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F71 - Battery Overcurrent Error - XW MPPT60 XW MPPT80

Issue:
MPPT is getting a very quick F.71 error that clears on its own, but seems to reset the charge cycle.

Product Line:
MPPT60, MPPT80

Environment:
Potentially any MPPT installation.  Generally, aging installations or newer installations.

Resolution:
Verify DC cabling is correctly sized from PDP to Battery bank and MPPT to PDP.
Ensure battery bank size meets minimum requirements

Cause:
The output stage of the MPPT60 and MPPT80 charge controllers have capacitors across them. When current is drawn out of these capacitors the charge controller will issue that fault. In a standard XW installation, the battery bus is commoned in the PDP. If the wiring from the PDP to the bank is inadequate, the inverter can pull current from the MPPT60 capacitors rather than from the battery bank. Think of these capacitors as the p-trap in a sink drain. If the air intake vent in a plumbing stack is impeded or can't keep up with a very fast flow down the drainage stack, the water from the trap can be sucked out.

It can also be thought of as a race in a millisecond range.  When the XW demands a load, it's up to the battery bank and the MPPT to provide the load.  If the MPPT wins this race, then it results in an F.71 fault.  Generally, this will happen in older installations as the battery bank ages.  It can also be attributed to impedance between the MPPT and PDP and/or the Battery Bank and the PDP.
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