Dual Voltage Power System?

[Badmiker]

Hey people,

I have a quick question for the builders/users here.

We are planning our build currently so are doing tone of research and planning including a healthy amount of CAD.

As we have lived the last 15+ years outside of our 'home' country we have become used to 220VAC products. As an engineer I am also more enamored with the higher supply voltages. I have seen that many European builds use a 220VAC inverter whereas the US and Canada use 110VAC inverters.

Has anyone used both? We would rather use 220V for the heavy lifting of things like induction cooktops and the like but some products like the Instant-Pot are only available in 110V...

I was thinking of a beefy 220V unit for the majority of the AC use and then a 2nd lighter 110V for a specific outlet or 2 to run very specific accessories/tools.

As we plan on using the vehicle globally, the 220V would also allow locally available components to plug in directly. More often ... ish. Stupid standards around the world.

So... thoughts?

 

[Badmiker]

Excellent!

I'm glad it does not seem like a stupid idea to someone else.

Now to see if I can run the DC side at 24-48V ...

 

[Neil]

If you want to travel world wide your system has to cope with between 90v and 230 and 40 to 60 Hz.

In some countries such as Brazil you will have 110 and 220 in adjacent sockets with no signs on them.

Charging is easy , many chargers can handle this range. If I am not sure I take all my power from an inverter so it's nice and clean and just let the batteries charge behind the scenes.

The best set up is being in a position that you can provide your own power. In 18 months in South America we have plugged into mains power no more than about 5 times. This is your best option if you can as some electricity is all over the place and you will never see an earth.

We however, are low users of power, the biggest appliance we have is about 800w and is rarely used. If you have big induction cookers eta and rely on plugging into mains power I would incorporate lots of protection such as breakers and surge protection eta

Neil

 

[Badmiker]

We are planning on a fairly large solar array to generate our own juice. I am also thinking of a larger engine alternator or possibly 2 if I can get them to fit. I am hesitant to install a generator at this point as the battery and solar options are getting better and better.

 

[Joe917]

We have a 2700 Watt 230 v inverter charger and a 300 watt 115v inverter. 230v washer, microwave,air con, and plan induction cooker to replace our propane. 630 watts solar. 500 AH lead batteries. Generator. so pretty much your planned system.
We almost never plug in.
Like Niel says get an inverter/charger that can handle all voltages if you can.
Our generator gets run for Air conditioning and when the microwave is run to take the load off the batteries.
Lithium is the way to go if you want to avoid a generator as high discharge current is hard on deep cycle lead batteries.(or avoid microwave, induction cooker etc.)

 

[DiploStrat]

As noted, there are several ways to do this. The usual is to create your own island of either 110v or 220v. While 220v has benefits, certainly, if the beast is going to spend most of its time in the US, then I would go with 110v. A lot also depends on where you are going to build. Build in Europe, then go with 220v appliances. Build in US, 110v might be best. (Small imports tend to be expensive and best saved for emergency replacements.) I'm not sure that the advantages of 220 are worth the effort, but there was one gentleman do did build a split system as he chose a 220v induction stove.

Remember that inverter/charger units want to pass shore power straight through. For one of these, a transformer may be the best solution. (Assuming that your loads are frequency agnostic - check the microwave.)

Another option is a multi voltage or two chargers. The multi voltage offering the advantage of being idiot proof. (Latins to use the same, unlabeled plug for 110 and 220v - I had a smoking TV .... ) Blue Sea makes one, and while they tend to be smaller, that may be enough, especially if you have a decent alternator and solar. (And remember, you are unlikely to get 30A outside of the US.)

The real goal is a truck that needs to plug in only rarely. This CAN be done, several of us have done it. Especially if you can live without A/C. ;-)

All the best.

