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Thread: inverter only puts out 91 volts

  1. #11
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    Quote Originally Posted by dlnelsonroca View Post
    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!
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

  2. #12

    Default 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!

  3. #13
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    Quote Originally Posted by dlnelsonroca View Post
    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.




    Quote Originally Posted by dlnelsonroca View Post
    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.

    Quote Originally Posted by dlnelsonroca View Post
    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.
    MSEE, PE

  4. #14

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    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!

  5. #15
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    Quote Originally Posted by dlnelsonroca View Post

    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.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

  6. #16
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    Quote Originally Posted by dlnelsonroca View Post
    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

    Quote Originally Posted by dlnelsonroca View Post
    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.
    MSEE, PE

  7. #17

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    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 1556'49.85"N and 9720'59.18"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!

  8. #18
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    Quote Originally Posted by dlnelsonroca View Post
    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 1556'49.85"N and 9720'59.18"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.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

  9. #19

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    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.

  10. #20
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    Quote Originally Posted by dlnelsonroca View Post
    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.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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