Coach batteries wont charge from shore power

[nehuge]

1995 Thor Residency, 30 amp system.
Suddenly the coach batteries stopped charging when being plugged into shore power. When plugged in, I’ll come out in a couple weeks and they will be dead. This is a lengthy writeup, but the following is everything I have going on to my knowledge as to be as thorough as possible.
The coach batteries will charge when the RV’s engine is running, and when the generator is running. (I put a multimeter right on the battery posts to determine this, and get 13+ volts). Turn the generator and/or engine off, wait 10 minutes and multimeter at the battery posts it shows 11.6 or whatever my batteries were at prior to starting the RV engine or the generator.
The CONverter/charger is under my entry steps in a ventilated metal cage from the coach builder. When plugged into shore power the charger’s LED light is on. I put a voltmeter directly onto its screw/lugs when plugged into shore power and it is outputting 13+ volts. (my coach batteries are maybe 60% now). My converter is more than 10 years old (switched it out 10 years ago myself and it works (or appears to work) great to this day, but it has had lots of Arizona sand and dust presented to it through the ventilation slots in the metal cage, so in advance just in case I bought a spare converter. I have hooked up that new converter in its place. Same result. A three prong outlet that the converter plugs into into in that entry steps cage is fused to the main circuit breaker/fuse panel. The fuse in the circuit/breaker/fuse panel is fine, and I know because the inverter has a power light on it that comes on when plugged into shore power. I unplug the fuse, converter light goes off. Plug fuse back in, converter light back on. Same result with flipping the breaker switch itself. The dual ground lugs etc are hooked up correctly as the old converter was.
My INverter on the other hand is up front next to the TV in the cabinets. It has “Dimensional” as the brand name and said quasi sine wave, but its model number sticker has worn off by now so I don’t know the rating. It is date stamped March 1995 on the underside LOL
I noticed that when the coach batteries stopped charging from shore power, that the inverter also stopped turning on. When I have the coach plugged into shore power, any “AC” 120V stuff plugged into the inverter (like the TV and blue ray) work just fine. But when I unplug shore power, my inverter will no longer turn on and power anything. All connections look fine. The black test button will pop in and out, and the red reset button doesn’t do anything. Even the AC out round shaped breaker push button doesn’t do any kind of reset. It looks as though its push to reset button is pushed in at all times. It has an AC input 3 prong plug that plugs into a 3 prong outlet that is part of the coach. It has a copper ground wire going to its lug, then a purple (to a purple wire from the coach), and white (to a black wire to the coach), and red wire (to a red wire to the coach) going into the “DC” 12v input in the inverter. The white/black wire and the red wire appear to be 10 gauge or thicker. Not sure which of those color wires go where on the coach (red to the coach batteries?) , but anyways it is about 12 to 15 feet maybe to the coach batteries which are next to the metal cage where the entry steps are. 10 gauge at 12 to 15 feet per some chart I saw online can carry like 30 amps or so. My TV and bluray up front are the only reason from the factory to have this converter and per my kill-a-watt meter they only use 40watts together or something close to like .53 amps. So even a small wattage replacement inverter would be just fine. I’m not looking to run PC’s or microwave or any kind of big stuff off of this inverter, just TV and bluray. I’ll use the genny to power those it not on shore power.
My generator is Onan Marquis 7000 I think, and its fuses on the side of it are fine and again it powers everything like microwave, AC, etc all just fine.

So my questions are,
1) why aren’t my coach batteries charging on shore but they do on genny and engine?
2) what type of replacement inverter should I get just due to its age, given the 15 feet distance and 10 gauge wire from it to the coach batteries?

Could an inverter being dead affect the coach batteries charging from shore or vice versa?

[enblethen]

If everything is working properly your question one is nothing. Genset may depending on way automatic transfer switch is wired transfer to genset power. I would not recommend this!
Question 2and 3, will not see anything happen running chassis engine. A meter connected to coach battery may see a slight increase in voltage.
Question 4 You could see a small increase in time it will take to recharge batteries. You should look at the amperage of the alternator on the Ford chassis. Need to look at what converter you have. One way to increase charge rate is to get a more powerful converter.
To lower power usage, I would converter lighting to LEDs!

[nehuge]

So I think I got it!!

The breakers/fuses (the type that are 1 inch x 1/2 inch black squares with the two threaded stud looking things coming out of them on mine I now am finding out that they are the manual reset kind.

