Battery stuff

[zabac70]

I support your opinion - cheaper is better (if the job in hand could be done with it).
As for stability that worries you - why don't you try to build a trike ? Those have plenty of room for batteries(and other stuff) between rear wheels and it don't have to be very wide if you are concerned about getting through narrow places (just as wide as your shoulders). There are versions with soft tail also , so the ride is more comfortable .
When you install NiMH pack , you can go green (just a suggestion) and use the SLAs you have, to build energy bank for a small windmill (great DIY project) and you can use that to recharge your bike or even for exterior lightning.
I still think that direct drive of some kind would be better and that hubs are the best (there is a variety of them and there are good ones as well as bad ones), but for your case I was thinking more like chain(or belt) drive on a pedal sprocket...
Anyway , keep up tinkering and keep us posted

 

[deacon]

actually i have been thinking about going with a guy on ebays bike parts. he bought a bunch of ebikes and has parted them out. he has a rear 20" wheel, 450watt motors @24v. I have been thinking I might just pick up one of each. I could use a 36v controller to jack it up to almost 700 watts which is the legal limit anyway. there is a post in this section on parts that has all the info about it. I have been considering it only for damp roads more than efficiency.

 

[deacon]

I have been keeping an eye on the one 12v nimh cell I built and it appears that the big downside is shelf drain, which isn't a problem for me since I use my bike every day. I also charge my bike using three chargers at once. I charge each 12v battery individually using a low amp charger. I might be okay with that system.

I guess what I am trying to say is i have decided after some good advice here to go right to the full 36v pack rather than do a mixed pack. It looks as though I can put togther a 36v 12ah battery pack for 100 bucks. That isn't much more than a large sla pack. How it compares for range is anyone's guess.

I probably won't have it ready for a month since it has to come from china, so bear with me.

 

[zabac70]

A month for delivery?! Does some guy walking from China (Marco Polo was faster , I think) , carrying your batteries in pocket? Some guys over here ordered some things for their bikes and they waited 15- 2o days (few days for customs to process package).
When it arrives , you'll definitely see the difference (comparing to SLA). NiMH need some pampering too , but you can check , in the meantime (while camels slowly progressing over Gobi desert , carrying your batteries) , on forums with digital cameras themes - they use same sort of batteries and know a thing or two about them.

 

[deacon]

Ill give it a look see. Hopefully the ones that are due in will be here before the new ones. I can construct one complete 12ah battery and do some shelf life testing on it.

The guy who has the new order take about two weeks to get it here, the other one has been since march 5 and still waiting. He said ten to 20 business days. Based on that time table, it could be next week sometime at the latest.

The next round of 100 are due in within two weeks I hope. Then of course I have to buy alum foil and duct tape to complete the construction. If there is a significant improvement in performance then the price is in line. If a 12ah nimh will perform as well as a 17ah sla I will be thrilled. The prices are very comparable.

I need about 150 aa batteries to make the 36v 12ah pack. I just bought a hundred with shipping for 67 bucks. That would make the full battery load only 100 bucks. i am sure I paid that much for the 17ah sla batteries. I can do 7 miles on the 17ah battery trailer and the batteries are still in the 13+volt range. I find the batteries are hot till 12.25 or so. After that they are pretty much useless.

I started out wanting to build a bike that would do ten mile at 10 miles an hour on a single charge. I am pretty sure the bike I have will do that now. It will easily do over 10mph even uphill. Now that I have it rigged at 36v it will do the ten mile range I am pretty sure. I think that tomorrow I will run it out to the lake to see how that does. It is mean hilly out that way and about seven miles round trip. I made it on 12ah but it was hard to make the last mile or so. I think with the 17ah it should make it easily.

Once i get the nimh battery pack made I will begin testing it for range and rechargeability.