Battery charging/electric issues - Montana Owners Club

MarkM · 07-10-2022, 12:04 PM

We have a 2019 3931FB.

Everything has been working great up until now. We typically store it plugged into 50amp service but due to the building being spray foamed I pulled it out and ran an extention cord with a 15amp step down just to keep the fridge running.

Well today I when to back her into her spot and my leveling Jack's wouldnt work. I scroll down to voltage and it is 10.8. Hmmm why wasn't it charging while plugged into shore power. I plugged it into my truck and Jack's work fine to disconnect and level.

Plug back into 50amp service and voltage is still low. Only one AC will run. Voltage jumps to 12.4 when I turn off everything.

Tried to run through the converter troubleshooting and from what I can tell I am not getting power from the 115 service through the converter module.

It has the Pd4575 converter.

Is it safe to assume I need to replace the module?

**AZ Traveler** · 07-10-2022, 01:54 PM

Mark,

Did you check to make sure you are getting 120v to the converter?

MarkM · 07-10-2022, 01:56 PM

Quote:

Originally Posted by AZ Traveler

Mark,

Did you check to make sure you are getting 120v to the converter?

I have 120v in the converter box.

C&P RV · 07-10-2022, 02:32 PM

I would check the fuses for the converter itself. They are usually adjacent to the all of the DC automotive type fuses for all of your 12v systems. Recommend you disconnect from AC power to check these fuses. You will have to pull them to check them

MarkM · 07-10-2022, 02:35 PM

I checked the reverse polarity fuses and they were good.

Also, Checked the 20 and 30 amp Fuses by the batteries.

C&P RV · 07-10-2022, 02:55 PM

Progressive Dynamics has a troubleshooting guide on their website with step by step instructions.
https://www.progressivedyn.com/wp-co...LESHOOTING.pdf

If you have a regular battery charger, you can turn off the breaker for the converter and try to charge the battery to see if it will hold a charge. That would allow you to rule out a bad battery. It's sounding line the converter itself is bad.

C&P RV · 07-10-2022, 02:59 PM

One other thought, since only one AC is working you may have one leg out on your 50Amp feed. And if the non working leg also has the converter on that side of the panel then it's not working along with the AC on that side.

MarkM · 07-10-2022, 04:50 PM

Quote:

Originally Posted by CM7018

One other thought, since only one AC is working you may have one leg out on your 50Amp feed. And if the non working leg also has the converter on that side of the panel then it's not working along with the AC on that side.

The surge protector shows both legs working.

That might be the same troubleshooting that I already went through but I will verify when on a computer and noty phone.

bcrvman · 07-10-2022, 11:04 PM

Quote:

Originally Posted by MarkM

We have a 2019 3931FB.

Everything has been working great up until now. We typically store it plugged into 50amp service but due to the building being spray foamed I pulled it out and ran an extention cord with a 15amp step down just to keep the fridge running.

Well today I when to back her into her spot and my leveling Jack's wouldnt work. I scroll down to voltage and it is 10.8. Hmmm why wasn't it charging while plugged into shore power. I plugged it into my truck and Jack's work fine to disconnect and level.

Plug back into 50amp service and voltage is still low. Only one AC will run. Voltage jumps to 12.4 when I turn off everything.

Tried to run through the converter troubleshooting and from what I can tell I am not getting power from the 115 service through the converter module.

It has the Pd4575 converter.

Is it safe to assume I need to replace the module?

If your jacks don't work, then the battery is not good enough and very likely dead if it isn't Lithium or a Trojan GC or equivalent.

To measure battery voltage, disconnect the negative battery cable and let the battery sit for at least an hour, now measure across tha battery posts.
A reading of 12.2 or lower means a dead battery.

MarkM · 07-11-2022, 02:53 AM

Batteries are good. I just put them in a couple of months ago plus when I disconnect the voltage goes to 12.4.

MarkM · 07-11-2022, 07:48 AM

Good morning. After sleeping on it I went out this morning and did some more testing.

My 50amp main breaker is in the middle of all the breakers. The breakers to the left all have power. The breakers to the right have no power. The converter and front AC is on the right bank so that is why it isn't charging my batteries and AC isn't working.

