200kwh battery? wtf

[Solardaveo]

hey we use around 32kwh aday, big family im trying to workout as we get reduced sun in scotland how to set up solar and what the best case is, as we will be moving come January to a remote spot

im opting for a generator which does oil, pekins engine, 12kw
and if i got 12kw solar array it says i need to get a 200kwh battery ( deep cell AGM as we dont use lithium)

how can i reduce the battery need? more solar panels? says a 12kw array is 28 panels already?
i cant afford £17,000 on batteries right now so wondering what options i have?

( my 32kwh is including my workshop and oven use in house which will be primarily on fire when i move but tool use will increase so left my useage high, )

 

[MattiFin]

Scotland? In winter?
Your only reasonable option is to use less electricity or move about 5000km south.
12kW panels and 200kWh AGM battery is next to nothing in the winter.

You'd need freaking 10 times more solar panels to even attempt to cover 32kWh daily consumption in Scotland winter.

 

[ConnerLabs]

What he said…

If you doubled the PV array to 24kWp, the average production in January would roughly cover your average consumption. Of course averages can be misleading. The problems start during non-average spells of weather.

The most important part of this system in winter will be the diesel generator. And the second most important part will be a good battery, so you don’t have to run the generator all the time.

The rule of thumb I’ve seen for an off-grid system is 3 days of battery storage. For you that’s 100kWh. Lead acid is usually sized to not discharge lower than 50% so I guess that’s where your 200kWh comes from.

However if you have a reliable generator rated for prime power, you arguably only need 1 day of storage.

And just saying, LFP batteries are a lot better than lead acid, and not really that much more expensive. The 50% depth of discharge limitation doesn’t apply.

 

[MattiFin]

What he said…

If you doubled the PV array to 24kWp, the average production in January would roughly cover your average consumption. Of course averages can be misleading. The problems start during non-average spells of weather.

I needed more than 40kWp of panels in the EU PVGIS tool to get 1000kWh/month(about 32kWh per day) for somewhere Edinbugh-Glasgow level. Or over 50kWp for Inverness.



Battery size would need to be absolutely insane without generator.

Basically this boils down to selecting good generator and thick wad of cash for diesel. Everything else is just icing on the cake.

 

[ConnerLabs]

I needed more than 40kWp of panels in the EU PVGIS tool to get 1000kWh/month(about 32kWh per day) for somewhere Edinbugh-Glasgow level. Or over 50kWp for Inverness.


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Battery size would need to be absolutely insane without generator.

Basically this boils down to selecting good generator and thick wad of cash for diesel. Everything else is just icing on the cake.

Ok so my 2x estimate was a bit optimistic, but it’s still not 10x.

Heating by oil/kerosene is quite common in rural Scotland, an old Perkins diesel should run fine off that. Get a water cooled engine for some micro CHP action.

 

[crossy]

Heating by oil/kerosene is quite common in rural Scotland, an old Perkins diesel should run fine off that. Get a water cooled engine for some micro CHP action.

If you're running on straight kerosene you need to add some lubricant to the fuel to avoid damaging your injection pump. Can you get red diesel which doesn't have these issues?

According to AI about 5% of 2-stroke, engine oil or ATF seems to be the preferred amount.

 

[Joel Jahn]

Sounds like your trying to run some very heavy electrical appliances off of solar. Cook stove, Hot water heater, room heat, and clothes dryer needs to use propane. Should be able to run refrigerator, freezer, clothes washer, clothes dryer motor, battery operated tools, and lights on solar with 12000watt array in winter. Need to hang up your clothes to dry in front of wood fire stove. but one large 48v forklift battery is needed. Don't leave lights on when you leave the room. train your kids to not waste. You will be able to run laptops computers for schoolwork. Do all your elective electrical use during the daytime. In the summer you will have all the juice you want.

 

[MattiFin]

Sounds like your trying to run some very heavy electrical appliances off of solar.

Looks like OP run out of battery before he had change to read any of the replies. (Seen last sunday)

 

[SunDave]

how can i reduce the battery need? more solar panels? says a 12kw array is 28 panels already?

Hi. There is a lot of detail left out of your post. If you are not going off-grid entirely, then a smaller battery is still useful for a short term outage.

It all depends what you are doing with it. Best of luck on your system.

 

[RobWMI]

For that kind of capacity, you might want to look into industrial flooded lead acid batteries (same chemistry, but different internals than standard auto or deep-cycle lead acid). They're built for electric forklifts and other machinery, and in the right place at the right time can be picked up used fairly inexpensively. Due to their industrial build they can be refurbished and used for many years. Search "IFLA solar" for plenty of info.