Shorted charge controller. Low reading now.

TazmanTazman Registered Users Posts: 14
I shorted my array at the 30 AMP SunForce charge controller. Before doing this I was getting 14.5 amps on a good day after shorting it fluctuated a bit then settled to 0.7 amps. I bought a new controller and now I get 0.4 amps under the same conditions. I've checked the diodes of the panels closest to the controller and it they seem fine. Any suggestions before I give the life history of my array?:D

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Shorted charge controller. Low reading now.

    This is why fuses were invented. :p

    Shorting the input side of a charge controller should not affect the controller; it should merely see this as '0 Volts' coming from the panels. Shorting the output of the controller could fry it. Shorts 'after' a fuse should fry the fuse and leave everything else intact.

    You need to check all the panels for output. If there's no fuse, a piece of wire or connector could be fried. There's always the possibility that a blocking diode has gone or a panel itself has been damaged.

    Check all panels for Voc to start with.
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Shorted charge controller. Low reading now.

    Wiring short? Shorting across panel should not hurt them.
  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    What will kill panels (and probably many charge controllers) is hooking them up to the batteries backwards... Even fuses may not protect from backwards connections to a battery bank.

    To check each panel--measure the open circuit voltage. Then set the meter to 10 amp full scale and measure the short circuit current through the meter (check Isc of panel and max current on meter). Note, Isc is pretty much porportional to the amount of sun light... Full noon time sun and clear sky--you will get close to Isc... clouds in sky, you may get 1/2 or less of Isc (that is normal).

    If the panels check out OK with this test, then there is a 90% chance the panels are OK and the problem is with the charge controller. (you can better test your panels by, correctly, connecting a "12 volt panel" to a 12 volt battery and measure the current--pass that test and the panels are 100% functional).

    And, always be careful with a meter set to measure current. NEVER PUT AMP METER ACROSS THE BATTERY TERMINALS. You will end up with lots of sparks and probably a smoked meter.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TazmanTazman Registered Users Posts: 14
    Thanks for the info BUT.

    Thanks for the info so far
    :confused:I've checked several panels for voltage and diode function. On the three I checked the diodes passed. Individually the panels produced 15-23 volts. When I reconnected the array I still get 15-23 volts at the array source. Where my Charge Controller is I get about 12 V which I expected due to the length of wire I need to run.
    I have not tried checking the amps at the panel.
    When checking the AMPS do I do that under load (connected to a battery?) or just across the + , - leads? I have several ampere meters that I could use, but don't really want to fry any.

    Can I check the current at the END of my download wires? Or should I do it at the download junction.
    :roll:Last: When is to much info to much on a site like this?

    Cheers
    Brian
  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    Solar panels are pretty much matched by the physics... If you have three panels in the same sunlight--Voc should be much closer than 15-23 volts... The low value panels are suspect.

    With the panel unconnected to anything else--Check the Isc of the panel and connect an amp meter with Max AMP > Isc (generally we just use the 10 amp scale). They will not be damaged by shorting with an amp meter...

    If you are worried that you connect the expensive mechanical amp meter correctly... Cover the panel first, connect the meter, and expose to sunlight slowly...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Thanks for the info BUT.
    Tazman wrote: »
    Thanks for the info so far
    :confused:I've checked several panels for voltage and diode function. On the three I checked the diodes passed. Individually the panels produced 15-23 volts. When I reconnected the array I still get 15-23 volts at the array source. Where my Charge Controller is I get about 12 V which I expected due to the length of wire I need to run.

    Well there's one problem; if you've got 23 Volts going in to the downlead and only 12 coming out at the charge controller it's going to be impossible to charge a 12 Volt battery. This is called "too much line loss" and is usually caused by undersized wires or sometimes incredibly long distances. Also, a variance of 15-23 Volts at the panels is suspect. Are they giving different results at the same time? Got shadows?
    I have not tried checking the amps at the panel.
    When checking the AMPS do I do that under load (connected to a battery?) or just across the + , - leads? I have several ampere meters that I could use, but don't really want to fry any.

