question

lo-g avatar image

Does this graph indicate my solar array is not keeping up with usage?

Hi, I've attached a screenshot of my VRM dashboard for the past 30 days for my remote cabin off grid system. I've had to reset 100% SOC a few times once my LionEnergy battery bank (2 - 12V in series 105ah) batteries are showing 28V (for some reason the BMV never seems to show them as 100% charged...i have to rest them when they get to 100% 28V). Those resets are indicated by the peaks in battery SOC at 100% in image. I only leave on a refrigerator in the cabin when I'm not there and have it on a timer to turn off between 10PM-1AM and 2AM to 5AM. Does this graph indicate that the 3.16kW energy harvested per day isn't enough to keep up with the draw/load? I have a 1.46kW array (using victron MPPT and inverter/charger).

charging batterybattery capacitysolar sizing
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3 Answers
klim8skeptic avatar image
klim8skeptic answered ·

You could look at whether your mppt has fully charged the battery every day. Check with Victron Connect, or Mppt state via VRM.

If your Mppt has gone through the absorb state and onto float each day, that would indicate the battery is fully charged (assuming you have set the mppt correctly for your battery type).

You might want to share those ^ details, and the mppt battery settings, and the BMV settings.


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charger-state.jpg (14.4 KiB)
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billknny avatar image
billknny answered ·

In looking at kWh produced, and kWh consumed, your system looks fine. You are making slightly more than you consume, which makes sense since there are efficiency loses through the system. There would be more to look at to confirm this, but that's my first take.

If your BMV is NEVER auto-resetting to "FULL", then it seems that the problem is more likely with the BMV settings. Can you post those as well as your charging system settings?



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Vance Mitchell avatar image
Vance Mitchell answered ·

Can you give us some more details about your system. What type and capacity batteries and what components are in your system?

If you are having to reset 100% regularly, I would be having a good look at your BMV settings to see if that is the issue. Another cause could be the shunt wiring. Is there any charge source connected direct to the battery negative?

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