40kw solar panel system

[Bali88]

Does the following setup makes sense?

The installation is 100% off grid. 230v single fase.
40kw solar panels
300kwh battery pack
45kva diesel generator

Four Sunny MC to the panels and load
Three Sunny Islands to the batteries, generator and load.

Location is Bali, Indonesia

Max load from 9:30 until 2:30pm is 14 kw (all pumps running etc.)
Max load all other times is 10 kw
24 hour period use is 140kw/h

But 10 days a year the maximum load will be 30 kw, this is where the generator is needed. Obviously the Sunny Islands don't have enough power, so generator autostarts when the load is to high (and when battery charge is too low.)

I know this system is undersized, but I don't mind having the diesel genset running once in a while

Many thanks, Sunny

[Sunking]

So have you built another house or building to hold 42,000 pounds (19,000 Kg) of batteries?

[Bali88]

So have you built another house or building to hold 42,000 pounds (19,000 Kg) of batteries?

400kwh would be around 10,900kg, but I think I will limit the bats to 250kwh, which is around 21,000 ah at 12v and weights around 6,300 kg. Yes there is a reinforced floor building for that.

[Naptown]

Why on earth are you considering using 12V batteries This would require multiple strings of parallel batteries to get to the AH you need.
At this power level you need to think above 48V batteries and all in a series string.

[Sunking]

which is around 21,000 ah at 12v .

That is probable the stupidest thing I think I have ever heard on this forum. You win the prize. At that power levels you are talking about is commercial operation. With Poly Phase somewhere up around 300 to 500 battery voltage.

40 Kw @ 12 volts is 3300 amps. Hope you own a copper mine and have a fire department next door. Heck you will need 40 charge controllers that cost $800 each you moron.

[Bali88]

That is probable the stupidest thing I think I have ever heard on this forum. You win the prize. At that power levels you are talking about is commercial operation. With Poly Phase somewhere up around 300 to 500 battery voltage.

40 Kw @ 12 volts is 3300 amps. Hope you own a copper mine and have a fire department next door. Heck you will need 40 charge controllers that cost $800 each you moron.

I can see your are passionate about solar.

Yes, it would be a relatively large system and expensive. As far as I can see three SMA Sunny Islands will be enough charging capacity.

Naptown: I which I could buy 48v deep cycle batteries, but they are not sold in Indonesia. Yes, lots of labor and cables to make 48v banks.

[Mike90250]

....

Naptown: I which I could buy 48v deep cycle batteries, but they are not sold in Indonesia. Yes, lots of labor and cables to make 48v banks.

That's what you will have to do. It's about the same cables, to put a bunch of 12V batteries in parallel, or 4 of them into series.

BUT, what should work well in your case, is electric forklift 48V battery packs. You would still need several of them in parallel, but you should be able to get them in a big city. You need deep cycle batteries anyway, you cannot (well, you can if you replace them all every 3 months) use regular auto or truck batteries. You will have to buy deep cycle batteries from somewhere, so consider the forklift batteries.

Mike

[Bali88]

Thanks Mike,

I am looking for forklift batteries.

The batteries that I have in mind for the project are the 200AH batteries at http://www.incoe.astra.co.id/eng/pro...4122010171119/

Sunny

[Sunking]

Again very ignorantNaptown: I which I could buy 48v deep cycle batteries, but they are not sold in Indonesia. Yes, lots of labor and cables to make 48v banks.

You will not be using 48 volt batteries. You will be using 2 , 4 or 6 volt batteries at the required AH capacity. There is no such thing as a 12 volt 21,000 AH battery. Largest capacity battery you can find is a 2 volt 4000 AH battery and it weighs 420 Kg for a single battery. If you buy 24 of them to make a 48 volt system is 48 volts @ 4000 Ah or 192 Kwh which is short of your objective of 252 Kwh.

