solar wiring question

You don't need any of it.

Moved from technology corner

You can short the panels all day without harm to the panels or wire. No fuse needed. Possibly a switch to disconnect power for service but at 12/18 volts it is not a huge deal.

If the connection to the battery goes through blind areas or any significant distance you should have a fuse or breaker close to the battery. 20a fuse is fine but not larger than the wire ampacity.

I use switchable breakers - On both sides

However as stated above not really needed unless you plan on; Future upgrades, Wiring changes, System maintenance, Firmware updates - Power cycle reboot often times needed, Potential fire prevention if the line to the battery shorts (as outlined by smk above), Complete battery isolation remember the controller gets power from the battery it's a small parasitic load when in the shade, Many controllers require the battery side connection made before the array connection, etc...

Enough issues for me to ALWAYS have disconnection capabilities on both sides
But I'm a bit anal when it comes to my installations

I use Bogart gear for my solar application. I installed 30 amp breakers on both sides of controller and a 250 amp catastrophe fues between the battery and the inverter. It is a small investment for safety

Some controllers require you to disconnect from both the panels and battery bank (in that order) to make changes to settings. Then connect back up to bank, then panels, in that order.

It's no different than hooking up a portable charger... hook up clamps first, then plug in to 120v.... when finished, unplug from 120v, then remove clamps.

controller to battery:

If controller and batteries are far apart, or difficult to access, install a fuse or cb near batteries to protect wiring, and an on/off switch near controller to disconnect/reconnect circuit.

If controller and bank are close to each other, and easily accessible, install a switchable cb near batteries to both protect the wiring and disconnect/reconnect circuit.


panels to controller:

install a fuse or cb near panels to protect wiring, and an on/off switch near controller to disconnect/reconnect circuit.

fuses/cb's sized to protect wiring... so higher than controller's input and output, but lower than what the wiring can handle without getting hot.

towpro wrote:
I am only buying 200w of solar. Charger is rated for 30A. Do I use 30A fuses (or breakers) or would you use 15A (which is more than I expect the panels to put out).

Between PV array & Controller: use series fuse rating found in panel specs (or on the panel itself) . . . probably 15A . . . use one of these for each panel

Between battery bank & Controller: breaker size = 1.56 x Output Current (so 30 x 1.56 = 47A. Since MidNite's breakers are rated for continuous current, I think you can use 1.25 multiplier instead.

Regardless, check out the MidNite Solar Forum for info.

No box nor connectors needed:

http://www.amazon.com/dp/B00HNOWWTI/ref=wl_it_dp_o_pd_nS_ttl?_encoding=UTF8&colid=2ZBKPJ1MXQ6H5&coliid=I8ANOA5HV79W8

Hi,

No fuse between panels and controller. Fuse between controller and battery as near to the bank as is possible.

+1 to all the prior: no fuse between panels and charger, and fuse RATED FOR THE WIRE ITS ATTACHED TO from batteries to inverter (if used).