    I think Bill explained this? You need an Ammeter that will read for your panel's max current output. Disconnect from everything else, and check across each panel's leads.
    Can I check the current at the END of my download wires? Or should I do it at the download junction.

    To diagnose problems, you often have to check each component individually. If the output of each panel is within specs at its output, then you 'move on down the line' and see where things start falling out of spec.
    :roll:Last: When is to much info to much on a site like this?

    Cheers
    Brian

    When we start discussing the operation of electronic equipment in terms of sub-atomic particle inter-action at the quantum level. :p
  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    Or when your significant other comes in and starts kicking your ankles for being on the computer too long ... ouch, ouch...
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    Thanks
    The 12 - 25 v was what my multimeter bounced arround. The "steady" V was 23 V.
    I try the multimeter test tomorrow.
    RE: The sig other, she's on her own computer.
  • TazmanTazman Registered Users Posts: 14
    Re: Thanks for the info BUT.

    Thank you
    I am running about 30ft of #10. Can I double strand this to improve? I have no local source of #8, #4, etc at a reasonable cost.
    I guess I need to reduce to my basics.
  • mike95490mike95490 Solar Expert Posts: 8,377 ✭✭✭✭✭
    Re: Thanks for the info BUT.
    Tazman wrote: »
    Thank you
    I am running about 30ft of #10. Can I double strand this to improve?

    30' x2 = 60' run should be good for 20A with not too much loss, wire length/gauge is not the major problem. Maybe a bad connection somewhere.
    Powerfab top of pole PV mount | 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
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  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    It is not code--but you can. Two wires in parallel (same gauge) is the same resistance as a single wire that is 3 gauges "larger" (smaller number 2x #10 = ~ #7 awg).

    At this point--I would be looking at the other problems first (bad panels, bad connections, etc.) and at the overall system design/needs before pulling new wiring.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    OKAY. So I got a new charge controller, tested all the connections and panels.
    When I check the voltage (I think its called open) across the leads going into my charge controller I get 20.4 volts and about 20amps (good day). As soon as I connect to the battery bank the volts drop to about 3 volts. The current remains the same. The Sunforce controller has a LCD screen and it just shows about 0.6 amp. My Cenco large scale 25 ammeter still shows about 20 amps.
    I am wondering if my batteries are the problem. But before I dismantle the covering I have on them I wanted some suggestions.:blush:
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Shorted charge controller. Low reading now.

    :confused: You get 20 Amps where?

    You don't get any Amps without a load on the Voltage.

    The only place you should be reading 20 Amps is from the charge controller to the batteries when there's sun on the panels.

    Something's not right, that's for sure.
  • PhotowhitPhotowhit Solar Expert Posts: 4,996 ✭✭✭✭
    Re: Shorted charge controller. Low reading now.
    Tazman wrote: »
    I get 20.4 volts and about 20amps (good day). As soon as I connect to the battery bank ...

    Did you read the instructions on setting up your charge controller? Usually they want you to hook up the battery bank first.

    What voltage does the battery bank read before you hook it up?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • RoloRolo Registered Users Posts: 11
    Re: Shorted charge controller. Low reading now.

    Did you check the connectors (MC4) for oxidation or dirt giving you a bad connection?
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    Battery voltage is 12.0 V. when connected to charge controller. All connectors have been cleaned retinned and checked. My open circuit voltage right before the charge controller is 20.1 V. Current between 15 and 25 amps (using a 25 amp DC meter). As soon as I connect the controller (in the correct order) voltage drops to 12.3 and current to 0.6 amps as shown on the controller.
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    I saw a site that suggested grouping batteries in 4 (parallel) then attaching each group to the inverter. Can I connect each group of four batteries to my controller output?
    Where should I attach the out to batteries from my controller.
  • tvengineertvengineer Solar Expert Posts: 31
    Re: Shorted charge controller. Low reading now.
    Tazman wrote: »
    Battery voltage is 12.0 V. when connected to charge controller. All connectors have been cleaned retinned and checked. My open circuit voltage right before the charge controller is 20.1 V. Current between 15 and 25 amps (using a 25 amp DC meter). As soon as I connect the controller (in the correct order) voltage drops to 12.3 and current to 0.6 amps as shown on the controller.

