Electrical issue

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MikeLight77

MikeLight77

Active member
Joined
Jun 15, 2021
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Location
Kansas
I posted this in another forum yesterday, and it was suggested that I redirect here:

We are on our first trip with our 2006 HR Neptune. Arrive at destination, no easy hookup to shore power, so we've been running off generator for a couple days. We have been running some AC, but not continuously.

This morning, I'm out hiking, and wife texts me that "something weird is happening"... I suspect the generator shut off. However, I got back and generator was on.

I did notice that there is a light on my EMS Panel that normally says "Gen Set" and that light was not lit up, and instead the 30 AMP light was on. So I decided to give the generator a break and restart later. Also ran to town to get a shore power cord.

By the time I get back, I attempt to restart the generator and it seems like the chassis batteries are dead or weak. Won't crank. Also house batteries are kinda weak. Hook up shore power cord (30A) and my EMS Panel just says "searching" like it's not receiving.

Also noteworthy, I have a Surge Guard 35550 in the electrical compartment, and ZERO lights are on. Not a fault light, nothing.

I don't currently have access to a multimeter to troubleshoot effectively... that's another issue. I may have to run to town for that next.

Any ideas or "red flags" you see above where maybe I can limp home, but then something really needs to be replaced?

Thanks!

Update after my original post:

I now have a multimeter. Chassis batteries are checking about 11V. Can I "jump" those like I jump a car or is that not suggested?
Shore power issue is something else. I've determined that the relay coming from the shore power is fried. Relay won't move in and out.
I'm thinking if I get the generator back going, I can go without the shore power - we are only here for one more day.
I'll need to get that relay fixed when I get home.
I also now think the "something weird" going on that spooked my wife was the EMS automatically dropping load because I had been running AC for quite a while at that point. 3 Hour Rule thing.

Also, is it possible that my chassis batteries are wrecked and I should just go get new ones and not risk it?
 
It sounds like you are not getting AC power to the battery charger.

Can you start the RV? It is OK to get a jump start on the chassis battery.

If you can while engine running check the voltage on the house side & the chassis side. In theory the chassis should not have depleted as it should have been isolated. But with the RV running the alternator on the engine should provide a third source of charging (gen + charger & shore + charger being the other 2)

With shore power connected are you getting lights/power on the microwave and fridge? AC on these devices and low DC power will cause lots of "control" problems with the AC side of things.

First theory is that the charger is not getting power from generator or shore power due to some failure that you have had.
 
Normally your gen should charge the house batteries when running. If your house batteries are weak after a long gen run time, the relay that sends power to them may be bad. Some rigs use a like a Trik-L-Start that will take a small amount of power from your house batteries and keep the chassis batteries charged. But it only works if your house batteries are over a certain voltage. The chassis batteries can be jump started like a car battery as long as the cables are put on the correct posts. A battery that reads 12.0 volts is about 50% discharged and getting pretty weak. A 11.0 charge is near dead and will take some time to come up. A plug in battery charger may be required to bring them back at all.
 
Clearly you have been running off battery power for a while and the RV is also draining the chassis batteries as well as (or instead of) the house batteries. What is the house battery voltage? Yes you can jump the batteries, whether chassis or house, and your coach has a built in function to jump house to chassis when needed (look for a switch labeled Aux Start or similar on the dash). But are the house batteries depleted as well?

You also have the transfer switch problem, which has probably prevented either shore or genset 120v power from feeding the RV's circuits. No battery charging if that happens.

The 30A light instead of Generator light on the EMS indicates the the EMS thinks the genset if not running. It determines that by the presence of +12v on a wire tied in some way to the genset, typically one of the genset remote start switches. However, that wiring is determined by the coach builder, so yours may differ.
 
Thank you all. I can confirm that I have not been on Shore Power at all. I did not have the correct adapters until yesterday and when I plugged it finally - no juice. I can confirm that from the shore power in, the first thing it goes through is my Transfer Switch - and the relay on the Shore Power side is toast. The relay on the generator side is good still.

Generator was running for several days continuously, and I should clarify, when I'm referring to "AC" in my original post, I'm talking about Air Conditioning, not "AC" Electrical. I have used very little AC in the RV - stuff plugged in. Only Air Conditioning. When the generator is running, my battery light says "full charge". However, seems to me that when generator is shut off, it depletes rather quickly. I do not run the AC (or much of anything) when the generator is off.

Right now - both Chassis batteries are 11V, 2 of the house batteries read 6V and the other 2 read 4V, so not sure why they are draining unevenly.

I will attempt to jump start and get the generator going, let it run for a bit, then check voltages... I'll update after that.

In hindsight I should have turned off the Chassis battery switch, I think, when I arrived at destination.
 
If I get the generator going, and use the "Battery Boost" to use the house batteries to start the engine, will the alternator sufficiently charge the chassis batteries? If I have ruined them or damaged them significantly, I'm not opposed to getting new ones.

We just got this rig and the first thing I did was get 6 new tires and had the engine serviced so I have a baseline to know where everything is. Batteries would be on the list in the near future anyway. I could just do it now.

Thanks!
 
Are the house batteries 12V batteries or 6V wired in series/parallel?

If they are 12V I would definitely isolate them from the chassis and get the chassis running.

I would buy a decent battery charger and put the house batteries on a charge cycle and see if they recover.

You say they are depleting quickly? If no failure is interfering with depletion rate then it is possible you either are not getting them fully charged, something is draining them or they have been damaged.
 
