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x-post from MTBR: Battery Charging Issues B4 24 hour race!(3 posts)

x-post from MTBR: Battery Charging Issues B4 24 hour race!shawndoggy
Aug 21, 2002 7:48 AM
"PLEASE HELP! Battery charging problems before 24 hr race!"
OK, so I'm racing the 24 hours of Tahoe this weekend and I am having major battery charging problems.
BACKGROUND: I have two light setups. 12 watt 6 volt specialized proview with 4.5 A/hr nicad mounted on the helmet, and 20 watt (2X10) 6 volt vistalite VL 430 with 5 A/hr SLA mounted on the bars.

EXTRA BATTERIES: I have built a few extra batteries using 4 A/hr SLAs from Home Depot (only $12 each!). I wired them using the spare specialized proview cords that specialized is selling on their website ($5 each).

EXTRA BATTERIES WORK INITIALLY: I have wired up the batteries and they work without charging. I've gotten about 2 hours on the 12 watt light out of them.

CHARGERS: I have a 300 mA/ 7.5 volt charger that came with the vistalite that I've been using to charge the SLA battery that came with the vistalite system and the extra batteries.

BATTERIES DON'T WORK AFTER I TRY TO CHARGE: I've been charging the extra batteries on the theory of 300 m/a means roughly 3:20 of charge time for every A/Hr, or about 13 hours of charge for a 4 A/hr SLA. When I charge on this basis, the batteries go dead after about 15-25 minutes of runtime. Not good.

WHAT DO I DO? Am I overcharging (don't think so)? If I've reversed the polarity of the battery when I've wired it up, would charging fry it (think I might have done this on one)?

PLEASE THROW IN YOUR $.02 ASAP -- I am racing on Saturday and need to get these suckers charged as sooooooooon as I can!
re: x-post from MTBR: Battery Charging Issues B4 24 hour race!JerryZ
Aug 21, 2002 12:10 PM
I do suspect that your spare batteries are toast. You should always fully charge the batteries before using them for the first time. This is especially important for NiCads which have the memory effect that causes the battery to resist a full charge. Also, if you have reversed a battery within the pack or with the charger, it can very quickly cause permanent damage to the battery. I'd recommend replacing the spares and get them on the charger before testing them. Also, if there is any wiring to do, be very careful to get it correct.
Good luck; if you need other ideas, let me know. I used to work extensively with battery packs. Jerry
thanks Jerry... looks like my charger was deadshawndoggy
Aug 21, 2002 12:23 PM
Just went and got a good charged with a no-brainer float charge feature so I won't have to stress about whether I'm charging them correctly. I'll let you know how it looks tomorrow!