As I was poking around with the multimeter I was checking continuity between the two lugs on each breaker/fuse by the entry steps converter/charger cage in my video and they all had continuity. So then I knew there were some of those types of fuse/breakers by the battery emergency start solenoid under the engine bay up front and one didn't have continuity. Upon looking closer, on the top was a little black peg that the others didn't have. I pushed down on it, felt and heard a click, and thought "hmm". I traced the wire from that breaker and it went down to the square battery isolator right side lug. Thought "hmm".
Went and plugged the RV into shore power, put my meter on the house batteries incoming cable, and WHAM 13.9 volts. I unplug shore power, and, yep, house batteries were down to their "naked" selves were at 12.3 or whatever before plugging shore power in. Plug shore power back in, BAM, up to 13.8 or 13.9 volts.

That was it! A stupid little breaker.

Well, anyways, each ground that I saw in the area, whether it be the grounds on the outside of the understeps charger/converter cage, or the ground lug for the charger/converter to the chassis itself inside the cage, or the main negative cable from the chassis battery to Ford frame, etc, were all removed, cleaned up to fresh metal too just for future reference.

It's kind of a good thing it happened this way because through you guys I learned a lot about how the system works in general. I mean geesh, alternator, charger/converter, inverter, emergency solenoid, battery isolator, its ridiculous.

I'm still gonna slap a new battery isolator in as well as an emergency start solenoid just for grins as they are 30 years old and cheap enough for piece of mind. I'm not usually a "throw parts at it" guy but its just the pure age and cycles that I think about. Now off to the front leaf spring bushings. Ugh.

p.s. one last set of questions, covering every scenario I can think of:
1) if the coach is plugged into shore power and one was to start the generator while hooked to shore power, what would happen?
2) if the coach is plugged into shore power and one was to start the Ford engine while hooked to shore power, what would happen?
3) if the coach is plugged into shore power and one was to start the Ford engine, and the generator along with the Ford engine while hooked to shore power, what would happen?
4) If the Ford chassis engine is running, and the alternator is charging the house batteries, and if the generator was fired up at the same time, do the house batteries get an extra boost of charge from both sourced combined or is it regulated so that the alternator and the generator don't gang up on the battery and its respective gauge of wire on the way to the house battery?

[enblethen]

Did you check the two circuit breakers, top terminals?
Look in the 12-volt DC distribution panel for a "BAT" fuse!

[nehuge]

Here's the setup too:

https://youtu.be/-jKwqmmYdnI

[Grit_dog]

If your converter works on genny power then the issue is likely with the shore power connection to the converter? If the rest of the AC circuits work on shore power then the issue is confusing to me.

Edit, re-reading your first post, I’m thoroughly confused why it doesn’t work.

[nehuge]

enblethen wrote:
First couple items to check
Fuse or circuit breaker near battery
Fuse in 12-volt dc distribution panel
Battery disconnect switch in off position.
Blown reverse polarity fuses in converter. Check first!

Fuse or circuit breaker near battery (hmm, dont see one).
Fuse in 12 volt dc panel (good, as I said I can switch it on and off and it controls the 3 prong outlet next to the converter/charger and the convert/charger will go off and on as I do so
Battery disconnect switch is on positon
Fuses in converter are good, tested them with multimeter too.

[nehuge]

So Mr. Wizard, you're saying the older brand of Dimensional inverter has a pass through, is this the same as a transfer switch?

I'll try those things and report in next couple weeks.

[MrWizard]

You have several proble ms.
The first thing:
i would do is disconnect the Batteries,
Second: i would connect the new converter directly to the batteries after all it is battery charger, 3rd Thing :
I would connect a power cord to the converter, and plug into an extension cord run from the garage or house, now you are charging the batteries directly,
Keep charging until voltage at the batteries is 14.2 volts
Then unplug the converter from 120vac, leave connected to batteries , take periodic voltage checks at the batteries,
This will let you verify the batteries good or bad
It sounds like you have multiple problems, your demensional inverter has a pass thru function for 120v, the contacts might be stuck, and not switching to inverter output, or it could just be worn out, its also possible you have a shorted cell in a battery so they do not get fully charged , and then loose what charge was obtained when charging is stopped , you haven't run. The engine long enough to completely charge the batteries, and verify whats going on.

[enblethen]

First couple items to check
Fuse or circuit breaker near battery
Fuse in 12-volt dc distribution panel
Battery disconnect switch in off position.
Blown reverse polarity fuses in converter. Check first!