Urgent - shore power not charging batteries!

MattyA · 05-01-2022, 07:26 AM

Help! I’m plugged in and the panel says I’m getting 50 amps from shore power. The inverter is in “standby”, when I hit the button to enable it, it works for 3 mins then says “disabled”. If I go under the coach and flip the battery disconnect switch off then on the inverter goes back to “standby”

Pleas help! Coach batteries are now at a critical state!

Forza 38w in case it matters

Many thanks in advance

**creativepart** · 05-01-2022, 07:49 AM

If your batteries are very low then turning on the inverter will naturally not work. So that error is probably not the issue. We don’t know enough about your Forza to provide complete help.

Yes, it very much matters what model RV you have. What year is your Forza? Is it a Xantrex inverter or a Magnum inverter? Do you know if your inverter is also the charger or do you have a converter/charger and an inverter. I believe the Forza is sold in both configurations.

If you have an inverter/charger the charger works automatically, you don’t turn on the inverter to activate the charger. Turning on the inverter only turns on that portion of the device.

It’s hard to guess what issue you have without knowing more information. Others will chime in with suggestions I’m sure.

MattyA · 05-01-2022, 08:07 AM

It’s a magnum inverter. I think the issue is that the inverter/charter (it functions as both) of not getting power from the shore line. For example I turned the cutoff to disconnect the batteries from inverter and the panel shows no AC input voltage or frequency, even though the main page panel shows show power is connected

Morich · 05-01-2022, 08:53 AM

Since the info is filed first by year, then model and length and finally possibly by serial number, we are hurting for getting specifics but this is a somewhat generic area and maybe a guess will get you started?

First year of the Forza seems to be 2017, so I went with that year but newer may be near the same idea and parts but in a different part of the RV????
Pssible newer design parts!
From a 2017 model year!!

Click these snips to get a better view.

The first trace in red is how the AC power gets from cord to transfer switch to get to first breaker panel and I would guess that is fine if major AC trouble is not reported?
But from that breaker, power goes to a different group of breakers where one goes into the inverter. It does show you have what I call a "combo" inverter/ charger which means the inverter portion turns DC power into AC, while the charger uses AC to make that DC!.

Second snip shows location in an outside compartment, with the others showing more detail and which wire is input and output.

CAREFULL!!!
If not up on dealing with electrical stuff, this is an area that can hurt you!
IF not finding breakers tripped, consider carefully before going deeper into the box of hurt!

If used to the deal, I would want to check breakers, then move to inverter to check if there is power coming out of the DC battery connections and then possibly look inside to assure it is not some loose wire on the AC connections?

MattyA · 05-01-2022, 09:17 AM

Many thanks. It’s a 2018, 38W. I also suspect the AC going into the inverter may be disconnected or something like that. But hard to see the side of the inverter that has the inputs and light that would show any error codes based on the way the inverter is mounted in the coach.

I’ll find out in about an hour when I turn on the engine if the slides depend on this power or if the chassis alternator can power the slides. Otherwise I’m headed for the emergency manual slide retraction procedure. The jacks too. Oh man I hope that all works

Morich · 05-01-2022, 09:50 AM

Quote:

Originally Posted by MattyA

I’ll find out in about an hour when I turn on the engine if the slides depend on this power or if the chassis alternator can power the slides. Otherwise I’m headed for the emergency manual slide retraction procedure. The jacks too. Oh man I hope that all works

Point of hope on this is the way the two battery strings are connected together when the engine is running!
If all is well on that area, the alternator, start battery and coach batteries are all connected. One reason to always start the engine first when using any of the high power items like slides, jacks or starting the genrator.

In theory and worst case, one can get the coach batteries charged if one drove far enough. Like six hours, maybe?

But for one time use, if one starts the engine and lets it run at a reasonably high rev, that will be pushing about 14 volts to both sets of batteriesand should operate slides and jackes well enough.

