Battery stuff

To be honest it will be the only test I have ever heard off where a sla and a nimh were compared side by side with the exact same stresses. No more than I ride the sla is fine for number of recharges, I haven't drained one in at least a year so they are never damaged by being drained too low. I alway store them full so I haven't have a problem with them going dead while in storage.

My two factors with SLA are weight and bulk. I hope the Nimh will cut both. I need 36v to feel comfortable. What I would like to do is to set up a minimum battery pack on board the bike. Like maybe a 36v ten ah nimh. One that can be strapped to the bike frame or carried in the front basket if the shape isn't right.

Then I could do away with the trailer, unless I had to go somewhere more than say four miles round trip. If I needed to go across town, I could just reattach the trailer and add another ten or fifteen miles. Now you guys with the really super efficient hub motor could probably at twenty, thirty more miles for a fraction of the LIPO price.

My prelim figure are about $100 for 36v `10ah home made nihm.

I would love to ride the bike to the mall or to the shopping center with the battery pack self contained but be able to easily increase the range with a trailer full of batteries. dropping that towed fifty pounds might make a big difference in the performance of the bike, but still be available with the tightening of a couple of bolts to add it back.

fasteddy said:

zabac70, your english was perfect. I'm putting a sidecar on my bike with a 400w eZee hud that has gears. The whole package with a Li poly battery is $1,800 Canadian. That includes a disk brake.

Better mileage and the fact that it can be charged up to 5,000 times is what sold me. The fact that it just plugs in and I can use it was a major factor in choosing it too.
What I know about electricity is how to turn it, off and on.
I bought it from ebike.ca in Vancouver British Columbia. I have seen a lot of people on endless sphere.com who have made batteries and powered bikes with different motors.

They have been very helpful and are involved in electric cars as well as bikes.
Few more weeks and I'm done.

Steve.

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I tried to think of all the things that where good and bad about each battery type before I tried to go with a more expensiive battery than the humble SLA,,, I think for long range. i'm going to keep my sla and trailer combo. Long range being more than three or four miles which most of my trips are within. I keep thinking that if my wife is gone or busy and i need to go a longer distance I will need the trailer full of batteries,

However for the under four mile trip, I would like a battery that is light weight and can be attached to the bike itself. I would really like something I can fit on the frame ect.

I chose to try to build one myself. I have the first 12v 2.5ah cell built and tested. Since I'm not into electronics that much, I looked around and from what I read the Nimh cell doesn't require special chargers or the balance circuit. That being the case, it seemed easier for me to manage.

I took a look on ebay and those batteries are still being produced in china, so I ordered a dozen 2500 mah aa cells. The preliminary test says that I can use my battery tenders from walmart on the 12v cells (I have almost always charged my cells individually) It looks as though I can build a 12v 10ah cell for about $30 or so. If it works out okay, I can build a 36v 10ah for about a hundred and twenty dollars. That should do the four miles, if the Nimh is as good as they say at discharging it's power. The only way for me to know is to wait for the rest of my ballteries to come from China and assemble the first 12v 10ah cell and test it with the sla I have. I should get a pretty good idea from that whether it will make a suitable on bike power supply.

The way I use my bike I have had great luck with the sla on trailer. I guess I just hate to not be doing something to teach myself something new. Anyway that is where I am now with the test platform. The small 2.5 ah cell has worked really well so far, but I can't do a real load test on it because it drains much faster than anything else I have.

The only thing I hate is waiting for the batteries to come from china.

Gss said:

The only reason I tell people about the cheap lithium is that I'm an electric bike user and I want to see the people who offer cheap lithium to make money and grow their business so I can keep using electric bikes in the future. If lithium is not cheap anymore, then I'm finished with my electric bike. I make no money off recommending this. I'm just doing this because I want to see lithium remain cheap and a viable option.

