Help?we’re lost!

[Hedges]

Some inverters are batteries optional. They can power loads while the sun shines, but only if sufficient PV production, and that has to be sufficient for the much higher starting vs. running power.
Just having automotive starting or marine batteries attached would let it deliver full surge capability.
If low-voltage disconnect is set for about 80% or 90% SoC, it should avoid draining battery (but may turn back on as soon as voltage pops up under no load?) So try to set disconnect/reconnect voltages to get desired operation.

I think a big PV array and suitable inverter with small battery (hardly cycled) should work well for daytime loads.
I prefer not to have a large battery unless it is necessary to store power for when there isn't sun.
My usable kWh from battery is approximately 1 hour's PV production. (but they are deep cycle, and also sized for one night's consumption.)

 

[Jamasarah]

Can we see the pictures of your setup?
Did the installer use combiner box?

I will take a picture, and no combiner box? I got 4 more batteries and I’m shot, sonow we have 8 in series, pos to neg right?

It would have been better to start over, with higher Ah batteries. Four parallel strings are not optimal, but you have to work with what you got. What I would highly recommend is that you bring each and every string up to the same state of charge BEFORE you parallel them. This might take only 1-2 days.

Please pay close attention to the diagrams on the proper wiring of parallel battery strings. Even some well-meaning battery sites get that one wrong. Here is a link to a proper parallel connection.

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

Method 4 is the best configuration, that minimizes string to string variance. In the pic, they are showing four parallel 12V batteries. In your case, you just need to replace this image in your mind with the four strings of 24V batteries. The wiring will be the same.
View attachment 58199
You have way more panels than necessary to keep these batteries charged, but you will need a good way to monitor what is actually happening. You actually need 100ah X 4 strings X 25Vcharging X 0.125C X 1.175FF = 1472W of panels, so 4000W is far more than necessary. Do these batteries have screw-caps for each cell? If so, invest in a battery hydrometer like this one.

East Penn Deka Temperature Correcting Battery Hydrometer #00231 | eBay

Find many great new & used options and get the best deals for East Penn Deka Temperature Correcting Battery Hydrometer #00231 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

It's the gold standard to measuring a battery's true capacity. Note that it has a temperature correction bulb. The specific gravity of the acid changes with temperature, so you need to take the temperature of the acid into account to get the best readings. Here is a link to a specific gravity chart.

https://i.pinimg.com/originals/b0/6c/87/b06c87518eb3b825bc5d5ab4604f65b2.jpg

View attachment 58201
Assuming your batteries are 100Ah and you have four strings of them at 24V, then you have 100Ah X 4 strings X 24V =9600Wh of power. Assuming you never want to deplete the batteries past 50%, that gives you 4800Wh of power, or 4.8kWh. At my own cabin, I consume ~2.5-3.0 kWh of power per day just with lights, TV, and the frig running 24/7. If your consumption is equivelent, I'd expect a battery of your size to last you up to two days before getting to 50%. But, that assumes you are starting out with a FULLY charged battery.

That's going to be YOUR job. You'll need to monitor the voltage and SG closely till you get your system optimized. You may need to get into the unit settings and tweek the charge settings to get them optimized for your battery. Forget about the installer coming every day to perform tweeks on your system. Judging how your system was put together, I don't think your installer was the most qualified person you could have selected. So, you're just going to have to step in and make sure that it gets done right. Keep asking questions, and we all can try to help.

so we have connected 8 12v batteries in series, all charged evenly. Our panels are putting out approx 65v- 68

It would have been better to start over, with higher Ah batteries. Four parallel strings are not optimal, but you have to work with what you got. What I would highly recommend is that you bring each and every string up to the same state of charge BEFORE you parallel them. This might take only 1-2 days.

Please pay close attention to the diagrams on the proper wiring of parallel battery strings. Even some well-meaning battery sites get that one wrong. Here is a link to a proper parallel connection.

