inverter only puts out 91 volts

[dlnelsonroca]

So, what do you all think about the another part of my previous post:

"So how many similar panels and batteries will I need to generate an average of 5 and 6 kwh daily at my latitude of 15°56'49.85"N and 97°20'59.18"W just a few hundred yards from the Pacific Ocean, and with an almost perfect east/west orientation? I ask for both 5 and 6 kwh a day because my budget is tight, and so I'll have to weigh the options."

"A lot depends on what season of the year you need to be assured of that much power (even at your low lattitude) . If you will need 5Kwh per day in midwinter, and allowing for cloudy days, you will need more panels. If you want to get 5Kwh per day averaged over the whole year or just during the summer, you may only need half as many."

"I need to know for the entire year since I live here year round. Where I have my house is flat, the nearest mountain being a few miles away. I have the panels mounted on a flat roof with a 15 degree inclination facing due south."

"We have sun all year long, but a definite rainy season during July through September. It usually rains hard every afternoon for an hour or two, and then the sun comes out again. There are usually a few times when it will rain less hard for two or three days without stopping. The lowest temperature on this coast is 70 degrees at night, rising into the 80s or 90s every day, winter or not."

Thanks again!

[inetdog]

I need to know for the entire year since I live here year round. Where I have my house is flat, the nearest mountain being a few miles away. I have the panels mounted on a flat roof with a 15 degree inclination facing due south. Should I mount them flat then?

No. I was just concerned that your mention of East-West orientation meant that you were going to mount the panels on an already more steeply pitched roof facing east or west.
That part of your setup will be just fine.

[dlnelsonroca]

I need to know for the entire year since I live here year round. Where I have my house is flat, the nearest mountain being a few miles away. I have the panels mounted on a flat roof with a 15 degree inclination facing due south. Should I mount them flat then?

We have sun all year long, but a definite rainy season during July through September. It usually rains hard every afternoon for an hour or two, and then the sun comes out again. There are usually a few times when it will rain less hard for two or three days without stopping. The lowest temperature on this coast is 70 degrees at night, rising into the 80s or 90s every day, winter or not.

[inetdog]

W

So how many similar panels and batteries will I need to generate an average of 5 and 6 kwh daily at my latitude of 15°56'49.85"N and 97°20'59.18"W just a few hundred yards from the Pacific Ocean, and with an almost perfect east/west orientation? I ask for both 5 and 6 kwh a day because my budget is tight, and so I'll have to weigh the options.

Thanks you again in advance!

A lot depends on what season of the year you need to be assured of that much power (even at your low lattitude) . If you will need 5Kwh per day in midwinter, and allowing for cloudy days, you will need more panels. If you want to get 5Kwh per day averaged over the whole year or just during the summer, you may only need half as many.

The east-west orientation is also going to hurt you if the mounting surface is sloped. Less of an effect it the panels can be mounted flat.

So, a little more information please.

[dlnelsonroca]

Wow, thanks. So I'll remove some electrolyte and add the special water I have for batteries until I get the hydrometer readings where they should be. I won't be able to get a better hydrometer for some months because of my location, but I'll get one.

So how many similar panels and batteries will I need to generate an average of 5 and 6 kwh daily at my latitude of 15°56'49.85"N and 97°20'59.18"W just a few hundred yards from the Pacific Ocean, and with an almost perfect east/west orientation? I ask for both 5 and 6 kwh a day because my budget is tight, and so I'll have to weigh the options.

Thanks you again in advance!

[Sunking]

I was told when I bought the system that the eight panels and four batteries should deliver an average of 6 kwh daily. Is that incorrect?

No I do not think so. For 6 Kwh of usable power your battery needs a capacity of 30 Kwh. Your batteries have a capacity of 14.4 Kwh. There is no way your 1000 watt panel array can generate 6 Kwh/day

My hydrometer is one I bought at Autozone, is about a foot long glass tube with a weighted float in it, and has a green area (1.275 - 1.3), and two other colors indicating lesser readings.

The readings this morning before dawn were:
1 - 1.3
2 - 1.3
3 - 1.3
4 - 1.275
5 - 1.3
6 - 1.3
7 - 1.3
8 - 1.275
9 - 1.275
10 - 1.3
11 - 1.275
12 - 1.275

A few weeks ago I removed some liquid and then added electrolyte to all the cells because they were reading below 1.225, I assume from being practically discharged several times, after which they were only charging during the day to 80%, and at night 10%. Since I added electrolyte the levels have been pretty much the same as above, charging each day to 100% with the morning charge levels written above.

