question

Bonjour @schopp

I run a 3ha farm Off-the-Grid in Estonia (I was living for 34 years in France and had enough) and my current power requirements are much lesser with only 20kWh for Field Watering a day, but your system with more then 100kWh per day is nice.

Since you probably water the day, it will reduce the need for big batteries since a 48V 4350Ah SOPzS Battery bank cost around 20.000€. If you need this dimension in LiFePO batteries, you will pay several times more.

4350Ah give you around 160kWh usable energy at DOD80 with 1500 cycles.

I a big farmer neighbour where I have recently installed 3 Quattro 48/15000/200-200 with this battery set, while the Inverters can deliver up to 36kW or 45kVA. I have coupled a three-pase Fronius Symo with 18kW on the AC out of the Inverter but also one RS450/100 DC coupled solar charger.

Note: you can NOT sell back energy with this Inverter, but you can reduce enormous the power requirements from the Grid.

Also 160kWh battery power can give you even in the winter nice backup, especially if you can be bothered to install a windmill in the 3,5 to 10kW class.

The 3,5kW version of "Braun Windturbinen GmbH" (Germany) deliver on a 9m mast around 16MWh a year or in the middle 43kWh a day, but cost around 21.000€, but I think, since your power requirement with more then 20MWh per year is quiet costly, the windmill justify itself.

The Size of your Solarpanels should match the Power Consumption of your Watering pumps and other permanent loads PLUS at least 25% reserve.

Hence if your system need 110kWh a day, your system should have around 20kWp of Solarpanels minimal.

Do you also water in cloudy weather?

If yes, you have to increase the Solarpanels.

In Estonia we pay currently per kWh 0,15€ at night and up to 0,35€ the day.

Have a nice day

Michelle

Thank you Michelle, I alo had a feeling that the battery I would need would be quite big but 160kWh? Is it safe to run that much Amperage on 48V? What are the dangers of such a large battery. My experience is only Lead acid and LiFePo4 running 2 John Deere Gator TE. I'll do a new post on my experience with them.

But boing back to Big battery; Is there anyone using more than a 100kWh of storage on this forum?

Best,

Schopp.

Note:

Currently I plan an installation with 8 Battery Sets of 48V/4350Ah which give in total 1,6MWh of energy!

My customer want to start with 6 MultiPlus-II 48/15000/200-100, 2 Fronius Inverter 30kWp each and 4-6 Victron RS450/200.

He has plans to install 2 windmills with each 40kW power output max on the AC OUT of the Victrons, which will be later 12 in total!

3 Phases 400V and 144kW or 190KVA.

The power rail must support in total 3700A and short term Impuls 5000A.

The biggest (electrolyt) copper rails I can get are 200x10mm and support only 2200A.

Have to bolt 2 together (with contact fett in between to get the 3700A (2200A*1,7=3740A).

Cabeling is done with 120mm².

And forget about the Car megafuses...

I have to use professional NH fuses!

Yes, you can, but this is nothing which you plan, design and install in one month!

Note: the whole installation without Building and Windmills cost 390.000€, which is a fraction of the money, the Grid provider Elektrilevi has ask my customer for a NEW cable and Transformator which support up to 500A @400V 3P. Currently he has only 125A (50kW)

Wow, this is huge, where is he, and what does he do with all that power?

For my setup, I am thinking 100 panels, 3 quattros 10 000 a 120kWh battery and a diesel generator that also heats water with its exhaust. I think my electric bill will be about 20K euros this year, so ideally I could invest 100K on a good setup.

For batteries that large my instinct is 48V modules all connected to a very well designed busbar. This way, a module can be removed or disconnecteded for maintenance without disruption and cables can distribute power on many evenly distributed points.

Best,

Schopp