Winter lithium battery removal

[dunnet]

Originally Posted by Jeremy Kessenich

I also have a 2023 5.0 and I was told by ETI to shut the MPPT controller off in the Victron app for the MPPT controller before disconnecting the batteries. If you do this you do not have to worry about covering the panels. If you aren't sure where in the app to do this I'm sure myself or someone else can post a picture, just let us know.

A bit of help would be appreciated, thanks.

[oldwave]

Best practice is always to install a physical dipole dc disconnect breaker between the panels and the controller.

[John in Santa Cruz]

Originally Posted by CE Vogel

Whether it is necessary to disconnect the solar panels or not when batteries are disconnected depends upon two things: the Open Circuit Voltage of the solar panels, and the Maximum Input Voltage of the charge controller. If the Open Circuit Voltage is less than the Maximum Input Voltage, it is not necessary to disconnect the solar panels.
The Open Circuit Voltage is considerably greater than the Operating Voltage of a solar panel. Sometimes solar charge controllers are installed that are OK with the operating voltage, but not OK with the open circuit voltage. As long as batteries are installed, the Operating Voltage is what the charge controller receives. When the batteries are disconnected and therefore no load on the solar panels, the Open Circuit Voltage is what the charge controller receives.
The solar panel Operating Voltage and Open Circuit Voltage, as well as the charge controller Maximum Input Voltage will all be listed in their specification sheets.

I've never seen a solar setup where the controller can't handle the open circuit voltage. My Victron 100/30 controller has a maximum open circuit PV of 100V, but my 360W panel has a max voltage of about 43V, and a max power of about 36V at 10 amps.

[JLG]

Originally Posted by CE Vogel

Whether it is necessary to disconnect the solar panels or not when batteries are disconnected depends upon two things: the Open Circuit Voltage of the solar panels, and the Maximum Input Voltage of the charge controller. If the Open Circuit Voltage is less than the Maximum Input Voltage, it is not necessary to disconnect the solar panels.
The Open Circuit Voltage is considerably greater than the Operating Voltage of a solar panel. Sometimes solar charge controllers are installed that are OK with the operating voltage, but not OK with the open circuit voltage. As long as batteries are installed, the Operating Voltage is what the charge controller receives. When the batteries are disconnected and therefore no load on the solar panels, the Open Circuit Voltage is what the charge controller receives.
The solar panel Operating Voltage and Open Circuit Voltage, as well as the charge controller Maximum Input Voltage will all be listed in their specification sheets.

Hello -- thank you very much for this information. I have a follow-up question: Would carefully/fully covering up the solar panel suffice to "disconnect" it for this purpose? [Pardon my ignorance, we have a new-to-us 2017 21C with one solar panel combined with 2 lithium batteries plus serious ignorance of the entire system overall. We are working to get all set up for winter in Minnesota because we are leaving the country until mid-December and want to care for our new travel partner properly yet have not had time to work thru what is a steep learning curve for us.]
J. L. Geurts