2 replies to this topic

[BobD]

Getting ready to start my solar install on '12 Eagle thanks to all the info on this site.  Thanks to all, what a wealth of information.  It's like drinking out of a fire hose!  I'm using the Morningstar MPPT-15L, which unfortunately won't fit in the battery well.  I'll be installing it on the back bulkhead of the cabinet in between the shore power and outside shower connections.  Pictures to follow.  My question is on the LVD/LVR dipswitch position (11.5V/12.5V Off or 11.0V/12.1V On) should this be on or off?  I did a search but didn't find any information, pro or con.  Hoping someone here can address this.

 

Thanks,

Bob

[Alley-Kat]

If you are running all your 12VDC loads via the MPPT-15L, (the + and - of the Load terminals of the MPPT-15L goes to something like a Blue-Sea fuse box which acts as your load distribution panel) then it depends on how low you want your battery to run, before the MPPT-15L turns off the power to the Blue-Sea fuse panel.

 

I have mine set up this way, i.e., all 12 VDC loads go through the Blue-Sea fuse panel from the load terminals on the MPPT-15L, and I've set the Low Voltage Disconnect/Reconnect to be the higher values... 11.50 disconnect, 12.60 reconnect, thus Switch 2 is OFF (down). I prefer to keep my battery at the higher values (I think it's better for the battery).

 

As I understand it, this MPPT-15L feature will not allow any loads that are connected to the MPPT-15L via the Blue-Sea fuse panel to drain my battery below 11.50 VDC (if Switch 2 is OFF), and will not allow them to operate until the battery gets recharged to at least 12.60 VDC.

 

I don't think I've ever experienced this feature being activated, as my amp/hr usage on a typical camping day is that I only use about 35-40 amps of the available 100 amp battery (12 VDC only DC compressor fridge, furnace, fan and LED lights). I further believe that during the day, the MPPT-15L is doing two operations... 1) recharging the battery from the usage overnight, and 2) running any loads that are connected to it. I believe that my 135 watt solar panel creates enough amps to allow both functions simultaneously if the solar panel is operating correctly.

 

If you have other 12 VDC loads that do not go through the MPPT-15L via the Blue-Sea fuse panel (they are connected directly to the battery), then your battery can be drained lower, and a set-up like that would defeat the purpose of Switch 2, so, in a case like that it probably doesn't matter what switch setting a person may use for Switch 2. I do not believe in creating an electrical system that is wired this way. I should also add that my camper battery is not connected to the truck charging system. I prefer to keep things simpler.

[BobD]

Thanks A-K, that's exactly the answer I was looking for, appreciated.  Now back to working in tiny spaces with appropriately interspersed metaphors.