Strange case of the C

Yes it's a trick title. I'm hoping to get someone with some experience with a battery of one C to answer. It is looking more and more like my home brewed battery pack has only 1C.

My question is this. When I finally get to the 25amp hour level of true current in my pack, am I going to need to go far above it just to keep the bike running at full speed. In other words am I going to need 35or 50ahs of battery to get full performance.

It will run now at about half speed but when I throttle down or get to a hill it either cuts out or it gets very slow. Which tells me it has hit the upper limits of the battery without getting it's needed amps for max performance.

Someone who has real world experience or even good theoretical knowledge would be most helpful.

Actually I'm building them as I go. It's an experiment as well as a battery to power a scooter I built.

What I don't know about the batteries. The true ah value the manufacturer lied. I am shocked at the chinese manufacturer would do that.

I am also shocked that the C is so low since I was told it was at least 1.7.

If I took the manufacture's numbers at face value I would have a 36ah 2c battery to power a 25 amp draw hub. Obviously one or both numbers are crap.

The fact that the pack isn't working now isn't unusual. It is just a matter of adding to the ah till I get enough. The question is even after there is enough to peak out the draw, how much will I need to give it some range.

Fortunately it is cold and wet and snowy here on the east coast so I have time to get it right. Just wondering what IC is like when it has enough power.

One thing that is interesting is that the volts hardly go down at all as it drains. Which is not like the SLA batteries which drain much more quickly I think.

Its actually very light, till I get my fat butt on it. It is probably close to 300 with me on it. I am running 36 volts, but I'm considering going to 48volts. I have it going about 3/4 power now without faulting. This next addition should bring it close to peak, then I can work on the distance.

I didn't trust the mfg numbers to begin with. Think I heard somewhere that the true ah of the aa batteries is closer to 1500 mah rather than 3000 the mfg claims.

The true mah of the C cells is 6000 not the 9500 they claim. So we shall see when I get it to peak for a sustained period of time, I should be able to tell what the true ah is for the pack. Some one described it seat of the pants reckoning. After that I will work on the range issues. Frankly range is secondary for me. I'm an old guy and my body cant take a long ride anyway.

The scooter does better hitting peak than the trike. The trike is heavier and wont hit it's peak power at all yet. I expect this weekend to get the trike up to speed then it's a matter of adding ah to get the range to about ten miles.

The one thing I notice which could be just the ah shortage is that the voltage seems smoother on the nimh pack than on any of my sla packs.

You are talking to a married man who two years ago fell off a gas bike at about 30 mph. (blacked out due to a brain tumor why I don't drive a car.) Broke six ribs my collar bone and collapsed a lung. Mama said no more bikes. But she agreed to a three wheeler and electric if I kept it down to 20mph top speed.

Then i flipped a three wheel scooter I was working on over and did some disk damage. That one I got to watch flip over backwards then jump up and down on me.

I gave mama my word to take it easy. The most I can get away with is 36volt 800 watt controller. I have run the controller on my trike at 48v same 20+ amps. it did just fine good speed and pull on the hills.

I might do something like that with this controller or buy a new one. Number one thing to do is figure out this battery pack which I expect to do before spring. Then I will probably tinker with the voltage since I can't stop tinkering.


The scooter looks more or less like this. I have changed the rear deck a little but not much.