Solar system review

[Sunking]

I will definantly do that.

This is getting mighty expencive and frustrating just to run two little appliances that only draw 150watts each!

Education is expensive, especially trying to learn after you jump off the cliff. What you are going to learn is going off-grid battery will cost you on average 10 times more for the rest of your life vs just buying from the power company. Just think you get to replace your batteries in a few short years. So when you do upgrade to 24 or 48 volts and replace the inverter too.

[mikejh]

I will definantly do that.

This is getting mighty expencive and frustrating just to run two little appliances that only draw 150watts each!

[Mike90250]

remove flamable materials from around the inverter. The low voltage inverters, generally cant take the heat they create.
(I mentioned their heat issues earlier)

[mikejh]

I guess I am pretty stumpped... Any suggestions other than spending another $2,500 to boost the voltage?

[Sunking]

Its a bit late to find that out How manditory is it to use 24V or higher?

It is not mandatory, just foolish to use low voltage if you do not have too. You will end up burning off a lot of heat in your wiring you can never recover. It also made you installation and material cost a lot higher. In addition you will probable find you inverter tripping off when under heavy load when the voltage sags. In addition you increased your fire risk by 400%.

[mikejh]

Its a bit late to find that out How manditory is it to use 24V or higher?

[Sunking]

You are operating a 2000 watt inverter at 12 volts? Why? At minimum you want 24 volts and if you ever wanted to go higher wattage 48 volts.

[mikejh]

There sitting in my garage...

[Mike90250]

I didn't know you had already committed to the batteries

[mikejh]

the low input voltage shut down on the AIMs 2000 is 10V. There are more specs listed here:

http://www.theinverterstore.com/the-inverter-store-product.php?model=pwri200012s-top-rgb#

I am not sure I want to spend another $2,300 on batteries to bump it up to a 24V system. How much voltage loss will there be? (if still running 12V)

I just contacted AIMs and they reccomend the 200A fuse, and 1/0 wire for thier 2000watt inverter.

[Mike90250]

for the fuse, use the one suggested in the inverter's manual. Order it from the same place you order the inverter from.

1500W is 125A at 12V
My 300W sure sine can supply huge surges, I belive it recomened a 80 or 100a fuse for it.

This brings up the problem of 12V systems. The amp demand is generally too high for the battteries and wires. Any losses, even half a volt, will bring the inverter close to shutdown. You at least are using huge 2V batteries, which can supply the amps needed. But you still have the copper (ohmic) losses in the wire and inside the inverter to deal with.

A 24V system (use 4v batteries) will only consume half the amps, and needs only to rewire the PV and reset the controller. (unless you have a lot of 12V appliances tou need to run off 12VDC).

[mikejh]

Thank you for confirming the diagram. I will probably just get a large inverter, being that it will allow me to add a few thing if needed. It sounds like a 2000watt (3000watt peak) will work just fine.

Fuses usually say "use with so many watt inverters or less". Should I get a big one, or one that will bairly work? They are usually about 100A per thousand inverter watts. Does that sound about right?

Also, what size wire should I use to link my batteries?

[Mike90250]

Ok.

Here is what I have as far as wiring my batteries. Is this correct?

[ATTACH=CONFIG]1232[/ATTACH]

I am assuming that I will connect the charge controller to the same terminals as the inverter, right?

EDIT: these are all 2V batteries in series to make a 12V system.

Yes, this will work for a 12V system. An awfully large 12V system. You need a fuse as close to the + battery terminal as practical, the inverter manual will say what size fuse, and the wires need to be large enough that the fuse melts before the wires melt, in case of an accident.

Inverters vary in their surge capacity, and motors vary on their surge draw. Hard to forcast, some electricatians have a "Peak Read AC Amp meter" you could have them test your fridge, or buy the $200 meter to test it yourself.

[mikejh]

Add up the loads you expect to have on at one time. 300 + 200 + 20 + ??????
That gives your baseline. Are any of those loads a motor ? Any large loads expected to come on, while baseline loads are on ? If your inverter cannot handle the starting surge of a fridge, while the lights are on at night, the lights go off ! The inverter will often try to reset it'self and blink the lights a couple more times, while the fridge is also trying to start.
I'm running a farmhouse, with a 1/2 hp well pump, and my inverter is rated for 200% overload for 10 seconds (12 Kw) It's a 6Kw inverter on 48V, so far has been fine running the pumps and the shop tools.

You need to see what the inverter overload specs are. Morningstar has a 300w inverter ,with overload of 600w for 10 min. It generally is not enough to start a fridge though. They are all different.

That is interesting. I was told that I would need at least a 1500watt inverter just to start the compresor for the refrigerator. I guess it probably depends on the unit.

As far as linking my batteries in series, is the diagram I drew up correct?

Also, should I have a in-line fuse in addition to the fuse in the inverter?

[mikejh]

Ok.

Here is what I have as far as wiring my batteries. Is this correct?

Battery bank wiring.jpg

I am assuming that I will connect the charge controller to the same terminals as the inverter, right?

EDIT: these are all 2V batteries in series to make a 12V system.