DC-Living, all DC appliances for new Tinyhouse -Offgrid project?

[eXodus]

Currently looking into moving to a new property (likely a blank Canvas)

Been doing a bunch of calculations on the power system, and since I'm getting all new everything.

I was wondering if instead of paying for a big inverter (AOI) - should just get all DC appliances and potentially a small inverter?

Just a few comparison:

DC - Living
Appliance	Cost DC	Cost AC
Refrigerator 10 cu	$900​	$800​	12V
Heatpump 24000 BTU	$3,000​	$2,500​	48V
100W USB-C charger	$35​	existing	12V
100W USB-C charger	$35​	existing	12V
Well Pump	$90​	$200​	48V
Pressure Pump	$200​	$200​	48V
MPPT 100A 500V	$400​		48V
Inverter/Charger AIO 6500W		$1,300​	48V
Total	$4,660​	$5,000​
Microwave	$335​	$100​	12V
Refrigerator Side by Side 16cu	$2,100​	$1,500​	12V

The smaller inverter and DC appliances should be more efficient - so I could also potentially save on battery capacity and solar.
The 6500W using about 80W continuous- the 3000w - only 40w or less standby.
Which means - 2kWh vs 1kWh. / 24h

What I like about the DC-approach is:
- it enables multiple redundancies. I can have parallel batteries, MPPTs, and every appliances is on their own. While with a central inverter - you always have a single point of failure.
- higher efficiency
- No permits necessary when no 110V (this could be a massive cost and time safer)

Just not sure about the conversion waste from 48V to 12V compared with the efficiency of 48->110V ?

At this point 12V is only for the fridge and lighting. There are 48V fridges - but very expensive and many of them are not "native 48V" so the just have an 48V-12V step down behind them.

 

[pvgirl]

One limitation with using DC appliances is there is a limited selection, and they can be more expensive then standard ac appliances.

 

[wopachop]

Any plans for a rockin sound system and maybe a TV?

 

[eXodus]

One limitation with using DC appliances is there is a limited selection, and they can be more expensive then standard ac appliances.

true, they are more expensive, but so far my research suggests it's actually not that much.
My question is - can I save whatever I pay more in the appliance - on the total cost level.

Like less batteries, less solar panels etc. No 120V breaker panel

A 12 circuit 12V fuse center is like $50, while a 12 Space panel costs you $300

Any plans for a rockin sound system and maybe a TV?

hehe

12V Projector with Bluetooth 12V RV Radio

Drive BT 100 RV Stereo AM/FM Radio/Bluetooth/Aux-In Sound System

RecPro has a wide variety of RV Products like furniture, baggage doors and blinds. Free Shipping on all items!

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https://www.etrailer.com/RV-Stereos/Jensen/JWM60A.html

Going to have a 120 inch "Screen"

 

[wopachop]

Are you avoiding propane all together? I wonder how many watts the 12v microwave can be? What about for a cooktop?

Im new to this but have read some members say that eventually more 48v appliances will become available as more people go off grid.

 

[CoolWill]

If a DC well pump fails, can you run down to Lowe's and pick one up? What about the fridge? I think using AC appliances affords you options and sustainability.

 

[eXodus]

Are you avoiding propane all together?

What about for a cooktop?

Propane is my cooking plan and backup heat-source. I'm currently testing that at my place, and when I just use propane for cooking I get by with 2-3x 20lbs propane cylinders in a year.

wonder how many watts the 12v microwave can be?

Im new to this but have read some members say that eventually more 48v appliances will become available as more people go off grid.

The 12V Microwave is 600-700w. Like a dorm Microwave, not insane powerful but should make a regular plate warm.
More and more 12V 24V 48V appliances are getting released all the time.

If a DC well pump fails, can you run down to Lowe's and pick one up? What about the fridge? I think using AC appliances affords you options and sustainability.

I have a Class A Motorhome where we currently live out from part-time. That is my backup solution for all those reliability problems. It always has a full water and gas tank.

My regular AC fridge just failed two months ago, just went through this exercise- do you really think Lowes/Home Depot has any spare parts which fit? Even most of the refrigerators there are DISPLAY ONLY You can only order in store and not take one with you....

So, I turned the fridge in my RV on - waited a few hours and moved all food from my house to the RV.
I figured out the broken parts and ordered it with Amazon overnight - and the fridge was running again the next day.

But I'm concerned about options and long term support, that is something I agree with you.

 

[OzSolar]

In "the bad old days" of $4/watt for 75 watt panel it kinda/sorta made sense (but not really) to do this but nowadays it doesn't even come close. Glass is so cheap now I would suggest you don't even think about it for a full time residence.

