EG4-6000xp (or other) Solar charge controller recover from battery shutdown

[smr.ruby]

I have a remote off-grid system that from time to time has enough power drain and snow on the panels to cause the LFP batteries to shutdown due low voltage. When the snow melts and the sun comes back there is no good reason that the solar charge controller (EG4-6000ex right now) couldn't supply 48 volts and the batteries would come back on. However, the batteries and the charge controller remain at an impasse : the charge controller doesn't see the batteries as being connected since they have their discharge FETs off so the charge controller doesn't supply power. If either the batteries OR the charge controller would "wake up" from this situation they would both reconnect. However if the batteries shut down on LV I don't see it as their responsibility to restart the "conversation."

I'm interested in taking Signature Solar up on the trade in program and moving to the 6000xp. Does anybody know if the XP can work through this situation and at least intermittently put 48V on the battery bus even if there is no voltage from the batteries? I want the charge controller to start charging again whenever it can without human intervention.

I would consider this a requirement for my off grid solar charge controller so if 6000XP can't do it I need another solution or a different charge controller (could be a small one in addition) that can.

 

[sunshine_eggo]

Important to set your inverter to shutdown BEFORE BMS discharge protection is triggered.

 

[smr.ruby]

The inverter is always left off when nobody is on site so the low voltage cutoff in it doesn't apply. The battery use is DC load.

 

[sunshine_eggo]

The inverter is always left off when nobody is on site so the low voltage cutoff in it doesn't apply. The battery use is DC load.

Important to set your loads to shutdown BEFORE BMS discharge protection is triggered.

Revised.

 

[Zapper77]

Interesting setup.

How about a standalone MPPT with a few panels?

What firmware version do you have installed on your 6000XP?

 

[Zapper77]

If you are on-site, you can active battery wakeup setting on the 6000xp.

 

[smr.ruby]

If you are on-site, you can active battery wakeup setting on the 6000xp.

Awesome! So that setting #17 in the manual does what I'm after? The description of what "Battery Wakeup" does wasn't clear but if it supplies 48v to wake up the battery that makes sense! Thanks

 

[Zapper77]

Awesome! So that setting #17 in the manual does what I'm after? The description of what "Battery Wakeup" does wasn't clear but if it supplies 48v to wake up the battery that makes sense! Thanks

Yes, welcome. I tried it last week.

 

[Samsonite801]

Also, it looks like the dry contact ports on the 6000EX can be set for low-volt trigger, you could have it signal a large enough relay to turn off your DC loads prior to BMS low-volt disconnect. Just a thought that came to mind...

Perhaps there are caveats and might not work as intended, but might be worth looking into further. There are NC (normally closed), C (common), and NO (normally open) contacts available on the unit.

 

[smr.ruby]

Also, it looks like the dry contact ports on the 6000EX can be set for low-volt trigger, you could have it signal a large enough relay to turn off your DC loads prior to BMS low-volt disconnect. Just a thought that came to mind...

good thought @Samsonite801 thanks!

It would be nice if I went with a DC disconnect relay to not also have to add new controls. Unfortunately though the way I read that table if the unit is powered off with no output (the inverter is off) then the dry contact doesn't switch state based on battery voltage. DARN! that would have been slick though. Because of the high standby load on that unit I leave it powered off and all of my critical loads are DC. (with the inverter off the solar charge controller still works when the sun comes up)

 

[Samsonite801]

good thought @Samsonite801 thanks!

It would be nice if I went with a DC disconnect relay to not also have to add new controls. Unfortunately though the way I read that table if the unit is powered off with no output (the inverter is off) then the dry contact doesn't switch state based on battery voltage. DARN! that would have been slick though. Because of the high standby load on that unit I leave it powered off and all of my critical loads are DC. (with the inverter off the solar charge controller still works when the sun comes up)

Yeah, I was wondering about that, that's why I said it may have caveats hehe... I wasn't sure if when the solar comes awake then would the dry contact then start working (even when inverter off).. Don't know really.

Also, a Victron BMV-712 battery monitor has a dry contact in it can could do that as well, and give a nice SoC indicator as well as cool app to keep an eye on stuff.. Just another thought (since that is what I use with my system, as I like the Victron Connect app ecosystem)..