 

[grizzlyj]

We have a 220v Instant Pot
You would need to choose wether to go for a universal charger which won't mind what you give it, or for instance a 220v charger with a 110v to 220v transformer for it's input as and when required. You would have to then check which you're going to give it and switch where the power goes accordingly beforehand.
You also need to choose what plug type and voltage you want inside. Some of each?!?

 

[Neil]

We have gone for 220v appliances in the vehicle with UK plugs.

Ref the input. If your charger or inverter are voltage critical and have no range . Ie they are either 110 or 220v then I think mistakes will occur pretty soon.

As said earlier some countries will run both and the two identical outlets will be side to side in the same bank. By testing one wouldn't guarantee the next one.

Luckily most plugs are 2 pin so reverse polarity isn't a problem. You can simply turn the plug 180 degrees

You would have to test with a meter each time. I personally am too lazy for that I like to just plug in knowing the system can handle anything you throw at it. With a manual system where you have to change it over each time I would forget and fry it

Earth are very rare so some protection devices struggle without it.

I am about to install the large copper stake and wire from the chassis approach. I have had too many tingles whilst working on the truck.

Neil

 

[luthj]

If the vehicle in question is mostly used off the grid, I would design as follows.

All vehicle AC systems can be driven from inverter or DC power.
Shore power is routed exclusively through a high powered DC charger directly to the DC buss. Select a charger that is world capable, and has good isolation to protect from a surge or dirty power. (More common than you would think).

Design the equipment to operate on a single AC voltage/frequency standard. This simplifies what will already be a complicated wiring scheme. If there is a specific piece of equipment that cannot feasibly be run via the shore->DC-Vehicle AC approach, then its best to isolate it to its own shore power line, or use some type of switching (Air Conditioner etc) The switching would need to detect if shore power is compatible with the equipment. Though a manual switch can work if the operator is unfailingly vigilant in checking before connecting.

If desired a few "straight through" outlets can be wired in the vehicle. These would be a different color, and powered only when shore power is connected. It is incumbent on the operator to know if these are compatible with the devices plugged in.

The only advantage of a dual 120/230VAC bus in the vehicle is being able to purchase and use handheld equipment in country and use it onboard. Given the availability of international shipping, I don't see much value in the extra complexity. If it is really a concern, a inexpensive modified sine inverter in the 200-1000 range can be wired for portability, and kept in a spares box for the rare need, or maybe wired to a single outlet. Though given the range of outlet plug types used the world over, you will likely end up splicing plugs or using adapters.

 

[Joe917]

The only advantage of a dual 120/230VAC bus in the vehicle is being able to purchase and use handheld equipment in country and use it onboard. Given the availability of international shipping, I don't see much value in the extra complexity. If it is really a concern, a inexpensive modified sine inverter in the 200-1000 range can be wired for portability, and kept in a spares box for the rare need, or maybe wired to a single outlet. Though given the range of outlet plug types used the world over, you will likely end up splicing plugs or using adapters.

Don't count on international shipping outside North America and Europe. Nobody wants to be waiting around for weeks for a package to clear customs, if it arrives at all.

 

[Badmiker]

The other reason we are looking at a 220 system is due to every other piece of electronics we have bought for the last 15 years being of that standard or, like modern mobile phone chargers, dual voltage. We plan on building in the USA but leaving once the vehicle is done. We would be doing this because while we have lived on Visas for the last 15 years and will be continuing for the next 4 years here in China, once I retire, no visa outside of the USA for a year or 2. Also, currently all my retirement funds are in USD and RMB.

@grizzlyj , where did you source a 220v instant pot? We would love to pick one up in the next few years as we transition from home living to vehicle living. We are currently using a traditional pressure cooker.

 

[grizzlyj]

Costco UK had the Instant pot, made in China! But I like our WMF pressure cooker much better

Years ago I was given a hook up cable that the earth lead came out of the plug to a long spike to whack in the ground. But I was later told that would be very dangerous, can't remember why, but never used it anyway.

