge duration of the battery. What configuration (Battery > BMS > Motor controller > Motor) would be recommended?

I was about to suggest using hobbyking and then I found this.


[youtube]bC7b5FkzmuM[/youtube]

Ha ha. Interesting! Ok. Seems like I have to check LiPo batteries and electric hobby engines out. Thanks!

If building a battery you can used Chevy Leaf modules and get the voltage you need as you put them in series