BernieM
- 280
- 6
I have been working with solar in one form or another for over 40+ years. A lot of that high temperature steam power generation using concentrators, so that doesn't apply to this of course. But I moved into a shack (literally) about 3 years ago, where this is no power (and nowhere near here to get it if I did want grid power.) I started out here with about 400 watts in 40 watt solar panels, and 4 deep cycle RV type batteries (group 27.) Later I increased that to 1KW+ and barely survived a summer (using a generator a significant portion of every day during the heat of the day. Went through 3 of them!)
The system I have now isn't very pretty as it has had to be installed on a budget and in a hurry at times (getting up at the break of day and trying to get panels installed, wiring done, supports built, etc., before the sun made it impossible to work.) Of course all of it needs to be redone actually, because it was done in stages and done cheaply or whatever, and once up, hard to justify tearing it all down and redoing it all.
But it does work and most of the time works very well. Other than this battery issue from time to time, I am never without power, or too low on power to do what I want or need to do.
The voltage on the system when I checked the a/c output and read 2 volts a/c was 28.8v.
Didn't I mention that this inverter is low frequency? They use high frequency in inverters so that they can use smaller inductors. That makes them cheap. This one uses a huge torroid, so they don't need to jack up the frequency. They can work at the output line frequency. However, the ACTUAL frequency that this inverter works with, I do not know for sure. It is possible it is 120Hz. I will check again on the frequency, but I am pretty sure it was 60hz. Regarding the waveform, guess in my editing of the last post, I accidentally deleted the part where I said sine wave. It is a sine wave. A very clean, well shaped sine wave.
There is one thing that just thought of. One of the indications I get just prior to a failure in a battery, is that my inverter will start whining about being overvoltaged. It's overvoltage point is 30.5v. Even in cases where I set the max. charge voltage to be say 27.2 volts, even this low, when a battery is in the throes of dying, the inverter sounds off and I have to blow off some power fast from the array (run microwave a minute usually) or the inverter will fully shut down after 1 minute in this state.
The no load voltage of my panels is 21.8v (42.6v in series.)
When this happened, I had it figured that when the batteries are fully charged, with nowhere for power to be stored, that the voltage would rise faster (near instantaneous) than the PWM charge controller I was using would poll the voltage and be able to turn off power from the array, and this was the cause. If this is the problem or related to it, now I guess the question would be: is the inverter seeing higher than 30.5v caused by the failing battery, or are intermittent short peaks of voltages higher than 30.5v causing the battery to fail? Every time I have ever checked battery voltage with a meter however, unless I am equalizing the batteries, I never see a voltage more than the charge controller is set at. But then the meter does not respond instantly either. Perhaps I should look for it on the scope or get the old analog meter out! I actually figured that it might even be an idiosyncrasy of the inverter iteslf (haven't ruled this out either.)
Is there a way I can post a picture directly up here without having to post it somewhere else on the internet first? If so I can post some pictures.
The system I have now isn't very pretty as it has had to be installed on a budget and in a hurry at times (getting up at the break of day and trying to get panels installed, wiring done, supports built, etc., before the sun made it impossible to work.) Of course all of it needs to be redone actually, because it was done in stages and done cheaply or whatever, and once up, hard to justify tearing it all down and redoing it all.
But it does work and most of the time works very well. Other than this battery issue from time to time, I am never without power, or too low on power to do what I want or need to do.
The voltage on the system when I checked the a/c output and read 2 volts a/c was 28.8v.
Didn't I mention that this inverter is low frequency? They use high frequency in inverters so that they can use smaller inductors. That makes them cheap. This one uses a huge torroid, so they don't need to jack up the frequency. They can work at the output line frequency. However, the ACTUAL frequency that this inverter works with, I do not know for sure. It is possible it is 120Hz. I will check again on the frequency, but I am pretty sure it was 60hz. Regarding the waveform, guess in my editing of the last post, I accidentally deleted the part where I said sine wave. It is a sine wave. A very clean, well shaped sine wave.
There is one thing that just thought of. One of the indications I get just prior to a failure in a battery, is that my inverter will start whining about being overvoltaged. It's overvoltage point is 30.5v. Even in cases where I set the max. charge voltage to be say 27.2 volts, even this low, when a battery is in the throes of dying, the inverter sounds off and I have to blow off some power fast from the array (run microwave a minute usually) or the inverter will fully shut down after 1 minute in this state.
The no load voltage of my panels is 21.8v (42.6v in series.)
When this happened, I had it figured that when the batteries are fully charged, with nowhere for power to be stored, that the voltage would rise faster (near instantaneous) than the PWM charge controller I was using would poll the voltage and be able to turn off power from the array, and this was the cause. If this is the problem or related to it, now I guess the question would be: is the inverter seeing higher than 30.5v caused by the failing battery, or are intermittent short peaks of voltages higher than 30.5v causing the battery to fail? Every time I have ever checked battery voltage with a meter however, unless I am equalizing the batteries, I never see a voltage more than the charge controller is set at. But then the meter does not respond instantly either. Perhaps I should look for it on the scope or get the old analog meter out! I actually figured that it might even be an idiosyncrasy of the inverter iteslf (haven't ruled this out either.)
Is there a way I can post a picture directly up here without having to post it somewhere else on the internet first? If so I can post some pictures.