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tommy_o · 04-27-2015, 04:05 PM

Hi folks! I apologize for starting this fairly broad, but I'm not sure where to start troubleshooting.

I picked up `78 Argosy 30 a few months ago. It's been a great temporary home while my wife and I build a house, but there is this one little problem that's bugging me (well, one main one).

The previous owner replaced the inverter with an IOTA DLS-55 and put in a new battery. They also ran another hookup out the back that is used exclusively for the inverter (the inverter is plugged directly to this extension).

If I plug the inverter directly into the 120v outlets in the Argosy, it immediately flips the breaker. Separately, the 120 hookup works fine and the inverter hookup works fine, but I cant get them workin right together.

Where should I go first to troubleshoot? I'm comfortable working with electricity, but I've never tackled a 12v + 120v system like is in an RV. Should I unplug everything non-essential (water heater, fridge, outlets if possible) and work my way back in?

If it's important, the water heater (not original) wont work on electric either -- it blows a fuse in the 12v fuse box. The refrigerator throws the breaker as well, and I've already unhooked that to no effect.

Thanks!

tommy_o · 04-27-2015, 04:52 PM

I posted this twice in 2 different subforms, but am not sure how to delete. I hope it doesnt offend!

mgjurina · 07-04-2015, 01:50 PM

I see your having electrical issues with your Airstream. I'm re-wiring my airstream, all new cables, 12 VDC and 120 VAC to include new inverter and battery. Fortunately, I'm an electrician (engineer) by trade. Let's talk DC first. 12 VDC systems will not parallel with 120 VAC systems. If you are blowing fuses, then the issues are: grounded leg, shorted terminals, or overload. DC fuses are rated and the rating is stamped on the fuse. Therefore, if your 20 amp DC fuse is blowing, you can be sure that you are exceeding the 20 amps. In 120 VAC systems, the following listed above is also true. Fuses are stamped with their rating. The first thing I would do is to isolate the AC to DC inverter and remove all AC and DC loads. Start with the simple stuff and work your way out. With all DC loads and AC loads removed, plug in the AC (120) on the inverter. Measure the DC output, you should read some value above 12 VDC. Now, disconnect the AC and connect your battery. Make sure you pay attention to polarity (DC+ and or DC-). Now plug your AC (120) back in and measure the voltage at the battery. The voltage should be above 12 VDC (around 13.5 VDC). Now unplug your AC (120) and check your battery voltage. The reading should be around 12.5 VDC. Now you have confirmed that your inverter battery charging circuit is operational. Now turn on the AC and start introducing DC loads 1 at a time. During this process, measure the current flow on the DC+ leg. Make sure you don't exceed the DC rating of your inverter. If you are, then you need a larger inverter. Now, with all the DC loads removed, repeat the process with AC loads starting with the smallest to largest. Measure the current on the hot leg (L). Make sure your current does not exceed the rating of the inverter input and the AC breaker. If it does, then you will need a larger inverter and/or breaker. Typically, I would use a 60 Amp breaker for my main breaker for AC loads and size my inverter to 60 Amps AC. I hope this helps.