Re-Do Converter vs. Inverter

[topjimmykw]

Hi I am re-doing the electric in my '75 Argosy, and I just want to understand how the electrical system should be laid out between converter and inverter? I get that I cannot have my Powermax Boondocker plugged into my Samlex inverter while I am running on battery power... do I just need to remember to turn off the Boondocker every time I switch to battery power? Or does something go on between the two that I am missing? Thank you!

[lewster]

Originally Posted by topjimmykw

Hi I am re-doing the electric in my '75 Argosy, and I just want to understand how the electrical system should be laid out between converter and inverter? I get that I cannot have my Powermax Boondocker plugged into my Samlex inverter while I am running on battery power... do I just need to remember to turn off the Boondocker every time I switch to battery power? Or does something go on between the two that I am missing? Thank you!

My first question to you would be: why are you messing with 2 basically inferior products when you could do a seamless installation of a Magnum inverter/charger that has 4-stage charging, temperature compensation and the ability to power whatever 120VAC circuits that you want (heavily dependent, of course, on the size of your battery bank...with the specific exception of your air conditioner).

Add to the mix the fact that if your Chinese built Samlex inverter goes down, it is a throw-away....as are just about every converter made today. ANY US-made Magnum inverter/charger is fully field serviceable in the rare event that you have an issue. Also, a complete understanding of AC and DC circuits and their inter-relationship would be very helpful in this situation.

[DKB_SATX]

Is your intention to use the inverter to power all of the 120v outlets in the trailer? Or are you going to put in dedicated inverter outlets?

Dedicated outlets (or perhaps a transfer switch to carry some of the house circuits) would be the easiest thing, because in addition to the converter, you'd want to make sure any automatic stuff like a newer refrigerator with an auto switchover to 120v doesn't get powered by the inverter, that would drain a battery in a hurry.

The converter is a pretty straightforward thing as far as 120v current is concerned... it's getting power or it's not, I don't know of any way for it to tell whether it's being powered by an inverter, a generator or shore power. If it's on a circuit the inverter feeds, it would come on and try to charge the battery bank the inverter is trying to discharge, and if you can get that perpetual motion machine to work you'll be a rich man!

In expensive setups, RV manufacturers use inverter/chargers that manage that switching themselves, but they also set those RVs up so that the inverter or inverter/charger doesn't power all the outlets, so you don't accidentally switch the refrigerator over or try to run the microwave off the inverter.

EDIT: Hehe... and while I was typing, Lewster was offering a much more authoritative recommendation for an inverter/charger, with brand name and all.

[topjimmykw]

Lew, thank you for the unpaid Magnum ad.

DKB, I was hoping to power all outlets with the inverter... I am trying to avoid dedicated inverter outlets. I thought of that, but then I thought there must be a way around it.
So maybe a transfer switch on the outlet powering the Boondocker?

Thank you!

[lewster]

It's relatively easy to select what outlets you want to power with your inverter. Does it not already contain an internal transfer switch? Any quality inverter should have the ability to pass thru 120VAC up to it's design limits to your 'inverter circuits' and when no 120VAC is present should then create 120VAC from your batteries for those same circuits.

Your converter should have no bearing on what circuits you power with your inverter, unless you want to run the entire trailer from it.

Most inverter installations are not wired this way..........

[topjimmykw]

Thank you Lew, I am going to check out that inverter. Good advice!

[perryg114]

Why you wanting to run 120 VAC with the inverter? If you are running off batteries only, the inverter will kill your batteries pretty quick. Inverters consume and more power than you get out of them. Just an inverter powering nothing will run a battery down pretty quick.

Perry

[lewster]

A quality inverter with an integrated transfer switch will use no battery power if not in the inverting mode, with the possible exception of a slight trace draw to power the remote panel. Most inverters will operate at 85% or less efficiency when inverting 12VDC to 120VAC, but you shut them off when not in use.