Quiet 3kW Cabin System Advice

[PreppenWolf]

Would like advice on doing a stand alone 3kW cabin build.

I have a full house build already. Here link to it.

EG18KPV (formerly 6500s) 120/240 Setup, 48V 105kWh Battery & Overkill 100A BMS Install

Edit 3/4/25 - EG4 18K has replaced the 6500EXs. No changes to battery or panel capacity. PV strings altered to 10s2p, 10s1p, and 10s1p for the (3) MPPTs on the 18k via a new 6 to 3 combiner box. EDITED: I've made this my build thread, so while there is an OP question below if you keep reading...

diysolarforum.com

I'm in NH so the batteries will be lead acid due to cold weather and no heat in cabin. I don't need help choosing batteries.

Planning on 48V.

Want 3kW 120V AC, single phase.

Panels I have covered and on hand already I can assign up to 5kW.

My big questions are:
Quiet inverter options? It's a small cabin 12ftx16ft.
Lowest idle consumption?
Ability to load shed excess to a heater for winter?

I'm currently thinking Growatt SPF 3000TL. Any reasons with my questions above I shouldn't go this route?

 

[ChrisG]

Victron will have less idle consumption. My testing 3000 SPF uses about 65w, so about 1.5kw a day to just stay on. You could get an additional 400w panel (assume 4 sun hours) to offset it or additional battery if you need the capacity.

Victron MP-II 3kva has two ac outs, believe you can decide how to use the ac out two power In configuration (possibly for load shed).

 

[JJJJ]

Another vote for Victron. Nice and quiet, easy to install and prices have dropped.

There has been concern about a lack of support for the Growatt brand lately. One of those reports came from a supplier.

 

[BobT]

I have a similar situation at my cabin in SE Oklahoma. The cabin is 12 x 24 with an additional 6 x 6 room for the solar equipment. I use the Growatt SPF 3000TL 24V along with two EG4 LiFePO4 batteries (we never see temps as low as you), only 1600 watts of PV. I only have one season on the cabin so far, it is still under construction, but last trip we powered our camper plus a small refridgerator and ran multiple power tools for two weeks without encountering any problems at all. The SOC would be down around 40% at the end of the day and back up to 100% by noon. The Growatt fans are a little noisy but, if you are as old and deaf as I am, you really won't notice it .

 

[Madcodger]

Victron will have less idle consumption. My testing 3000 SPF uses about 65w, so about 1.5kw a day to just stay on. You could get an additional 400w panel (assume 4 sun hours) to offset it or additional battery if you need the capacity.

Victron MP-II 3kva has two ac outs, believe you can decide how to use the ac out two power In configuration (possibly for load shed).

I have a Victron Multiplus 3000 KVA inverter (120 volt) in a 10x20 exercise studio. I work remotely (rural Maine) and moved my office to this building a few weeks back until my new office building on the property is completed this winter. So, I hear every pin drop in this building. With a couple of LED lights, a Mac mini, two monitors, and other odds and ends electronics plugged in and running, I don't even know the Victron is there. It's super quiet until I turn on a big load like a window AC, which of course makes the fans spin up a bit and is much louder than the inverter. Those fans also spin up if the inverter is passing through generator (shore) power to recharge the batteries when needed, so that's something to think about (probably with any inverter/charger). But on just "regular" use, I all but forget the inverter is even there, just a few feet from me.

The inverter consumes about 30-35 watts on its own but this can be reduced further if no loads on it, via a setting. I don't even bother with that as I leave the Mac on all the time. I am very happy with my Victron equipment and am looking at buying more for a house we're building a few miles away. Other than the price, of course, my only complaint is that you still need VE Config to make some configuration changes and it only works on Windows (which I despise).

 

[iamrich]

Not the LV2424, the fans under load will drive you crazy, no matter how deaf you are... If you could put the setup in a soundproof room/closet maybe, but otherwise I would look at building a small shed next to your cabin with a thermal/sound break (in other words not touching the cabin). There are a lot of pluses to adding a solar shed especially if the cabin is going to be unattended for long periods. At least if the shed goes bad, it shouldn't affect your cabin, plus you can vent it for the batteries, and the inverter itself will provide some heat in winter.

 

[Mark Halvorson]

Another vote for Victron, as the idea is like 15 watts, I love my EG4 3000EHV-48, but the idle is 60 watts and the fans run all the time.

 

[LydMekk]

Victron.

I wouldn't touch Growatt with a 10 fot pole after my experiences...with someone else holding the pole...

 

[Will Prowse]

Sounds like you need a victron.

 

[xy74]

I am still deciding on my equipment for a small 900 sq ft cabin and had almost decided on a Victron 3k. But the more I read about it, the more I find that it might be pretty noisy for a small cabin. I am now leaning towards a Morningstar Sure Sine inverter. (2500) This will mean going with individual components rather than an all in one approach. Plusses are fan-less design, LF inverter with a lot of surge capacity, extremely low consumption (19 watts with the AC output ON), and excellent overall efficiency. Downside may be price when you add in a charge controller? Fairly new on the market, so not finding much about them on here. Morningstar is geared more towards commercial than the DIY market, but they seem to have an outstanding reputation with their charge controllers. I'm still pondering.

 

[Mark Halvorson]

I had never heard of Morningstar before, looks to be well built.