I bought a 36v20AH Thundersky lithium pack from elitepowersolutions.com . They come in 12v20AH packs for $104. I spent about $330 total including shipping to get them and I've got 25 cycles on them and they are awesome. As long as you don't use more than 2C on these batteries, they are good. So for a 36v20AH THundersky, you can only use 35 amp controller max and maybe a 40 amp controller. I'm using a 35 amp controller and after a long ride, my batteries don't even get hot. I'm not using a BMS either but am only using about 10AH and no more but that alone gets me 20 miles so I'm very happy with my purchase. I use a 12v black and decker charger and a 3.2v lifepo4 charger from all-battery.com to top them off and balance them. That's it.

Shipping for 36v of Thunderksy was around $20 for me. I definitely recommend these guys. She does things a little different. You buy the cells and then she sends you another bill for the shipping which is usually about $20 and then that's it. She ships them very quickly. I think I got my cells in 3 or 4 days and I'm on the other side of the USA from her. She's in Arizona I believe.

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That sounds like a plan to me. I also want to see battery technology stay within reach, It's alot easier to hide the cost of the batteries in a car's sticker than in a bike. I hope I can build a 36v 10ah for around a hundred bucks with nimh just for the weight. My plan is to keep my sla in packs of about 17ah to 19ah on a trailer. I hope to use the Nimh for running to the mall or to the park, When necessary I can hook up the trailer to go a longer distance. The two together would give me about thirty ah which is a pretty good amount.

I hook my controller up to the end of a household extension cord. I hook the batteries up to the matching end then just plug them in. I can plug in more than one battery pack at a time for a parallel connection to add to the distance. After I'm finished I should be able to tug along 40ah or more without adding more than the 1oam nimh pack.

I will know a lot more when i get the next order of batteries from hong kong. The test of those will tell me something. I am really chomping at the bit to try them out. I guess yjat is what happens with ebikes. When you move past the mechanical hardware, I suppose it becomes about the batteries and then the electronics.

anyway I can hardly wait.

I personally like the concept of plug and play. If there was a bike supplier near me who actually had everything to do the replacements with, I might have well gone that way. I did buy a complete system sans batteries once when I got this crazy urge to try hub motors. I burned the controller up somewhere in the middle of it, so I bought a new controller on line and it never worked quite right again.

But plug and play is definitely the way to go if possible and if you can drive to a bike shop to pick up a part that might fail. Bike building is my only physical hobby. All the rest of them or more mental than physical so I need the manipulation thing. My dad used to say, "A man is never happier than when he uses his hands." There is a lot of truth in the for me and my brothers.

My dad's rule was you can walk away, but you can never give up. Even if it takes years to get back to it. Lots of things humble me, but not too many beat me.

I'm wondering something. The bike i have now at 36v pulling a trailer with about 40lbs of batteries has more power than I need. What I wonder is after i build the lighter battery and put it on the bike, will 24v be sufficient to do the trick. I suppose the only way to know is to just test it once i determine that the nimh batteries will do the trick. I still haven't gotten the last order so that I can make the 12 12.5 ah battery to co-mingle with my sla batteries to see how it performs. Once that test is complete, i think I will build another one the same size to do some 24v tests.

I gave that battery repair some thought but I couldn't find a source for the used tool batteries. I have never had a problem with my sla and they still hold a good charge. I was looking for something that would allow me to put it on the bike without the bike being dangerously over loaded. I had three 7ah sla on a three speed once with those skinny tires. It flipped while I tried to mount it. I thought it was going to break my leg. I never put another sla on a bike after that. I am willing to try it with the nimh battery pack since it will be considerably lighter. The most I ever got with a 12ah sla 24v pack was about 5 miles. I can get about 8 to 10 easy with a 17ah set with 36v setup. I haven't tried to see how far it will really go max. The range is another reason to try the 36v setup. It seems to do better all around. Better speed,. better pulling, and better range so I might just build a 36 smaller ah setup for the bike. It all depends on this next test though.

