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Topic: Rig not fully switching to 12v after being plugged into shore power? (Read 645 times) previous topic - next topic
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Rig not fully switching to 12v after being plugged into shore power?
So I’ve been having this ongoing problem pretty much since I’ve had my 2005 26’ MB (11 years). It has recently gotten much worse.

After being connected to shore power for as little as 24 hours, when I then am disconnected and try to use anything requiring power, the results are like my house batteries are dying or nearly dead. They are not. This occurs after sundown when no light is getting to the solar panels. During the day, all electrical works fine. After this first night, everything goes back to normal.

In previous years all I would really see was the HPV-22B controller would go from about 13.2 quickly to the mid-11 range, then lower. This is just using a few lights and the TV. After a day unplugged, the controller would then show a more normal decrease during the evening down to the usual mid to low 12’s.

One evening, out of pure frustration when we couldn’t even watch the TV without the inverter sending out a warning sound, I just started adding more and more electrical load to see what would happen. I turned on a bunch of lights which flickered (lED), then turned on the water faucet to run the pump. Everything flickered madly as you’d expect, until suddenly all power energized back to normal. Lights stopped flickering, inverter warning ceased, etc. It was like adding the extra load pushed through whatever problem was blocking the power. After this all power was normal again until the next time I plugged in.

What started happening on our last trip is there is a much quicker decline from full charge to 11 and lower after a night plugged in. In the morning when I attempt to turn on the generator, all I hear is the clicking sound of a dead battery not able to turn over the motor. In this case, I started the rigs engine, then got the generator started. After running the generator for only a minute or so, then shutting it off, it would start normally again using the switch inside.

I have tested the voltage of the house batteries with a multi-meter and they always test in around 12.4. They are a bit on the old side at 6 years and I do think their age may be a contributing factor, but other than the day after shore power, they have always held plenty of charge through the night - even without getting fully charged on some cloudy days.

Could this be a case of a bad transfer switch? I’m not sure I can troubleshoot and repair this on my own, but having an idea what to tell a repair shop what might be going on would help tremendously.

Thanks,
David G.
2005 MB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #1 –
David,

Check all 12V power and ground cable connections to make sure they are corrosion free and tight.  Even check the condition of crimped on cable lugs.  If you are not familiar with removing battery cables, I'd recommend finding someone who does to help. Batteries can produce a lot of current if accidentally shorted!

Art
Art and Barbara
Settled in Atterdag Village of Solvang
2015-2022 fulltime in a 2016 Tiffin Allegro Bus 37AP
2002-2015 2002 LD MB
Art's blog
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #2 –
An issue that has recently been recognized is poor contacts in the battery disconnect switch - if you have one. It would be located in the battery compartment between and above the batteries. When the problem recurs, try turning the switch back and forth to see if the problem changes.

Steve
2004 FL
2013 Honda Fit
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #3 –
Cables all look pretty good, but my battery disconnect is in need of replacement. I'll try that. Thanks.

David G.
2005 MB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #4 –

I have found a several bad factory battery switches through the years.
When they go south, it results in a intermittent connection that cause all sorts of strange symptoms.
Check for voltage drop across the switch, while turning the switch on and off a few times. 

The link below shows the switch that LD used for your year model.
Amazon.com: HELLA 002843011 2843 Series 100A Rating Battery Master Switch:...
While it looks like marine rated switch, it isn't water-proof or vapor-proof.
The switch's contacts can corrode and eventually fail.
At least, they are cheap.

Larry
As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #5 –
Larry, is there a non-cheap, moisture-proof, less susceptible to corrosion, heavy duty, marine-rated battery switch that you can suggest?  ;) 

Joan
2003 TK has a new home
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #6 –
Hi David,

I am NOT an electrical guru, so these comments may not have much useful info. But:

You seem to think your batteries are ok because you get a volt reading of 12.4 volts. You are only around 70-75% of full charge at that reading.  I also think you are supposed to let the batteries rest for a few hours (6 hours is what I believe the Trojan battery website states) with no draw OR charge being applied before taking the reading. A fully charged set of batteries should read around 12.65 volts

I would also suggest using a battery hydrometer to check specific gravity of each cell.

