Additional 3.8 PHI

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Posts: 1519
Joined: Thu Feb 17, 2011 11:12 am
My RE system: VFXR3648, FM80, 3k panels, Mate3s, FNDC, 4ea 3.8 PHIs. EU7000is AGS.
Location: PNW

Re: Additional 3.8 PHI

Post by JRHill »

I've gone 10 days of consistent operation with the additional (4th) battery so here are the averages as measured from the shunts:

Inverter: 6.35kwh
ChargeC: 6.71kwh
LowSOC: 74%
LowVDC: 52.9

The above is from solar, no gen time. The CC Absorb is set to 54.6 for .5hr with Float at 53.1 and the Days Since Parameters Met has reset each day.

It is curious to note that SimpliPhi's chart of battery SOC per the voltage shows the batteries as 100% at anything over 52.5vdc so according to that I never go below 100% but that is just not true. But if I were to take them to 56.4 it makes a heck a difference to the low readings. But I believe that is partially because the time that the CC shuts down is extended a few hours. Also at 56.4, at this time of the year, I never see any float as the batteries stay above the set point as the sun gets out of range so I head into the higher evening power use a bit higher.

So I believe I've hit my goals which were:
1) Have the extra battery in case of a failure of one in the winter. I could get by on two but it would be a lot more gen time. The 4th battery and falling back to 3 should cover that;
2) Keep the generator to one warm up and run per day in the winter. I could play with reducing the Absorb at that time - we'll see;
3) Keep the batteries in a very conservative midrange SOC. I'm hoping for a long, long life and well past the max warranty of ten years.
4) Get rid of the thought of any more panels and another CC. They're not needed in the summer and more panels producing nothing in the winter is worthless.
5) Maintenance reduction and sustainability by someone having to be actively involved with monitoring and adjusting if necessary.

Granted this project was no small investment. But as I've kicked around other ideas over the years, storage seemed to be my best advantage. If I had stayed with lead acid all I could really do is go to a 48v bank of 2v cells. No thanks.
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