Electric Trail 70 - a distraction

I put it all back together with the higher voltage, larger battery.  I had misread the manual for the controller and found the high voltage cut off is at 32V.  The 8S10P set up will work nicely.  I charged the battery to 32.2 volts and the controller didn't like that.  It has an LED that will flash codes for various issues and I got the high voltage code.  I was able to bleed some volts off with an old coil battery load tester, burned some dust off the coil pretty quickly feeding it 32V.

I got it down enough for the controller to come on and headed out for a test ride.

Everything was going great until it wasn't.  The average speed was brought way down because of the walk back to the shop.  LED code on the controller says the problem is between the controller and motor.  I didn't have time to check parts today to see if it is the motor itself or the contact relay.  Motor doesn't have "The Smell" so I'm crossing my fingers.

I also decided 27mph is just fine for a pit bike.  Acceleration was good enough too.  If it has survived I'll be happy with the performance. 

I got it working after taking the system apart and checking things with a multimeter.  The only thing I can think of is the contactor doesn't like the higher voltage.  Whatever the issue was it healed itself and I rode it around the neighborhood near my shop.  I ended up putting about 5 miles on it total and only lost 2.2 volts on the pack.  With 8 volts to play with between full and discharged that gives me about 18 miles of range on the high speed setting.

Top speed hit 28 at one point.  I'm going to put the stock 35 tooth rear sprocket back on and see how it affects acceleration compared to the 45 tooth on there now.  If I get the same rpm out of the motor under load that will put me at 33-34mph.

Now to pretty it up a bit.

In reply to jgrewe :

Awesome!

This is neat. Do you have any reccomendations for books and such to learn electronics like this? I've been wanting to build an electric bike for awhile.

I would recommend heading over the a forum called "Endless Sphere" to start and also checking out the website of the battery kit people "Vruzend".  I had done a bunch of reading on ES a few years ago when I ended up with all the parts but forgot about it until I started this up again.  Fleabay has turned out to be the best place to source the li-ion cells that I could find.  And the charger I bought is the most awesome piece of technology I've purchased in a while.