Strange Power Drop Issues. How do you know the ATS is going bad?

Rshepard · 01-11-2021, 05:39 PM

Hello everyone. I'm having a fun little time dealing with some electronic gremlins on our 2017 Thor Aria 3901.

The issue I'm currently trying to figure out is this. Two times in the last 10 days I've lost power in the coach. The led lights flicker for about 10-20 seconds and then the AC circuits drop (Microwave and TVs turn off and back on).

The story has a little more detail but for now I'm wondering if anyone else recognizes this issue and can recommend where to look first.

Setup Background/Context. We are on shore power (SP) and I've got a SP monitor which shows the incoming power is clean and free of errors. My inverter is in passthru and both of my batteries are now in float charge mode. The Float mode turns off and on over time, and this morning when the glitch happened again, both my coach and chassis batteries were absorbing/recharging in float mode. I'm unclear why my batteries would be charging when I've been on shore power for a long time. Maybe it's a indicator to the issue.

I was told to look at the Converter? and the ATS by people I've spoke to in the park we are at but also wonder about the Inverter (Magnum MS2812) in all of this. I'm still learning about the power setup of this RV and have more to learn, AND I've got an RV repair visit setup for later this week. Just trying to wrap my head around this and understand the electrical system/setup.

Thanks in advance for any info.

pneumatics · 01-11-2021, 06:21 PM

That sounds SO much like a loose wire somewhere on the AC side and a good place to start is the ATS. These are rock and roll houses.....
However first check the power pole from the campground, these receptacles are known to wear quickly and a simple bump of the power connector could cause what you are describing. Have you been connected to the same pole over the last 10 days?
If you can, grab some of the wires one by one where they come out of the ATS and the distribution box (not inside the electrical box) and just pull and push then a little bit. If you duplicate the problem then you know where to look.
The inverter.... any power burp will cause it to reevaluate the battery charge and it's status, after a few minutes should return to normal.
Troubleshooting is always a process of eliminating what is working to fine what is not..... Good luck.

Pete'sMH · 01-11-2021, 10:51 PM

It does rather sound like a loose connection somewhere. I believe that if my ATS ever gives me a problem I’ll just ditch it. Wire the generator to a 30A outlet in the electrical compartment then just plug your shore power cord into it whenever it’s not actually in a shore power outlet. My Winnebago came that way and it seems like a simpler and more reliable system. Good luck.

TurnerFam · 01-12-2021, 12:01 AM

- your coach doens't have a CONVERTER, only an INVERTER
- your experience is more in line with a power issue at the Pedestal, not in your coach
- yes, your Charger will always be in Absorb or Float mode since your batteries are ALWAYS providing power to ANY 12v items - lights, fans, thermostats, furnace, etc.
- by your explanation, and if the power is coming back on by itself, the pedestal is the first place to look, whether the outlet, a loose wire, or even your own shore power cord end. It could also simply be a loss of power from the utility, or somewhere else 'upline' on the property. If no breakers have tripped, it doesn't sound like your own issue, but if nothing else shows, check all your wire tightness within your ATS, your Shore Cord, and even your Main Breakers in your panel.

Lt Keefer · 01-12-2021, 12:36 AM

I had a similar problem with my 29M when new and it was loose wires in the birds nest under the bed.

Rshepard · 01-13-2021, 01:32 AM

Thanks for the input!! I was waiting for it to happen again, and it just did.

I appreciate the input, which helped me look specifically at things. I went to look at the power inputs on the tower, and was getting 119V, 60H, and 0A on Leg1, and 12A on Leg2. So it appears power is still flowing into the coach even with the inverter set to "Disabled". This may be normal. I was told to keep the inverter off and NOT in pass-thru mode, like I was doid, while on shore power. So I did that part differently prior to this issue occurring this time.

This issue also appears under load, when we are cooking and have a rather large drain/load on the system. The lights flicker and then we loose power. It goes down and then comes right back, on battery. I think the ATS is not the issue based on the following.

There is a small "INPUT 30A" pop-out breaker which is popping on the front of the Magnum Inverter. It's very small and easy NOT to seee. So I'm guessing this is due to us not realizing we can't have everything on at once, BUT, I would expect things to SHED instead of pop an input breaker. So maybe SHED is not working too??

Not sure I know the problem, but it's narrowed down.

Googling now for more. Thoughts???

Now I'm looking into

pneumatics · 01-13-2021, 08:04 PM

So you have a 50Amp unit with the energy management system? These units can be real picky when it comes to the ground and neutral coming from the pedestal. And will cause problems if there is a faulty or intermittent connection on either one. Is there an indicator fault light on the energy management system that lights up?