For the same price, get the victron, with support from someone real.
https://www.currentconnected.com/product/victron-48v-multiplus2-3000va/.

Keep reading, there are many options out there

 

[PreppenWolf]

I'll dig into the Victron. I'm assuming you need a separate MPPT to use with the Multiplus?

 

[Mark Halvorson]

Yes the Victron system requires a separate MPPT. They do have outstanding reporting and monitoring using a separate item a Cerbo GX

 

[rhino]

The quietest inverter you can get is a Morningstar SureSine. They have one that is continuous output of 2500W. It is quiet because it is completely designed for passive cooling with large heat sink. There are no fans. I have the 150W version. You'd need separate charge controller.

 

[PreppenWolf]

Yes the Victron system requires a separate MPPT. They do have outstanding reporting and monitoring using a separate item a Cerbo GX

I don't care about remote monitoring. I would never network my offgrid setups. The entire intent for me is airgapped systems. I've got two legs. I can walk over and look if I want to know my system's status.

 

[Madcodger]

I am still deciding on my equipment for a small 900 sq ft cabin and had almost decided on a Victron 3k. But the more I read about it, the more I find that it might be pretty noisy for a small cabin.

As noted in another post in this thread, I own that Victron inverter and find it's basically silent with normal use, in a 10x20 building where I work all day, and I am very easily distracted by noise. Other than when it's charging batteries via shore power, anything you'd turn on to make the fans spin up would likely be louder than the fans. And I've yet to find a motor start it can't handle. It's a beast.

Also, I use a Raspberry Pi 3 running Victron's free Venus package, and it does much of what the Cerbo GX does for monitoring, while leaving $300+ in my pocket. Works great and I can monitor from anywhere I have an internet connection. Someone noted they wanted to keep their system airgapped from the internet. That now has me wondering if I can see the Victron graphs with the RPi disconnected from the internet, on a local screen. Hmmmmm.....

 

[littleharbor2]

I had never heard of Morningstar before, looks to be well built.

For the same price, get the victron, with support from someone real.
https://www.currentconnected.com/product/victron-48v-multiplus2-3000va/.

Keep reading, there are many options out there

You live in the USA and never heard of Morningstar? Hard to believe.? Morningstar is one of the oldest, most solidly built off grid equipment mfg. out there. One of their strong points is their products are so efficient they are built with passive heat sink based cooling only, no fans.

 

[45North]

Would like advice on doing a stand alone 3kW cabin build.

I have a full house build already. Here link to it.

EG18KPV (formerly 6500s) 120/240 Setup, 48V 105kWh Battery & Overkill 100A BMS Install

Edit 3/4/25 - EG4 18K has replaced the 6500EXs. No changes to battery or panel capacity. PV strings altered to 10s2p, 10s1p, and 10s1p for the (3) MPPTs on the 18k via a new 6 to 3 combiner box. EDITED: I've made this my build thread, so while there is an OP question below if you keep reading...

diysolarforum.com

I'm in NH so the batteries will be lead acid due to cold weather and no heat in cabin. I don't need help choosing batteries.

Planning on 48V.

Want 3kW 120V AC, single phase.

Panels I have covered and on hand already I can assign up to 5kW.

My big questions are:
Quiet inverter options? It's a small cabin 12ftx16ft.
Lowest idle consumption?
Ability to load shed excess to a heater for winter?

I'm currently thinking Growatt SPF 3000TL. Any reasons with my questions above I shouldn't go this route?

Between low sun angle and snow load I don't think you need to worry about excess winter production.

 

[PreppenWolf]

Between low sun angle and snow load I don't think you need to worry about excess winter production.

I have adjustable panels, clear any snow daily and the shed won't be used often, so the batteries will remain at 100% most of time. I do pretty decent thru winter.

 

[hwy17]

You live in the USA and never heard of Morningstar?

I never had either. We weren't all in the off grid scene back when.

 

[littleharbor2]

I never had either. We weren't all in the off grid scene back when.

Understandable. I've been doing off-grid solar for 25 years so I guess I just take it for granted that everybody, (not everybody), knows Morningstar.

 

[rhino]

The heat sink on the Morningstar charge controller is MASSIVE! I've never seen one so large:

 

[Brucey]

The quietest inverter you can get is a Morningstar SureSine. They have one that is continuous output of 2500W. It is quiet because it is completely designed for passive cooling with large heat sink. There are no fans. I have the 150W version. You'd need separate charge controller.

Is there any transformer hum like a Victron? Looks like the SureSines have Bluetooth support out of the box in addition to various hardware interfaces.

 

[rhino]

Is there any transformer hum like a Victron? Looks like the SureSines have Bluetooth support out of the box in addition to various hardware interfaces.

I only have the 150W and it's barely audible. They also still do not have the iOS app available for bluetooth access but the Android one is available.

 

[Brucey]

I only have the 150W and it's barely audible. They also still do not have the iOS app available for bluetooth access but the Android one is available.

I only have Android but this doesn't work for you?

‎SureSine Utility

‎Morningstar Corporation - The World’s Leading Solar Controllers and Inverters. Use the SureSine Utility App to connect a mobile device to your Morningstar SureSine Inverter via Bluetooth. The app supports the following functionality: - View real-time operating information - View product...

apps.apple.com