Inverter questions

[mattbaxter]

Literature on our Roadtrek says to only have inverter on to (1) charge batteries when plugged into shore power or (2) provide household current when not plugged into shore power.

Wondering if you experienced folks leave the inverter off if not meeting these two possibilities, and if turning it off in the control panel above the sliding side door is enough or if I need to go in the back of the van and toggle the off switch on the inverter itself.

And on a somewhat related note, the air conditioning unit comes on fine when plugged into shore power but does not without shore power. Even if the vehicle was recently plugged into shore power and then went on a ten hour drive (under hood generator). Without shore power, A/C makes a brief sound like it's about to turn on but then doesn't. Could this be a bad battery or inverter?

Thanks for any advice!

[markopolo]

Usually, if the inverter has a remote panel then you turn it on/off from there.


How much battery capacity does your RV have? Are the batteries lithium or lead acid (like AGM)?

[mattbaxter]

So you would leave the switch "on" on the inverter and just switch the remote on and off as needed?

Four AGM batteries, 2 under hood, 2 elsewhere.

No A/C after a long charge is a new problem.

[markopolo]

Hopefully someone with the same model inverter will answer your question.

I've had a few inverters with remote switches and all were controlled from the remote with no need to do anything at the inverter itself.

Does the air conditioner start when the under hood generator is running? If so, that will indicate that the inverter is working as expected.

Batteries do get used up & need to be replaced at some point. It could be other things also such as a battery connection or ground that's loose or corroded.

[Yoshimura]

Originally Posted by mattbaxter

So you would leave the switch "on" on the inverter and just switch the remote on and off as needed?

Four AGM batteries, 2 under hood, 2 elsewhere.

No A/C after a long charge is a new problem.

No, leave the switch on the inverter to OFF and use the remote switch to control it. If the switch on the inverter is set to ON, the remote switch position won't have any effect and your inverter will always be on. Set the switch on the inverter to OFF and forget about it.

With the basic 105Ah AGM battery, people are getting about 15 min of AC run time time when the battery if fully charged. Try with the engine running (using the GU - Underhood Generator). If it works, the problem is your battery. If not, it could be the inverter.

Which model you have?

[mattbaxter]

Thanks to you both. Appreciate the off switch suggestion.

With engine running, A/C comes on for about 10 seconds. Then cuts out. You both seem to say that indicates an inverter problem.

It's a 2016 Roadtrek SS Agile

[booster]

Originally Posted by mattbaxter

Thanks to you both. Appreciate the off switch suggestion.

With engine running, A/C comes on for about 10 seconds. Then cuts out. You both seem to say that indicates an inverter problem.

It's a 2016 Roadtrek SS Agile

As was mentioned earlier by Marko, did you try to run the inside air conditioner through the inverter, no shore power, with the engine running? It is possible you have a bad UHG or separator and are not charging the batteries when running the engine so they aren't full enough to run the inverter and are going out on the low voltage cutout. If it runs the AC with engine running, the inverter would likely be OK.

[Yoshimura]

Originally Posted by mattbaxter

Thanks to you both. Appreciate the off switch suggestion.

With engine running, A/C comes on for about 10 seconds. Then cuts out. You both seem to say that indicates an inverter problem.

It's a 2016 Roadtrek SS Agile

What our inverter look like? What the inverter does when A/C cuts out? No alarm?

[markopolo]

As Booster noted it could be the UHG.

If there's a problem with the UHG / regulator with output being low or not happening at all then you'd get the result you reported. Check the voltage at house batteries with engine running.

Do you know if the primary alternator is used at all for the house side? I recall that at least some Etreks utilized both alternators for house battery charging & loads but don't remember anyone mentioning that with the newer builds.

Yoshimura makes a good point. There should be an inverter alarm & that could help with the diagnosis.

[Yoshimura]

Also, when the A/C start, it will initially just run the fan (light load) and the start the compressor (heavy load) a few seconds later to reduce the initial load. At least, on my unit. So, I'm surprise it only did a brief sound. Is your inverter able to run other AC appliances?

[booster]

I just looked at the brochure for a 2018 SS Agile that listed the 4 AGM battery setup as an option, and the UHG as a separate option, so I think it may or may not have one.



Either way, it doesn't negate the need for an engine running test to see it will work that way as a stock alternator should come very close to providing enough at idle until it gets too hot.

[Yoshimura]

Originally Posted by booster

Either way, it doesn't negate the need for an engine running test to see it will work that way as a stock alternator should come very close to providing enough at idle until it gets too hot.

I think he tried it.

Originally Posted by mattbaxter

With engine running, A/C comes on for about 10 seconds. Then cuts out. You both seem to say that indicates an inverter problem.

[booster]

Originally Posted by Yoshimura

I think he tried it.

Yep, looks like it. That would also be the time it would take to trip a breaker in the engine to battery line, too, so would be good to get a meter on it like Marko said to be sure the alternator is connecting.