Also, having watched people on construction sites put a building's earthing rods in with a special and expensive meter, and those rods getting whacked in several meters more often than not (in S.E. U.K. at least) before a sufficient earth was obtained, I don't think anything you could use that would be retrievable rather than disposable would be worth actually relying on.

Part of Ulrich Doldes book talks about possibly including some sort of Faraday cage in the camper construction if you opt for fibreglass throughout, not much point if you then try to earth yourself

Badmiker I would suggest that you aim to be as self reliant in solar and battery capacity as possible, but also remove the need for mains at any voltage. The only reasons IMHO to have lots of mains power are a/c or induction cookers as said already. Gas hobs are OK in my view, a/c could be run from a genny carried specifically and only for that. That leaves no reason to deviate from a 12 or 24 volt only camper. Pick a laptop, tv, phone charger, diesel heating, fridge etc etc that are happy to run at that. Minimal inefficiencies then in using what will be a precious battery resource.

Since I always check for an earth before hooking up I don't see it as a big deal to check the voltage at the same time as and when appropriate?

 

[dwh]

I used to use one of these to drive ground rods. In the U.S. they are 8' x 5/8" copper clad, with a part number stamped into one end and a point on the other end. Inspectors look for the part number to make sure you didn't drive it halfway, hit a rock and got stuck, then just sawed off the extra.

Even in rocky conditions it would always eventually drive it in all the way. Of course, I have no doubt a few of those rods probably came out looking like corkscrews underground, but they passed inspection.

If the resistance is greater than 25 ohms, then you have to drive a second rod at least 6' from the first.


The thing about ground rods is that under normal conditions, they are never supposed to actually carry any load. They are purely a backup in case something goes wrong, there is still a path to ground so a breaker can trip.

But...I've seen several cases where the neutral to the transformer was dodgy (high resistance) and the cold water ground was dodgy, and the gound rod was carrying the return load for the whole building.

And the rod gets hot...as in you can feel the heat with your hand.

If you plugged your truck into some dodgy shore power, then drove a rod to ground your truck, you could potentially create a situation where your truck's wiring and ground rod becomes the path of least resistance and carries the return current for...well, maybe the whole frigging campground.

At least...until your ground wiring melts...

 

[dwh]

As for two inverters...no worries. I'm looking at doing the same thing. A 240v to power a high-efficiency Fujuitsu mini-split a/c, and a 120v for everything else.

For global use, as mentioned, just make sure your battery charger can accept either one.


It gets a bit more complicated if you intend to have a transfer switch that feeds the shore power directly to the receptacles. In that case, you would likely need an isolation/boost transformer.

http://www.charlesindustries.com/main/ma_iso_boost.html

The "gotcha" with those, is that they transform the voltage, but not the frequency. So say you use it to step down 240v/50hz to 120v...well, it'll be 120v/50hz.

That's not a deal breaker. Generally the only issue is with digital clocks/timers that operate by counting freqs running slower (or faster if it's designed for 50hz and you run it at 60hz).

 

[dwh]

Just remembered another case, where the rod was stuck into sandy high-desert soil about 2', and about halfway up it had a 90 bend in it and was pushed up against the building. You could just flick the thing with your fingers and watch it swing around the other way. A 6 y.o.could have yanked it out of the sand with one hand.

The reason they called in the electricians was because the coax cable for their cable TV went up in smoke. When the cable guys came out to take a look, they freaked out.

See, at the main cable distribution box at the street, there was a properly installed ground rod. So when the crimp on the neutral drop from the transformer crapped out, and the cold water ground hadn't been hooked up for who knows how many years, and the ground rod was utterly useless...the coax became the current return path that carried the load for the building. Until it went up in flames.


The fix was, A) cut loose the drop from the pole, B) reconnect the cold water ground and drive two new ground rods, C) cut off the crimps and reconnect the drop using split-bolts and D) put in a call for the linemen to drop by and install new crimps whenever they got around to it.