[RE-wrenches] GTWB outage monitor question

[Mick Abraham]

Happy Friday, all~

Allan & Todd were discussing the issue where a "reset type" amp hour
battery monitor (such as TriMetric) never gets to "reset to full" when
operating on a GTWBB "grid tie with battery backup" system...because the
battery stays in float and the monitor never sees a bulk charge voltage.

The problem here seems to reside more with the chicken than with the egg. A
battery in "float" for long intervals will actually still undergo some self
discharge,  so it needs an occasional "rebulk" charge to restore full state
of charge.

*Inverter manufacturers please take note that a simple addition to your
code base could cause a GTWBB inverter to rev up the battery charge voltage
back through the bulk/absorption phase on a calendar basis such as once per
month. *Victron Energy already does this with their inverter/chargers but
Victron is not certified for US terrestrial and it's not set up for grid
tie.

If the inverter system would do an occasional "rebulk", that would also
cause the battery capacity monitor to reset. Until that function becomes
automatic within the inverter(s), the next best suggestion is for the
client to manually simulate a power company blackout once per month by
cycling the input AC breaker off, then on. This kicks up a bulk cycle,
ensures good SOC on the battery, stirs up the electrolyte if the batteries
are floodies, and resets the battery capacity monitor all with a single
intervention.

The same manual intervention might also serve as a good time for the owner
to check water levels on a flooded pack, near the end of the charge cycle.

The Wrench List is the bomb! Jolliness,

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675
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