At 252 Kwh the lowest voltage you can run is a 60 volt battery @ 4000 AH, which is still IGNORANT, That would take 30-2 volt 4000 AH cells weighing some 12,600 Kg or 27,778 pounds, requiring 400 amps of charge current. The real solution is to use 516 volt batteries @ 500 AH using 86-6 volt 500 AH batteries. That will get you down to a manageable 50 amp charge current that does not explode or cost a fortune. Industry also makes real nice 3-Phase inverters with 500 volt DC input. You gotta a lot to learn before you kill or injure someone.

[Bali88]

What do you have against creating 48v banks with 4 12v batteries and run them parallel (yes with buss bar)? Or 60v banks with 12v bats. (not ideal, but in Indonesia they only make 6 and 12v batteries)

Three strings, each with 9 or 10 48v banks. Each string attached to a SMA Sunny Island 5048

[Fatawan]

Bali

I think you should inquire at www.corvus-energy.com The cost is high, but it would simplify everything you are trying to do. I read that it is $1,100/kWh, but there is no maintenance, 20 year life, you can draw it down fully, has BMS, etc. It might be worth the extra expense.

I joined to see if anyone has any experience with these Corvus batteries in a solar storage system. I couldn't find anything in a search online

[inetdog]

Bali

I think you should inquire at www.corvus-energy.com The cost is high, but it would simplify everything you are trying to do. I read that it is $1,100/kWh, but there is no maintenance, 20 year life, you can draw it down fully, has BMS, etc. It might be worth the extra expense.

I joined to see if anyone has any experience with these Corvus batteries in a solar storage system. I couldn't find anything in a search online

No experience to report, but just for clarification the earlier discussion was on LiFePO4 batteries, Corvus are Lithium/ Nickel-Manganese-Cobalt (NMC). That has a significantly higher energy density than Lithium/ IronPhosphate chemistry, but it is not as inherently safe and has a shorter life span. (2000 cycles to 80% DOD is still pretty good!) (Reference: http://www.dowkokam.com/resources/Ce...Info_Sheet.pdf, you will have to register to view or download). What Corvus does is package the DowKokam cells with a complete integrated BMS to deliver an industrial grade package.

I am not sure whether this level of energy density is suitable for a home system, based on operator training, battery location, etc. But it sure does look interesting.

The Corvus website does indicate Solar PV as a suggested use for (some of?) their products.

[russ]

Bali

I think you should inquire at www.corvus-energy.com The cost is high, but it would simplify everything you are trying to do. I read that it is $1,100/kWh, but there is no maintenance, 20 year life, you can draw it down fully, has BMS, etc. It might be worth the extra expense.

I joined to see if anyone has any experience with these Corvus batteries in a solar storage system. I couldn't find anything in a search online

Let someone else be the tester - after a few years when the bugs are worked out one will know whether or not to buy them.

[Fatawan]

I am not sure whether this level of energy density is suitable for a home system, based on operator training, battery location, etc. But it sure does look interesting.

The Corvus website does indicate Solar PV as a suggested use for (some of?) their products.

Can you expand on that first sentence? Why would it not be suitable for a home system? I was imagining a 25kWh-ish system to be used as a sink for solar PV, backup power, electric vehicle charging, etc.

[inetdog]

Can you expand on that first sentence? Why would it not be suitable for a home system? I was imagining a 25kWh-ish system to be used as a sink for solar PV, backup power, electric vehicle charging, etc.

My main concern is that for industrial use, the system will (presumably) be designed, specified, etc. by a professional engineer, the location will be selected based on the risk factors and environmental conditions appropriate to the energy density of the batteries and (nominally) trained operators will be responsible for the maintenance and monitoring of the system. I am not under any illusion that a responsible private system operator could not do just as well, but the dangers involved in not addressing all of these concerns, with that kind of energy storage, is high.

That large an FLA or AGM system is pretty well understood, and the risks of thermal runaway, short circuits, etc. are well known.
The Corvus system is more of an unknown at this point.