You should not have done that. You also need to get rid of that Autozone hydrometer and get a good hydrometer. You SPG indicate cells 4, 8, 9, 11, and 12 indicate 100% charged. The others are severely overcharged which is likely caused from you removing and replacing electrolyte.

[inetdog]

A few weeks ago I removed some liquid and then added electrolyte to all the cells because they were reading below 1.225, I assume from being practically discharged several times, after which they were only charging during the day to 80%, and at night 10%. Since I added electrolyte the levels have been pretty much the same as above, charging each day to 100% with the morning charge levels written above.

Thanks again! I look forward to getting this issue solved!

Unless you know exactly what you are doing, you should only be adding distilled water to the batteries, never sulfuric acid electrolyte.
If the SG does not go to the level of a new fully charged battery it is usually an indication that some of the sulphur is tied in the form of sulphate clinging to the plates. Increasing the SG by adding acid will give you a false sense of battery health and will distort what would otherwise be a good diagnostic indicator.

Also, if you bring up the SG while the battery is still able to accept charge (even slowly) you run the risk of the SG going too high and causing other problems like plate erosion and increased self-discharge.

The only time you are justified in adding electrolyte is if you know for sure that some was actually spilled rather than just "boiled" in the gassing stage of charging or equalization.

[dlnelsonroca]

Thanks for your help! The controller is a PWM, and the panels are sending the 26-28 volts, only showing 37-38 if I flip the breaker to the controller.

The 75% comes from the computer reading when I hook it up to the controller, which shows an state of battery charge evening percentage, 100%, and a morning percentage of 75%. That's without the refrigerator plugged in overnight. With the fridge it shows 25%, and sometimes lower in the morning. I haven't had the fridge hooked up for a week now.

I was told when I bought the system that the eight panels and four batteries should deliver an average of 6 kwh daily. Is that incorrect? Because my house should be using an average of a little under 4 kwh daily according to what I and the solar salesperson calculated.

My hydrometer is one I bought at Autozone, is about a foot long glass tube with a weighted float in it, and has a green area (1.275 - 1.3), and two other colors indicating lesser readings.

The readings this morning before dawn were:
1 - 1.3
2 - 1.3
3 - 1.3
4 - 1.275
5 - 1.3
6 - 1.3
7 - 1.3
8 - 1.275
9 - 1.275
10 - 1.3
11 - 1.275
12 - 1.275

A few weeks ago I removed some liquid and then added electrolyte to all the cells because they were reading below 1.225, I assume from being practically discharged several times, after which they were only charging during the day to 80%, and at night 10%. Since I added electrolyte the levels have been pretty much the same as above, charging each day to 100% with the morning charge levels written above.

Thanks again! I look forward to getting this issue solved!

[Sunking]

The panels are consistently producing between 37 and 38 volts, and charging the battery bank of four Surrette S-600, 6V, 600 Ah @ 100 hr for the 24 volt system.

Correct me if I am wrong but you did say you have a PWM controller correct? Assuming the batteries are demanding full current you had better not be seeing 37 to 38 volts from the panels. You should be seeing only about 26 to 28 volts or 1 volt higher than the batteries. Only time you would see 37 to 38 volts is after the batteries are fully charged up when the PWM controller duty cycle drops off.

Early in the day they are fully charged, according to the computer datalogger on the separate controller. But at night they go down often to 75%, and that's with almost no load during the night, sometimes one ceiling fan for a few hours, and no appliances plugged in. I've checked the electrolytes with a hydrometer, and they're staying between 12.25 and 12.75.

That is not possible to have a Specific Gravity of 12.25. Did you mean 1.225 to 1.275?

How do you determine they go down to 75% and what do you mean? 75% State of Charge or 75% DOD. The only way to determine the true state of charge is with a temperature corrected hydrometer reading.

In my house we only have ceiling fans which I run only one at a time for less than eight hours daily (BTW it's NEVER cold here), a fairly new refrigerator, advertised as being energy efficient (plugged into an outside source presently), LED lights, which are only on in the room that I'm in for maybe five hours daily, a cell phone plugged in, a gas oven plugged in for the spark that ignites the burners. I have a washer and gas dryer, also new, which I've rarely used and only in the late morning. With the refrigerator plugged in the remaining power by morning is usually at about 25% or less!

The system uses eight 135 watt Solarworld panels and the four batteries, with a pure sine wave 1500 watt inverter. Is the system sufficient? Or have I ruined my batteries? Or do I have an electricity drain somewhere? The datalogger (with the refrigerator not attached for several days) tells me, if I remember right, that I'm using an average of 80 amperehours daily, with an excess of 15-20.

