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.
Thanks, Deron.
hi Deron,
At the higher voltage, your motor will draw more amps, not less.
a 18% increase in voltage will result in 18% more current drawn and 39% more power. unless of course your controller controls current, than the current drawn will stay the same.
matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
I screwed up on my first post, I ment to say the NiMH run 29 volts no load.
Matt
What should I be expecting from a pack 28V 10AH Lithium pack compared to my stock SLA pack of 24V 12AH? From what you are saying it sounds like the bike will get me up to speed quicker and I will climb hills easier. Will I get less range? I think speed will be the same as the controller on the bike will still cut off power at 18 MPH. Both packs will have about the same wattage output of 280 and 288.
Deron.
Deron,
compared to your stock SLA pack, you will accelerate faster, and depending on how it your setup determines top speed, you may experience a higher top speed, your top speed should be the same as when you had the nimh pack.
Maximum range should stay the same with the lithium, as both your lithium and lead packs will have a max dischargable capacity of about 9AH. however the usable range will be considerably more with the lithium. This is because the maximum and usable ranges for the lithium are the same, whereas the usable range is typically half to 3/4 the max range for the lead, for decent cycle life. This assumes your setup is able to maintain 18mph, when the batteries SLA batteries are low. If the 18mph is reduced at lower voltages, your useful range with lithium compared to lead could be much greater.
Having had a closer look at your application, your peak current draw will increase, due to the higher voltage, and you will accelerate (much) faster. Since the kit limits your speed at 18mph, your continuous current draw should be less.
hope that made sense,
regards,
Matt
EDIT: I changed my post as the first time round i missed the 18mph regulated max speed. This piece of information is rather important. sorry for any misunderstanding caused.
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km