Hi David, do you have any pictures of this that could be shared? Chris
On 1/20/2017 12:52 PM, Dave Palumbo wrote:
Following is an entry from a Backwoods Solar email that I received
today. I would like to share this as a teachable point for RE techs
not familiar enough with proper battery bank care and as a reminder
for those of us with years of storage battery experience.
I have underlined the two issues in the Backwoods email copied below
my bullet points to highlight the teachable issues.
·Checking wiring connections: Check not only for tightness but also
for temperature. There are two simple methods that work well: #1) Use
an IR Thermometer to ensure all connections are of a similar moderate
temperature. #2) Use your fingers to check temperatures. I'm
practiced at this second method because inexpensive IR thermometers
were not available when I began to care for storage batteries. I
simply use my bare fingers (with a light coating of petroleum jelly)
to wiggle test each battery cable at the battery terminal. Fingers are
sensitive enough to gauge proper temperature. I have easily found
several warm or hot connection points over the years caused by loose
or corroded hardware. Do this as preventive maintenance every time you
water the batteries or bi-monthly with sealed cells. Corrective
measures (tightening, or taking apart and cleaning, or replacing, and
reinstalling) are taken immediately when a warmer than usual
connection is identified.
·It is not recommended by most veteran wrenches to use any
"anti-corrosion paste" on the terminal connections. This has been
discussed a few times over the years on the Wrenches list. Most of us
have found that a thin coating of petroleum jelly (Vaseline is one
brand) does the best job of protecting against corrosion while still
allowing some visual inspection.
from Backwoods Solar 1/20/17. << This past summer Backwoods had a
visit from one of our retired co-workers, xxxxx. While it is always
good to have friends visit, the circumstances for his dropping by were
less than ideal.
A small, catastrophic failure had led to the loss of a battery bank,
two inverters, and a voltage converter. Ultimately, the failure was
traced back to a single nut and bolt in the battery bank cable
connections, that had developed hidden corrosion over time. Corrosion
causes resistance to the flow of electricity, which in turn generates
heat. With enough corrosion, and enough current flow, the amount of
heat generated can be sufficient to melt battery terminal connections;
which is exactly what happened in xxxxx’s case. The melted metal
flowed between the negative and positive terminals of his industrial
battery, causing a high power short that was beyond the capabilities
of any of the circuit protection, resulting in the damage to the
equipment.
Now keep in mind, xxxxx is one of the more detail-oriented people
we’ve had here at Backwoods. The discipline of a military background,
along with critical thinking of an engineer, were still not enough to
overlook one very tiny detail. xxxxx does his mechanical maintenance
on a routine schedule; _checking for tightness in wiring connections_,
cleaning accumulated spray off battery tops, cleaning out dust and
spider webs, _and keeping his battery terminal posts coated with
anti-corrosion paste._ This is not the type of person you’d expect to
see such a failure.
So what happened? It all boiled down to the battery terminal
connections. What xxxxx had NOT done, was dissembled the nut and
bolts from the battery terminals and cables to check for internal,
hidden corrosion. It had been about 6 years since he had done that
level of inspection. When previously reviewed, the hardware had been
thoroughly inspected, cleaned, and re-assembled, and then coated with
_anti-corrosion paste on the exterior_. In one of the 16 nut/bolt
pairs, a small bit of contamination or moisture must have been left
trapped inside. Over the course of the next six years, the corrosion
grew, contaminating the entire connection; but was NOT visible
externally at all! >>
Best regards,
Dave
David Palumbo
Independent Power LLC
462 Solar Way Drive
Hyde Park, VT 05655
802-371-8678 cell
802-888-4917 home
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