Help me set-up my system correctly please.

Sorry @AndyIvy - I must have made a mistake when I said that 2 strings of 3 would be OK.  I'll go back and re-look at that.  If you ended up with 3 strings of 2 per pole, it meant you had potentially higher current, so you needed bigger wire. Did you end up using #10 wire from the pole combiner to the CC?

I looked at the Rolls Surrette manual. It looks like for your 48V configuration you'll need to set up your CC with the following parameters (others here can double check my work, hopefully):

1. Bulk / Absorption voltage: 60V
2. Float voltage: 54V
3. Equalization voltage: between 62.4V and 63.6V

These voltages need to be temperature compensated. Your CC should have come with a BTS (Battery Temperature Sensor), which should connect to the CC. The sensor itself should be mounted on the terminal of one of your batteries or on the surface of the case. Rolls says the temperature compensation should be set to 5mV /deg C/cell. In your 48V configuration you have 24 2V cells, so your temp compensation should be 120mV.

Rolls also recommends end amps be set to 2% of the 20AH rating of the battery. For your 856AH bank, that's about 17A. If your CC has a setting for end amps (or "return amps") you can set it. I know my Schneider CC doesn't have a setting for end amps, but instead just goes for 2%.

There's also some stuff about the max absorption charge time in the manual, but it is computed based on your normal charge current. 

You would want to get down to 50-60% in a day or two. Avoid having them sit at that level for more than a day or so. Anything under ~75% will allow for a "bulk" charge, during which the batteries accept maximum charging current, which helps "form" the plates to bring the bank up to full capacity. If loads or charging capacity are limited until you move in, it's not a big deal to hold off doing it. I did it once or twice a week for the first 2-3months using the bank. In my case, the system got finished in fall and didn't get used much over the winter, so most of the break-in was the next spring.

As Dave said, the main thing is to get SGs fairly close between cells, and as close to spec as you can.

The rule of thumb is 50-60% SOC, but there are really 3 inter-related factors; the SOC, the length of time sitting at low SOC, and the bank temperature. For example, a bank at 50% SOC and 95°f will sulfate much faster than at 35°f.

I normally fire up the generator at ~60% and charge up to ~80%, unless I'm pretty certain the day will be sunny enough to fully charge with solar alone. At this time of year, the days are too short and sun too low for solar alone in my location. In spring/summer, pv alone would easily charge to full from that level on a sunny day.

I am always interested to read about high altitude CO systems! I haven't seen anyone mention it yet, but maybe it has already been discussed.  I would imagine your panels will put out more than they are rated for at 9,000'.  I have a 3,100 watt array at 10,000' in CO and highest output I have seen so far was ~4,100 watts. Just hit 3,500 watts yesterday. So POSSIBLY your array isn't as undersized as it may appear on paper? Just a thought from a guy that doesn't know very much! 

At altitude, you get the benefit of thinner air and likely lower temps. In winter, I'm not suprised to hear you're seeing better than STC output. What's it like in summer?

Estragon said:

At altitude, you get the benefit of thinner air and likely lower temps. In winter, I'm not suprised to hear you're seeing better than STC output. What's it like in summer?

Estragon - I can't easily answer that with exact numbers.  I installed my system in late July and left a few days later. I went back thru the logs in late September and saw the 4,100 watts in early September. (I was mainly just looking at high power and float time). I did not get the My Midnite app working until early November so I don't have easy access to the August data at this time. I do know they often exceeded the STC from what I quickly looked at in the log. I will say that thru all the reading I did before I installed my system I never saw a single thing about breaking in the battery bank so I did nothing to break my batteries in.  Not sure how much that affects them in the long run.  Luckily, it's a "cheap" set of GC batteries.