External Hand Held Starter

I am looking to build an external hand held starter for a motorcycle engine. Figured this would be a good first project before tackling a powerwall.

The company calls for 2 lead acid batteries in series for 24 v with 900 cold cranking amps each and I want to build it out of 18650.

So the question I cant seem to figure out. My options:

1. Build a 24 volt battery with 900 Ah. Seems unlikely due to the size and volume of cells.

2. Build a 24 volt battery with 450 Ah since cells have a 2C max discharge rate. Seems likely since the battery would only operate for couple seconds at a time, but i could be at the limit of the cells and burn them up.

3. Build a 36 volt battery with 300 amp hours to get the same wattage just more volts for better cranking.

Thoughts?

Welcome
1. Its not 900Ah.. Its 900A max current. Ah is the capacity and you most likely dont need much.
2. Once again not Ah. 450A current would need 20cells in paralell with HIGH current capacity to do that. thats 7*20 cells in total...
3. Still not Ah or?

Neither less if you want something that can give HIGH current look at LiPo instead. You can get those fairly cheap and they can deliver 100s and 100s of Amps without problem. 18650 is not really the best choice for what you want ie up to 900A...

Though on a motorcycle i would say you dont need much at all. Most engines can do with 100-200A. But what motor type is it?

Its a built high compression motor. I tested it with the starter off my Ford v10 Truck and with two regular car batteries in series, it couldn't crank the motor.

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I didn't realize my other post in the Batteries section actually posted, thought it errored out. Sorry for the double post.