Chain drive DIY kit questions

[akgunsmith]

I am building a Ebike for my kid. I want to buy the 450w DIY chain drive kit due to cost. The controller is 36V but I was wondering if I could slow the bike down by using a 24v battery. I wanted to slow it down and still have capability of going faster later once I put a 36V battery on it. He is 7 years old and I have heard of people using bigger batteries to go faster, so any info is much appreciated.

 

[Al P]

Why not get a 36v battery now and lock the gear shifter in the gear that gives you the maximum speed you desire. When you want to increase the speed, unlock the shifter. Of course he or she wouldn't be able to downshift, but for a kid that shouldn't be a problem.