Why a built-in and an extra inverter ?

simointe · 06-23-2021, 04:01 PM

Hello,
In my Roadtrek 190, 1986, I see there is an 30Amp 110V and the frig seems to be connected to one of the 2 outlets. So there is a second free 110 output.
I don't understand why the previous owner installed another inverter inside. The outlets in the van are the outputs of this very extra inverter. I guess there is something I don't understand ...
Is it because of lack of power ?

rowiebowie · 06-23-2021, 04:14 PM

Quote:

Originally Posted by simointe

Hello,
In my Roadtrek 190, 1986, I see there is an 30Amp 110V and the frig seems to be connected to one of the 2 outlets. So there is a second free 110 output.
I don't understand why the previous owner installed another inverter inside. The outlets in the van are the outputs of this very extra inverter. I guess there is something I don't understand ...
Is it because of lack of power ?

Welcome to the forum!

Kind of hard to trouble shoot if the prior owner did modifications. Generally, the vans were built with a transfer switch. This switch passes through 110/120v power when plugged in, generator power when it is running, or inverter power (only on certain outlets) if not plugged in.

Not sure what the unused plug is for, but I'll bet the prior owners mods were not due to a "lack of power" from 110/120v or generator. Most likely there was either no inverter originally, or they wanted more (and perhaps pure sine wave) power from the batteries when not plugged in.

simointe · 06-23-2021, 04:22 PM

The extra inverter is modified sin wave...
So you mean that the generator power and inverter power are exclusive ?
It seems not be my case cause obviously my house battery is charged while truck running and the frig works also, it can be on electrical mode when no propane.

GeorgeRa · 06-23-2021, 07:00 PM

I am guessing that you have the fridge outlet connected to shore/generator power input and other outlets to the inverter. So, you have two circuits, shore/generator power and inverter, no switching of shore and inverter with a transfer switch commonly done. This could be incorrect as you call this inverter an extra inverter, do you have two of them?

If my guess is correct and you have two circuits there is nothing wrong with this approach, I also have separate circuits of shore and inverter. You could consider replacing the converter with pure sine wave because modified sinewave could cause issues especially with inductive leads.

booster · 06-23-2021, 07:10 PM

Biggest question to me is what kind of frig it is. AC only dorm frig? AC/DC compressor frig? To or three way gas/electric/

It makes a huge difference if trying to run off inverter unless it is only while driving.

simointe · 06-23-2021, 07:15 PM

Yes I think you're right, even if I'm a little bit confused about the terminology: the thing that you called shore/generator power input, so the shore is when I'm connected to the grid for instance and the generator power input is when the camper convert the DC battery current to an AC current to the frig ?
I think I'm wrong when I call extra inverter, but for me this generator power input acts like an inverter, is that correct ?
Extra inverter in the sens that it is not built-in in the roadtrek.

GeorgeRa · 06-23-2021, 07:22 PM

Quote:

Originally Posted by simointe

Yes I think you're right, even if I'm a little bit confused about the terminology: the thing that you called shore/generator power input, so the shore is when I'm connected to the grid for instance and the generator power input is when the camper convert the DC battery current to an AC current to the frig ?
I think I'm wrong when I call extra inverter, but for me this generator power input acts like an inverter, is that correct ?
Extra inverter in the sens that it is not built-in in the roadtrek.

From the perspective of outputs in a van shore or generator or inverter are almost the same meaning they all provide 120VAC, but they use different energy source: generator < fuel, shore < grit, inverter < battery12VDC. Is you fridge absorption or compressor type?

- Absorption fridge can be powered by LPG, 120VAC or sometimes by 12VDC, - Compressor fridge by 12VDC or 120VAC.

simointe · 06-23-2021, 07:36 PM

Gas and 120, so according to the definition is Absorption fridge.

booster · 06-23-2021, 07:48 PM

Quote:

Originally Posted by simointe

Gas and 120, so according to the definition is Absorption fridge.

If that is the case, then you would not want to run the frig on the inverter unless you have a lot batteries (not at all likely) or are driving (that is commonly done by those that don't want to drive with the propane on and others to save propane)

When on shore power you would use the shore power AC or propane, and the propane will likely cool much better than any electric source.

The previous owner probably was moving the plug from one to the other outlets, depending on what situation they were in.

simointe · 06-23-2021, 08:03 PM

In fact the frig has an auto mode, which mean that it selects on the spot the gas in the first place if there is some gas, otherwise it uses electrical. Since I've already noticed that the fridge is functionning while the gas is off, it definitivly means to me that it could use the power inverter.
I have no problem with that if it uses the house battery (and not the truck battery).

booster · 06-23-2021, 08:14 PM

Quote:

Originally Posted by simointe

In fact the frig has an auto mode, which mean that it selects on the spot the gas in the first place if there is some gas, otherwise it uses electrical. Since I've already noticed that the fridge is functionning while the gas is off, it definitivly means to me that it could use the power inverter.
I have no problem with that if it uses the house battery (and not the truck battery).

Like I mentioned, you don't want to run on the house or van battery through the inverter unless you are driving and running the inverter off the alternator outpu. An absorption frig through an inverter takes too much 12v power and will kill a 100ah battery in a matter of a few hours, in most cases.

Sure, the frig will run off the inverter, but not for long, and it will also leave you sitting with no 12v power for anything else after it kills the battery.

Bertiboo · 07-02-2021, 03:47 PM

Are we sure the original poster used the correct terminology? A 1986 RV seems unlikely to have a factory installed inverter. Most RVs through the early 2000’s and even today had a Converter, not an inverter. A converter converts 110v ac power into 12v DC power to run the 12v lights and accessories in the Rv and to charge the coach batteries. The 110 source can be shore power, or from a generator if the unit has one. Many RVers hav e bought standalone inverters to use when you don’t have a source of 110v power….boondocking. This enables you to use your 12v power to output 110v through the inverter only up to the wattage rating of the inverter. Sorry for the elementary lesson, but if this is a terminology error, then the previous responses may not be answering the question.

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