Hello Thomas and all, I have came to the realization that amps don't mean near as much as power! I can pull 50KW for about the first second, but that quickly drops to 30KW, and 20KW by the end of the 1/8th mile. A better senario would be a constant 30-40KW. OK. I'm learning. Watch out Thunderstruck......
Darin Gilbert Bad Fish Racing Thomas Cook Wrote: Hi Darin, I don't think I have ever talked to you, but I have heard some about you as I played a big part in the building and racing of the Thunderstruck Pocket Bike. >From what I understand, you are probably pushing your batteries too hard. Remember you want peak power, not peak amps. If they are sagging below 6v, I highly doubt it is worth it to get the amps. Have a look at the graphs on the Manzanitamicro.com website. Rich hasn't done any testing on your specific batteries, but an old optima is up there, the small svr batteries that we use, an old hawker 38? and a nicad battery. We are about to put larger SVR batteries in an electric car that is going racing in woodburn, so we have some experimenting to do too... I think in your case, if you need that much current, you need to get a larger battery. Then again, you could probably just pull a bit less current and have a little bit more power to play with. After that it is all about weight transfer, traction, efficiency, gearing, etc. Reading your message again, it sounds like you are concerned that your batteries are bad. I don't think they are, just being over worked. 40 volts at 300amps isn't too bad at all. Heck, try putting one of those cheap loadtesters that only does 50-75 amps on a new, fully charged and cycled hawker, and you might be surprised at how low it goes with only the tester attached. You ask what we see with our batteries. Um, I have been pushing for some data gathering stuff, but we don't have anything that we can put on a vehicle right now. We are running a controller in the bike that probably ramps up to 650 amps maybe 50 feet off of the line, and then falls steadily from there. We are almost at top speed coming out of the 8th. Have Fun! -Thomas Cook >From: [EMAIL PROTECTED] >Reply-To: [EMAIL PROTECTED] >To: [EMAIL PROTECTED] >Subject: Hawker voltage sag >Date: Thu, 29 Aug 2002 01:43:41 +0000 > >Hi all, > >I recently got a fluke scopemeter and have an abundance >of voltage/amperage data to analyze. I'm surprised at >my voltage sag on my 48V 16ah hawker genesis pack. > >900 amp draw > 33.2 volts >after about 1 second >812 amp draw > 22.8 volts >after amp draw falls to about 300, volts come up to >about 40. > >Um, that's less than 6V per battery? What do you guys >see, or what do you guys with SVR batteries see? > > >thanks in advance, > >Darin Gilbert >
