Advice on building my 7920KW system off grid solar system

[crustbottle]

I am a newbie to solar but have been doing a lot of research on how to setup an off grid system. I have some questions regarding where would I put circuit breakers or fuses. Like should I put one before or after the battery bank. Let me know what you guys think of my system so far in the picture. I'm using a 96 volt system because I got the charge controller and inverter basically for free.

[J.P.M.]

7,920 kW (7.92 megaWatts) is a pretty big system for a newbie.
Hope you have about 50-60 acres to put it on.

Maybe you mean 7.92 kiloWatts, or, 7,920 Watts ?

[max2k]

7,920 kW (7.92 megaWatts) is a pretty big system for a newbie.
Hope you have about 50-60 acres to put it on.

Maybe you mean 7.92 kiloWatts, or, 7,920 Watts ?

details, details- who needs them?

[sensij]

Please post the specific model numbers of the inverter and charge controller. Among other things, you will probably want strings to be longer than 4 panels.

[J.P.M.]

details, details- who needs them?

Well, Maybe not the OP, but I figured a newbie either, 1.) might want to know how much area a 7.92 mW array might take+/- 10 acres or so, or 2.) that his research didn't include some of the basics like the difference between a Watt, a kWatt and a mWatt before attempting a system design. But then, what's 3 to 6 orders of magnitude +/- a few ?

[crustbottle]

Haha yes I meant 7.92 kw. Sorry about that. The inverter is a 96 volt and rated up to 8000 watts it's Chinese. The charge controller is mppt 96 volt and 70a. You think I should do more than 4 panels in series. I was worried about the voltage getting to high.

[max2k]

Haha yes I meant 7.92 kw. Sorry about that. The inverter is a 96 volt and rated up to 8000 watts it's Chinese. The charge controller is mppt 96 volt and 70a. You think I should do more than 4 panels in series. I was worried about the voltage getting to high.

if you'd like to get more useful responses please post model numbers of your equipment including panels & batteries. Their country of origin is not that important.

[crustbottle]

Here are the specs: HXENGY MPPT Solar Charge Controller (96V 80Amp)

The inverter does not have a model number but the specs are pure sine wave 96 volt inverter 8000 watts

Midnight dc combiner box

VMAX XTR4D-200 12V Battery I will have 24 of these

BSM330M-72 solar panels

[SunEagle]

Hmmm. Chinese 96v equipment and 3 sets of 8 12volt batteries wired in parallel. Seems like there could be an issue with that system.

[J.P.M.]

Hmmm. Chinese 96v equipment and 3 sets of 8 12volt batteries wired in parallel. Seems like there could be an issue with that system.

Also sounds like equipment selection used initial price as governing criterion.

[NEOH]

I am a newbie to solar but have been doing a lot of research on how to setup an off grid system. I have some questions regarding where would I put circuit breakers or fuses. Like should I put one before or after the battery bank. Let me know what you guys think of my system so far in the picture. I'm using a 96 volt system because I got the charge controller and inverter basically for free.

Answer ...
YES, you should put a DC Rated circuit breaker or fuse on the battery terminal.

Are you installing this equipment in the USA?
Will it require a permit and an inspection?

My view of your drawing, is cut-off at the bottom.
I do not even see the DC-AC Inverter on your drawing.

I see...
24 @ 330 Watt PV Panel = 7,920 Watts, wired as 6P4S
One Combiner box
Two (2) MPPT controllers
24 @ 12 Volt Battery Bank, wired as 3P8S <<< image cut-off here

How do plan to connect the two (2) MPPT Controllers to the 24 PV Panels?

[max2k]

Also sounds like equipment selection used initial price as governing criterion.

batteries are expensive- $499 each x 24 = 12k sank in those ... OP: please do not buy anything until you clearly see your entire project, it's much easier & cheaper to 'replace' things on paper than in reality.

[crustbottle]

The batteries I got for $1500 from a store that was closing down.

NEOH:

-I will put a DC rated fuse on the battery terminal thank you for that info.
-This is an off grid system in the woods i don't think I will need permits but I will confirm that with my local government here in florida.
-To connect the mppt to the solar panel I was going to have the DC combiner box output to the two mppt charge controllers. Is that okay?

The rest of the drawing is the battery bank wired in series for 96 volts then that gets connected to the inverter. After that the plan is to have the inverter go to a breaker panel box to connect all the outlets.

[sensij]

The batteries I got for $1500 from a store that was closing down.

-To connect the mppt to the solar panel I was going to have the DC combiner box output to the two mppt charge controllers. Is that okay?

No, not OK. You can't have two mppt's on the same set of panels. Do you have any documentation that indicates the maximum input voltage for those controllers? I couldn't find that specific model, but it looks like the 40 A version accepts 300 V max.

[ButchDeal]

The rest of the drawing is the battery bank wired in series for 96 volts then that gets connected to the inverter. After that the plan is to have the inverter go to a breaker panel box to connect all the outlets.

Is this going in the US? if so you want it to be 48V not 96V