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Old 11-15-2018, 02:58 PM
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William Slaughter William Slaughter is offline
Join Date: Jan 2005
Location: Houston, Texas
Posts: 471
Default EarthX battery pirep

I purchased an EarthX ETX900 for my rear battery RV-8 for the substantial weight savings and increased electrical capacity over the Odessey 680 I'd previously selected. Since the ETX900s terminals are on the centerline of the battery, you have to install the cables before installing the hold-down clamp. I of course have an insulating cover for the positive terminal, which I had believed was sufficient. But it was not. While wriggling the holddown and bolts into place, I managed to momentarily short the battery to ground. This resulted in an impressive flash and bang, and a noticeable divot in the hold down bolt. Removing the holddown bracket and bolts, I noticed that the top part of the battery was quite warm to the touch, but that seemed logical after the energy dump which had just taken place. I immediately set to work thoroughly insulating the holddown bolt (the bottom of the bracket was already insulated), and when finished, crawled back in to re-install, but the battery was still just as warm, just short of hot. I removed it from the plane and called EarthX. They diagnosed it as an internal short in the damaged BMS, and suggested I fully discharge it and send it back. They suggested a resistive load such as a light. I brought the battery home, checked the voltage (12.9) and attached a 55 watt driving light. In spite of being wounded, the battery drove that light for quite a few hours. I returned the battery, EarthX repaired (probably just replaced it actually) it at no charge, and sent it back.
My take homes:
Despite being wounded, the battery did not rupture or catch fire, and continued to provide useful voltage for a substantial period of time.
The customer service at EarthX is just outstanding - I made it clear that this incident was entirely my fault.
I have no qualms about putting the battery back in.
Now before someone replies that a regular AGM battery would have been unharmed by this momentary short, that is undoubtedly true, but beside the point. You can make a similar argument against a carbon composite prop because you can't just file out a small ding like you can on an aluminum prop. "There ain't no such thing as a free lunch."
William Slaughter
Houston, TX
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