I'd start by isolating the house and charging them as a 12V bank.

The problem with using the engine alternator and (many) RV chargers is they don't have multi stage charging and will just try to cram in amps at whatever the battery will accept.

A multi-stage battery charger will be kinder in bringing the dead bank back to life...
 
OK, update:

New chassis batteries. Generator fired right up. Engine fired right up.

Generator to power panel seems to be normal (Gen Set is lit). I don't have anything on. My panel says "bulk charging" at the moment. My status lights say "full" on battery power. Status lights on Surge Protector (adjacent to Transfer Switch) are all normal / green.

Question is, what killed my chassis batteries.

I have a theory, maybe you guys could substantiate: When everything fired back up, I heard air blowing, but the dash A/C was off. There was an Aux Def (Defrost, I assume) switch that was pushed and so air was blowing at the windshield.

If that has been flipped on for 6 days... might that be the culprit? And I didn't hear it running because it's up front with the generator.

What other systems run off the Chassis batteries? The way I understand it, the Chassis power runs everything as if it was a car or truck and not a coach. So like anything associated with driving. Dash A/C, lights and systems like the steps, etc...
 
A couple takeaways for you. The "battery status lights" are nothing more than a coarse voltage indicator. Charging batteries are nominally 2V higher than at rest, so even a "dead" battery will indicate "full" on these gauges when being actively charged. Lesson here is the battery status lights are only moderately useful as a battery gauge, and of no use when being charged.

A "bad" chassis battery can behave perfectly normally even to the point of having the guts to start the engine, but will fall flat the minute there is an extended draw or time element involved. The alternator will charge it and keep it topped off to the extent it has capacity, but that capacity may be very small. So the only real test is a transient load ("load tester") to know if your battery is really any good, or just make believe. This lesson is you can't go by voltage alone for either house or chassis battery, there has to be some element of load and time to know the capacity.

Lastly, a review of your converter (house) and alternator (chassis) is in order. Odds are they're OK but it wouldn't hurt to watch them under shore power/running engine to know they're operating properly and not under or non-charging your batteries. If you're so inclined you can do your own merit testing of the batteries to independently verify their integrity, which might be a good data point if you don't have history on these things. I would want to know that before I arbitrarily replaced all your batteries, only to find there was a problem with the charging side.

Mark B.
Albuquerque, NM
 
Thank you! What specifically could be draining my chassis battery when parked and running off generator? I thought I could shut off chassis batteries with generator running, but that was not the case. Generator shut off when I tried that. I did put new batteries in today and I don't want to ruin them right away if something is draining them. I haven't run the motor very long yet to check the alternator, but plan to do that tomorrow. What readings should I be looking for off of the converter and alternator? Thanks in advance!
 
What killed the chassis battery?
Ok, Older RV's the isolator system was one way
The Engine charged the house batteries
But the house converter had no effect on the Chassis (Engine) battery

Modern RV's usually have a B.I.R.D. (BiDiredtional Isolator Relay Device) and both the house converter and the engine alternator charge both house and chassis.

2006 is in transistion.. Might or might not (My 05 had a bird)

Second... Headlights or parking lights left on
Radio (Dash)
and on one car I had... (This is rare) the alternator did not properly ground. as a result the rotor remained energized when the engine was off and it sucked the battery down and fast.. Took me forever to figure it out (I measured voltage between the alternator housing and the engine block, that should be impossible) Removed a mounting bolt and added a star washer under it all good.

I seriously doubt that's the issue.
but clearly somethign hung up.

Also steps, jacks and optionally slide outs may be on the chassis instead of the house.
 
The Aux Def switch is a likely culprit for the chassis drain. Surprised that ran with the key off though.

I'd invest in a cheap voltmeter that you can plug into the cigarette plug and monitor chassis voltage.

I also have a 400W inverter I use for the TV and WiFi hub. Mine has a VM display so I can also monitor the house batteries.
 
I have had the two new batteries in now for about 16-18 hours, and they are still checking 12.5 V with the engine off.

I did fire the engine up for an hour or so, and they were checking 14.-something (I don't remember exactly - it was last night)

I am annoyed that I don't have a Chassis Voltage display in the dash, so thanks for the tip about buying a plug in version. Great Idea - I will Amazon that as soon as I get home!
 
MikeLight77 said:
I am annoyed that I don't have a Chassis Voltage display in the dash,
Click to expand...
I'm not familiar with the dash on your Neptune, but surprised there is not a way to cycle thru some menus and get system voltage and other details. Maybe not convenient, but ok for troubleshooting.

Do you have the owner manual? It has some useful stuff, including chassis electrical, aux start & jump start, etc. Including troubleshooting procedures.
https://big.nyc3.cdn.digitaloceanspaces.com/revgroup/general/2006_Neptune.pdf
 
Last edited:
His conjecture is that "Aux Def" meant Auxiliary Defrost, because he heard a fan blowing. I once had a coach that had two small fans mounted near the top of the windshield for that purpose (but the switch was unlabeled!).
 
Gary RV_Wizard said:
His conjecture is that "Aux Def" meant Auxiliary Defrost, because he heard a fan blowing. I once had a coach that had two small fans mounted near the top of the windshield for that purpose (but the switch was unlabeled!).
Click to expand...
I thought that is what was posted, hence my assumption that it was running on the chassis battery. I am wondering if it is some sort of electrically heated element as most defrosting is a water heat exchanger.
 
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