Assuming you have everything wired correctly and your numbers are accurate, you should have more than enough capacity. 80 AH @ 24 volts is roughly 2 Kwh, and you have 1080 watts of panels using a PWM controller which means you need at least 4 sun hours per day of sun which is no problem with your location. I can only assume you are not interpretting the data correctly specifically your battery Specific Gravity. The battery SPG tells th etruth assuming you have a good hydrometer.

Try this late tonight or better first thing in the morning before the sun comes up. Measure the SPG in each cell and report back with Cell #:
1
2
3
4
5
6
7
8
9
10
11
12
Readings. Do not bother with voltages, we do not need to know them.

[dlnelsonroca]

are my batteries damaged?

It's been a while since I wrote, but I've been trying to figure out what's going on, and getting data. I appreciate your responses already, and hope to get it all sorted out before too long. There's no one anywhere near where I'm at that knows much about this!

The panels are consistently producing between 37 and 38 volts, and charging the battery bank of four Surrette S-600, 6V, 600 Ah @ 100 hr for the 24 volt system. Early in the day they are fully charged, according to the computer datalogger on the separate controller. But at night they go down often to 75%, and that's with almost no load during the night, sometimes one ceiling fan for a few hours, and no appliances plugged in. I've checked the electrolytes with a hydrometer, and they're staying between 12.25 and 12.75. I don't have access to a carbon pile load tester here. The batteries are less than a year old, although early on they did get discharged to less than 10% probably a dozen times.

In my house we only have ceiling fans which I run only one at a time for less than eight hours daily (BTW it's NEVER cold here), a fairly new refrigerator, advertised as being energy efficient (plugged into an outside source presently), LED lights, which are only on in the room that I'm in for maybe five hours daily, a cell phone plugged in, a gas oven plugged in for the spark that ignites the burners. I have a washer and gas dryer, also new, which I've rarely used and only in the late morning. With the refrigerator plugged in the remaining power by morning is usually at about 25% or less!

The system uses eight 135 watt Solarworld panels and the four batteries, with a pure sine wave 1500 watt inverter. Is the system sufficient? Or have I ruined my batteries? Or do I have an electricity drain somewhere? The datalogger (with the refrigerator not attached for several days) tells me, if I remember right, that I'm using an average of 80 amperehours daily, with an excess of 15-20.

This probably is unrelated, but the LED lights sometimes slightly flicker.

I greatly appreciate your well thought out answers and advice to my dilemma! Thanks again!

[inetdog]

The controller charges throughout the day (there's great sun here, with a good east/west orientation), and it tells me that at the end of the day the batteries are charged between 80% and 100%. But the charging indicator still registers that it's charging until the sun goes down. So I'm assuming that this means that the batteries don't really get fully charged. By bedtime the controller shows about 50% or less. Is that because of the PWM controller? And, if so, should I get an MPPT controller instead. Or does that indicate something else.

These results are from running a medium sized refrigerator, no more than eight LCD light bulbs, and an occasional ceiling fan for short periods of time. We have a few other small appliances, but we haven't run them in the house yet, it being very new still, actually just finished, and moving in today!

Thanks again for your help in figuring this out with me!

OK. Your Vmp for the pairs of panels in series is indeed supposed to be around 35 volts. They should produce about 6 amps each at MPP, for a total current of 18 amps for six or 24 amps for 8. An MPPT controller is not absolutely necessary for this configuration, but if you need every last bit of power, especially in cold weather, you could get as much as 20% more from the panels.

For a 24 volt system, your batteries should just be in series rather than series parallel, and you do not state how many Amp Hours each of the 6 volt batteries is. That will have an effect on how well the panels can charge the batteries. But if your CC show 50% every day, you are pulling more from the batteries than your panels can put back and you are in danger of ruining your batteries.

You need to determine just what your load wattage and times are!

[Sunking]

By bedtime the controller shows about 50% or less. Is that because of the PWM controller? And, if so, should I get an MPPT controller instead. Or does that indicate something else.

It means you have a serious problem if that is 50% State of Charge. You should be no lower than 80% by sunrise the next day. It means you do not have enough panel wattage, battery capacity, and/or both.

[dlnelsonroca]

the controller is PWM

Hi, again. Thanks for such a complete answer! I'm learning. I checked the documentation on the controller, and it's a PWM, Phocos CX40. I'll attach a drawing of how I wired the panels, plus a description of the panels. What I do know off hand is that there are eight panels of 130. I had seven, but bought another. I don't have documentation for the eighth panel, but it's either 130 or 135. The drawing shows six panels with an outline for the other two, which I installed. I haven't disconnected the solar array yet from the fuse box and controller to measure how much voltage they're producing presently, but before I dismounted and remounted them to waterproof the roof they're on, there were six, producing 35 volts total.

