Confused about 12v disconnect

[moonlitsouls]

Hope all is well

My solar charge controller is not pulling any amps , it lights up and clearly has power but no amps are being drawn from the solar panels , after review of the troubleshoot tips from the manufacturer, it was determined my first orders of business were to check the connections at the back of the solar charge controller


I started by pulling the 12v disconnect switch on the camper itself , it was my understanding this disconnects all 12v systems including the battery

I then unscrewed the solar charge controller from the wall mounted space and then proceeded to unplug the battery cables one and two, my intention was to inspect the connections

upon attempting to screw the positive battery wire back into the solar charge controller (this seemed loose so I started with that). I saw the solar charge controllers lights flicker and I hear a spark when I attempt to screw it back in correct

why am I seeing a spark at the charge controller when I disconnected the 12v battery system?

 

[Bob B]

While you are doing the troubleshooting .... it would be a good idea to install manual disconnects for the solar panels and batteries. That way you can check the wiring connections without power being applied.
Not sure what caused your sparks ... are there any "haired" out wires that may have caused a short?

 

[svetz]

My solar charge controller is not pulling any amps , it lights up and clearly has power but no amps are being drawn from the solar panels ,

Is the battery fully charged? If so, the SCC stops the current flow so they're not overcharged.

why am I seeing a spark at the charge controller when I disconnected the 12v battery system?

Most likely it's because when the SCC is disconnected the internal capacitors self-drain. When you make the connection there is a voltage difference causing a spark.

 

[moonlitsouls]

While you are doing the troubleshooting .... it would be a good idea to install manual disconnects for the solar panels and batteries. That way you can check the wiring connections without power being applied.
Not sure what caused your sparks ... are there any "haired" out wires that may have caused a short?

Is the battery fully charged? If so, the SCC stops the current flow so they're not overcharged.



Most likely it's because when the SCC is disconnected the internal capacitors self-drain. When you make the connection there is a voltage difference causing a spark.

my main concern is my safety while working on the equipment, i want to learn and teach myself , but i also feel a bit nervous around live wires because ive had a couple issues building my DIY Lithium battery that have deff gotten my attention

if i dont trust the 12v disconnect , im not sure how i can test the wires around me to make sure im not going to hurt myself

Maybe i can disconnect the batteries completely instead

 

[svetz]

...if i dont trust the 12v disconnect ...

I don't know about camper van disconnects, so take this with a grain of salt. In AC power, switches disconnect at 0 volts so no arc. DC is different - switches are specifically designed to minimize/eliminate arc because the voltage isn't 0 and current is flowing.

...my main concern is my safety while working on the equipment, i want to learn and teach myself , but i also feel a bit nervous around live wires ...

The way to avoid the spark when there is a voltage difference is to use a resistor to charge the capacitor before connecting the terminal. Will shows how to do it in some videos, although usually, he's demonstrating it on the battery to the inverter. Hope that helps!

 

[moonlitsouls]

the process of learning to work on these systems can be a bit frustrating, but im going to try not to let it get to me and keep pushing through until i understand it better.

 

[diyernh]

Hope all is well

My solar charge controller is not pulling any amps , it lights up and clearly has power but no amps are being drawn from the solar panels , after review of the troubleshoot tips from the manufacturer, it was determined my first orders of business were to check the connections at the back of the solar charge controller


I started by pulling the 12v disconnect switch on the camper itself , it was my understanding this disconnects all 12v systems including the battery

I then unscrewed the solar charge controller from the wall mounted space and then proceeded to unplug the battery cables one and two, my intention was to inspect the connections

upon attempting to screw the positive battery wire back into the solar charge controller (this seemed loose so I started with that). I saw the solar charge controllers lights flicker and I hear a spark when I attempt to screw it back in correct

why am I seeing a spark at the charge controller when I disconnected the 12v battery system?

Did you read your SCC manual? Most say to disconnect the solar panels first, then disconnect the battery from the SCC. The SCC may need the battery regulated power to run it's control circuitry. When you disconnect the battery first, the logic in the SCC could become confused and may dump the full solar voltage and amps into the battery.

Always disconnect your solar panels first. If you don't have a switch between the panels and the SCC, you can cover the panels with cardboard, or a tarp to block the sun. The battery has a lot of stored energy that can weld things together. The solar panels can supply higher voltages and a decent amperage to shock you.

