Post by kit on Oct 4, 2016 18:10:42 GMT
Hi Mikey--I'm pretty new to it too and have had exactly the same frustrations, often reading conflicting information about fusing and such. I'm putting together a basic off-grid system like yours, and I came across this Renogy manual for an off-grid kit. See page 58 for its recommendations of wire sizing and distance between battery and controller:
www.renogy.com/template/files/Manuals/Off-grid-General-Manual.pdf
Basically, it says "as close as possible" between battery and controller but gives no specific distance. I came across other references that state that the controller should better not be kept in the battery box (assuming you're using one) so I've put my controller in a separate box with 3.5ft 8-gauge wires to the battery.
The Renogy manual on that same page also counsels that 8-gauge wire is good for this connection up to 55 amps, which is far better than your controllers capacity anyway, so anything bigger--like 6 gauge--would just be a waste of copper for your current setup. BTW My 30-amp controller will fit 8-gauge max, and I really have to squeeze it in there. It would not even be possible to fit 6-gauge in there.
Assuming you're operating a 12v system, if you're planning to add MORE than your current two panels, you might run into an excessive amp problem because the extra panels could produce more amps than your controller is rated for. My 150w panel is rated at about 8amps, so four of them would be too much for my 30a controller, I'm assuming.
I came across another reference which counselled to just use the same gauge wire for controller to battery as you used for panels to controller. Distance-wise, 8-gauge seemed ideal for my panel to controller, so I just used the same for the controller to battery.
12-gauge sounds a bit small to me for your panel-to-controller wires unless maybe the run is very short. You might check two good easy websites for distance/gauge calcs. Larger gauge will have less energy loss.
www.freesunpower.com/wires_cables.php (contains a chart) and
www.freesunpower.com/wires_cables.php (scroll down to "wire size calculator")
Interestingly, if you google about it, you can find that some people even combine smaller wires to "make the gauge" of a bigger one. For example, two #11 wires will equal a #8 wire. Some people even use copper speaker wire for this sort of arrangement. Important thing is make sure you know what you're doing, but still you gotta keep on truckin!
www.renogy.com/template/files/Manuals/Off-grid-General-Manual.pdf
Basically, it says "as close as possible" between battery and controller but gives no specific distance. I came across other references that state that the controller should better not be kept in the battery box (assuming you're using one) so I've put my controller in a separate box with 3.5ft 8-gauge wires to the battery.
The Renogy manual on that same page also counsels that 8-gauge wire is good for this connection up to 55 amps, which is far better than your controllers capacity anyway, so anything bigger--like 6 gauge--would just be a waste of copper for your current setup. BTW My 30-amp controller will fit 8-gauge max, and I really have to squeeze it in there. It would not even be possible to fit 6-gauge in there.
Assuming you're operating a 12v system, if you're planning to add MORE than your current two panels, you might run into an excessive amp problem because the extra panels could produce more amps than your controller is rated for. My 150w panel is rated at about 8amps, so four of them would be too much for my 30a controller, I'm assuming.
I came across another reference which counselled to just use the same gauge wire for controller to battery as you used for panels to controller. Distance-wise, 8-gauge seemed ideal for my panel to controller, so I just used the same for the controller to battery.
12-gauge sounds a bit small to me for your panel-to-controller wires unless maybe the run is very short. You might check two good easy websites for distance/gauge calcs. Larger gauge will have less energy loss.
www.freesunpower.com/wires_cables.php (contains a chart) and
www.freesunpower.com/wires_cables.php (scroll down to "wire size calculator")
Interestingly, if you google about it, you can find that some people even combine smaller wires to "make the gauge" of a bigger one. For example, two #11 wires will equal a #8 wire. Some people even use copper speaker wire for this sort of arrangement. Important thing is make sure you know what you're doing, but still you gotta keep on truckin!