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Old 11-18-2011, 09:23 AM   #13
JohnnieB
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Default Re: 84 Marathon resistor cart project

Quote:
Originally Posted by rlw View Post
...................I beat my head against a bad APC UPS and a bad Linksys router at a customer's all day today. That got me to thinkin' about hooking up the Crowns in series to an old APC UPS I have. It seems to me that the charger in that device does some conditioning to keep the gel cells up. I wonder if it would do a good job on cart batteries. There's my mad scientist experiment...............
Good Grief another Geek AND Numbers Nerd. I was beginning to think I was the only one of that breed around here...

Your mad scientist experiment is roughly the same as the one I suggested, put them in the gassing phase and leave them there for an extended period of time.

Using an old UPS might work, but the low power units APC builds have Gel-Cells. You have to get above 3KW before they use wet cells, and even then they use Sealed wet cells, which has nearly the same charge profile as Gel-Cells, so based on a 12V battery, the "Float" voltage is going to be about 2.0V less that the "Equalize" voltage needed.

If the APC UPS sensed the pair of 6V wet cells as being discharged, it would try to charge them up to about 14.4V (2.4V per cell) and then float them at about 13.8V (2.3V per cell). To "Equalize" them, we've got to get them into the 2.6V to 2.8V per cell range and let them cook until there is no longer any increases in the Specific Gravity of the electrolyte between measurements taken an hour apart while on charge.

Here are some links to some battery info you might find interesting.
http://www.trojanbattery.com/pdf/TRJ...dSpecGuide.pdf
http://www.trojanbattery.com/Battery...ngStarted.html (Read all the "Related Links" in the menu of the right side of page)
http://www.trojanbattery.com/pdf/TRJ...dSpecGuide.pdf

BTW - You might find some halfway decent used batteries at the place you mentioned, not all trade-ins are bad.
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