Are there any small AIO off grid inverters designed to run batteryless?

[NorthTown2022]

I'd like to find a safe and simple solution to heating an unoccupied small insulated shed.

I've got a bunch of 445W bifacial panels that were damaged in shipping but still work. I am wondering if I can get a small AIO inverter and hook it directly to a small heater. So basically if the sun is shining I'm hoping I may be able to power a small thermostatically controlled heater ~400W

 

[Steve Fractals]

The MPP Solar MT series of inverters can run battery-less. I have the 6048MT and did run it battery-less for my first 8 months of use.

 

[Madcodger]

As others will doubtless chime in, people do what you are asking. But at least where I live we have stretches of winter with very little sun, so if you want that building to have heat then, that battery might be very handy. There's also nighttime, of course...

As for the heater, I ran a 10 ga 100 foot extension cord to an RV outlet to power a small 5' x 7' shed built on a utility trailer, that I used as an office. It has 2x4 walls, foam board insulation, and three double pane "builder grade" windows. I used it for three winters in Maine using an oil-filled electric "radiator" heater set to the middle (I think about 750-900 watts) setting, to avoid taxing the extension cord. It stayed 68F at -11F outside. The heater cycled on and off depending on the outside temps and how often I opened the door, but it worked great. Just understand that heat is perhaps the hardest thing to supply with solar, 'cause it takes a lot of energy. For the next buildings, I'm going with both propane and a mini split.

 

[SamDeleted]

Also consider , any small cheap AIO and some car batteries. Set the low volt cut off to 12.5v/13v depending~

Essentially the same as working in batteryless mode . Car batteries will take a small hit every night but shouldn't be an issue

 

[NorthTown2022]

The MPP Solar MT series of inverters can run battery-less. I have the 6048MT and did run it battery-less for my first 8 months of use.

Great to know. The 6048 is overkill for my needs and budget but I will look at their lineup. Thank you.

As others will doubtless chime in, people do what you are asking. But at least where I live we have stretches of winter with very little sun, so if you want that building to have heat then, that battery might be very handy. There's also nighttime, of course...

I have an inverter in the shed consuming ~40W and other electronics consuming a little more creating a bit of heat. I'm going to build @FilterGuy's Simple 20W Battery Box Heater so the cells will already be in an r10 to r15 insulated box, within the R24 insulated shed. I'm sure protection will kick in at some point but hoping this alone will be enough to keep it operational a good portion of the time.

As for the heater, I ran a 10 ga 100 foot extension cord to an RV outlet to power a small 5' x 7' shed built on a utility trailer, that I used as an office. It has 2x4 walls, foam board insulation, and three double pane "builder grade" windows. I used it for three winters in Maine using an oil-filled electric "radiator" heater set to the middle (I think about 750-900 watts) setting, to avoid taxing the extension cord. It stayed 68F at -11F outside. The heater cycled on and off depending on the outside temps and how often I opened the door, but it worked great. Just understand that heat is perhaps the hardest thing to supply with solar, 'cause it takes a lot of energy. For the next buildings, I'm going with both propane and a mini split.

Nice! I'd like to go propane as well but it poses its own challenges here. For now I am able to remotely start a similar oil heater for short bursts but like you said, "it takes a lot of energy".

Also consider , any small cheap AIO and some car batteries. Set the low volt cut off to 12.5v/13v depending~

Essentially the same as working in batteryless mode . Car batteries will take a small hit every night but shouldn't be an issue

I've given this some thought as well and may go this route in the future if all else fails. A bank of used communication tower cells would sure be nice!

 

[MisterSandals]

Looking at this differently, why not connect the panels directly to a water heating element(s) in a 55 gallon drum? The water will heat and dissipate gradually heating the shed.

When the sun shines, it heats. If you get to the point of the water getting too hot, look into a thermostat to cut the solar.

What could be simpler and cheaper?

 

[SamDeleted]

Looking at this differently, why not connect the panels directly to a water heating element(s) in a 55 gallon drum? The water will heat and dissipate gradually heating the shed.

When the sun shines, it heats. If you get to the point of the water getting too hot, look into a thermostat to cut the solar.

What could be simpler and cheaper?

Yea great idea

 

[rhino]

Since you want to heat air and not water can use chassis mount resistor instead.. go from 1/4W all the way to 5000W: https://www.digikey.com/en/products/filter/chassis-mount-resistors/54

I've used a couple larger ones as a dump load in past.

 

[NorthTown2022]

Looking at this differently, why not connect the panels directly to a water heating element(s) in a 55 gallon drum? The water will heat and dissipate gradually heating the shed.

When the sun shines, it heats. If you get to the point of the water getting too hot, look into a thermostat to cut the solar.

What could be simpler and cheaper?

Ok you got my attention on this but the first thing that comes to my mind is high humidity. I will research this.

 

[NorthTown2022]

Since you want to heat air and not water can use chassis mount resistor instead.. go from 1/4W all the way to 5000W: https://www.digikey.com/en/products/filter/chassis-mount-resistors/54

I've used a couple larger ones as a dump load in past.

I'm running a Quattro 48/5000/70 and an MPPT 250/100 with (8) 445W bifacial panels in a 2s2p configuration.

I also have an unutilized MPPT 150/60 to go with the (4) 445W damaged but working panels. Is a battery required for dump load?

Sounds like dump load is the way to go whether heating water or air. Just need to learn how to do it now.