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

Method 4 is the best configuration, that minimizes string to string variance. In the pic, they are showing four parallel 12V batteries. In your case, you just need to replace this image in your mind with the four strings of 24V batteries. The wiring will be the same.
View attachment 58199
You have way more panels than necessary to keep these batteries charged, but you will need a good way to monitor what is actually happening. You actually need 100ah X 4 strings X 25Vcharging X 0.125C X 1.175FF = 1472W of panels, so 4000W is far more than necessary. Do these batteries have screw-caps for each cell? If so, invest in a battery hydrometer like this one.

East Penn Deka Temperature Correcting Battery Hydrometer #00231 | eBay

Find many great new & used options and get the best deals for East Penn Deka Temperature Correcting Battery Hydrometer #00231 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

It's the gold standard to measuring a battery's true capacity. Note that it has a temperature correction bulb. The specific gravity of the acid changes with temperature, so you need to take the temperature of the acid into account to get the best readings. Here is a link to a specific gravity chart.

https://i.pinimg.com/originals/b0/6c/87/b06c87518eb3b825bc5d5ab4604f65b2.jpg

View attachment 58201
Assuming your batteries are 100Ah and you have four strings of them at 24V, then you have 100Ah X 4 strings X 24V =9600Wh of power. Assuming you never want to deplete the batteries past 50%, that gives you 4800Wh of power, or 4.8kWh. At my own cabin, I consume ~2.5-3.0 kWh of power per day just with lights, TV, and the frig running 24/7. If your consumption is equivelent, I'd expect a battery of your size to last you up to two days before getting to 50%. But, that assumes you are starting out with a FULLY charged battery.

That's going to be YOUR job. You'll need to monitor the voltage and SG closely till you get your system optimized. You may need to get into the unit settings and tweek the charge settings to get them optimized for your battery. Forget about the installer coming every day to perform tweeks on your system. Judging how your system was put together, I don't think your installer was the most qualified person you could have selected. So, you're just going to have to step in and make sure that it gets done right. Keep asking questions, and we all can try to help.

 

[Jamasarah]

I will take a picture, and no combiner box? I got 4 more batteries and I’m shot, sonow we have 8 in series, pos to neg right?

so we have connected 8 12v batteries in series, all charged evenly. Our panels are putting out approx 65v- 68

I will take a picture, and no combiner box? I got 4 more batteries and I’m shot, sonow we have 8 in series, pos to neg right?

so we have connected 8 12v batteries in series, all charged evenly. Our panels are putting out approx 65v- 68

Before he followed your instructions, he wanted to see if maybe it was just not enough storage, so this is what he did. I got the 4 new batteries and he charged them to equal capacity, And they are hooked up together in series.
The MPP unit gave us a reading 65-69v coming out plugged in a couple of fans and it did fine, but when we turned on the skill saw...it shut down, with red fault light, with a code of 72 (current sharing). What does that mean?

 

[12VoltInstalls]

it shut down, with red fault light, with a code of 72 (current sharing). What does that mean

I don’t know what that means. I speculate that it means ‘overload current’ translated into broken English, or insufficient incoming amps. Universal motors are like a direct short for a split second on startup.

 

[Hedges]

I will take a picture, and no combiner box? I got 4 more batteries and I’m shot, sonow we have 8 in series, pos to neg right?

so we have connected 8 12v batteries in series, all charged evenly. Our panels are putting out approx 65v- 68

!!!

If you had four, 12V batteries in series that was nominally 48V. Maybe 42V low-battery disconnect and 60V charging.

If you get four more and connect eight, 12V batteries in series you have 96V nominal it it will probably burn up all the electronics.

They would need to be connected as a second group of four, 12V batteries in series, then that in parallel with the first set.
"4s2p"

 

[Bud Martin]

!!!

If you had four, 12V batteries in series that was nominally 48V. Maybe 42V low-battery disconnect and 60V charging.

If you get four more and connect eight, 12V batteries in series you have 96V nominal it it will probably burn up all the electronics.