EDIT:
Looks like thisdrawing is correct for 2018 and the same as above.
https://www.winnebago.com/Files/File.../000211500.pdf

Morich · 05-01-2022, 09:56 AM

A bit different thought?
If hard to get the inverter down, possible any way to reach the DC connections? Looks like they might be some form of disconnect that could be taken off, so that one could check the DC coming out of those connects. That would let you see if you have an inverter problem due to no output OR if there is output but nothing reaching the batteries, then you would need to chase that path?

Morich · 05-01-2022, 10:03 AM

Different thought?
Is it possible to access the connections without moving the inverter out?
If possible,I might want to remove the DC connections to/from battery, then check for oputput out of the inverter /charger.
If there is output coming out of the inverter charger, one would need tomove along that path toward the battery and could avoid the trip of getting the inverter down/out????

But assuming life is not easy, more info on the wiring? I assume this would be inside the box.

wyocamper · 05-01-2022, 10:10 AM

There is a coach battery disconnect switch in the entry stairwell that can be accidentally bumped off and is easily overlooked. Have you verified that the switch is On?

MattyA · 05-01-2022, 10:23 AM

Yes well aware of the disconnect switches. In fact I disconnected the chassis battery last night out of an a abundance of caution in the event it was getting drained like the house batteries.

In any case, coach is running and slides are in and jacks are down. THANK GOODNESS!! And all the stuff that shut down when the house batteries went critical (like interior lights) are on. AC outlets working too so I guess the alternator is successfully powering stuff that shore power or generator wasn’t. Control panel says “no charge” in the “charger” section but finally “enabled” for inverter. Although AC input volts for inverter is still 0 and it indicates “faults”.

Well at least I’ll get home!!!!!

If anyone has more diagnosis ideas that would be awesome. Thanks for all the quick replies.

MattyA · 05-01-2022, 10:38 AM

Another thing I discovered. On the surge protectors unit where the shore power connects to the coach there was a red light and a blinking red light. Once the coach was started both of those lights went off. I’ll look it up in the surge protector manual but might be an issue there.

Morich · 05-01-2022, 12:37 PM

Okay, new info brings a new outlook as it sounds like the real problem was that you were plugged in but not actually getting AC power!
Not at all sure of the lights on each surge protector but red lights are almost always "NOT GOOD".

Were you using any Air units as they draw big power and will not befed by the inverter, so them running would be an indicator of whether you wer actually getting the full AC power to the RV!

MattyA · 05-01-2022, 12:47 PM

Wasn’t using a/c units. Tried to turn them on yesterday but they didn’t go on. So seems to be favorable for the hypothesis that the Coach wasn’t getting the AC power (didn’t realize those won’t run off inverter so good to know). Although house batteries apparently not charging with engine running despite alternator successfully feeing the inverter.

Morich · 05-01-2022, 02:45 PM

This is where things get really muddy but I have looked at these drawings enough to feel I see some things that are not really shown?

Looking at that first snip I did, I put red line all over the parts you may need to see but there are two big wires that show as red and black and they are 4 gauges with 3 wires (4-3?) that go from the transfer switch to the first main breaker panel. That is all your power coming in from genset or cord,so we can see they feed two matching breakers that then feed each air unit.
But we know there has to be a connection inside that breaker from those two wires to feed the rest of the RV! Not shown but has to be there. I would question why they show the black wire feeding what they label red line 1 at the breaker and the red wire feeding what they call green line 2????

But that's what they do and one or the other or both have to feed the rest of the breakers some way, even though they don't show us!

A big point on the inverters is that they use battery to make AC power, so they are usually not too big as that would require lots of battery to run very much. Your's seems to power more than I often expect but it is limited to 2000 watts. It looks like it will run your microwave? That is about as power hungry as I normally see running on an inverter, so be aware that when using it and not plugged into shore power, you will be sucking the batteries down pretty fast! Good thing we don't use the microwave very long and it gets it done quick!

