Tweet
Hey folks, Having a bit of trouble with my standalone system, maybe I can get some good feedback from here. my system consists of 6, 215 watt panels wired in series. this goes to an outback charge controller.Mod MX-60 MPPT. then to 8, 6v batteries wired to send 48vdc to an Outback Inverter Mod# FXR3048A. The panels are new and the Inverter is new the charge controller is 11+ years old. the batteries I installed 1 year ago. We upgraded the system in May and it worked for a month or so then I started getting strange readings from controller digital readout. I am getting 78 vdc to the input at the controller but nothing going to the batteries. It goes like this. The controller readout reads "wakeup" then goes to "sweeping" mode when it goes to sweeping the in voltage drops to 59vdc then it goes to "MPPT" the vdc stays at 59v for a min or 2 then back to "sleeping" mode and the in voltage goes back to 77vdc. Sometimes during the MPPT mode it will show a couple amps out but only lasts for a few min then cycles back to sweeping and goes through the cycle again. It does this every 5 min or so. It will show "low Light" sometimes during peak sun conditions and start the cycle all over again with no charge going out. If I am missing some info let me know and I will get it. The contractor that did the upgrade sent a tech to try to find the problem but could not nail it down(new guy to the business) but he was leaning towards the controller.
-
-
when you reinitialized the charge controller, did you connect the batteries before you connected the array? what is the SOC of this battery bank? -
So what is the problem? You burned up your controller. You got exactly what you asked for.
A 215 watt panel has a Voc of roughly 40 to 50 volts. With 6 panels wired in series is going to have a Voc of 240 to 300 volts. Your controller is limited to 150 Voc. You burned it up with improperly configured panels. .
Easy to fix, buy a good MPPT controler with at least 150 Voc input, and reconfigure your panels to 2 x 3.Last edited by Sunking; 08-02-2016, 10:50 PM.MSEE, PEComment
-
> 6, 215 watt panels wired in series
What sunking said.
Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-ListerComment
-
Thank you sunking, I was waiting to hear from you, seems like you know your stuff. I mistakenly omitted a bit of info in my original post. the modules are set up in 2 runs of 3 wired series then they go to the combiner box. at the charge control I have voc of 125-130. I am going to learn some things with you guys. I will do more test when I get back to it today.Comment
-
Could it be a bad (high resistance) connection that is limiting the current coming from the combiner box to the controller?
Can you measure the short circuit current from the panels at the controller?
SimonOff-Grid LFP(LiFePO4) system since April 2013Comment
-
You are welcome, but that was an important omission and changes everything..
OK sounds like you have a way to measure voltage, can you measure current?
Previously you said you measured 77 volts at the input of the controller which would normally indicate you have current flowing. If there were no current flowing you would see Voc of the 3 panels in series of 120 Voc. That voltage is telling you the Controller is doing something because it is taking current from the panels. Question is where is it going.
Does your controller feel warm or hot to touch? 77 volts sounds like a Vmp voltage of 3 panels in series witth a Vmp of roughly 25 volts each.
OK there are a few things you can do to isolate the problem.
First is the painful question. Are the batteries taking and giving a charge? I have to ask because what you are describing could be a battery problem. Easiest way to tell is measure the battery voltage under a heavy load. Simple to do measure the battery voltage on the battery term post with everything turned on. If the batteries are good and charged up, the lights in the house will stay bright and you should not see a lot of voltage sag. Example with everything off after sunset you should see roughly 50 volts on the batteries. Turn all the lights and gizmos on, you should only see the battery voltage drop a volt or two under load if they are good and charged up. Hopefully you have a generator and keeping your batteries charged up.
If the batteries are OK, most likely you have a bad controller. Way to prove this is with an Isc test of the panels. This is where you need to be able to measure current. Before I tell you how, convince me you can do this and have the equipment. You will need to be able to measure up to 20 amps DC. Otherwise get your contractor to do the Isc test. It has to be done around noon time on a bright sunny day.