I suspect that you aren't getting your batteries fully charged. Could be they are needing replaced because they don't have the capability of being charged.

I was recently dealing with a similar thing. Rig was parked in a shady area foe a couple weeks, leaves blocking the solar panel and a low volt reading . Checking specific gravity found all the cells reading lower than they should. Plugging it in, cleaning the panel and more sunlight has my batteries back to normal.

One other thing. I had a similar variation in volt readings a long time ago. It was a pain to figure out. In my case, it turned out to be a Shurflo waterpump that was putting a "phantom" draw on my batteries when the pump was on but not running. A conversation with Shurflo confirmed my suspicion and a new pump put an end to that problem.

Good luck!
Steve K
Steve K

2003 Mid-bath
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #7 –
A reply to Joans querry; I'm not Larry, but Perko Marine has a good reputation. This switch is 'Ignition protected'. The single battery disconnect, 9621 shouldn't allow gasses like Hydrogen to accumulate inside, or generate a spark. Different mounting options are available, and it has a rather sturdy looking black handle. Hope this helped.
   On the original topic I'll chime in with Art/Steve/Larry that a connection is likely the problem. That could account for the not fully charged symptoms of your batteries. Many times connections can look ok, but there is corrosion where you can't see it. A disassembly of each connection could reveal the culprit. To eliminate the battery switch from consideration, I would remove it out of the circuit completely. I've never used one yet. I just slide the batteries out and remove the end of the inter battery cable closest to the compartment door. RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #8 –
I will look into the battery cut-off switch, but it seems to me that if it were the problem, it would be more of an intermittent thing. The behavior is consistently happening ONLY after being connected to shore power - then normal again a day later, or unless I force it as described in my original post.

David G.
2005 MB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #9 –
Quote from: Larry Wade  - 
I have found a several bad factory battery switches through the years.
When they go south, it results in a intermittent connection that cause all sorts of strange symptoms.

Larry

I have a 2001 RK. Do I have a battery switch?  If so, where might it be?

Bob
'01 RK
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #10 –
Bob, the cutoff switch is an option purchased from the M'ship when new. It is sort of a thick cardboard-like material that is a little taller than the batteries and about four or so inches wide. It is placed between the two batteries, has bolts to attach to your batteries and a plastic key in the middle that you turn one way for power, the other way to interrupt power.

I got one even though I had a then-optional solar panel installed. I got it so that I can work on the electrical system without doing myself harm, lol! If you have one and a solar panel always remember to pull the solar panel fuse too before working on your rig!

Dave
Ruby, the red 2004 26' RK hauling Dave and Kristine hither and yon
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #11 –
Quote from: huskerblue  - 
Bob, the cutoff switch is an option purchased from the M'ship when new. It is sort of a thick cardboard-like material that is a little taller than the batteries and about four or so inches wide. It is placed between the two batteries, has bolts to attach to your batteries and a plastic key in the middle that you turn one way for power, the other way to interrupt power.

I got one even though I had a then-optional solar panel installed. I got it so that I can work on the electrical system without doing myself harm, lol! If you have one and a solar panel always remember to pull the solar panel fuse too before working on your rig!

Dave

Thanks, Dave.  I'll look at see if I have one but think I would have notice it.  I've only had the rig for about a year and a 1/2. The switch would be nice.

Bob, '01 RK
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #12 –
Yeah, you don't likely have it or you would have noticed it. The red plastic key is large and sort of looks like it belongs on a Fisher-Price children's toy. You wouldn't miss it.
Ruby, the red 2004 26' RK hauling Dave and Kristine hither and yon
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #13 –
Quote from: huskerblue  - 
It is sort of a thick cardboard-like material that is a little taller than the batteries and about four or so inches wide. It is placed between the two batteries, has bolts to attach to your batteries and a plastic key in the middle that you turn one way for power, the other way to interrupt power.