They would need to be connected as a second group of four, 12V batteries in series, then that in parallel with the first set.
"4s2p"

It does not make sense at this point to me either, may be she is not using the correct terminology, pictures of the setup will surely help for sure.

 

[Jamasarah]

It does not make sense at this point to me either, may be she is not using the correct terminology, pictures of the setup will surely help for sure.

I will send pictures, but partner got the diagram off line on how to do it, and took a reading (50.4), before he turned it on, which ran fine, till he ran the saw, and then we got the alert, and shut down?‍
I believe he said the low voltage is set at 54v?but I’m not sure, going out now to take a picture.?

 

[Jamasarah]

Some inverters are batteries optional. They can power loads while the sun shines, but only if sufficient PV production, and that has to be sufficient for the much higher starting vs. running power.
Just having automotive starting or marine batteries attached would let it deliver full surge capability.
If low-voltage disconnect is set for about 80% or 90% SoC, it should avoid draining battery (but may turn back on as soon as voltage pops up under no load?) So try to set disconnect/reconnect voltages to get desired operation.

I think a big PV array and suitable inverter with small battery (hardly cycled) should work well for daytime loads.
I prefer not to have a large battery unless it is necessary to store power for when there isn't sun.
My usable kWh from battery is approximately 1 hour's PV production. (but they are deep cycle, and also sized for one night's consumption.)

Yes, I ran the fans TV and the Internet till 10 o’clock last night and I checked the battery setting on the readout and it was still fully charged, after three hours of use
I think it’s in the settings somewhere because he’s checked everything he did and rechecked everything he did and it’s all set up correctly but I’m still gonna go take a picture of it.
He is going to redo his cables and make them sano, As soon as we get it running correctly, and don’t have to change anything, anymore ?

 

[Jamasarah]

Yes, I ran the fans TV and the Internet till 10 o’clock last night and I checked the battery setting on the readout and it was still fully charged, after three hours of use
I think it’s in the settings somewhere because he’s checked everything he did and rechecked everything he did and it’s all set up correctly but I’m still gonna go take a picture of it.
He is going to redo his cables and make them sano, As soon as we get it running correctly, and don’t have to change anything, anymore ?

 

[Hedges]

Is that 8 awg for battery cables? Larger voltage drop at high current and not rated for very high maximum current. How long are the wires?
We would usually use 2/0

Pictures of battery bank would help.

 

[Jamasarah]

Hope you can see, it’s awful small

 

[Hedges]

I think I see the wires spliced and branched, probably is 48V as it should be.

I've heard that using the "accessory" stud on a starting battery isn't as good for high current as using the fat part of the battery terminal. More voltage drop at high current.

I would have used fatter cables. When you run a 2000W appliance, drawing about 40A which isn't terribly high even from one string of batteries. Now 4s2p, only 20A per battery. But starting surge could be a few times that, so voltage at inverter drops more. Fatter wires could be an improvement.

Limited run time off the batteries. 100 minutes reserve at 25A? That's fully discharging, not good for them. Figure maybe 15 minutes, then recharge.
Best if your PV can supply 1kW to 2kW.

Measure voltage drop from one battery terminal to the next while running a load. Also from last battery to inverter. See how much is lost.

 

[Jamasarah]

Is that 8 awg for battery cables? Larger voltage drop at high current and not rated for very high maximum current. How long are the wires?
We would usually use 2/0

Pictures of battery bank would help.

Battery cables r 4g, from battery to battery appox 8”long, and from the battery to the unit is about 2 feet, but will be less when we mount it all permanently ?

 

[Hedges]

Red wire for ground. With a splice covered in yellow tape.
I suggest at least using green tape at the ends to indicate it is ground. Better to have black wire with green tape, or green wire.

It goes to handle mounting screw. Was there a designated place for it?

 

[Jamasarah]

Is that 8 awg for battery cables? Larger voltage drop at high current and not rated for very high maximum current. How long are the wires?
We would usually use 2/0

Pictures of battery bank would help.