Rshepard · 01-13-2021, 08:28 PM

I think I figured out the situation. Because we are new to RV life I wasn't connecting the technical dots correctly.

We use a 50 Amp input with our coach, which is two 25 Amp legs. The Magnum MS2812 inverter's 30Amp Input breaker is PER LEG. I didn't realize that. Because it's winter, the wife and I are running our electric fireplace and a small floor heater to keep the coach warm and toasty. When we go to cook dinner and use the induction cook top AND the microwave while watching TV, it's TOO MUCH. The load crosses over the 30 Amp per leg limitation/protection and trips the breaker.

To answer your question, yes our coach comes with and EMS. For whatever reason though it's not shedding the load. I need to figure out how to properly set that up so this doesn't happen again. I'd rather lose/shed a TV instead of pop a breaker.

So it appears everything is working as designed (minus the EMS). The fact that it happens when I've got my hands full cooking was preventing me from seeing the issue clearly. Also I pull up the docs and can see that the 30 Amp input breaker is in-line with the power pole input power. When it trips I shouldn't get any power from shore, and it should all pull from batteries.

There are some other factors associated with upgrades I've done since we got the coach 5 months ago as well, which further confused me, but those are also understood now. So much to learn, but we're getting there. Live and learn.

pneumatics · 01-13-2021, 09:23 PM

Great, sometimes symptoms over lap and create confusion.
Note that the 50Amp is 50Amp X 2 legs. So you have a capacity of 12Kw from the power pole (should never need that). There is ton of posts about how to measure the voltages at the pedestal and in the coach.
For EMS, that is different than the inverter. Here is what a typical EMS does (copied from Progressive power):

Will automatically shut off power to the RV when AC power falls below 104 volts, or is higher than 132 volts.
Will not allow power to the RV when there is reverse polarity, open neutral, open ground, or when 240 volts is detected.
Will shut down power if AC power frequency deviates +/- 9 hertz from 60 cycles per second.
Designed for outdoor use with a security locking bracket to prevent theft.
Time Delay for Reset: 136 seconds but will vary by manf.

My bet is that the EMS is functioning as it is intended to do, something is causing the drops external to that.
Good luck.

lwmcguire · 01-13-2021, 09:27 PM

Quote:

Originally Posted by Rshepard

I think I figured out the situation. Because we are new to RV life I wasn't connecting the technical dots correctly.

We use a 50 Amp input with our coach, which is two 25 Amp legs. The Magnum MS2812 inverter's 30Amp Input breaker is PER LEG. I didn't realize that. Because it's winter, the wife and I are running our electric fireplace and a small floor heater to keep the coach warm and toasty. When we go to cook dinner and use the induction cook top AND the microwave while watching TV, it's TOO MUCH. The load crosses over the 30 Amp per leg limitation/protection and trips the breaker.

To answer your question, yes our coach comes with and EMS. For whatever reason though it's not shedding the load. I need to figure out how to properly set that up so this doesn't happen again. I'd rather lose/shed a TV instead of pop a breaker.

So it appears everything is working as designed (minus the EMS). The fact that it happens when I've got my hands full cooking was preventing me from seeing the issue clearly. Also I pull up the docs and can see that the 30 Amp input breaker is in-line with the power pole input power. When it trips I shouldn't get any power from shore, and it should all pull from batteries.

There are some other factors associated with upgrades I've done since we got the coach 5 months ago as well, which further confused me, but those are also understood now. So much to learn, but we're getting there. Live and learn.

If your coach is 50 amp it is per leg, 100 amps available from a typical 240v pedestal or outlet

Rshepard · 01-25-2021, 10:14 PM

I believe the issue to this has now been fully uncovered. Taking the information input provided and reaching out to Magnum, I believe the culprit is this.

I had replaced my Magnum ME2012 with a MS28212 to utilize the increased watt/power capacity, and had it installed by an RV tech. It turns out they did a clean drop in and replace. Magnum said that the gauge of wire required for the MS28212 is bigger than the cable used for the ME2012. In hindsight that makes perfect sense. Because the gauge of wire was the old/smaller gauge, the true increased capacity of my new MS2812 was not being realized. The increased resistance over the smaller/older cables DURING (cold weather) PEAK USAGE was generating an increased resistance and popping the 30 Amp input breaker.

The sad part about this is that I now have to replace/upgrade all of the wires from the coach batteries over into the power box involved with inputs and outputs to the inverter. I'm told it's going to be about 30 feet of 4/0 gauge wire. That's not cheap stuff. Oh well. Add it to the list. It's all good.

Going forward, now I know that in very cold weather, with many things running, like a floor heater or the fireplace and heat pump, I need to turn things off prior to cooking with induction and/or microwave/convection.

Live and learn. Thanks for everyones input on this!!

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