Need Help/Advice

[upnorth]

But the system as it currently sits is hooked up as 12V. Is it a danger having it hooked up as is with everything feeding into the one midnite 250 with a 12V system?
I am unable to change the orientation of the panels due to the ground mount system being fixed.

 

[Hedges]

I don't believe way over-paneled is any big deal for an MPPT controller.
Look at the power vs. voltage and current vs. voltage curve:

Photovoltaic (PV) - Electrical Calculations

myelectrical.com

With two series strings connected instead of one, rather than being at the peak of the curve it needs to be half way down. Voltage increases slightly, current falls to about half. Charge controller delivers same power as for one string, just operates at slightly higher voltage, around half way between Vmp and Voc.

Where the ground mount is located relative to the cabin, you don't want to tilt toward the West anyway, because it is shaded in late afternoon.
You might be able to tilt half for summer sun, half for winter. That's not nearly as large an angle as morning/afternoon, but maybe could increase output in winter.

 

[SolarQueen]

Midnite has said it is fine to leave them all on for now if you can't turn off the breaker.

As Hedges said, if you switch to one of the other Classics, you can't keep the panels wired at 5 in series. I'm pretty sure I gave a scenario a few pages back where you could keep it at 12V and use 3 Classic 150s, but you'd need to change it to strings of 2 or 3 to keep the input voltage low enough.

Have you been able to talk to your supplier yet? I'd love to know what they have to say.

 

[Ryang]

I would let solarqueen ring them. I think she wants to tear them a new one....

 

[SolarQueen]

I would let solarqueen ring them. I think she wants to tear them a new one....

Hell hath no fury like a queen looking at a bad design. Or something like that.

 

[HRTKD]

Hell hath no fury like a queen looking at a bad design. Or something like that.

It's good to be the Queen.

 

[GSXR1000]

Hell hath no fury like a queen looking at a bad design. Or something like that.

sadly it wasn't even close ?

 

[upnorth]

Ok I have finally got things sorted with the supplier and he has agreed to exchange the 12V inverter for a 24V inverter. I will also be getting another Midnite 250 charge controller.

So I think the plan is to have 5 panels ran into one Midnite 250 charge controller and then the other 5 panels ran into the other Midnite 250 charge controller. I think I will also have to upgrade the breakers in the combiner box to 300 watt 15 amp breakers?? And then have the 4 batteries connected in series and then connected to the 24V inverter. Does this sound correct?? Thanks.

 

[Hedges]

You probably need to pull more wire from the panels to the charge controllers.
Breakers aren't needed on the PV side, but can function as a switch. (They also don't know watts, just amps and maximum voltage) If you already have two breakers, keep using them but no longer combine there output, just wire straight to two charge controllers.

You'll probably at a breaker between second charge controller and battery.

Of course you'll have to convince the original charge controller that 24V is correct, not over-voltage of a 12V battery. Not sure if you just disconnect PV and connect to new battery arrangement first, or maybe have to tell it explicitly.

 

[GSXR1000]

also an option

 

[SolarQueen]

Ok I have finally got things sorted with the supplier and he has agreed to exchange the 12V inverter for a 24V inverter. I will also be getting another Midnite 250 charge controller.

So I think the plan is to have 5 panels ran into one Midnite 250 charge controller and then the other 5 panels ran into the other Midnite 250 charge controller. I think I will also have to upgrade the breakers in the combiner box to 300 watt 15 amp breakers?? And then have the 4 batteries connected in series and then connected to the 24V inverter. Does this sound correct?? Thanks.

Darn, I was looking forward to going up there and giving them what for

That's great news. Yes, you need to swap out the 150V breakers for 300V (not watt, I'm guessing that was a mistake). You'll have to bring a little hack saw blade or a dremel tool to cut the plastic face to allow 2 double breakers, not a big deal unless you have no way to cut it. Even then, you can just leave the face off if needed. You'll need to bring another positive lead back from the combiner box to the second charge controller. They can both share the negative wire that is already there. Four 6V batteries in series will give you 24V. Do you have a fuse or breaker for between the battery bank and inverter? For a 24V 3000W inverter, you only need a 175A or 200A.

 

[upnorth]

Well sorry to report that I am once again looking for advice from the experts on this site that have been super helpful in the past. I was supplied with a faulty design from the beginning of this process trying to get an off grid system set up at my cabin in Northern Saskatchewan. I rectified the design according to the advice from the experts on this site......SolarQueen, Hedges, GSXR1000, Digital Steve, and Steve_S just to name a few.

I had everything hooked up with a new electrician as per their advice. However there was some down time in the winter that the system wasn't working due to the initial poor design and as a result the batteries were just sitting in -30 Celcius(-22F). I have 4 Rolls 6v AGM batteries that I bought brand new in April, 2020 and paid over $2000 for all 4.

Now, according to the new electrician I have hooking the system up, all 4 batteries are completely toast and will not hold a charge!(after trying to cycle the batteries at least 10 times at a specialty battery shop and they would not stay up). He says they all need to be replaced.

Obviously I am super disappointed that I essentially through away $2 grand on these batteries and now have to replace them. My question to the experts on this site......is this possible that the batteries are completely useless after only 1 season of use??? Is there anything I can do??? I looked up the batteries on the Rolls site and they apparently have a 3 year replacement warranty but I would assume this doesn't apply as the batteries I guess froze due to the cold temps and faulty design??

Any help or advice would be very much appreciated!! Thank you in advance!

 

[John Frum]

faulty design

What was the fault with the design?

 

[HRTKD]

If the batteries weren't charged and the temperatures got low enough, that could have damaged them.

You could try to get them warrantied. You don't get what you don't ask for.

 

[upnorth]

I have very little knowledge regarding solar components and design. But the main fault with the design as I found out thru this site was there was 2 strings of 5 panels with a total of 3100 watts feeding into a midnite 150 charge controller. Also had the wrong inverter so had that changed over to a 24v inverter and had the batteries hooked up in series.

 

[John Frum]

I have very little knowledge regarding solar components and design. But the main fault with the design as I found out thru this site was there was 2 strings of 5 panels with a total of 3100 watts feeding into a midnite 150 charge controller. Also had the wrong inverter so had that changed over to a 24v inverter and had the batteries hooked up in series.

Nothing ^ jumps out as a battery killer.
I was expecting something like "low voltage disconnect inappropriately low or non-existent".

Like @HRTKD I think you should try the warranty route.