Impressed with A123

[Jozzer]

Yay, after a month of waiting for bits, I finally dropped a 4.2KG pack of A123's into the KMX trike :lol:
Simply amazing, only 3 cells in parralell and it can put out 30A with only 2.5v voltage sag! The trike feels like a different beast (I took out 14KG of NiMh to make room for the A123's, and recently changed to the lighter puma motor).
@ 66v35A the trike quickly gets to a top speed of around 34mph in a 24" wheel.
We did a quick comparison with Nick's modded curry driven bike (48v40A) at equivilent power, and found they were neck to neck till 15mph, then the puma pulls away. (Nick has an upright bike, perhaps wind resistance was to blame, though we did try a tailwind too.) :lol:

Its wonderfull to be able to power even hungry motors with a couple of kilo's of cells. Me goes to look for an etek and some more cells

 

[The7]

What is the current limit of your controller?

 

[xyster]

Range?

Did you bypass the BMS?

More pack build details?

Now try your six-pack 3s2p for 99v 4.4ah.

 

[NickF23]

I think Steve's controller was set at 25 amps. We were both apparently drawing 1400 watts. As predicted by Jazzer I blame the air drag ( I was also wearing a big jacket at the time)

That said I was mightely impressed with the Puma, it seemed not to get hot at all.

 

[Jozzer]

It was indeed around 25A when we "raced". I noticed shortly afterwards that the limiting pot was on 3/4. For the rest of the ride, it was peaking at 34A. Using a 20A controller with upgraded fets and adjustable current.

I stripped the packs after balancing the cells, and rebuilt/soldered into two 10s6p packs, bridged all the balance points (so each cell is attached to its buddies). I run the packs with a par/series relay, and switch them to parralell 33v to charge, or to prove how legal my bike is should the need ever arise, and to let e-bike noobs try my bike safly :lol:
I've not had a chance to do a full pack discharge yet, the weather being pretty poor, and me having lots of guests for the weekend, but I'll report back ASAP.
If it returns the expected WH's (400ish, or maybe 350 for a shallower discharge), I should get 14 miles out of it @ 25mph @ 25wh/mile. THats based on the wh/mile from the bike with 14kg of nimh...so it may have improved.

Unfortionatly, I dont think the puma could take 100v. I'm fairly certain that the motor is turning at near its maximum speed @ 35mph. 72v wouldnt kill it maybe, but the pack would be a pain to charge. I do have some spare cells, I could make a booster pack to drop in with a relay to add a few more volts, but I actually don't really feel the need....its great like this! Now more amps....that I think it could take.! Before trying out my new 40A controller with modded fets and adjustable current to 60A , I will need to sort a VERY good torque arm. Cant keep the damn thing from spinning! Also, I want to fit a temp sensor directly into the hub, since I am not sure that the motor just feels cool because there is poor transfer of heat from the centre (which would be bad!). Then I think I will find out what it can handle. For the first time I DONT have to worry about the batteries handling all that power, which is just amazing considering how small the pack is!

And Nick, perhaps next time you should try a bigger jacket, attached to a flagpole for greater "wind assist" for the tailwind bit? :lol: or maybe you should just get a recumbent too 8)