 

[moonlitsouls]

Did you read your SCC manual? Most say to disconnect the solar panels first, then disconnect the battery from the SCC. The SCC may need the battery regulated power to run it's control circuitry. When you disconnect the battery first, the logic in the SCC could become confused and may dump the full solar voltage and amps into the battery.

Always disconnect your solar panels first. If you don't have a switch between the panels and the SCC, you can cover the panels with cardboard, or a tarp to block the sun. The battery has a lot of stored energy that can weld things together. The solar panels can supply higher voltages and a decent amperage to shock you.

i did read the instructions to troubleshoot and this is what it says (im dealing with both of these issues)

Controller does not charge batteries/Controller shows "0.0" amps charging
Troubleshooting steps:
1. Ensure batteries are not full, charging amps will drop to near zero if batteries are full (meter the batteries, don't trust the display from the controller)
2. Ensure solar panel is clean and is in direct sunlight. An obstructed/dirty panel will yield poor results
3. Check input voltage at controller from solar panel (~18V based on solar panel rating)
4. Check wiring from solar panel to batteries
5. Check for any fuse in-line in the system
6. Perform a hard reset on device. Disconnect all four wires from back of device and let sit for 15 minutes - reconnect all four wires and recheck
7. Replace controller

Moon Symbol on Solar Controller

If there is a moon symbol appearing on the controller then the controller is not seeing voltage coming from the solar panels. The first step here is to remove the wires on the back of the controller coming from the solar panel. Use a multi-meter to measure across the two leads. In sunlight, you should see between 20-18 volts. (this number maybe lower on cloudy days). If you do not see this voltage at this point the next step would be to check your panels and work your way back down to the controller with the multi-meter.
Put the meter across the leads of each panel. The voltage should be very similar (20-18 volts based on the type of day). If one panel is lower than this then there is an issue with the panel. If all are the same then trace the wires back to the controller with the meter and determine if there is a connection issue.

 

[moonlitsouls]

Moon Symbol on Solar Controller

If there is a moon symbol appearing on the controller then the controller is not seeing voltage coming from the solar panels. The first step here is to remove the wires on the back of the controller coming from the solar panel. Use a multi-meter to measure across the two leads. In sunlight, you should see between 20-18 volts.

Does anyone know which two leads they are referring to?

 

[Bud Martin]

It may help if you provide the make and model of your SCC and also the pictures, right now we have no idea what we are dealing with.

 

[moonlitsouls]

It may help if you provide the make and model of your SCC and also the pictures.

hey Bud , ok i will report back tomorrow with pictures and details

 

[diyernh]

Moon Symbol on Solar Controller

If there is a moon symbol appearing on the controller then the controller is not seeing voltage coming from the solar panels. The first step here is to remove the wires on the back of the controller coming from the solar panel. Use a multi-meter to measure across the two leads. In sunlight, you should see between 20-18 volts.

Does anyone know which two leads they are referring to?

"the wires on the back of the controller coming from the solar panel."

I don't know your SCC manufacturer or model. But if you have disconnected the wires from the solar panels, you would be measuring the voltage on the two wires to the panels, ie the ones you disconnected from the back of the controller.

If you did cover the panels to avoid them from generating power while working with them, they would need to be uncovered/ exposed to sun to measure the voltage..

 

[Sillyputty]

Always disconnect your solar panels first.

I have a fused circuit breaker box between the solar panels and the solar charge controller for just this purpose. If you are disconnecting wires at the solar charge controller to 'check' them per the troubleshooting instructions without interrupting the power from the panels to the battery first by disconnecting the cables or completely covering the panels to block out all light, this may be the cause for your sparking.

 

[moonlitsouls]

I have a fused circuit breaker box between the solar panels and the solar charge controller for just this purpose. If you are disconnecting wires at the solar charge controller to 'check' them per the troubleshooting instructions without interrupting the power from the panels to the battery first by disconnecting the cables or completely covering the panels to block out all light, this may be the cause for your sparking.

i guess i assumed the panels had no power because the amps on the controller showed 0.0 , the wires from the panels were still attached to the controller. that does make sense. I am going to work on it tonight again in the dark. this time i will disconnect all 4 and attempt the reset listed above and see what happens. I am going to start pulling panels apart so i can trace the wires from the roof to the battery , i am determined to become proficient in these systems and be able to service them myself

 

[moonlitsouls]

"the wires on the back of the controller coming from the solar panel."

