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  • GP7 batteries

  • Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.
Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.

Moderator: GOLDEN-ARM

 #292391  by bat@grumman
 
At Florida Gulf Coast, the Geep batteries run down each week. They are 8 volt batteries. Probably about 15 years old. We jump it, and run it for a few hours. Whats the correct charging voltage across each battery? And what kind of charging current should I be seeing through the whole string? Thanks. -Pat

 #292427  by BR&P
 
The batteries total 72 volts so charging voltage should be about 74 or so. At 15 years old they may be nearing the end of their life. Batteries are funny, some last a lot longer than others for no apparent reason.

You might try taking specific gravity readings for each cell. Off the top of my head I don't recall what it should be but someone here will no doubt know. Also make sure the tops of the batteries are clean, ditto the cables, as you can get a loss of juice if they are too cruddy.

Have you checked the unit for grounds? Has anybody jury-rigged some accessory which could be causing a drain - refrigerator, radio, etc?

 #292504  by DutchRailnut
 
The total batteries is 8 cells x 8 volt or 64 volts for battery voltage, with the locomotive running the charging voltage is 74 volt.
Check each individual cell for power and how much to find if you got bad cells, best way to tell is with a battery acid tester.

 #292635  by BR&P
 
Dutchrailnut is exactly right, I had a brain freeze and somehow came up with 72 volts. The correct number is 64 as he says. Sorry to throw you a curve.
 #292679  by bat@grumman
 
A single lead acid cell,when charged, is 2.1 volts. So the one battery with 4 cells should show 8.4 volts, and all 8 batteries together should show 67.2 volts. Not 64. If it was 64 they would be mostly discharged. I'll do a float test and see if we have any bad cells. Thanks. -pat