 

[Jacob89]

It would make sense to me to have a small, cheap 12v system to run cheap low power 12v stuff (lights, chargers, even small 12v pumps and fridges). But for all the higher powered stuff I'd rather spend my money on having a back up inverter(for redundancy) and be able to buy and use whatever regular, cheap, easily available AC appliances I want.

 

[v_green57]

One thing to always keep in mind with 12V -

For a given load, 1/10 the voltage vs. 120V means your wiring is carrying 10X more current. Requiring larger gauge wire. Which is more expensive.

 

[v_green57]

It would make sense to me to have a small, cheap 12v system to run cheap low power 12v stuff (lights, chargers, even small 12v pumps and fridges). But for all the higher powered stuff I'd rather spend my money on having a back up inverter(for redundancy) and be able to buy and use whatever regular, cheap, easily available AC appliances I want.

Live in a travel trailer. Already pre-wired for this exact scenario.

It's what I am doing. Not as "cool" as a tiny house, but in my world, practical wins over cool every time.

 

[Jacob89]

One thing to always keep in mind with 12V -

For a given load, 1/10 the voltage vs. 120V means your wiring is carrying 10X more current. Requiring larger gauge wire. Which is more expensive.

That's a good point. OP mentioned a 24000btu heat pump(which seems huge for a tiny house). Even at 48v that's going to pull some significant current and need some expensive heavy cable if it's not right next to the batteries. Plus high current dc fuses and circuit breakers are more expensive than for AC.

 

[yodamota]

every time i look at going all dc for appliances, things usually just look cheesy. a 12v coffee maker pulls 14amp at 12v. it makes 20oz of coffee in 20 minutes. that means two people could have one 10 oz cup of coffee. lol.
than a water kettle at 12v (pulls 12.5amp) 30-40 minutes to boil one liter of water. LOL good lord. I also see a 12v water kettle(pulls 8-10amp) which holds 375ml. boils 375ml in 16-20 minutes!

I do however wish i could find 120v appliances which operated at lower wattages. I opted for a 1000w inverter for my tiny house. Id love a 700 watt induction cooker. most are rated for more than that. or an electric kettle in the 700 watt range.

 

[eXodus]

That's a good point. OP mentioned a 24000btu heat pump(which seems huge for a tiny house). Even at 48v that's going to pull some significant current and need some expensive heavy cable if it's not right next to the batteries. Plus high current dc fuses and circuit breakers are more expensive than for AC.

The 24k heatpump needs 1300w - so roughly 26A - not a giant cable. I've put it on there - because the 12k is only $200 cheaper and there is nothing in between. Since it's variable speed compressor and fans I'm not concerned about oversizing.

Many of the DC appliances are highly efficient - so the current is manageable.

In "the bad old days" of $4/watt for 75 watt panel it kinda/sorta made sense (but not really) to do this but nowadays it doesn't even come close. Glass is so cheap now I would suggest you don't even think about it for a full time residence.

Yes, solar panels are cheap, batteries are not yet, part of my calculation is getting the standby draw down. Inverters burn through a bunch of power doing nothing.

I'm thinking about a Solar-Carport- Bifacial - Pergola attached to the tiny house. The roof would be not big enough to produce sufficient power over the winter months.

For a given load, 1/10 the voltage vs. 120V means your wiring is carrying 10X more current. Requiring larger gauge wire. Which is more expensive.

The 12V fridge has a 6A ramping.

I currently have a 3000W AIO inverter in my RV on a 24V system. So I'm used to running large conductors. True, large cables are expensive but aside of the DC microwave - all the DC appliances are sub 30A. most are sub 10A, Nothing a 10 gauge can't handle.

a 12v coffee maker pulls 14amp at 12v.

Coffee is going to be a problem no coffee no workie. Guess all the short time use kitchen appliances will be the biggest hurdle. (and washer/dryer)

I'm not against running a inverter, just want to minimize the use of it. Most of the things around me running on DC current - so everything has power brick attached to convert down from 120V.

Live in a travel trailer. Already pre-wired for this exact scenario.

It's what I am doing. Not as "cool" as a tiny house, but in my world, practical wins over cool every time.

Currently live in a 25ft RV during season, it is very practical, just the insulation leaves a bit to be desired. I had been considering some better insulated 4 Seasons RVs but the built quality lately is pretty horrible.

But I agree, some the newer RVs aimed at working professionals are pretty amazing and check most of the boxes for DC living.

Have you seen the IBEX RV-Suite and the Cherokee Timberwolf Mini Loft? Those are like Tinyhouse - Travel trailer Hybrids.

