2000k system only puts out 500 watt why?

[sensij]

Batteries are good but I am open to ideals at this point! I went with a off grid system because we get snowed in and lose power for a month at a time in winter. This is why it is so important for me to get this system backup and running correctly.

If this is really so important to you, I think you should take this opportunity to step back and really evaluate the system you've put together.

You said your batteries are 70 Ah AGM, maybe something like these. 70 Ah * 24 V * 50% DOD = 840 Wh of energy available. Yet, you are using a 6000 W inverter? That 70 Ah rating is a 20 hr discharge rating... 70 Ah/20 h = 3.5A * 24 V = 84 W. Discharging at even 1000 W continuously is way more than these batteries can handle.

What loads do you need to power in winter? How much energy per day? The performance problems you've been assigning to the panels could easily be a result of a battery that has been worn out.

[charles2,david000k]

I just don't understand why when we got done setting up we pulled 38 volts and 64 amps from the combiner box with the rest of the system disconnected and no one touched the system until after it had it's drop to 34 volts and 17 amps. I did the same test the same way unless there is some thing wrong with the panels or my meter. ok some new findings may be I pulled my meter apart and found three fuses inside two inuse and one extra fuse. Now I don't know if this is the correct way of doing this but I took my little back up meter and turned it to ohms and stuck the +- probes to the different side of the fuses after pulling them out and got nothing off the two that was in use but the back up fuse got a reading does this mean these fuses are blown and is why I am getting a bad reading?


brb going to google the fuse

I think I am going to replace the two fuses and put that meter away and get a clamp type meter. Then I will get back to you guys with the new reading I really hope it's the meter or the way I take the readings.

[charles2,david000k]

Solinoid? That is even worse than PWM

Nothing is wrong with your system, you just do not know how it works.

I just don't understand why when we got done setting up we pulled 38 volts and 64 amps from the combiner box with the rest of the system disconnected and no one touched the system until after it had it's drop to 34 volts and 17 amps. I did the same test the same way unless there is some thing wrong with the panels or my meter. ok some new findings may be I pulled my meter apart and found three fuses inside two inuse and one extra fuse. Now I don't know if this is the correct way of doing this but I took my little back up meter and turned it to ohms and stuck the +- probes to the different side of the fuses after pulling them out and got nothing off the two that was in use but the back up fuse got a reading does this mean these fuses are blown and is why I am getting a bad reading?


brb going to google the fuse

[Sunking]

How would you correctly test a single panel while pulling power from it? .

You don't. You have to use VOC and Imp test.

[Sunking]

Doesn't float require less current?

No sir. Float can draw full power aka full current.

[Sunking]

Solinoid? That is even worse than PWM

Nothing is wrong with your system, you just do not know how it works.

[charles2,david000k]

There are only two things you can test in the field without a lot of very expensive test equipment.
The first is open circuit voltage. test by disconnecting the panel from everything and test voltage under no load.
The second is to disconnect a panel and short the panel by connecting the + to- and reading the current with a clamp on amp meter.
Both are a bit tricky as the voltage will drop with higher cell temperatures and the amps will drop with insolation( how bright is the sun and at what angle is it to the panel) and the cell temperature.
The factors are both listed in the panel specs on the data sheet.
At minimum yu need a clamp on volt / amp meter and a pyronometer to verify insolation.

Can't do a pyronometer I just check real fast and it was $600 + used. I was thinking of a new meter though I am starting to think there might be something wrong with my Fluke probe meter I have now but don't know of any way to test the meter itself? It is old!! It was given to me by my dad but that man can break anything never knew anyone else that could roll a riding mower on flat ground I don't know how he does it but he can roll anything with wheels if you leave him alone.

[LETitROLL]

Now when I seen the retailer test the panels the directly probed the mc4 connector from the panel for voltage and then they connected positive + and negative - together and used a clamp type meter to test for current.

Now I don't really know a whole lot about solar just what I have picked up from other but I would think going positive to negative would cause power to build up in the panel and would not give a real reading of the panel under load.

P.s please feel free to correct me this is a learning experience for me.

Hooking the + to the - on the panel is a direct short circuit and that is how you test the short circuit current of a single panel (it wont harm the panel unlike a lot of other power sources). And you just check voltage with your meter lead + to panel + and - to panel - (sounds like retailer did it correctly) if you don't have a clamp on amp meter and your multimeter has 10A or higher dc amp setting you can use that by placing it inline in the short circuit (make sure to have meter set correctly or you can fry it)

[Naptown]

There are only two things you can test in the field without a lot of very expensive test equipment.
The first is open circuit voltage. test by disconnecting the panel from everything and test voltage under no load.
The second is to disconnect a panel and short the panel by connecting the + to- and reading the current with a clamp on amp meter.
Both are a bit tricky as the voltage will drop with higher cell temperatures and the amps will drop with insolation( how bright is the sun and at what angle is it to the panel) and the cell temperature.
The factors are both listed in the panel specs on the data sheet.
At minimum yu need a clamp on volt / amp meter and a pyronometer to verify insolation.

[charles2,david000k]

The controller appears to be an inexpensive model and not MPPT, so as someone else mentioned it cannot effectivly utilize any voltage above 28v in your current system.

How would you correctly test a single panel while pulling power from it?

I disconnect all the panels except one. The one I want to test and I put my meter probes into the other socket on the mc4 branch connector to test the volts and amps pulled by the charge controler to the batteries from one panel.

Now when I seen the retailer test the panels the directly probed the mc4 connector from the panel for voltage and then they connected positive + and negative - together and used a clamp type meter to test for current.

Now I don't really know a whole lot about solar just what I have picked up from other but I would think going positive to negative would cause power to build up in the panel and would not give a real reading of the panel under load.

P.s please feel free to correct me this is a learning experience for me.

[lkruper]

Switching to an MPPT CC will not necessarily help with Absorb stage, but it will give you a minimum of 50% more current during Bulk with no other changes.

Doesn't float require less current?

[inetdog]

Switching to an MPPT CC will not necessarily help with Absorb stage, but it will give you a minimum of 50% more current during Bulk with no other changes.

[LETitROLL]

The controller appears to be an inexpensive model and not MPPT, so as someone else mentioned it cannot effectivly utilize any voltage above 28v in your current system.

[LETitROLL]

What really had the second tech crew stumped was the first and second day they came out they got the same readings with completely different weather one day almost no light dark dark clouds almost like a cloudy night and the second day clear blue skies. That crew also mentioned the possibility of a voltage leak but were unable to find it.

If they were testing the panels under no load to see if they were within spec that seems normal. Solar panels are a current source (amps), the voltage usually varies only slightly under no/low load conditions, but can bog down and drop quite a bit if under heavy load for the amount of illumination it is receiving, the difference between cloudy and sunny will make the current (amps) vary greatly, but the voltage not so much.

[charles2,david000k]

OK, the picture you took is of a voltage triggered relay. From what I can see the 28 V under load you are getting is exactly what it is designed to do. Even if the panel voltage had degraded, it would have zero consequence in this system because it does not operate at the panel's maximum power point anyway.

You may be able to get some help here, but understand a couple things:

1) The system is really not very good, and was probably a waste of money.
2) The panels are probably perfectly healthy, and only your misunderstanding of how PV works is leading to your angst.
3) Your batteries are probably dead from mis-use.

If you can accept these three things as fact and still want to figure out how to move forward, we can start over and figure out what you should have bought to begin with.

Batteries are good but I am open to ideals at this point! I went with a off grid system because we get snowed in and lose power for a month at a time in winter. This is why it is so important for me to get this system backup and running correctly.