Could the main breaker be bad?

I know a little about electrical but not enough to figure this one out.

C&P RV · 07-11-2022, 07:55 AM

It could be the breaker but it's also possible its between the external electrical connection and the RV.

You mentioned a surge protector. Take that off, connect your power directly to the 50 amp outlet and see if it works. My SurgeGuard surge protector (by southwire) had one of the terminals come loose inside the box and I had the exact same issue.

If that isn't it you can test your power cord just in case one of the ends has gone bad.

MarkM · 07-11-2022, 07:58 AM

I already eliminated the surge protector.

Unfortunately my 50amp cord is on board so a simple continuity test won't be easy.

MarkM · 07-11-2022, 08:11 AM

OK unrolled the cord and found an access panel. Tested all four legs and they omh'd good.

C&P RV · 07-11-2022, 08:26 AM

From my perspective you seem to have narrowed this to the main breaker. I assume you have already tried to reset it? I would think you would hear it click/pop if it tripped as you did a reset.

You might be able to get a multimeter on the feed into the breaker and the neutral bus to see if there is power going into the breaker. Those boxes are tight, so not much room to do that test.

MarkM · 07-11-2022, 08:35 AM

I pulled the main breaker and checked continuity on both sides. Both ohm'd OK.

I also ohm'd between the top bar where the breaker attaches and the bottom leg of the breakers and had continuity.

This is blowing my mind. All I did was pull the RV about 50 ft forward and plugged into 110. Everything worked prior to that.

C&P RV · 07-11-2022, 02:19 PM

You are checking the breaker without a load on it so it would probably check ok on a continuity (ohm) test.

Can you confirm that power is getting to that leg? Checking AC voltage across the heavy gauge 50Amp wire that connects to that side of the breaker and the neutral bus should give you 120 volts if power is getting that far and that would isolate the issue to one side of that dual main breaker.

bcrvman · 07-17-2022, 03:16 PM

Quote:

Originally Posted by MarkM

We have a 2019 3931FB.

Everything has been working great up until now. We typically store it plugged into 50amp service but due to the building being spray foamed I pulled it out and ran an extention cord with a 15amp step down just to keep the fridge running.

Well today I when to back her into her spot and my leveling Jack's wouldnt work. I scroll down to voltage and it is 10.8. Hmmm why wasn't it charging while plugged into shore power. I plugged it into my truck and Jack's work fine to disconnect and level.

Plug back into 50amp service and voltage is still low. Only one AC will run. Voltage jumps to 12.4 when I turn off everything.

Tried to run through the converter troubleshooting and from what I can tell I am not getting power from the 115 service through the converter module.

It has the Pd4575 converter.

Is it safe to assume I need to replace the module?

Sounds like the batteries are done. Take the cables off and let the battery sit for at least an hour. Now measure the voltage across the terminals. Anything less than 12.2 is dead, the 100% is 12.7 so thats a range of 0.5V between 100% and 50% which for a lead acid battery is dead.
In order of expense your options are
Another POS like you have now,
A real deep discharge battery (NO CCA, MCA, or the word CRANK on the battery)
A pair of Golf cart batteries like Trojan T105 (the most popular RV battery amongst those in the know)
AGM
Lithium

Mr Smith · 07-17-2022, 08:44 PM

I have the same year and model Montana, had the same issue, turned out to be a 50amp fuse up in the battery box, replaced it and everything went back to normal, I will try to post a description

Gloaso 12V - 24V DC 50 Amp Type 1 Automatic Reset Circuit Breakers T1 Replacement 50A Auto Reset Breaker with Cover Stud Bolt for Automotive Marine 2 Pack

It say auto-reset but it was fried and would not recharge the batteries!
Let me know, hope this fixes your problem!

Wayne · 07-19-2022, 04:47 PM

Mark, I have the same 2019 3931FB coach. If your coach is set up for a generator you have a transfer switch located behind the wall in storage area. Keystone has problems with them. Maine had the same issue as yours. Power to transfer. Only one leg coming out. Check for stuck relay in transfer switch.

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