Shutting down a system for the winter...

[dcaulton]

My system is in a 2-3 season cabin in the woods. When I'm not there, I really want to make sure things are safe.

Basically, I have a controller that connects to (1) solar panels (2) batteries. Diagram is below (by the way, any feedback on my wiring and fusing appreciated!). My plan is to add the ability to cut off the panels and the batteries. Then there's no power coming into the wiring or appliances, so it should be safe, right?

Here's the question: if I just cut off the positive or negative wires, is that enough? or do I need to fully cut both + and - to fully deaden the circuits? I want this to be simple, yet fully 100% safe. I'd hate to cut just one line, then have a mouse short out a wire and ground something, allowing current to flow. But maybe I'm off base.

thanks.

 

[Deleted member 165]

To keep it simple, you could use these and just manually trip them on your way out. On the positive DC side-one between the panels and the charge controller, and one between the charge controller and the batteries. You only need to disable one side-preferrably positive, to protect your gear.

https://www.amazon.com/gp/product/B07KF2PV6V/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

 

[dcaulton]

To keep it simple, you could use these and just manually trip them on your way out. On the positive DC side-one between the panels and the charge controller, and one between the charge controller and the batteries. You only need to disable one side-preferrably positive, to protect your gear.

https://www.amazon.com/gp/product/B07KF2PV6V/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Actually, I think I'd need to put it between the battery and the whole circuit since the DC loads go straight off of the bus bar. But yes, thematically that makes sense. For the rest of my family I"m still toying with a full unplug since then it's SUPER CLEAR if it's been done or not.

Am I right that it's important to disconnect the positive to avoid a short? EG, if you disconnect the negative but then somewhere in the house something gets grounded current can still flow from + to ground? or is that too simplistic?

But to be certain - if you just switch disconnect the POSITIVE line there's no way a lightning surge can burn things out through the negative line? or that the battery can be drained by a short through the negative line?

 

[Will Prowse]

Just one wire is fine.

One disconnect between solar array and SCC. One wire, either one. Turn this switch "off" first.

Then disconnect the negative wire from the battery. Ensure battery terminals are protected. If one of the main battery terminals is disconnected, nothing will have power no matter what. All good to go.

 

[dcaulton]

for setup, always connect the battery first, then the solar cells. for shut down, always disconnect the cells first. Basically, I never want power going into the controller with no place to put it, correct?

Hey, one more question while I have your attention. I currently have 4 100 watt cells on a renogy 30 amp controller. At maximum production, this would be as much as I can really do since while 400 watt output at 12v is right at the 30 amp limit. However, my cells are not perfectly angled so even at midday I get less than this. Can I thus go ahead and add another for 500 watt (theoretical) instead of angling? I don't like the idea of angle mounting the cells when winter storms are sometimes intense.

Another option is of course adding another controller...

 

[Will Prowse]

Exactly which controller is it? really depends. some have the ability to over panel. depends on the model

 

[dcaulton]

Just one wire is fine.

One disconnect between solar array and SCC. One wire, either one. Turn this switch "off" first.

Then disconnect the negative wire from the battery. Ensure battery terminals are protected. If one of the main battery terminals is disconnected, nothing will have power no matter what. All good to go.

Does this seem like a good solution for switching both?

Exactly which controller is it? really depends. some have the ability to over panel. depends on the model

renogy rover li 30 amp

 

[Will Prowse]

400w max

 

[dcaulton]

makes sense. Was hoping to make up for poor angling with more cells.

 

[Archetype-IS]

makes sense. Was hoping to make up for poor angling with more cells.

Not sure what type of batteries you have. It doesn't like to be idle too long without charging them in the cold. Maybe you could take the batteries with you and trickle charge it at home? Disconnect all the solar to charger. Protected the PV wires with PVC pipe if your worry about the critters. Good luck.

 

[dcaulton]

Not sure what type of batteries you have. It doesn't like to be idle too long without charging them in the cold. Maybe you could take the batteries with you and trickle charge it at home? Disconnect all the solar to charger. Protected the PV wires with PVC pipe if your worry about the critters. Good luck.

I fly home to Seattle, so have to leave the batteries. So I bit the bullet and did Lithium which I hope will self discharge little and tolerate the cold.

 

[BoloMKXXVIII]

Lithium batteries discharge slowly so you should be good for part of a year. You are not leaving them at 100% charge are you? Also, make sure they are warm enough before you start trying to charge them again.

 

[Archetype-IS]

I fly home to Seattle, so have to leave the batteries. So I bit the bullet and did Lithium which I hope will self discharge little and tolerate the cold.

In that case, get a battery insulated box to keep it warm. Hope where the wood cabin is located will shielded some of the colds. Or even put a blanket over the battery box to help on the self-discharging.

 

[dcaulton]

Lithium batteries discharge slowly so you should be good for part of a year. You are not leaving them at 100% charge are you? Also, make sure they are warm enough before you start trying to charge them again.

No I’ll discharge first. I assume that the cold isn’t an issue while being stored, right? Just on recharge (which will be in warm spring weather)?