[RE-wrenches] Dual radian system stopping selling on sunny days

[Dave Tedeyan]

To the Outback extraordinaires,

I've got a dual radian, grid tied system that has been in service for about
9 years. Recently, it has started this behavior where it will stop selling
to the grid on sunny days. Looking back at the data, this has happened
intermittently and very infrequently a couple years ago. But now we are at
the point where it happens every sunny day. Once the batteries get up to
fully 100% charged (not 99%), the selling stops and the system only
harvests enough solar to cover the backed up loads.

I got a hold of the USB card data. It appears that the inverter goes from
"Sell Enabled" to "Offset" when this happens. I cannot tell whether the
inverter randomly decides to switch mode and then stop selling, or whether
it is the stopping selling that puts it in "Offset" mode. The sell voltage
is set at 52V, and float is set to 54.4V. It looks like the batteries are
generally sitting around 54V when this happens. Once the inverter enters
"offset" mode, then the battery voltage stays steady at 54.0V

Does anyone have any idea what can be causing this to happen?
Cheers,
Dave

-- 

[image: Logo] <https://www.sungineersolar.com/>
Dave Tedeyan, P.E.
Owner | Sungineer Solar
p: he | him | his
a: 1653 Slaterville Rd. | Ithaca, NY 14850
w: www.sungineersolar.com <http://www.sungineersolar.com/>
c: (607) 270-0370
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