I don't know your SCC manufacturer or model. But if you have disconnected the wires from the solar panels, you would be measuring the voltage on the two wires to the panels, ie the ones you disconnected from the back of the controller.

If you did cover the panels to avoid them from generating power while working with them, they would need to be uncovered/ exposed to sun to measure the voltage..

to do this im just using the multimeter and touching the open end of the wire or the metal screw point at the back of the controller yes? Ive been using my multimeter to test my cells and other parts of my BMS during battery assembly , but i have yet to attempt to test the voltage of a wire , to test the voltage of my battery cell was pretty simple , but im still confused about how to test wires

 

[diyernh]

to do this im just using the multimeter and touching the open end of the wire or the metal screw point at the back of the controller yes? Ive been using my multimeter to test my cells and other parts of my BMS during battery assembly , but i have yet to attempt to test the voltage of a wire , to test the voltage of my battery cell was pretty simple , but im still confused about how to test wires

It's just like testing a battery. Set your multimeter to DC voltage. If you have a range, set it so it can read 50 volts or so. Positive lead on the red wire from the solar panel, Negative lead on the black wire from the solar panel.

Remember that there needs to be sunlight on the panels to get voltage from them.

 

[moonlitsouls]

Hey guys , I just tested the wires labeled “solar panel + and -“ and there is no voltage coming from them

I also tested the white and black wire (black was connected to battery + and white -)

there is full 13.6 volts coming from those wires (despite the fact the 12v disconnect was enabled)

I believe this implies there is a missing connection between the solar panels and the charge controller

 

[diyernh]

Hey guys , I just tested the wires labeled “solar panel + and -“ and there is no voltage coming from them

I also tested the white and black wire (black was connected to battery + and white -)

there is full 13.6 volts coming from those wires (despite the fact the 12v disconnect was enabled)

I believe this implies there is a missing connection between the solar panels and the charge controller

The battery voltage may always be connected to the SCC. The "12V disconnect" may only disconnect the loads from the battery. The solar could keep on charging the battery when you have disconnected the loads.

It does look like you have no power from the solar panels. You will need to follow the wires up to the panels. Look for a fuse or broken wire. Eventually, you may be unplugging each panel, and testing the voltage only on one panel at a time.

The fuses may not look apparent. If you have MP4 connectors on the panels, you could have a small cylindrical MP4 connection that has a fuse inside it.

If you do find a panel that is not putting out power, it could be totally failed, or maybe just the diode. Solid panels have a diode on the back, inside the connection box. That could totally fail, breaking the supply of power. Usually they don't break totally, but instead short out. A diode is made to only pass voltage out the positive wire, and not allow voltage/current to be fed backwards. If it allows the voltage to be fed backwards, then you could end up with different issues. Like, one panel is in the sun, and feeding power out. But the second panel in parallel with that is shaded and has a shorted diode, allowing the power to go backwards into the shaded panel. I don't think the diodes are your problem. Look for fuses or broken wires first.

Get some electrical tape or wire nuts on the battery connections. You probably don't want them shorting out. You may be looking for more blown fuses on the battery side. Hopefully it is fused. If not, it could be a really hot wire if you short them.

 

[Sillyputty]

Not sure about much else at the moment, but these two wires going into the charge controller look almost shorted out (if they haven't already)
and need to be cleaned up.

 

[diyernh]

Not sure about much else at the moment, but these two wires going into the charge controller look almost shorted out (if they haven't already)
and need to be cleaned up.

View attachment 43898

Yes, that could have blown a fuse on the panel connections. Some of the SCC's don't have big enough connections to allow the larger wires. If that's the issue, you could clean up enough strands and cut the excess. They sell crimp ferrules to make that cleaner, but soldering the wires will hold them in a solid shape for inserting into the SCC.

Edited...
Did you separate the wires to test for voltage? Solar panels can be safely shorted. The YouTube video I posted earlier showed shorting out the panels and measuring the current (Amps). Maybe the few stray wires could short out the panels and not blow any fuse. The fuses would be protection against shorting them on a maximum sunny day or feeding power to the solar cells.

Maybe you can see voltage after separating the wires?