Am I A/C, D/C or Bi- Current?

[YankeeDespot]

Howdy. Ready for wiring. My bus came with camper guts, so I have a 32 amp converter, I have an inverted generator and will get and inverter soon.
So, seems I just need “house” dc for water pump and some interior stock lights I like. I have an absorption fridge, propane range and will install a wood stove come the chill. Do I need the converter for so little DC use? Worth it to charge the bus main batteries, or should I wire it to charge house amg batteries.
I guess, practically, are folks running more d/c gear, and will I wish I anticipated more d/c draw, or safely wire for a/c with an inverter. I’ll be adding solar as budget allows.
I’ve read a lot and can run wire, even built a tube guitar amp, but am confused as to which way to go.
Thanks in advance.
Doug
The Blunderbus

[john61ct]

Terms matter.

A/C is usually aircon,

AC being shore power or grid.

DC not d/c for your House battery and auxiliary loads circuit

kept separate from the Starter battery, engine loads.

What USian RV industry calls a converter is (should be) nowadays just a higher quality charger, which is responsible for recharging the House bank as well as running DC loads, either from shore power or a generator that produces AC, usually 110V in the US.

The inverter is opposite, from DC input to AC output.

Some people with really tiny DC needs (standard unit is 12V system, Ah per day) can make do with a very robust higher capacity "dual use" battery as their Starter, do without a separate House bank.

Might save say $400, but taking chances on being stranded needing a jump start. Some say the big versions of those little lithium jumper packs are enough as backup.

I advise against that, unless you get an Ah-counting battery monitor and actually measure your Ah per day usage, have to know what you're doing, just how much you can take out before cranking ability is compromised.

A pump and some lights could be anywhere from 5Ah to 30Ah per day, lot of variables involved.

Fans? Recharging screen devices? Can be lots of energy, again depends. . .

I'd say start with a couple Deka/Duracell 6V FLA from Sam's Lowes or Batteries+

An IGN solenoid will let you charge off the Starter (engine) circuit while driving

and of course a gennie is great if camping off grid for days

but to get good lifespan 5+ years from the House bank, really need at least a little solar.

Some kits go for under $300, and if it turns out you don't need the genset at all, quick payback there.

[JDOnTheGo]

Originally Posted by YankeeDespot

I guess, practically, are folks running more d/c gear, and will I wish I anticipated more d/c draw, or safely wire for a/c with an inverter.

What is your mission Doug? How do you plan to use your bus?

If you are living in it and want most of the typical "RV" style comforts, you will probably wish you had a 120VAC system (both inverter and shore) as well as a 12VDC system.

[YankeeDespot]

Ok. Thanks y’all. . I plan to travel a bit, then buy land and live in here while I build a shop for my guita making business.
I’ve thought more, and thinking of d/c DC (direct as opposed to Alternating) and fans, chargers, minimal lights when the generator is not running, I’ll want some DC equipment. I’ll get proper batteries. For those things I’ll need to run dedicated correct voltage DC lines. Coffee maker, microwave, air conditioner of course will require (I’m not spending huge $$ for specialty dc appliances) AC. The point of my original question I guess, is that to do it right I’ll want the converter to charge, and run the DC gear, and inverter for the AC gear. It’s ok. Just don’t want too much duplication, and wondered if I was missing some Big Secret.

[john61ct]

There are combi type inverter/chargers, but good ones like Victron are very expensive.

[dzl_]

Your core system will be DC in an off-grid build (and mobile systems are by definition off-grid). Your PV array is DC, your batteries are DC, and your vehicles electrical system is DC. And as an aside, almost every piece of common electrical equipment you come across (other than some motors, powertools, and a few other things) is DC.

All other things being equal DC will be more efficient for off-grid, the conversion from DC (batteries) to AC (at the inverter), is inefficient, you will lose 10-20% in the conversion, and the idle power consumption of the inverter can have an even larger impact if your inverter runs 24/7

On the other hand, AC wiring (by nature of being higher voltage 120v or 240v) is generally more efficient for high power appliances.

Its generally not a question of "which way to go" as much as it is a question of to what extent to use one or the other. Personally (because of the aforementioned efficiency advantages, and because low voltage DC is less likely to be fatal) I prefer to use DC for as much as possible.

But you will find others who prefer AC for almost everything (either because they have more familiarity with home wiring than DC, because they have a lot of high power household appliances, or because they want to be able to use the familiar and often cheaper residential appliances and gadgets they are used to using in their house and want to keep the creature comforts and familiarity of home).

Most people will fall somewhere in between.