This is different: The category-busting Timberwolf 16ML

Today’s RV review is of something very, very different—the Forest River Timberwolf Mini Loft 16ML. To be honest, the RV industry has been a bit shy in the i

www.rvtravel.com

https://www.rvtrader.com/blog/2023/...rv-open-house-2024-ibex-rv-suite-rvs1-preview
no idea what they cost

 

[Madcodger]

As others have noted, it's probably not the path I would take. DC appliances offer fewer options and can be much harder to replace. With AC appliances now being much more energy efficient and having a much wider selection available, the larger inverter option is the path I'm taking.

 

[CoolWill]

You could also go with a mixed system. Make the lighting DC, but put the AC appliances on an inverter that you turn off at night. You could use a DC refrigerator or you could use an inverter dedicated to the fridge that's just large enough for that load only.

 

[pvgirl]

The 24k heatpump needs 1300w - so roughly 26A - not a giant cable. I've put it on there - because the 12k is only $200 cheaper and there is nothing in between. Since it's variable speed compressor and fans I'm not concerned about oversizing.

While the compressors are variable speed they still have a range of outputs they operate in, and as you go up in size the lowest output they can operate also goes up.

 

[wopachop]

I use my 120v coffee maker as a pour over all the time. Boil water with propane stove.

Even on 120v I will let the coffee maker fill the pouch. Let it steep 5 or 10 mins and turn the power back on. Guy on YouTube mentioned that trick for more flavorful coffee.

If you hit Walmart, check their sale section. They always have fancy expensive coffee on sale where I live.

I just woke up. I can you tell what's on my mind???

 

[AHTrimble]

If a DC well pump fails, can you run down to Lowe's and pick one up? What about the fridge? I think using AC appliances affords you options and sustainability.

My DC well pump controller died after a bad lightening storm. Contacted the company and had a replacement the next day. Pump would have been the same resolution. Lowes in this area doesn't carry well pumps. The biggest expense and wait time would have been a well company to come out and pull & replace. But I resolved that by initially installing the well pump myself with flexible gas pipe that can be pulled with my UTV. Thankfully I have a 1100 gal water tank for storage with a 330 gal emergency storage to carry me through most any wait period.

Now, I totally agree with you...AC appliances are the way to go.

 

[AHTrimble]

The 24k heatpump needs 1300w - so roughly 26A - not a giant cable. I've put it on there - because the 12k is only $200 cheaper and there is nothing in between. Since it's variable speed compressor and fans I'm not concerned about oversizing.

Many of the DC appliances are highly efficient - so the current is manageable.

Yes, solar panels are cheap, batteries are not yet, part of my calculation is getting the standby draw down. Inverters burn through a bunch of power doing nothing.

I'm thinking about a Solar-Carport- Bifacial - Pergola attached to the tiny house. The roof would be not big enough to produce sufficient power over the winter months.


The 12V fridge has a 6A ramping.

I currently have a 3000W AIO inverter in my RV on a 24V system. So I'm used to running large conductors. True, large cables are expensive but aside of the DC microwave - all the DC appliances are sub 30A. most are sub 10A, Nothing a 10 gauge can't handle.


Coffee is going to be a problem no coffee no workie. Guess all the short time use kitchen appliances will be the biggest hurdle. (and washer/dryer)

I'm not against running a inverter, just want to minimize the use of it. Most of the things around me running on DC current - so everything has power brick attached to convert down from 120V.



Currently live in a 25ft RV during season, it is very practical, just the insulation leaves a bit to be desired. I had been considering some better insulated 4 Seasons RVs but the built quality lately is pretty horrible.

But I agree, some the newer RVs aimed at working professionals are pretty amazing and check most of the boxes for DC living.

Have you seen the IBEX RV-Suite and the Cherokee Timberwolf Mini Loft? Those are like Tinyhouse - Travel trailer Hybrids.

This is different: The category-busting Timberwolf 16ML

Today’s RV review is of something very, very different—the Forest River Timberwolf Mini Loft 16ML. To be honest, the RV industry has been a bit shy in the i

www.rvtravel.com

https://www.rvtrader.com/blog/2023/...rv-open-house-2024-ibex-rv-suite-rvs1-preview
no idea what they cost

My research showed bifacial is not cost/benefit realistic at all...at least in my area. I bought used panels from Santan and varied the orientation for max production winter/summer. Great cost/benefit ratio.

My Victron Quattro 48v/5kw inverter uses about 30w in standby.

Keurig for wife's tea, no issues at all. Heats up super quick with little power usage. I hear it does coffee as well.

I spent 3 years planning our 100% off-grid glamstead...AC house wiring and appliances were hands down the right way to go. And 4 years living with it has proven it. The DC well pump is a completely separate system and fantastic!!