David Brandt wrote: > > Boy, am I steamed. I put all that effort into getting good pack isolation,
David, yes, it's possible but unlikely with new batteries. Disconnect the pack from the controller. Connect the resistor between the most positive end and the frame. Resistance is pack voltage/5mA. Measure the current through the resistor. It will be be 5 mA in worst case (if negative end happened to be shorted to the frame). You likely get less value (than 5 mA) If you get no current, connect to the negative end and repeat. If no current, connect controller and repeat. Don't measure it while charging. If still no current, your charge's GPF itself is faulty because >5mA must leak to the frame somewhere to trip it. If you get current, move resistor connection point toward middle of the pack until the current is minimal. This battery is at fault. Now, connect 100k resistor parallel to your meter to lower its resistance. Now if you measure voltage with it between positive terminal of suspected battery and the frame and get *steady* +4.2V (not disappearing in a few seconds to 0V), and between negative of the same battery to the frame -8.4V, you have the leakage path from internal cell #2 through the microscopic crack in the battery case (which wicked conductive electrolyte) to the frame. It is very hard to wipe clean and insulate bottom and sides of the battery. If it has side crack/pinhole with connection to internal cell through electrolyte, it may be enough to trip GFI no matter how clean the top surface is. To verify, remove this battery, put it near by onto insulating surface, (better outside the car, in 3-4 polyethylene shopping bags), connect it back electrically (long thin hook up wire is OK for test) and try to charge. It should not trip (if GFI itself is OK). If this is the case, find the leak. Connect one lead of voltmeter to a square piece of thick foil (2x2") and other end - to neg. or pos post. Pressing the foil against battery body sliding over its sides and bottom will locate the leak point - the voltage will indicate that. For internal cell leakage it will not be zero whether neg. or pos post used for measurement. Victor