The controller charges throughout the day (there's great sun here, with a good east/west orientation), and it tells me that at the end of the day the batteries are charged between 80% and 100%. But the charging indicator still registers that it's charging until the sun goes down. So I'm assuming that this means that the batteries don't really get fully charged. By bedtime the controller shows about 50% or less. Is that because of the PWM controller? And, if so, should I get an MPPT controller instead. Or does that indicate something else.

These results are from running a medium sized refrigerator, no more than eight LCD light bulbs, and an occasional ceiling fan for short periods of time. We have a few other small appliances, but we haven't run them in the house yet, it being very new still, actually just finished, and moving in today!

Thanks again for your help in figuring this out with me!solar panel config.jpgsolar panel config.jpgSunmodule-offgrid-sw-130-135-140-poly-R6A.PDFsolar panel config.jpgSunmodule-offgrid-sw-130-135-140-poly-R6A.PDF

[inetdog]

Thanks for your previous help. I ended up returning the first inverter, and got a pure sine one, as suugested. Now the house voltage is at 110+. I may have a new problem, however.

I measure the DC voltage from the solar panels to a 30 amp fuse box that's between the panels and the controller, and it's measuring a little over 27 in full sunlight. I thought it should be more. I have eight 130 watt panels (four negative and four positive) wired in series for my 24 volt system. Shouldn't that produce substantially more voltage than it's producing before going to the controller?

Also I notice that the 30 amp fuse box, and the #8 gauge wires connecting the panels to the box and also the box to the controller are pretty hot to the touch.

Those are my clues and problems. Any input would be greatly appreciated. I live in southern Mexico in a small fishing village, and there aren't many solar power resources any where near by!

If you are using a Pulse Width Modulation (PWM) charge controller (built into your inverter-charger?), then the voltage you read at the panels will be at most a few volts a above the voltage that the batteries are holding at. If you want to check the voltage of your panels, you can measure the open circuit voltage (Voc) with the panels disconnected from the charger and compare it to the Voc specification for the panels. If you use a Maximum Power Point Tracking (MPPT) charge controller, then the voltage you measure at the panels will be the maximum power voltage (Vmp) of the panels while the batteries are capable of accepting the full output of the panels and then it will rise toward the Voc as the charge to the batteries tapers off.

An MPPT charge controller will get up to twice the power from that panels as a PWM controller will. But they cost a lot more, and if you have more than enough panel power to keep up with the drain on your batteries, it will be an unnecessary expense.
However, if as you get toward midwinter and the panel voltage gets higher while at the same time the available sunlight decreases, the extra power from an MPPT CC may make the difference between keeping your batteries charged and having them steadily drop.

Your description of your panel wiring (8, 4 negative and 4 positive, in series) does not quite make sense. Can you draw us a diagram and also include the specifications of the panels?
If your panels are really producing much more then than the 30+ volts it takes to charge the 24 volt batteries, then you are wasting a lot of power.

If you are taking 8 130 watt nominal 12 volt panels and wiring them in series-parallel, then you could be producing as much as 26 amps. If they are nominal 24 volt panels with Voc = 35 volts, then it could be as much as 34 amps. That will definitely heat up a 30 amp fuse, although it will not cause it to blow. Similarly, the #8 wire is on the small side for running both from the panels to the fuse box and from there to the charger.
For example, 20 feet of distance and two #8 copper wires will drop 1 volt at 34 amps.
This is considered on the limit (~5% power loss) for a solar installation.
If you use an MPPT controller, you will be able to put your panels in a series string (2, 3, or maybe even 4 panels in a string) and use much smaller wire or keep the #8 you have and get only 1/4 the voltage drop and 1/16 the power loss.

[dlnelsonroca]

switched to pure sine, fuse box hot, panel voltage may be low

Thanks for your previous help. I ended up returning the first inverter, and got a pure sine one, as suugested. Now the house voltage is at 110+. I may have a new problem, however.

I measure the DC voltage from the solar panels to a 30 amp fuse box that's between the panels and the controller, and it's measuring a little over 27 in full sunlight. I thought it should be more. I have eight 130 watt panels (four negative and four positive) wired in series for my 24 volt system. Shouldn't that produce substantially more voltage than it's producing before going to the controller?

Also I notice that the 30 amp fuse box, and the #8 gauge wires connecting the panels to the box and also the box to the controller are pretty hot to the touch.

Those are my clues and problems. Any input would be greatly appreciated. I live in southern Mexico in a small fishing village, and there aren't many solar power resources any where near by!