4g

Battery cables r 4g, the Panel wire running is the 8 awg

 

[Jamasarah]

Close, but our unit is 6000 48v,
Thank you for all your help, Greg is putting together the panel configuration you suggested, And download the table you suggested that he use.
We just are not getting enough voltage into our unit.

 

[MichaelK]

I may have caused some confusion in my last post because I was writing as if you had a 24V system. Sorry about that. The proper way to document it is to say you have two parallel strings of four 12V batteries to produce a 4S2P 48V battery bank.

Here's what the specifications of your unit state.

So, with two panels in series, and putting out ~60VDC, it is below the recommended lower limit of 90VDC. That's part of the problem. With 8 parallel strings each producing ~8amps at 60V, you are going to be way over the amperage limit of 18A per controller section. ~8A X 8 strings = ~64A total. One controller input circuit can only handle 18A. Even split between the two circuits, that would be ~32A each.

The first thing you should do is to re-wire the panels in a 4S4P configuration. Then, each parallel string of four panels will be putting out ~8A at 120VDC. There should be a combiner box with a 12A breaker for each of the four-panel strings. Configure your combiner so that strings 1 and 2 go into controller circuit 1, and strings 3 and 4 go into controller circuit 2. That way, each controller circuit will get no more than 16A at 120VDC. With a Midnight combiner you'd to that by taking a cut-off wheel and physically cutting the positive bussbar in half. The screw terminal on the left could be combined solar circuit #1 and the right could be combined circuit #2.

And yes, 4 gauge wire for battery connections is far too small. I agree with Hedges on using at least 2/0 gauge for the battery. If you re-organize the physical postions of your batteries in a U configuration, you'd use a lot less 2/0 wire than what you've got picted right now.

 

[Jamasarah]

I may have caused some confusion in my last post because I was writing as if you had a 24V system. Sorry about that. The proper way to document it is to say you have two parallel strings of four 12V batteries to produce a 4S2P 48V battery bank.

Here's what the specifications of your unit state.
View attachment 58584
So, with two panels in series, and putting out ~60VDC, it is below the recommended lower limit of 90VDC. That's part of the problem. With 8 parallel strings each producing ~8amps at 60V, you are going to be way over the amperage limit of 18A per controller section. ~8A X 6 strings = ~48A total. One controller input circuit can only handle 18A. Even split between the two circuits, that would be ~24A each.

The first thing you should do is to re-wire the panels in a 4S4P configuration. Then, each parallel string of four panels will be putting out ~8A at 120VDC. There should be a combiner box with a 12A breaker for each of the four-panel strings. Configure your combiner so that strings 1 and 2 go into controller circuit 1, and strings 3 and 4 go into controller circuit 2. That way, each controller circuit will get no more than 16A at 120VDC.

And yes, 4 gauge wire for battery connections is far too small. I agree with Hedges on using at least 2/0 gauge for the battery. If you re-organize the physical postions of your batteries in a U configuration, you'd use a lot less 2/0 wire than what you've got picted right now.

I certainly appreciate the clarification and we will be figuring out how to do it all it’ll take me a while I’m sure?this will really help?

 

[Jamasarah]

I certainly appreciate the clarification and we will be figuring out how to do it all it’ll take me a while I’m sure?this will really help?

Sorry that it’s taken so long to get to get back to you guys but we’ve been trying to figure everything out bought more batteries we now have eight. There are still a couple of questions we have:
Should we fuse each panel that we are setting up for strings in series parallel ( diagram attached ) and if so what size fuses and where to install them . We apologize for our short term memories and greatly appreciate everybody’s input. Thank you so much for All your help.???

 

[MisterSandals]

Should we fuse each panel that we are setting up for strings in series parallel

When you have 3 or more strings connected in parallel, each string (not each panel) needs to be fuse.
Your diagram shows 4 strings in parallel so you'd need 4 fuses.

I see there is a 4:1 parallel connector. I think they make some of them with built in fuses so that might be something that would simplify things.