New to solar and building a small system for emergency backup.

[Chris.Jones]

I’m new to solar and have researched for a long time now, getting more confused as I go lol.
I have 6 100 watt Renogy solar panels, 80 feet from my house where I plan to put the charge controller, batteries and inverter. My plan is to buy a midnite solar classic 200 connected to 2 x weize 12 volt 100 AH lifepo4 batteries connected into a 24 volt system to a giandel 24 volt 2000w inverter. My question is will this work, will 600 watts be enough solar to operate it and what size wire will I need to run from my solar panels to the charge controller. I’ll just be running some lights, charging some power tools and running a deep freezer and fridge in an emergency. Thanks.

 

[Chris.Jones]

I’m new to solar and have researched for a long time now, getting more confused as I go lol.
I have 6 100 watt Renogy solar panels, 80 feet from my house where I plan to put the charge controller, batteries and inverter. My plan is to buy a midnite solar classic 200 connected to 2 x weize 12 volt 100 AH lifepo4 batteries connected into a 24 volt system to a giandel 24 volt 2000w inverter. My question is will this work, will 600 watts be enough solar to operate it and what size wire will I need to run from my solar panels to the charge controller. I’ll just be running some lights, charging some power tools and running a deep freezer and fridge in an emergency. Thanks.

also, those are 12 volt solar panels

 

[12VoltInstalls]

also, those are 12 volt solar panels

Somewhat irrelevant

will 600 watts be enough solar to operate it and what size wire will I need to run from my solar panels to the charge controller. I’ll just be running some lights, charging some power tools and running a deep freezer and fridge in an emergency

I’d say just barely enough solar panels and marginal on battery capacity for overnight.

Did you do the ‘energy audit?’ I cannot guess your daily usage of the freezer and fridge, do nothing can be computed factually.

I run a 5CF fridge on 300Ah of lead acid batteries with 800W solar array. That works well most of the time but a) a cloudy day (or two) can be an issue and b) the fridge is only 60W-80W running. I expect you’ll be higher wattage and two devices.
An advantage for you is lithium batteries won’t care if they hang midway-charged for a few days.

I’d at least add one more battery and consider 800-1000W of panels. Depending on your energy audit, you will probably want even more battery and perhaps more panels.

But that’s wildhat town-pump conversation and guessing without knowing you daily watthours of need.

 

[DThames]

I know you have those panels already but if you can find some used full size (250w or larger) panels locally, you can put in a lot more PV watts than buying those 100w panels at $90 a pop. It is hard to have too much panel power, when your battery is low, the sun is not perfect, and you want to run some load during the day.....while charging the battery for tonight.

 

[MichaelK]

At my own cabin, on days that I am away, and only the refrigerator is running and nothing else, I find I'm consuming about 1800Wh of power. That's what both the refrigerator AND the inverter consume, when left on 24/7. Add another 500W for a freezer, and you need 2300Wh of power. Add some light, and a few wall chargers, and you're at 2500Wh (2.5kWh). Depending on the season, and cloud cover, 600W of panels is not going to cover that.

I agree with DT, that the 12V panels were a poor choice. They are 90$ right now? Two months ago, I bought 260W grid-tie panels for 65$ each. So, the choice is 100W for 90$ or 260W for 65$. Stop shopping for 12V panels and look for some grid-ties.

The 100Ah battery most likely is also too small. Let's say the power goes off during a storm, and the solar is minimal or zero. You have to go on battery power only. Assuming you shouldn't deplete those batteries less than 80%, then all you've got is 100Ah X 24V X 80% = 1920Wh. With the load identified above, your batteries won't even last you one full day.

 

[The Dish Doc]

I was told it's recommended using at least 200 Watts of Solar per 100 Ah of battery capacity.

 

[12VoltInstalls]

I was told it's recommended using at least 200 Watts of Solar per 100 Ah of battery capacity.

Ish. That’s a decent estimate.

 

[Rednecktek]

I was told it's recommended using at least 200 Watts of Solar per 100 Ah of battery capacity.

That also really depends on your location and weather. I know in my case 300w of panel to a 36Ah battery isn't enough for 4 months a year.

Otherwise I couldn't argue with the rough thumb.

 

[DThames]

That also really depends on your location and weather. I know in my case 300w of panel to a 36Ah battery isn't enough for 4 months a year.

Otherwise I couldn't argue with the rough thumb.

Emphasis on the "at least" clause

 

[Bvillebob]

Check out the idle power draw of the inverter you're considering. A lot of the less expensive inverters have very high idle power draws that can use up a good portion of the power generated by a small system just keeping the inverter turned out, before it even starts powering. your gear. A good inverter that size will draw less than 20 watts, some draw close to 100, many around 50-70. Even 60 watts is 1.5 kWh per day of idle consumption, about the same as your fridge.

 

[12VoltInstalls]

good inverter that size will draw less than 20 watts, some draw close to 100, many around 50-70. Even 60 watts is 1.5 kWh per day of idle consumption, about the same as your fridge.

That’s one of the reasons why overpaneled smaller systems make sense.
My MPPSolar 1012LV-MK is ~32W - 40W which is 800Wh or more/day. The Reliable 2000W measured 11W (which is only 260W) when I tested it.
The Giandel 1200W was moderately low but I can’t recall 18 or 26??? watts.

Those are all low imho but with a small system on a cloudy day? Significant.

 

[gnoeld]

I hope this will help you
I have 1200AH (600AH usable) of Lead Acid Batteries connected to 12 volt 3000 watt inverter (Soon to be rewired for 24 Volts or 48 with new inverter)
I can run 2 refer/freezers and 1 stand up freezer overnight (12 hours) and only run my batteries down to 65%.
I have 1500 watts of panels from SanTan and 1200 watts of cheap chinese flex panels (better than nothing!!)
I have the flex panels connected to a 60amp CC and the SanTan Panels connected to another 60 amp CC both to same battery bank.

 

[DThames]

I hope this will help you
I have 1200AH (600AH usable) of Lead Acid Batteries connected to 12 volt 3000 watt inverter (Soon to be rewired for 24 Volts or 48 with new inverter)
I can run 2 refer/freezers and 1 stand up freezer overnight (12 hours) and only run my batteries down to 65%.
I have 1500 watts of panels from SanTan and 1200 watts of cheap chinese flex panels (better than nothing!!)
I have the flex panels connected to a 60amp CC and the SanTan Panels connected to another 60 amp CC both to same battery bank.

Is that 65% of 1200AH?

With good sun, what is your recharge time with your loads running? (I know they don't all run all of the time) Do you recharge by noon?

 

[gnoeld]

I start getting sun at 6 am
by 9 am i am fully charged while running the same load
Easily by noon on cloudy days
Yes that is 65% of my battery capacity. Because they are lead acid I never run below 50% which gives me 600AH of usable power

 

[DThames]

I start getting sun at 6 am
by 9 am i am fully charged while running the same load
Easily by noon on cloudy days
Yes that is 65% of my battery capacity. Because they are lead acid I never run below 50% which gives me 600AH of usable power

Just to be clear, you are taking them down by 1200ah x 0.35=420ah daily (about)

 

[Risky Rob]

I have a similar system, but more battery capacity. My advice is to set it up and test it. I use about 250W per hour, and my lead acid battery bank is charging and running the inverter all day, then about 7 PM, I can switch to a charged 2500W LiFePO4 bank and run all night.