Need a battery genius or professor's help

Okay here is what I know. From experience I can run a lead acid battery of 7ah to power my 36volt bike. Not for a great distance but it will run it without over heating and at pretty much full speed till it runs dry.

I know I can build a nimh battery pack of the same size and it will will run the bike much slower and will overheat very quickly. Something about the c factor I'm told. I think you would need a 25ah build to run a 25amp motor at full power.

Lithium I expect has a better usage in some ways. It will run a bike at full speed with half the ah rating of your max amp usage. Ie a 25amp motor would need a 15ah battery pack. But I don't think you get max power out of say a ten ah battery pack on a 25amp drain. At least that is my understanding.

Here is what I can't find out on the net, probably because I don't know enough to interpret the answers that are out there. Is the discharge rate for alkaline batteries the same as lead acid. or more like the Nimh pack I built.

Before you tell me I'm nuts to consider anything other than Lithium, I have been told that hundreds of time. I am an experimenter. Someone has to try it first to find out what it's like, even if it is crap like the nimh packs I built.

So if, you are nuts is all you can add to the discussion please don't bother.

Thanks for the answer. I do appreciate it.

I'm still hung up on the desire to have charged batteries on the shelf, just in case I want to go while my battery pack is being recharged. You know the old interchangeable battery pack.

I also worry especially for experimental bikes that might at any time get a wire crossed and short the whole thing out. It happens a lot these days as my mind gets more and more muddled.

Trust me I have spent the price of a lithium battery pack many times over experimenting with nimh and various other materials. Mainly the C factor sucks for every alternative source of power Most of the time the alternative battery source is c1 and that means building a twenty five ah battery pack to run a bike with a big motor. Not cool of course no one told me that I had to have a pack that big when I started.

SLA still fits the bill for experimenting best for me I think. And my trip use and the fact that it is a trike also make them a good fit for now. But I do appreciate those of you who love the lithium. I'm still waiting for the charged capacitor.

Actually someone is working on a battery with many of the traits of lead acid without the weight, I hear. Something about suspended lead compounds so the lead particles can hold a charge in all sides not just the two out grid sides. Don't ask me how this works but the promise is when it makes it the the shelves they will cut the weight in half and double the charge life. That might be something.

My complaint is the BMS. Me and electronic things suck. I can handle Electric stuff but electronic leave me cold. It seems to me the BMS treats each cell individually not the unit as a whole like a simple lead acid does. So for now till I get a bike I truly love, I think I'll stay with the lead acid. One thing I am looking at though is a way to recharge them quickly. I do a ride out to the city lake to fish. It is three miles and I can do it with a 7AH battery.

I usually fish for two hours so the recharge time isn't a problem. I really would like to be able to recharge in about 30 min or so small a pack. If I did that, I could probably plug the pack in anywhere.

You also have to remember I live almost downtown. With a twelve hour battery pack and an efficient motor, and power conserving use of my pedals, I can get most anywhere I want with a 12 ah pack.

The main advantage to me would be the ease of moving the thing around. I'm finding I like to move a full 36v 12hour battery pack around less and less all the time.

yes I have a total of 31 ah of sla spread over three packs. I have room, and the weight on the wheels is no more than a child riding on the rear.

I run one charged on the trike with the hub motor and have a spare for the second trike I experiment with the friction drive one. The third is being charged. I rotate them around. I also have a spare set of batteries on the shelf not wired in a pack. Those hold a charge fine, but I'm a little leery of them, since the cases have swollen from too much voltage into them during an experiment lol.

I also carry a battery charger since I have three of those. At home I use two charges on a pack if I want them to charge in a hurry, but I have to be careful to disconnect one of them. I also have a wall switch on the line from charger to the batteries to prevent accidental shorts in the charging circuit. I always turn the charger off at that point before I disconnect it. Its a pretty good system I use these days.

The big advantage I have is my geographic location near to downtown. I mean there literally are scores of restaurants, donut shops, grocery stores, drug stores, banks, coffee house, discount department stores, hardware stores, and a state of the air hospital comples within a three mile radius of my house. One 12ah pack will take me all over town.

That's why I say to people who talk about batteries and drive motors to first decide how they want to use the bike. If you just want to go three miles to the shopping center or coffee shop you need a lot less stuff than if you want to commute 20 miles one way every day. If you live in a level area you hardly need any power at all, but in HIGH POINT you really do need the torque, well I have to have it.

So my advice seems pretty lame but I try to work on things that would make sense for the average guy in a similar situation. Let others build the commuter bikes and trikes. Sometime we forget that once size does not fit all.