Augmenting a small off-grid system.

softdownsoftdown Posts: 1,893Solar Expert ✭✭✭✭
Talking a roofer I know well into traveling to S Florida and helping me roof next month. My best bet is partial payment , at least, via fixing up his somewhat ail solar system. This is what he has:
1) Small house and a wife.
2) Tiny fridge
3) Three hooked up 185 watt panels. One 250 watt panels not hooked up. #8 wiring, he had some help. Panels put out "30 amps" at 12 volts.
4) Good newish charge controller, he had some help.
5) Cheap modified sine wave 1500 watt inverter. Radio works poorly - static. I told him this could be high THD with cheap modified sine wave inverter. 
6) Two very good 112 amp 12 volt solar batteries with good cabling. 

I'm a bit rusty. Thousands of solar facts and figures and theories it seems. I'm thinking priorities should be:
1) More battery back-up. 
2) Pure sine-wave inverter about 1500 watt.
3) Hook up extra 250 watt panel. Basically delivering 185 x 4 = 740 watts. Better than existing 555 watts.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • mcgivormcgivor Posts: 2,206Solar Expert ✭✭✭✭✭
    What nominal voltage is the 250W panel ?
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • softdownsoftdown Posts: 1,893Solar Expert ✭✭✭✭
    mcgivor said:
    What nominal voltage is the 250W panel ?
    Good question and I didn't check. The purpose of the visit was to find a roofer. Then I took a quick look at his solar. 

    The 185 watt panels are likely in the 40-45 volt range. What range can we still work with in the 250W panel?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • PhotowhitPhotowhit Posts: 4,705Solar Expert ✭✭✭✭
    If the panels are all 60 cell / 26-32 VMP or all 72 cell 35-40 VMP, then you could likely get the "...185 x 4 = 740 watts..." effect you desire. 

    I'm not a fan of adding new batteries to old. If they are nearly new adding batteries puts you in the 3 or more string situation that I also like to avoid. I personally, like to add solar panels to help charging on overcast days, and expect to switch to a higher voltage system when the batteries do fail. This allows spreading out the expense a bit. Shoot for compatibility when they transition to a 24 volt system.

    Static on the radio can be better handled by the 'hams' around here. As I recall twisting the DC wiring can help. Since it's a 12 volt system, you might suggest a car radio and shieling it from the interference from the inverter. 
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • softdownsoftdown Posts: 1,893Solar Expert ✭✭✭✭
    it is somewhat unlikely that this scenario can be changed to something that pleases the pros. This was hob cobbed together then had some assistance by someone who knew some things. 

    The batteries were over $500/each when new. Bought used and likely well used at this time. He isn't going to toss and start again. These folks aren't too far from 3rd world living. Once you leave the city, that is somewhat common in modern, rural America. Real jobs are very scarce and usually pay minimum to $10/hr.

    These folks are a bit hand to mouth. Exceedingly common in construction. He is pretty good at roofing and interested in going to Florida and helping with the nightmare of a lifetime. I both want to help and lower my cash out of hand bill. I have lots of solar gear from my ill fated rush into cabin solar. That might have taken off but Hurricane Irma had other plans.

    I am also not in a position to give valuable stuff away. I have no idea why so many come off as "Be a philanthropist dude."

    I need to go back and gather more data. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • PhotowhitPhotowhit Posts: 4,705Solar Expert ✭✭✭✭
    Please note, I was working with what he had and suggested no additional spending in the near future, other than possibly adding some solar panels. Use the batteries until they die. They may live on for quite a while. You described the batteries as being "very good", now they are "well used".  The fact is that batteries don't last forever.

    I've lived "hand to mouth" from time to time. A bit of a safety net in that I could move into town, but choose to live rurally. I have trust issues and prefer to do what I can for who I can... I certainly am not putting you in the position of being a philanthropist...

    I think you can ask them to read the back of the 250 watt panel and count the cells of the 185 watt panels. Do you know that they have a MPPT type charge controller? He might even have old Evergreen Cedar panels that are 12 volt nominal at 185 watts.

    If he's a roofer, and can deal with heat, it's a job that pays well when there is a market in Florida. It way up there on the tolerance scale. Add a hurricane and he can hang a sign around his head and get hired in a hurry. I love to tell the story of living in Tallahassee Florida during the housing boom in Central Florida and whole crews had been hired off of a roof for 1.5x the money and room and board, to move to Tampa/Orlando to work.

    If he's bi-lingual Spanish/English he can look forward to be in very high demand.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • softdownsoftdown Posts: 1,893Solar Expert ✭✭✭✭
    They cost over  $500 when new - hence "very good batteries". I also think they are well used at this time, he bought them used. I spent a minute or so looking at things. 

    He lives in Colorado - not moving to FL. Just a trip. I have a tornado of things going on right now.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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