Ok. Going back to Dec 17 when I was in camp & could get pics of graphs right after a system crash while using a 4.5kW water heater.
I see the Absorb Charging Voltage followed by a Float Charging Voltage then sunset. Looks like batteries settled at @ 50.8 V or 85%. Right off the bat, I think our Absorb time needs upping. currently set at 1hr, should be 2-3hrs to really get batts fully charged. Voltage should settle at 52 when charge voltage is removed.
The gradual voltage drop overnight looks reasonable. But I don't understand why it takes so long to start and Absorb charge once it's light out.
Absorb is basically a fast charge. Float is more like a trickle charge.
I kinda wish I had a couple days of normal system data. Instead, I see a couple 1hr absorb cycles. Then the water heater kicks in.
I'm guessing it was drawing more power than the panels were producing, so that cut all charging off. Batts immediately drop to 48V. That would normally mean the batt was at 50% but I don't know how much of a heavy current draw voltage drop we have. I'd guess that at best the batt only got charged to 75%. And the heavy draw rapidly drained the batts.
I think the heater then kicks off and battV recovers to 50%, but there's no sun so no more charging. When the heater kicks in again, voltage drops below cutoff and system crashes.
So now the weirdness. That was pure battery voltage. And using charts for State of Charge SOC depending on resting, no load voltage of a 48V AGM battery bank.
If I look at the computer generated SOC. It's all topsy turvy. Says the batteries were at 90% and steady until the sun went down, at which point they magically fill to 100% overnight.
Then they start draining when the sun is out. But popping back up to 100% as soon as a heavy load was added.
And thus our system crashed from low voltage while also saying our batteries were at 100%
Would LOVE to find someone who manages an off-grid Outback Solar system.
Our non-profit's system was installed by someone who then kind of disappeared. It was supposed to come with Outback training for 2 people, but that never materialized.
It has run surprisingly well without any attention to speak of for nearly 6 years. But probably at a steep cost to the health of our batteries.
I have an electrical engineering background, so am a fast study. But a lot of the terms and setting names don't immediately make sense.
Would be helpful to be able to ask questions, or explain my understanding of something and get confirmation or correction of my understanding.
Need help figuring out a few things with our completely off-grid outback solar system. Starting with the batteries. We have a 48V system with 3 parallel channels each consisting of 8 6V AGM batteries in series.
1st Question is what should the absorb charge time be? Our system was set up by and recently checked by an Outback tech, but the absorb time is set at 1hr. And that seems too short to me.