I finished up most of my solar install today and I noticed an issue when hooking up the solar controller to the batteries. I'm using an A/B Both switch to control what bank or banks I want to run.Prior to the solar controller I had only two things tied to the output of the battery switch, my inverter and the connection to the converter in the distribution panel. Which worked fine.When I went to connect the output or battery connection of the solar controller to the A/B switches output terminal, out of habit I just lightly touched the wire to the terminal and noticed a spark nothing big but as spark none the less. At the time I was running on the generator so I'm assuming the voltage was from the converters output. Sure enough when I measured the voltage it was 14.7 volts DC which is the output voltage of the converter/charger. I'm guessing I shouldn't have made the connection with the converter being powered up.So as a sanity check before I make the connection permanent I want to make sure I'm not doing something wrong. I'm assuming that the solar controller is made to accept the converters output when running shore power. And the small spark was just normal :-) Ron W.

If your controller is like mine, it gets its power from the battery bank. Just connecting it could cause a small spark.

I haven't got to do any installing yet but I think there is some DIODES involved to keep certain things out of the solar picture... Sounds like theleg beween the solar controller and the on-board converter might be a good spot for a DIODE...Ro Ken

Double check, then triple check the polarity and make the battery connection.Check the instructions but I believe you should connect the battery side first then connect the panels to the controller. Controller may have issues if you disconnect the battery before you disconnect the panels. May need to be careful of using the switch OFF position but again check the instructions.

Hi,The output of the solar controller should be in the 13.2 to 13.8 volt range. However if it is a PWM controller, it might be as high as 21 volts when not connected to the battery.Once you connect the solar controller to the output of the battery, then the controller output will be slightly higher than the battery voltage before making the connection, or if over 13.8 volts (or the shut off voltage for your controller) it might not read any different than the battery voltage. As for the spark, if the polarity was wrong, you probably tripped a fuse, or everything is OK if the polarity is right. A tiny spark is acceptable. Good luck!Fred.

the controller will "IGNORE" ? the converter voltage applied at the output side from the batteriesit will NOT accept it on the Input sidethe correct procedure for hook up1. batteries only, no converter no generator no shore2. connect controller to the batteries first, controller needs to sense battery system voltage before panels are connected3. connect solar panels to batteriesDO not get these steps backwards..some controllers will be damaged if connected to solar panels and there are no batteries to accept power output4. you can now use any additional charging you want..shore, generator, driving, external battery charger

Question on solar controller hook up? | Good Sam Community

30 Replies

BFL13
Explorer II
Dec 14, 2014
MrWizard wrote:
traveler
i think that depends on the particular controller
my blue sky will shut down

with many less expense controllers
the danger comes .. because users install and hookup in the day LIGHT hours
panels could be a full Voltage potential before being connected

many controllers come with this hookup warning
but the instructions never seem to say what happens if the fuse blows

but assuming it is properly fused..then the controller is already "malfunctioned" or the fuse would not be blown

I was thinking if something bad happened at the battery end.
MrWizard
Moderator
Dec 14, 2014
traveler
i think that depends on the particular controller
my blue sky will shut down

with many less expense controllers
the danger comes .. because users install and hookup in the day LIGHT hours
panels could be a full Voltage potential before being connected

many controllers come with this hookup warning
but the instructions never seem to say what happens if the fuse blows

but assuming it is properly fused..then the controller is already "malfunctioned" or the fuse would not be blown
BFL13
Explorer II
Dec 13, 2014
CA Traveler wrote:
OK, If the controller doesn't like a panel only connection what happens if the fuse to the battery blows?

That stopped the controller-battery pos wire from becoming the fuse and melting at the controller terminal, so the controller is toast anyway?

The OP is ok at 14.8v when connecting the 12/24 controller (no array connected yet) ISTR if it sees under 18v it will decide it is on a 12v battery and if over 18v it will decide it is on a 24v battery. so at 15v it will go 12v as desired.
CA_Traveler
Explorer III
Dec 13, 2014
OK, If the controller doesn't like a panel only connection what happens if the fuse to the battery blows?
rjsurfer
Explorer
Dec 13, 2014
Thanks for the feedback, looks like I was doing everything OK. Will go back tomorrow and reconnect everything in the proper order with shore power off.

Ron W.
MrWizard
Moderator
Dec 13, 2014
the controller will "IGNORE" ? the converter voltage applied at the output side from the batteries

it will NOT accept it on the Input side

the correct procedure for hook up

1. batteries only, no converter no generator no shore

2. connect controller to the batteries first, controller needs to sense battery system voltage before panels are connected

3. connect solar panels to batteries

DO not get these steps backwards..some controllers will be damaged if connected to solar panels and there are no batteries to accept power output

4. you can now use any additional charging you want..shore, generator, driving, external battery charger
Golden_HVAC
Explorer
Dec 13, 2014
Hi,

The output of the solar controller should be in the 13.2 to 13.8 volt range. However if it is a PWM controller, it might be as high as 21 volts when not connected to the battery.

Once you connect the solar controller to the output of the battery, then the controller output will be slightly higher than the battery voltage before making the connection, or if over 13.8 volts (or the shut off voltage for your controller) it might not read any different than the battery voltage.

As for the spark, if the polarity was wrong, you probably tripped a fuse, or everything is OK if the polarity is right. A tiny spark is acceptable.

Good luck!

Fred.
time2roll
Nomad
Dec 13, 2014
Double check, then triple check the polarity and make the battery connection.

Check the instructions but I believe you should connect the battery side first then connect the panels to the controller. Controller may have issues if you disconnect the battery before you disconnect the panels. May need to be careful of using the switch OFF position but again check the instructions.
RoyB
Explorer II
Dec 13, 2014
I haven't got to do any installing yet but I think there is some DIODES involved to keep certain things out of the solar picture... Sounds like theleg beween the solar controller and the on-board converter might be a good spot for a DIODE...

Ro Ken
JiminDenver
Explorer II
Dec 13, 2014
If your controller is like mine, it gets its power from the battery bank. Just connecting it could cause a small spark.

Forum Discussion

Question on solar controller hook up?

30 Replies

About Technical Issues

Related Content

Another solar question.

Solar Charge Controller question

Sway Control

Solar questions

Recommendations for solar charge/controller