MPP Solar Operating Temps?

[JAS]

Hey all,

I'm thinking about getting a MPP Solar (or possibly a GroWatt) AIO for my off-grid cabin. My power shed that houses all my equipment is not insulating nor heated. I'm in central PA and cold weather temps can get well below freezing. I see the operating temp low end for both MPP Solar and GroWatt is 0C or 32F. Should I risk using these units in the winter when temps are below freezing? Or am I stuck with looking at more expensive units (like Victron or Samlex) that have a much lower advertised operating temp?

Thanks,

Jeff

 

[JAS]

Really? nobody using these AIO's in a cold environment?

 

[Lt.Dan]

Would it be very hard to throw some insulation in the shed? The AIO units produce a good bit of heat, so if you insulate, it'll probably stay warm enough in the shed.

 

[mrzed001]

Really? nobody using these AIO's in a cold environment?

Many MPP Solar inverters have a -10 °C = 14 °F limit.
But because of the battery you have to isolate to be over 0 °C = 32 °F (or use self heating battery)

 

[JAS]

Would it be very hard to throw some insulation in the shed? The AIO units produce a good bit of heat, so if you insulate, it'll probably stay warm enough in the shed.

It's a Lowe's DIY shed. The wall studs are only 2x3's. So I couldn't really get any fiberglass insulation in there. I could probably rig up foam boards. But their R-Value isn't much. More importantly, though... after the cost of buying/installing insulation, I'd probably be at the same or more than just going with a Victron/Samlex setup that is rated for colder temps...

 

[JAS]

Many MPP Solar inverters have a -10 °C = 14 °F limit.
But because of the battery you have to isolate to be over 0 °C = 32 °F (or use self heating battery)

Not following here? I know the LFP's can't charge below freezing, but they can be discharged. And the BMS will protect it anyway

 

[mrzed001]

Not following here? I know the LFP's can't charge below freezing, but they can be discharged. And the BMS will protect it anyway

Yes LFP can discharge in the cold all night long (and gives less power).
But what happens on the next day? They are still cold when the sun comes up and CAN NOT be charged.
Also use XPS-EPS boards for cabin isolation. Solves all your problems.

 

[JAS]

But what happens on the next day? They are still cold when the sun comes up and CAN NOT be charged.

Yes, I'm aware of that issue. I'm only at the cabin on weekends and I suspect the battery can last two days without any charge. I can then bring the battery home if necessary to fully charge. That being said, I am thinking about ways of keeping the battery warm. It is already stored in an old small chest freezer and should not be hard to warm up the space for the battery.

Also use XPS-EPS boards for cabin isolation. Solves all your problems.

Can you expand on what you mean here? IE: What do you mean by "cabin isolation"?

 

[mrzed001]

Yes, I'm aware of that issue. I'm only at the cabin on weekends and I suspect the battery can last two days without any charge. I can then bring the battery home if necessary to fully charge. That being said, I am thinking about ways of keeping the battery warm. It is already stored in an old small chest freezer and should not be hard to warm up the space for the battery.

If you put PV on the roof (or somewhere) then that will charge the battery for you. Not easy to move the batteries, can be heavy.
To put the battery (and inverter) into a freezer ... that is a good start. But if you do not use them no heat will be generated.
You can buy silicone heating pads with thermostat to keep them warm automatically :

Or you can buy heated LFP batteries :

Can you expand on what you mean here? IE: What do you mean by "cabin isolation"?

With XPS boards you can thermal isolate a room, a cabin, a cabinet, a freezer ... anything.

 

[Sanwizard]

If you put PV on the roof (or somewhere) then that will charge the battery for you. Not easy to move the batteries, can be heavy.
To put the battery (and inverter) into a freezer ... that is a good start. But if you do not use them no heat will be generated.
You can buy silicone heating pads with thermostat to keep them warm automatically :

Or you can buy heated LFP batteries :

With XPS boards you can thermal isolate a room, a cabin, a cabinet, a freezer ... anything.

I bought the pads shown by Will. They seem to be a great solution, as they have a built in thermostat. Use roxul for insulation if possible. Stuff is awesome and waterproof/fireproof/soundproof.
I added one pad per side of my cells. So 4 all together, within an insulated aluminum tool box with locking cover.
I am on Long Island, and it gets to minus 10f here at times.

 

[JAS]

I think I'm just going to try it as is...

My current inverter is also not "rated" to operate below freezing. But, I reached out to their customer support and they said it should be fine. And, I've been using it thru 2 winters now

 

[Trout]

On the cold weather AIOproblem. Does this problem exist if the unit is turned off and just running dc from battery? Obviously it would need to charge batteries at these same cold temps . Assuming battery temperature problem is solved, has anyone tried it in cold weather with inverter off?

 

[Sanwizard]

On the cold weather AIOproblem. Does this problem exist if the unit is turned off and just running dc from battery? Obviously it would need to charge batteries at these same cold temps . Assuming battery temperature problem is solved, has anyone tried it in cold weather with inverter off?

I dont get the question. Tried what with the inverter off? And what AIO problem are you speaking of?

 

[Trout]

Apparently most of the all in one inverter / charge controllers don’t operate at low temperatures. My point was , is it the inverter that doesn’t like the cold temps or the charge controller. I won’t be using the inverter side of my lv24/24 very much . On this unit you can shut the power switch to off and the controller runs off dc . I was hoping someone had tried this . I haven’t built my system yet so just looking for information

 

[Lt.Dan]

The inverter will also naturally heat itself just sitting idle, I don't think cold temps are a problem at all.

 

[Trout]

Thanks Lt.Dan, going up tomorrow forgo start the build . I’ve got my panels up ,conduit run and heated battery boxes built . So it go time!

 

[Sanwizard]

Apparently most of the all in one inverter / charge controllers don’t operate at low temperatures. My point was , is it the inverter that doesn’t like the cold temps or the charge controller. I won’t be using the inverter side of my lv24/24 very much . On this unit you can shut the power switch to off and the controller runs off dc . I was hoping someone had tried this . I haven’t built my system yet so just looking for information

LiFePo4 does not like cold temps. The inverters dont care. They are more heat sensitive than cold.

 

[Trout]

Thanks for the help guys

 

[OffGridInTheCity]

Hey all,

I'm thinking about getting a MPP Solar (or possibly a GroWatt) AIO for my off-grid cabin. My power shed that houses all my equipment is not insulating nor heated. I'm in central PA and cold weather temps can get well below freezing. I see the operating temp low end for both MPP Solar and GroWatt is 0C or 32F. Should I risk using these units in the winter when temps are below freezing? Or am I stuck with looking at more expensive units (like Victron or Samlex) that have a much lower advertised operating temp?

Thanks,

Jeff

To me, its not hardware that's the limiting factor - its the lithium batteries. I have MPP Solar 3048 in my trailer + 14s88p 18650 lithium-ion battery - so I use the ambient or mini-split or maxxfan (depends on time of year) to keep the temp between 50F/10C and 90F/32C for the sake of the batteries. The MPP Solar unit is secondary - e.g. less sensitive temp wise than the batteries

 

[JAS]

Just a follow up...

I contacted Ian at Watts247.com and he said he has many of these units running for years in much colder temps than PA gets.