Considering Off-Grid Solar Options

[new2solar2]

I'm sure there are a billion posts comparable to this, so I apologize in advance.

I'm setting up a new off-grid solar solution to power a cabin.

I'm thinking I'll need ~8kw a day when I'm out there, but I will likely only ever be there for two consecutive days. That said, I never want to run out of power.

I'm looking at two different inverters as options:
1) Growatt SPF 12000T DVM
2) Outback Radian GS8048A-01 8,000 Watt Advanced Inverter/Charger
Leaning toward the Growatt as it is 1/4 of the price as the Outback.

I'm thinking of getting 20 335W, 24V Solar Panels, but NOT connecting them in series to produce 48V as I'm worried it would actually be more than 48V.

The batteries I'm considering are 4 eg4-lifepower4-lithium-battery-24v-200ah, connecting paralleled pairs in series so there are 2 48V battery packs, providing 20.48kwh total.

Anything that is obviously wrong with a set up like this?

Thanks!

 

[Bobert]

If you will only be there 2 days in a row I would go heavy on the batteries and lighter on the solar. If you are planning a 24v system the wire size will be huge to run a 8k inverter. If you go 48v your panels must be in series and exceed 60 volts to charge your batteries. At 24 volts you will probably need a handful of very expensive charge controllers to divide the potential of almost 300 amps from the panels. If you have enough battery to power yourself for 2 days then you will only need solar enough to recharge when you are away.

 

[new2solar2]

If you will only be there 2 days in a row I would go heavy on the batteries and lighter on the solar. If you are planning a 24v system the wire size will be huge to run a 8k inverter. If you go 48v your panels must be in series and exceed 60 volts to charge your batteries. At 24 volts you will probably need a handful of very expensive charge controllers to divide the potential of almost 300 amps from the panels. If you have enough battery to power yourself for 2 days then you will only need solar enough to recharge when you are away.

Based on the specs, I think both of the inverters I'm considering are all-in-one devices that include the charge controllers. Good idea though about expanding the battery capacity.

 

[Bobert]

Based on the specs, I think both of the inverters I'm considering are all-in-one devices that include the charge controllers. Good idea though about expanding the battery capacity.

The growatt you mentioned requires at least 60 volts from your solar to work. You will have to exceed 48 volts with your solar to use any 48v charge controller. You will probably need to connect 3 panels in series to get a good working voltage for the growatt. I didn’t look up the Outback but it’s probably similar specs.

 

[timselectric]

If you are going with a 48v system. Buy 48v batteries.

 

[Bobert]

If you are going with a 48v system. Buy 48v batteries.

This is true 4 48volt eg4 batteries will give you better ballencing than 4 24v and identical watt hours of output.