I e-mailed Ping and he says he can build a special pack for me. He wants some more information though, rated wattage of my motor and maximum continuous amperage. On the Gaint Lafree the motor is listed as a 400W continuous and 1,000W peak. That works out to 16.7 amps continuous and 41.7 peak with the 24V SLA's I have in it. Now I will be running at a new higher voltage, 28V. So do I now give him the ratings at the higher voltage (14.3 continuous and 35.7 peak) or will the new voltage change the rating of the motor and I will end up drawing the same amperage as the 24V rating?
As soon as I can get this information out to him, I will be ordering the new pack as long as he does not want a whole lot more to build this special pack and charger.
I think this type of performance increase will be a pretty good way to go. Hopefully the controller, electronics and motor will handle the extra voltage, if they do it will be a lot easier way to go, instead of changing out the controller... I mean these things have a voltage range they are designed to work in. The SLA's start out at a high of maybe 26 volts, then drop to something over 20 volts after running them down. Not sure what the actual voltage of Ping's batteries are. Also these bikes are designed to run on NiMH batteries that have a pretty high no load voltage of close to 39 volts. It looks promising.
You guys have any idea what I should experience in the way of performance out of these batteries? Dropping 10 pounds is a obvious one, that will be nice 2% to 5% increase in performance.