Would you be able to post a picture of this switch?  Don't think I've ever seen one or at least I can't remember if I have.  Thank you in advance.
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #14 –
Quote from: Traxless  - 
Would you be able to post a picture of this switch?
In reply #4 Larry posted an Amazon link of the switch. You'll find a photo there.
Andrew
2008 Rear Bath
(previously 1999 TK)
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #16 –
Not to muddy the waters here, but... I have seen at least one Lazy Daze with what looked like a big knife switch mounted between the two 6 V batteries. Dunno whether this was an earlier incarnation of the factory-installed battery disconnect, or an aftermarket add-on. Anybody know more about this? (Yes, I know that a switch in the battery compartment should be safe against explosive gases, so the knife switch was not a good idea.)
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #17 –
Quote from: Traxless  - 
So that disconnect switch would also be the same on an '09.
I suppose there's a slight chance it might look different on your '09, but it's what the switch looks like in my '08. It doesn't seem the kind of tech that changes significantly over the years.
Andrew
2008 Rear Bath
(previously 1999 TK)
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #18 –
Please forgive my general LD ignorance, but is the optional battery shut off switch the only way that LD engineers to cut power to the house, or is the switch an auxiliary switch used primarily for repair and maintenance purposes?  I ask, because in other motor homes we have owned, the house switch is usually mounted inside the door.  I'm not passing judgement on the design, just curious.

Ray S.
2017 RB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #19 –
"Not to muddy the waters here, but... I have seen at least one Lazy Daze with what looked like a big knife switch mounted between the two 6 V batteries."

This type of switch was used in the older, pre-2000 models, not sure exactly when they switched to the Hella battery switch.

To answer Joan's question about a better replacement, it appears this Hella switch is a similar size and is sealed, unlike the stock switch.
This should provide a longer service life.
http://www.jamestowndistributors.com/userportal/show_product.do?pid=54043&familyName=Hella+100+Amp+Master+Battery+Switch
LDs, that have AGMs. do not suffer damage from battery fumes, unlike the older lead-acid batteries.

FYI- if you plan on upgrading to a big inverter, especially one with a 100-amp charger, the stock Hella switch will need to be replaced  with a  higher amperage capacity switch, the Hella is rated at 100-amps max.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #20 –
Thanks, Larry!  ;)
2003 TK has a new home
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #21 –
I had similar problems that I traced to the power distribution/fuse board.

Wierd electric system problem

Russ
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #22 –
Quote from: russtang94  - 
I had similar problems that I traced to the power distribution/fuse board.
Wierd electric system problem
A lot of electrical issues can be traced to the Power Center.
It is good practice to periodically disconnect all 120-VAC, 12-VDC and solar power, and their fuses and, then tightening all the connections inside the Power Center, on both the 120-VAC and 12-VDC sides.
I do it every other year, while also checking all the connections between the Power Center and the battery, including the fusing.
This is not a project for those not experienced and comfortable working on high voltage equipment, please be safe.

The hidden circuit breaker is another unknown trouble spot and may be the cause of David's electrical problem.

A good skill to learn is how to find the voltage drop, over a circuit, using a digital voltmeter.
It makes tracking down these types of problems a lot simpler.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #23 –
Quote from: Larry Wade  - 
The link below shows the switch that LD used for your year model.
Amazon.com: HELLA 002843011 2843 Series 100A Rating Battery Master Switch:...

In looking for a new battery cutoff switch (as in the above link), I've noticed that none I've found online or in RV stores, come with the narrow board that the switch attaches to and slips in between the batteries. I could try to reuse the old one, but it is deteriorating and I'd rather replace it as well. Is there a resource for these?

Thanks,
David G.
As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
2005 MB
Re: Rig not fully switching to 12v after being plugged into shore power?
Reply #24 –
In a pinch, I would use 1/8 plywood. Usually the big box stores sell one-quarter size sheets. And they will cut to size for you if you don't have a saw. You could coat it in epoxy if you want it to last a long time.

I am wondering why the fiberboard piece is in sad shape? Is there evidence of corrosion in the battery compartment?
bumper turned me on to soaking two paper towels in a soup of baking soda and while wet lightly molding them to the top of the batteries. No more corrosion.

Awaiting to learn the source of this strange problem.
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy