system status when away from part time cabin

blindcowboy

So for the good news I got my off-grid system up and running this weekend.  Now that I've got it running even more questions pop up.

So I have a cabin my wife and I visit every 2-3 weeks during the summer and more often in hunting seasons, holidays, etc.  I know I should let batteries charge and discharge when not here but how do I handle that?  Should I leave powercenter on and just turn off the breaker in the cabin when not here, turn everything off and just turn it on when here, or leave everything on?  How do those of you in this situation handle it?

ramloui

I am in a similar situation and I turn all of the loads off when I leave the cabin. The charging side of the equation is left on so that the batteries are always being kept in a full charge.

This is the prudent approach...

However, there is another side of me that wants to leave some of the loads on while I am away: security cameras. I am in a pretty remote area but there is some traffic on the trail that runs in front of my cabin. I have signs that say there are cameras and the cameras are readily visible. This will probably not discourage a professional thief but it will certainly discourage the "opportunistic" thief.

So leaving this load on while i am away always makes me nervous that when I go back to the cabin something could have gone sideways and my batteries are dead or worse. I guess it is about choosing the lesser of 2 evils.

Cheers!

706jim

My place is used pretty much full time in the summer months, on weekends spring and fall and not at all from November to May. I just leave the panels charging the batteries with the inverter off and have had good results so far.

blindcowboy

ramloui said:

I am in a similar situation and I turn all of the loads off when I leave the cabin. The charging side of the equation is left on so that the batteries are always being kept in a full charge.

This is the prudent approach...

However, there is another side of me that wants to leave some of the loads on while I am away: security cameras. I am in a pretty remote area but there is some traffic on the trail that runs in front of my cabin. I have signs that say there are cameras and the cameras are readily visible. This will probably not discourage a professional thief but it will certainly discourage the "opportunistic" thief.

So leaving this load on while i am away always makes me nervous that when I go back to the cabin something could have gone sideways and my batteries are dead or worse. I guess it is about choosing the lesser of 2 evils.

Cheers!

I've had the same thought regarding loads.  I'de love to leave my hot spot plugged on so thought I could connect a wireless access point to my charge controller and keep an eye on what it's doing.  Also being just outside of Del Rio TX a cold drink when we arrive in the middle of August would be nice.  In fact my next purchase is a decent fridge.  I currently have one of the dorm sized ones but it's turning on every 5 minutes.  I'm going to get a no frills normal sized one that will hopefully use less energy.

BB.

For everyone--Before you purchase anything, do a power budget analysis...

Wifi/Internet/cameras/refrigerators can use wildly different amounts of power. And throw in Weather (7 days of stormy weather where the solar array outputs less than 1% of rated power)--And you can end up with dead batteries.

Simple answer--Very small loads relatively to typical system capacity (10% or less for "away" loads).

Complex answer--Add an alarm so you can call somebody (or drop by yourself) to turn of loads/run backup genset/etc.

Even more Complex answer--Add a load cutoff system when battery falls to 75% or 50% state of charge--Do not restart loads until battery is >80% state of charge.

Engineering+Account answer--Run the system with minimal "away" loads--Cross fingers and hope that all is OK--And buy a new battery bank every few years when things "go south".

-Bill

blindcowboy

BB. said:

For everyone--Before you purchase anything, do a power budget analysis...

Wifi/Internet/cameras/refrigerators can use wildly different amounts of power. And throw in Weather (7 days of stormy weather where the solar array outputs less than 1% of rated power)--And you can end up with dead batteries.

Simple answer--Very small loads relatively to typical system capacity (10% or less for "away" loads).

Complex answer--Add an alarm so you can call somebody (or drop by yourself) to turn of loads/run backup genset/etc.

Even more Complex answer--Add a load cutoff system when battery falls to 75% or 50% state of charge--Do not restart loads until battery is >80% state of charge.

Engineering+Account answer--Run the system with minimal "away" loads--Cross fingers and hope that all is OK--And buy a new battery bank every few years when things "go south".

-BillThanks.  I'm don't worry I'm doing that.  With the refrigerator I'm also considering the fact that my climate is hotter than most and adding that as best I can into the equation and estimating on the high side.  My magnum inverter has a cut off setting.

BB.

Remember, that if you use the default AC inverter cutoff voltage (10.5 volts typical for a 12 VDC system)--The cutoff voltage will still "kill" the battery bank. Cutoff voltages are set to "protect" the AC inverter from low DC input voltage (and overheating the inverter components/wiring).

If you want to protect the battery bank, you would set the AC inverter to ~12.0 or 11.5 volts cutoff voltage (at least when you are away from the cabin)--And reprogram back to 10.5 volts when you are back and running (possibly) heavy loads.

-Bill