    Hate to say it.. but it is starting to sound like your batteries are already charged and the controller is doing what it is supposed to and limiting the current???
    Does the current go up if you put a load on the battery???
  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    No--it sounds like the battery needs charging. The controller should pull the battery up to ~13.5-14.5 volts--depending on a lot of things.

    Ether the charge controller is not passing current, or the circuitry measuring current/voltage is not working correctly. Either case, sounds like the controller is in need of serious help.

    Check the voltage on the panel side when charging--I believe the Sunforce is a PWM controller--so if it is working correctly, the Vpanel input voltage should be within 1 volt of the Vbatt voltage (if battery is 12.3, then the Vpanel would be 12.3-13.3 volts or so if the controller is trying to charge the battery bank).

    You could have a high resistance open circuit in one or more of your panels... They read Voc (21 volts) when connected to a DVM, and read near full Isc when connected to a amp meter (dead short)... Does not happen often, but is is possible for a part of a panel to to damaged such that it does not give full current and full voltage at the same time.

    To double check the panels, connect them directly to your 12 volt battery bank through your 25 amp meter and see what it reads (careful, don't reverse connections, should have a 30 amp fuse or so).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Shorted charge controller. Low reading now.

    Might be a good idea to check each battery individually (how many are there?) for SG & Voltage and see if there's a problem there like an 'open' cell.
  • GroserGroser Registered Users Posts: 10
    Re: Shorted charge controller. Low reading now.

    How do you have the panels wired? seperately or in parallel? I suggest you hook up one panel at a time. check your readings for each panel seperately. take a volt reading at the input side connector of the controler. then take a volt reading on the output side of the controler. write down the readings for each panel. Do you have the controler earth grounded? Are the panels earth grounded?
    good luck
    groser
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    I thought about that. My inverter shows load (led lights) as well as input (from battery) voltage (meter reading). No change. I'm going to go right back to the beginning and connect one panel to my controller to one battery to a small load, then increase my panels a section at a time. Then I'll add a battery at a time. Hopefully I will find the fault.
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.

    Twelve. I used to have a hydrometer but over the years found no use for it. Can I assume if the levels are up and the battery is putting out 12 V that it is okay?
  • TazmanTazman Registered Users Posts: 14
    Re: Shorted charge controller. Low reading now.
    BB. wrote: »
    No--it sounds like the battery needs charging. The controller should pull the battery up to ~13.5-14.5 volts--depending on a lot of things.

    Ether the charge controller is not passing current, or the circuitry measuring current/voltage is not working correctly. Either case, sounds like the controller is in need of serious help.

    Check the voltage on the panel side when charging--I believe the Sunforce is a PWM controller--so if it is working correctly, the Vpanel input voltage should be within 1 volt of the Vbatt voltage (if battery is 12.3, then the Vpanel would be 12.3-13.3 volts or so if the controller is trying to charge the battery bank).

    You could have a high resistance open circuit in one or more of your panels... They read Voc (21 volts) when connected to a DVM, and read near full Isc when connected to a amp meter (dead short)... Does not happen often, but is is possible for a part of a panel to to damaged such that it does not give full current and full voltage at the same time.

    To double check the panels, connect them directly to your 12 volt battery bank through your 25 amp meter and see what it reads (careful, don't reverse connections, should have a 30 amp fuse or so).

    -Bill
    BB
    Let me get this right the first time. (I do have my panels wired in parallel into a junction box with a 30 amp breaker then down to my contrtoller.) From the breaker box run the neg side to the battery(s) and the positive through my mechanical 25 amp meter then to the pos on the battery?
  • BB.BB. Super Moderators, Administrators Posts: 29,511 admin
    Re: Shorted charge controller. Low reading now.

    Yes, you want the +18-21 volts of the panels connected to the +12 volts of the batteries... And the neg panel to neg of battery. Just like you where going to parallel two 12 volt batteries together.

    Solar panels can be connected to lower voltage battery banks without any problem (in fact, you can put a dead short on a solar panel too).

    If you connect + panel to - negative of battery--you will be needing new panels. It would be like hooking two 12 volt batteries together + to - ... Nothing good.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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