8 250w 36v panels, what else do I need?

[DigitalScar]

Hello everyone, I picked up 8 solar panels and wanted to set up a backup power supply in case of a power failure (to power some lights fans and a small fridge I would also like to power my shallow well pump if possible.). The panels are 36v 250w each. I know I will need a controller, batteries and an inverter but I have no idea what to get. Any assistance would be great. Thanks in advance. Also a couple of them have cracked glass is there a way to seal them?

[Sunking]

With 2000 watts of panel minimum battery voltage is 24 volts @ 640 AH minimum with a 80 amp charge controller, 48 volt 320 AH minimum with a 40 amp MPPT controller. 80 amp controller will set you back roughly $600, and a 40 amp around $500. Batteries will set you back $2300 for a cheap walmart 2 year battery, or $4000 for a decent 5 year battery.

[DigitalScar]

With 2000 watts of panel minimum battery voltage is 24 volts @ 640 AH minimum with a 80 amp charge controller, 48 volt 320 AH minimum with a 40 amp MPPT controller. 80 amp controller will set you back roughly $600, and a 40 amp around $500. Batteries will set you back $2300 for a cheap walmart 2 year battery, or $4000 for a decent 5 year battery.

Thanks for the quick reply!

So to generate power to run a couple lights a few hours a night, a fan during the night and a mini fridge 24hr/day for maybe a day or two (and if possible power up the well pump a few minutes a day) , it will cost that much?

I used a 45w solar kit from harbor freight with 2 marine batteries and a 750w inverter and it ran lights (led) and a small fan for 32 hours and kept my phone charged.

I know you are the expert but are you sure that I can't get out cheaper than that? Maybe I am using too many panels?

Thanks again

[SunEagle]

Thanks for the quick reply!

So to generate power to run a couple lights a few hours a night, a fan during the night and a mini fridge 24hr/day for maybe a day or two (and if possible power up the well pump a few minutes a day) , it will cost that much?

I used a 45w solar kit from harbor freight with 2 marine batteries and a 750w inverter and it ran lights (led) and a small fan for 32 hours and kept my phone charged.

I know you are the expert but are you sure that I can't get out cheaper than that? Maybe I am using too many panels?

Thanks again

The system Sunking provided information on was based on the 2000 watts those 8 panels are rated for. If you use fewer panels then you can use a smaller battery system and charge controller.

But you have this all backwards. You should first determine what you daily watt hour load is. Then size your battery system, then you panel wattage and charge controller. Not panels first and ask "can I make this work cheaply".

A solar battery system is a fine balance of panels, CC, batteries and inverter. If any component is either too small or too large then you run the risk of an under-performing system or equipment failure.

So first things first. How many watt hours will you use in 24hr running your fan, lights, fridge, etc?

[Sunking]

I know you are the expert but are you sure that I can't get out cheaper than that? Maybe I am using too many panels?

The issue you have is 2000 watts of panel power. With that much power requires the minimums I just gave you. You did it backwards.

[DigitalScar]

The system Sunking provided information on was based on the 2000 watts those 8 panels are rated for. If you use fewer panels then you can use a smaller battery system and charge controller.

But you have this all backwards. You should first determine what you daily watt hour load is. Then size your battery system, then you panel wattage and charge controller. Not panels first and ask "can I make this work cheaply".

A solar battery system is a fine balance of panels, CC, batteries and inverter. If any component is either too small or too large then you run the risk of an under-performing system or equipment failure.

So first things first. How many watt hours will you use in 24hr running your fan, lights, fridge, etc?

Approximately 1600 Watt hours for a 24hr period. This system would only be used in the event of a power outage (I live in Florida, so during hurricane season, last year I was only out of power once for approx 36 hours).

BTW I didn't intentionally put the cart before the horse, I was given the solar panels, and because I don't know much about solar, I came to the professionals here for some assistance. ☺ if I can't do this fairly economical then I will sell the panels and buy a generator, I would prefer to stay green.

Thanks

[Sunking]

Approximately 1600 Watt hours for a 24hr period.

OK to do that in FL during Hurricane months of June to Mid November will take.

Panel Wattage = 750 watts based on what panels you already have using 3 of them, 2 is not enough.
MPPT Charge Controller = Morningstar 45 amp TriStar = roughly $350
24 volt battery @ 225 AH, Trojan T-105RE x 4 = roughly $750 to $800
1500 watt TSW 24 volt battery inverter. = roughly $300

[SunEagle]

Approximately 1600 Watt hours for a 24hr period. This system would only be used in the event of a power outage (I live in Florida, so during hurricane season, last year I was only out of power once for approx 36 hours).

BTW I didn't intentionally put the cart before the horse, I was given the solar panels, and because I don't know much about solar, I came to the professionals here for some assistance. ☺ if I can't do this fairly economical then I will sell the panels and buy a generator, I would prefer to stay green.

Thanks

I too live in Florida and understand your reasoning. Although even with getting free panels the cost to run 1600 watt hours a day will not be cheap. It will be less than the system Sunking suggested for 2000 watts but will cost more than a nice small quite generator.

So with a need to run 1600 watt hours daily you are looking for about a 24volt 320 Ah battery system. Go with a 6volt 320 Ah battery and get 4 of them.

Living in Florida you would only need about 750 watts or 3 of your panels with a good 30 to 45 amp MPPT type charge controller.

And finally you will need some type of generator to properly maintain those batteries. Even in Florida we can get days without good sunshine and you will want to keep your batteries properly charged.

To let you know I have built a small solar battery system for "power outages" as well as have both gasoline and propane generators. What I spent on my solar battery system could have gotten me a much nicer and larger propane generator that would handle 10 tens the electrical load the battery system can. Also using solar and batteries is anything but "green" so don't fool yourself thinking you are saving the environment.

There are a lot of places to get prices on batteries and Charge controllers. Just stay with quality manufacturers. Their products cost more but you will get what you pay for instead of a lot of that cheap trash you find on eBay.

Oh. I forgot about the inverter. Get a 24volt 1000 to 1500 watt true sine wave inverter.

[DigitalScar]

OK to do that in FL during Hurricane months of June to Mid November will take.

Panel Wattage = 750 watts based on what panels you already have using 3 of them, 2 is not enough.
MPPT Charge Controller = Morningstar 45 amp TriStar = roughly $350
24 volt battery @ 225 AH, Trojan T-105RE x 4 = roughly $750 to $800
1500 watt TSW 24 volt battery inverter. = roughly $300

Awesome, thank you! Now, do I connect the panels positive to positive, or positive to negative?

[Sunking]

All three wired in series.