[joecarrow]

I did search, and I am pretty sure that the answer will be, "No, sorry." but in my experience it never hurts to ask!

I'm an engineer who's rebuilt a power wheelchair for sport use, on the US national power soccer team. The chair draws a peak of 160 amps from two 65 AH 12 volt AGM batteries- Odyssey PC1500 to be exact. Before these we were using Optima Yellowtop D34-78's, and wore them out in a little over six months. The Odyssey's are delivering the power now, but they added about ten pounds to the system weight.

Acceleration is very important in this sport, so I'm looking for anything that can give what we need in a lighter package. Lithium is an obvious choice, but the practices rotate around the country, national tournaments require travel, and the 2011 world cup is in France. Lithium is illegal to fly with on a passenger flight in capacities over 300 watt hours, and I need at least three or four times that capacity for acceptable range.

In summary, I am looking for a solution that can stay below 31 volts at its charging peak, can stay above 22 volts under a 160 amp discharge, is OK for air travel, weighs less than 90 pounds, and can compete with the lead based batteries named above on the basis of cost/discharge cycles.

Whether or not you have any suggestions, here are a few videos of the sport.

Thanks!

http://www.powersoccerteamusa.org/multimedia

http://www.youtube.com/watch?v=1gwYMYXi6rc

http://www.youtube.com/watch?v=uYtHUQT8yAA

 

[dimitri]

Lithium is illegal to fly with on a passenger flight in capacities over 300 watt hours, and I need at least three or four times that capacity for acceptable range.

So you can't fly with lithium, but its OK to fly with flooded Lead Acid or NiMH, both of which are prone to fire and explosions when shorted.

The world is a sad sad place

Sorry I can't help with your actual questions, never used large NiMH myself.

 

[joecarrow]

It's a little bit like the federal agent I heard of who was going through the security line with a loaded semiautomatic, two clips of ammo, and of course all of the proper ID and documentation for flying with these things. As he walked through the metal detector and the inspector handed him back the gun that he'd just X-rayed, he said "I'm sorry sir, I'm going to have to confiscate your nail clippers."

True story!

What I think the regulations are really about is how the materials react to the fire suppression systems in the cargo hold. A study showed that large lithium batteries continue to burn, but I don't know of any similar studies about nickel or lead batteries- just that lithium are illegal. Also I haven't been able to get any word regarding lithium iron phosphate batteries- which should be a good deal safer.

 

[piotrsko]

I'd just get a couple of spare packs and ship them to the next venue either ground or make them small enough to air transport and reassemble later.

 

[tinrobot]

I need at least three or four times that capacity for acceptable range.

Could you fly with 3-4 people and give them each 1/3-1/4 of the pack?

 

[Dolphyn]

I might know a source for NiMH. I sent you a PM because I don't know if he'd want his information published or not.