Off grid cabin 16 months later

yeahgofigure

Wanted to give real world update on my new off grid cabin system in Mount Charleston area of Las Vegas. Was here last year asking a lot of questions and got a lot of wonderful feedback that really helped out.

So far system has worked great! We live in our 1300sf cabin almost like home with just a few adjustments. I got everything for lowest power consumption. 2 LED TVs on satellite, simple low power fridge, LED light bulbs, a portable evaporative cooler for hot summer days, main great room fan with brushless motor that uses a trickle at low speed, and heating / stove on propane. Even ok with luxuries like microwave / toaster oven / hairdryer as long as used sporadically. The only times we had trouble was last winter when visited during a freeze and little sunlight for 3 days which generator fixed up. Also a few times we tripped the inverter to go off when overloaded system like using microwave and toaster oven at same time.

System is 6 240 volt panels, Xantrex XW4024 Inverter, Xantrex MPPT 60 amp charge controller, 24 volt system with T-105 batteries (8 banks of 4 each), and Honda 7000is generator for backup. Also have a small old set of panels and charge controller we converted to power DC backup. How previous owner got by on 300 watts of main panel power is beyond me. DC came in super handy when lights went out which happened a few times.

I've seen charge controller max out at 1200 watts even though panels rated for 1440. It typically does about 800 to 1000 watts in morning settling down to 300 to 400 by afternoon. If system has been idle it trickles in about 100 watts.

The previous owner left the old generator and true to Honda it still runs like a champ. It's connected via 240 volt to inverter to charge the batteries faster which is one reason why chose XW4024. I run generator every month or two upon visiting and do it after a long night use so it charges harder and causes batteries to mix up fluids. Even though it's rated 7000 watt it typically peaks about 145 amps (3500 watts) and after two hours it's down to 30 amps when shut it off as solar does that. We have to be careful what we do when running generator, like cannot use microwave, otherwise generator overloads and powers down.

Oh and funny story. Northern Arizona Wind & Sun had best deal on inverter and charge controller. Kinda didn't make sense once shipping fees came into play but just about then happened to by on vacation to Sedona so a few extra miles and viola saved myself $600. Nice little outfit there.

Marc Kurth

Re: Off grid cabin 16 months later

You said eight banks of four. Generally, all of the batteries together would be a "battery bank" and individual sets of batteries in series would be called "strings." I'm not trying to correct terms - just want to be sure that we are on the same page!

Just to be sure I understand your system, do you have (32) batteries total?

Marc

Cariboocoot

Re: Off grid cabin 16 months later

Because if you do you have 8 * 225 Amp hours or 1800 total and that array is woefully small for so much battery. Chances are you don't need them either, as that would be 21+ kW hours stored. Look at your cumulative Watt hours on your controller and see how that compares.

SkiDoo55

Re: Off grid cabin 16 months later

Side note; sounds like you don't have generator support turned on and amps limit set to draw from generator. When enabled it wil only draw set amperage form tenants provide remainder of load from inverter/batteries. When surplus available from gen it will charge batteries.