first nimh battery built

So I went for the first nihm build of the season today. The batteries came from china. I still don't believe the ah rating so I'm proceeding carefully.

I connected thirty 1.2v c cells using some folded alum foil. I folding it about eight layers to make the connectors. The I taped them to the top of bottom of the cells I used pieces of an inner tube for a tensioner over the connections.

In the end I had 39v more or less and they said 9.5 ah. so after it was all connected I took it out to my shop to an old brushed motor I set up with a controller to run a 36v 300 watts. I figued it would draw 10amps. more or less./

It ran with a lot of resistance for about fifteen minutes wide open. Then it was dragging. So I have the battery on the charger now. I figure it needs about an 80% charge, which will be about 7hrs at 1.5 amps. I have it in the house so I can check the charge every hour or so.

I checked the batteries constantly while they powered the motor and they did not overheat at all. So I think they might allow for a 10amp drain at least. I dont have a 500 watt controller or I would test it with a 15amp draw to see if it will do a 2C.

I'm waiting to see how the charger does, It is going to take a long time to charge it seems. I might have to look into a higher amp charger. A three amp charger would cut the time in half.

At least that is true if my calculations are correct. When I start adding ah to the pack it might prove to be a problem.

Not sure with my poor welding skills i would risk it. I have built several packs this way over the years that is never what failed. What failed last time is I tried to run it parallel with a sla battery they were not even close to balanced. so the pack over heated.

Of course I never threw one across a room either. that would probably make the foil fail.

I find that I must not have drained it completely the first time I ran it. It took only an hour to get what appears to be a full charge on it. Well I have a lot more experimenting to do.

The first 9.5 ah 36v pack cost 96 bucks for the 30 1.2 cells and prob ten bucks in tape and alum foil but I can build ten more using the same tape and foil.

Right now I'm trying to get the feel of the charging using a sla 1,5 amp charger. I am going to have to wait for my next set of batteries at least before I try the batteries on a real bike..

When I finish with that one I will have less than 200 bucks in a 36v 19 ah battery with a 2c load according to the information I have. I will check it very carefully since if it isn't 2c i can get a third pack relatively inexpensive and have a 28,5 pack for 3oo bucks.. thats where I am now.

So Im going to wait patiently for at least two more weeks. I will try to make some picture of the packs as I go., They are really easy to build.