Battery meltdown update

Feedback from WFCO engineering...

Everyone,

Here’s a reply from WFCO engineering on the battery meltdown article I posted last week. Read the previous article HERE.

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Here is feedback from one of the WFCO electrical engineers in Elkhart, Mike Miles.

Most likely one cell failed and pulled too much current, destroying the rest of the cells in series. One or more shorted cells will cause the entire series battery bank to be subject to significant excess current. As the voltage on a failed cell drops, the high current will persist and the temperature of all cells will rise. Meanwhile, the high current prevents the charger from entering storage mode (13.2 volts) so the absorption mode (13.6 volts) would likely be sustained. A shorted cell might even have kept the charger in bulk charge mode, putting out full current. Either way, with one shorted cell, all the other cells would eventually self-destruct with any voltage over 11 volts applied to the series pair.

At normal room temperature, the output voltage of WFCO chargers should be fine for AGM batteries.

Back to me…

So you can see that a shorted cell in a battery will reduce the nominal voltage to the point where the charger could go into bulk charge mode. And that could cause the battery to melt down in the matter of days.

I still think that a small battery tender with limited current output is much safer for unattended battery storage over the winter than a built-in charger/converter that could supply 80 amps of current if a battery cell shorts out.

Let’s play safe out there… Mike