JDH: CB750 Conversion - Upping the volts!

jdh2550_1's picture

Well, when I'm not reading the daily soap opera posts (and participating from time to time!) over on the message boards I have made some progress with the CB-750. At the moment the new front runner is a 96V system, based on 55Ah UB12550's and an ADC MT2113.

Here's the original 72V graph, followed by the new 96V graph:

I'm not sure I can go as small as 9 teeth on the front sprocket - I need to check into that. If I can't not sure whether I'll just go as small as possible and settle for a higher top speed and less acceleration or whether I'll get a larger rear sprocket.

The 8 UB12550's fit better on the bike than the 6 UB121100. But, of course, I sacrifice range. The 6 110Ah's were a definite stretch in terms of packaging and overall weight. Plan was 4 in the engine compartment and 2 as saddle bags. With the 55Ah's I can get all 8 in the engine compartment. However, that might mount some of the weight a little too high - so I might go 6 up front and 2 in saddle bags. Of course, I could go with 120V and do 8 up front and 2 in saddle bags (or go completely mad and put 4 in saddlebags for 144V). OK, I'll stop getting greedy - and go forward with the idea of a 96V / 55Ah combination. However, I will check into motor options to see if I can find a motor rated for up to 120V or 144V and a suitable controller as well. That way I can start at 96V and then go crazy later if it doesn't all end in a nasty mess before then.

I'll post some pictures of the two different sets of battery configurations.

Next up:
1) Research 96V capable motors
2) Mock up motor and motor mount
3) Mock up battery box

Oooh, it's exciting isn't it? ;-)

before comments


great work, john.

You have shown what most ppl dont get. The realtionship of all the factors that determines your top speed.

BTW that evcalc on hempev.com is also a good resource.

I appreciate that graph link. I am gonna use that one.

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