Need a battery genius or professor's help

deacon

deacon

minor bike philosopher
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.
 
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Alk have very little power delivery.....when pushed they usually fail...they cant deliver any amps....its why they're not in tools etc....only low draw for them and not much storage available and no recharge
 
Dang! That's what I was gonna say..trk Lithium batteries come in different c ratings from 1 up to I think around 12 so it depends on the cells and bms. ( multiply ah by c# to determine max amps). I strongly urge you to make the jump to lithium! You wont regret it!
 
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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.
 
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The term "lithium" is pretty wide. LiPo, LiPoly, LiFePo4 - all have different performance & charging needs.

There are LifePo4 batteries with high discharge rates. When looking at those types of batteries you need to look at the C rate. Some hobby batteries will do 30C with bursts to 50C

I have been using Ballistic Batteries in my motorcycles for years. They work with the standard lead-acid charging system just fine. I can let my CB750 sit for 3 months, and it starts right up on that battery. I have never charged that battery other than having it hooked to the original charging system on the 1972 motorcycle.

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Just Make multiple LA battery packs so you always have a charged one and take a spare along if need be, it's a trike so may have room.

Another option is just 3 big 'ole LA 12V Marine batteries, one will run a trolling motor all day ;-}
 
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.
 
Deacon? I'm not going to advise you to get a lithium pack. Because I am in no shape or form an "expert" and you probably know more about them than me. Of course You already know they weigh a lot less. Seems to me a 36v12ah SLA pack should be all you need to go at least 10 miles unless they are wearing out. You just need 2 trikes that's all and don't worry about recharging until you get back home that way you can leave the batteries on the trike while it charges and just have a nice fishing trip and if you decide to come home a little early no prob. Another idea is take an extension cord with you and just run it to an outlet to charge leaving the batteries on your trike. You don't need to be killing yourself picking up stuff that heavy. You know, I look on ebay and its amazing the battery pack choices we have now compared to 5 years ago when I bought my first hub motor kit. Have you considered a portable solar charger? That might cost an arm and a leg though. Might not be worth it. Yeah,.. You just need a couple of backup trikes that way when one horse is eating you can ride one of the others
 
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