Hopefully you see where this is going. Isolate and Eliminate the sub systems. First is test batteries, second Panels, third Controller. Cross your fingers it is not batteries. From what I gathered I suspect the controller or possibly batteries. Remote chance it could be a panel problem. When it is a panel problem usually voltages are way to low. Normally panel voltages run from as low as battery voltage to Voc. With a MPPT controller as low as Vmp and up to Voc
FWIW if you do not have a genny to charge your batteries, bypass the controller and connect the panels directly to the batteries during the day. Hint that will test both panels and batteries. Without a controller you will need to watch voltage. When it reaches 57 to 58 volts, disconnect the panels. If that works, you know your Controller is the problem. DO NOT LEAVE th epanels connected after late afternoon. The panels will likely discharge the batteries when dark.Last edited by Sunking; 08-03-2016, 11:35 AM.MSEE, PEComment
-
Sunking, negative on the current measure, The controller does not feel warm and the fan does not come on. when everything was working good on the hot days the fan would run several times a day. I have a dial volt meter, my new digital multimeter is in my boss's office 70 miles away I will receive it maybe Saturday.Comment
-
Get your batteries on a generator and reread my last post. Also get a volt meter and connect panels directly to batteries. Read my last post again, I edited it. We are going to make you the Charge Controller. This is beginning to sound like a possible panel wiring problem.
When you disconnect the panels from the controller, be real careful. Just lift one wire off the controller. Then measure the voltage on the two wires from the panels. You should read Voc of around 120 volts. You really need to be able to measure current, but we can get around that by connecting the panels directly to the batteries.
Before you connect the panels to the batteries, measure the battery voltage. Should be around 48 to 51 volts. When you connect the panels the voltage should rise a little bit like a volt or so. As time passes and the batteries charge up, you should see the voltage creep upwards. When it gets to 57 to 58 volt range disconnect. Takeaway here if the voltage goes up with the panels connected tells you the panels are OK.
Here is what you DO NOT WANT TO SEE. Measure the battery voltage and it is low like 40 to 48 volts before you connect the panels. Then voltage jumps up to say 55 to 120 volts when you connect the panels after a short period of time, grab hold of your wallet and say Ouch! Bad batteries. I don't suspect that is the case with 1 year old batteries.
I still suspect the Controller, and second suspect is panel wiring problem. Hope for you it is a panel wiring problem as that is cheap to fix, but hardest to find. Your idiot Contractor should be able to find the problem in 5 minutes or less. Sorry you got a moron of a tech out there. Very first thing he should have done is a Isc test.Last edited by Sunking; 08-03-2016, 12:00 PM.MSEE, PEComment
-
Going away from system for a few days I'll repost when I get back, I'll have better test equipment when I get back. Sunking, by bypassing the controller is there a potential for damage as the panels voltage is higher than the batteries?
Comment
-
As I wrote in my first post it will charge sometimes. I left the cabin to talk to the canoeists coming by my station and when I come back it was charging, as much as 8 amps(charge controller reading) going to batteries, depending on sunlight to panels. The batteries were going up in charge and while I was typing this it stopped working with the batteries at 50.0v it went to sleep mode again. No settings have been changed as the controller is password protected and no one knows the #.Comment
-
Hmm. Either the batteries are charged and happy or you have a Ghost in the Works.
Sorry. Couldn't help myself being sarcastic.
Comment
-
Ok, Back to the solar system at the cabin. I got an ammeter when I came back into cabin. I was getting no amperage coming from the combiner box. The Voc was correct but no current. I checked all the connections in the combiner box and found a couple wires that were loose and one just not tight and pulled out of breaker. checked again and what you know I am getting amperage and am charging 8 amps to the batteries. but something is still wrong I should be making near 18 amps with 1290 watts of panels at peak sun. Back up on the roof I isolate each string and what you know one string is producing 7.5 amp and one string is at .5 amp. I disconnect the .5 string and am working on one string for now. I am making 8-9 amp in ppeak sun. I ran from the roof and drove 30 miles to call the contractor that did the upgrade to come and check their new panels or their wiring of the panels to find the problem. He arrived on Friday and found issues with one dead panel in the bad string. He is ordering a new one and will be in next week to replace it. We should be good to go after this. I am glad I got the clamp ammeter. Batteries tested perfect under load test. I pulled what remaining hair I had out over this issue and all had to do with loose wires and bad panel but without the ammeter would have been hard to find. Thanks for the help guys. I am a happy guy, Making power again and no Genny running in the background.Comment
-
Comment
Comment