It would take some deep looking but I suspect the inverter/ charger actually passes AC power through when plugged into shore but makes the AC when not plugged in??? It may do lots of "automatic" stuff that can be confusing but that would let you run things as long as wanted on shore but not be totally out when not plugged in--- as long as the battery power lasted.

The coach battery charging off the engine is a different part of things . On older models there is a mode solenoid which operates when we turn on the ignition and start the engine. That solenoid is just a set of big contacts that close and connect two big lugs together. One lug has a cable to the coach and the other to the start battery where the engine alternator is expected to be charging that battery. We can see and feel it work but on newer like you have it has changed to solid state and we have a harder time seeing/feeling it work, even though it does the same thing.

You have a "battery management system" or "battery isolator" like in these snips. maybe in outside compartment driver's side near the rear? Might want to look in there if not used to the RV.

Lots of things to find when we change up what we are doing, so I never expect to know the thing for a few years! Good luck and enjoy!

**creativepart** · 05-01-2022, 05:09 PM

I can’t tell if you mentioned it but there is a small round rotary disconnect mounted high on the compartment wall that doesn’t disconnect the inverter from shore power but does disconnect the inverter from the Batteries. Have you checked that?

But it does sound like an issue with the “surge protector” interrupting bad or questionable shore power.

Morich · 05-01-2022, 05:48 PM

Quote:

Originally Posted by creativepart

I can’t tell if you mentioned it but there is a small round rotary disconnect mounted high on the compartment wall that doesn’t disconnect the inverter from shore power but does disconnect the inverter from the Batteries. Have you checked that?

But it does sound like an issue with the “surge protector” interrupting bad or questionable shore power.

Good point to mention on those small unseen switches but what made me have somedoubt about it only being a switch is the last report mentioned the batteries not chargingwhile the RV engine is running. That throws me into thinking there are possibly two kind of unrelated problems on charging or possibly just some lack of understanding how batteries act.
Maybe it just needs a good charging to get things back in order before jumping top too much study.

One issue seems to be getting the power from the inverter charger section to the battery but that uses a different route than the engine alternator power getting to the battery. But both could be as simple as a dirty cable at the battery post?
Both sources might be getting to the clamp on the battery but if that clamp is dirty, it still doesn't work!

Maybe they can get it found and report back on the fix?

MattyA · 05-01-2022, 06:11 PM

Update. house batteries SAID they weren’t charging, but after 4.5 hours on the road, they were plenty charged.

Btw totally tried to cycle the battery-disconnect-from-inverter switch you mentioned. That was in the very first post. No dice!!

MattyA · 05-01-2022, 06:16 PM

Btw I’ll report on the ultimate diagnosis and solution when I sort it at a service center

Wayne M · 05-02-2022, 10:33 PM

I'm confused. All this is about a battery not charging and mentioning of an "inverter" problem.

My confusion is, an inverter turns DC power into AC power and AC power is not going to charge a battery.

A converter changes AC power into DC power and is what is used to charge a battery.

Help! What am I missing here?

BobC · 05-03-2022, 06:32 AM

Quote:

Originally Posted by Wayne M

I'm confused. All this is about a battery not charging and mentioning of an "inverter" problem.

My confusion is, an inverter turns DC power into AC power and AC power is not going to charge a battery.

A converter changes AC power into DC power and is what is used to charge a battery.

Help! What am I missing here?

Technically your description of an inverter is accurate but there are also inverter/chargers that incorporate the battery charging function as well as the inverter function. These are more expensive than the simple 1000W inverters found in many of our RVs for powering our TVs, etc.

Most of the converters found in RVs are actually converter/chargers but there are converters that simply provide a constant DC voltage without the battery charging function.

In both cases, the battery charging function varies the charging voltage depending on the battery's state of charge. Modern inverter/chargers and converter/chargers incorporate a "smart" multi-stage charger.

Just as most of us refer to our converter/chargers as "converters", many inverter/charger owners (especially those new to RVing) refer to their inverter/charger as an "inverter".