zabac70 said:

Volts = speed , Amps = torque (the thing that moves the bike around) , Ah = range . At 24 V you'll just go slower (if the same amount of amps goes through the motor). If you "mingle" NiMH with SLA it will be lighter , but it will perform almost just as if you have only SLA. That is because of different discharge rate of those batteries; soon as SLA drops the voltage , NiMh will start to charge it , because electrical tension likes to equalize. However , you'll see some improvement in performance , due to smaller weight (a bit better acceleration) and in terms of range , because you'll be able to use more energy from "mixed" pack, than pure SLA pack. Pure NiMH pack (24 V) will perform significantly better in terms of range (more energy can be used from them).

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It was my plan to use a nimh battery mixed and to ride it a couple of miles then read to see what the drop in voltage was. I know that it isn't V that counts but it does correspond to battery charge. I might have to go with a second nimh battery before I can judge the difference then.

Actually I think from experience that you are right about what voltage and amps do but range seems to be better with 36v than 24 even though it is dragging more batteries around. I know that the increase in voltage more than compensates for the extra weight speed wise. I think that maybe the lighter battery pack might give the bike good performance even with less voltage. Just wont know for sure till i try it.

But 36v is much, much faster than 24 that is for sure....It even climbs hills stronger though that could be just a speed thing, since I run friction drive. lately I haven't gone far enough to get into the gray area of low charge on the sla batteries even.

I might just go ahead and order the nimh cells to make a bigger battery pack and get it over with but I still want to co mingle them for a couple of rides. I plan to leave the trailer full of batteries home except for longer rides then i will carry them as spares but not use them at the same time thanks to the information.

I worry when people figure me out that well lol... Yes range is not a big factor with me. I know my system is less efficient but you know I have that hub motor sitting in a corner rotting away. I just didn't like it at all. I actually didn't find it all that much more efficient but I was pulling sla batteries around as well. I think to be honest after months and months of testing these things, that you need to build and buy for what you need.

I met a man at the bike store who didn't even want to talk to me,. He had a bike with a 1200 dollar system. He had a small lithium battery pack that made me very jealous, but he also had a hub motor that didn't. I think the day will come when somebody figures out how to build a low cost, low weight battery pack, that levels the playing field.

Lets put it this way, if my bike is 25% less efficient, but I can build or buy a battery pack to give me a speed and range that suits my purposes, then am I not just as well off. To be honest I have a 36v 17ah pack and I can't stand to be on the bike long enough to drain it. I would like to have that amount of range in a battery pack that did not require a forty pound extra load. That is my next project. The trailer system pulls it pretty well, but when not moving under power it is a pain to move around. IE in and out of the shop.

The bike I build now is easy enough for even a first time builder to put together. It is inexpensive enough so that if he changes his mind, he won't feel he has to keep riding it. If this new battery project works out, I can put a 12.5ah set on my bike and save the trailer mounted big set for trips across town. Of course in my usual way of doing things I have three different sized 35v sla packs. I will have to do something with them. Use them till they wear out comes to mind, but I never ride more than five miles out and five miles back. Still summer is coming and the new photo project will be starting soon. That should get me out more.

One thing that does concern me is that a lot of the stability of my bike is because I have a trailer with two wide wheels helping to hold it up. I'm not sure how stable I will be on just two wheels. I might go for a mini sidecar design.

On a money note... I have done the testing for the next guy. So he can find a kid's electric scooter on Craig's list for 25 bucks. Mostly they have bad batteries. If the battery project works he would be tossing them anyway. So he uses the motor, the controller, and the throttle from the scooter. Five bucks for a bed frame from goodwill, and couple bags of 1/4" nut and bolt sets later he has a frame. He can most likely have the drive without batteries up and running for fifty bucks. Now if I can build a battery pack he could possibly have an ebike drive system for around a hundred bucks. That would be a good deal and hopefully get more people into motored bike transportation.