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Loss of 12v power when shore power is disconnected

10David43
Explorer
Explorer
I have a 2018 Shockwave 5th wheel, with a Go Power solar system. About one month ago, I had to replace my batteries because they did not seem to hold a charge, by morning the batteries would be almost dead from very moderate use of lights and water pump. I have never been able to run the heater at night, very moderately, without completely killing the batteries before morning. I choose to convert to 6v batteries wired in a series. It is at this point I noticed some electrical problems, though I had some electrical problems were addressed under warranty.

The first thing I noticed is my batteries would not charge to 100%, after being hooked up to shore power for a couple of days. I was checking at the Go Power control panel, while hooked up to shore power, when someone turned on a hair dryer. My battery levels began to drop quickly, indicating that my Go Power inverter was powering the hair dryer. After lots of research I found that, from the factory, my inverter had been set to run the 120v outlets all the time, probably why my batteries were shot so quickly. I turned the switch at the top of my inverter from โ€œIโ€ to โ€œIIโ€. The online Go Power manuel said it should be set to โ€œIIโ€ when there is a remote control panel in the RV. That seemed resolved the issue of my inverter always powering some outlets.

Next issue I notice, my Go Power control panel says the batteries are sitting at 13.8v, but when I put a meter on the batteries they are now reading 18v. I am assuming I am having an issue with my converter and I also notice that my converter fan is not running when I plug in shore power. I was not able to deal with the issue for a few days and when I come back, the batteries seemed to have returned to normal voltage, so I did not think anything more about it.

Fast forward a month and we are going camping for the weekend. The 5th wheel has been hooked to shore power, the refrigerator is cold, and everything is fine, until I unplug from shore power. At that point all 12v items powered by my fuse panel go dead. I can still use my leveling jacks and start my generator. Starting my generator will re-power my 12v system. I do a complete search for a possible blown fuse. The circuit breaker going from the battery to the panel is good and there is power on both sides of the circuit break, but there is no power at the panel. I cannot see where the positive power wire goes after leaving the circuit breaker, there is no access to the wire from the circuit breaker to where it comes into the panel. I do not know if it goes to the inverter first. I pulled my converter and I can see that it does not go to the converter, so it is not running through the converter. Which should eliminate the converter from being the problem. I have checked my battery cut off switch and it is open and also providing 13.5v on both sides, prior to the circuit breaker.

I know this is a long question, but I have been pretty thorough with my diagnostics. My issue is I have no experience with inverters, this is my first RV with one. Any suggestions or ideas would be greatly appreciated.
14 REPLIES 14

DrewE
Explorer
Explorer
wa8yxm wrote:
IF the Go Power said 13.6 and the meter 18.. I am guessing the meter had a problem. Perhaps it was set on AC not DC (THe relationship is the square root of 2 or about 1.414 right about the error you saw) But I'd have to think some to figure out which way is which.

Peak voltage on a a 12 volt RMS is just shy of 18 volts.


Most meters that aren't true RMS meters measure average voltage on AC mode and scale the reading to display RMS voltage for a sine wave. Peak responding meters are pretty rare and are not be very useful if there's some superficial noise on an AC line (they'd read the spikes rather than the line voltage).

I suspect most ignore DC in AC mode, though perhaps not all. Based on a quick test, my meter does.

At any rate, a meter that is peak responding and senses DC in AC mode would read too low, since it needs to scale the actual peak voltage down to get the equivalent RMS value.

10David43
Explorer
Explorer
The high voltage was a bad meter and that has been resolved. I cut into the corrugated plastic under the 5th wheel to trace my wire. When I did acorn shells were found, I may have a rodent issue. We will see tomorrow. What I do know is where the wire leaves the circuit breaker and disappears I have power and where it re-emerges at the rear of the panel I donโ€™t. Tomorrow I will fine the cause.

wa8yxm
Explorer III
Explorer III
IF the Go Power said 13.6 and the meter 18.. I am guessing the meter had a problem. Perhaps it was set on AC not DC (THe relationship is the square root of 2 or about 1.414 right about the error you saw) But I'd have to think some to figure out which way is which.

Peak voltage on a a 12 volt RMS is just shy of 18 volts.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

BFL13
Explorer II
Explorer II
10David43 wrote:
I have eliminated my converter and my inverter. Neither can effect my 12v input to the panel. The inverter has no 12v output it only takes 12v in to make 120v and my converter 12v wires directly into the panel were 12v comes from the battery. Per my good meter, the circuit breaker is closed allowing power to flow. So somehow and somewhere between there and my panel, I have an issue. Unfortunately it is going to require pulling the paneling off of the bottom of the trailer to trace the wires. Thank you for giving input, I do appreciate it.


You don't need to get at those wires.

You are just confused about how your rig operates when on and when off shore power.

Yes voltmeters read high when their batteries are near dead. New battery should fix that.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
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CA_Traveler
Explorer III
Explorer III
Typically inverters don't pass 12V, they use 12V as input. Charger/inverter units use the same 12V wires to charge the batteries.

"I have checked my battery cut off switch and it is open and also providing 13.5v on both sides, prior to the circuit breaker."

Open means off and this is your problem. Turn the switch on or closed. Voltage on both sides does not mean the switch is closed.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

10David43
Explorer
Explorer
I have eliminated my converter and my inverter. Neither can effect my 12v input to the panel. The inverter has no 12v output it only takes 12v in to make 120v and my converter 12v wires directly into the panel were 12v comes from the battery. Per my good meter, the circuit breaker is closed allowing power to flow. So somehow and somewhere between there and my panel, I have an issue. Unfortunately it is going to require pulling the paneling off of the bottom of the trailer to trace the wires. Thank you for giving input, I do appreciate it.

time2roll
Explorer II
Explorer II
Replace the battery in your voltmeter. At least verify a reading from you truck battery.

10David43
Explorer
Explorer
Old-Biscuit

It is a Go Power 1500 watt inverter
At this point, I think I have eliminated my converter from my issues. I was not able to locate a brand, but I got a model number off of it.

I have located the main, master fuse, for the Go Power system and it is good. As far as other inline fuses, I so far have not found any.

I have 2 6v batteries wired in a series and they are wired correctly.

My wiring search goes on...

10David43
Explorer
Explorer
I do have solar, and I do know they should never be 18v. It appears that situation was a bad meter. This morning I pulled out my other meter and the voltage is correct is 13.5. I will not be throwing away my older digital meter. As far as the batteries go, they are hooked up correctly. I am pretty good with electrical and have taken automotive electrical courses. I have never dealt with inverters. At this point, I think my issue maybe my inverter. I am now looking up the wiring schematic for my Go Power unit to see if my 12v power runs through it before going to the 12v side of my panel. There are a lot of wire connected the batteries. I think I have determined where they all go (generator, jacks, solar, converter...) . The Go Power system has a master 12V fuse, T-class, and it is not blown. I will just keep hunting till I find the problem.

Old-Biscuit
Explorer
Explorer
Lets start with basics

Brand/Model Of INVERTER
Brand/Model Of CONVERTER

How many 6V batteries...2 wired in series OR 4 total with 2 wired in series then the 2 groups wired in parallel?

Converter....Reverse Polarity Fuses
Check if blown.....no charging and no battery supply'
Large 30A or 40A fuses ON converter

Battery in-line fuse....follow Battery POS Cable
S/B an in-line fuse on POS Cable CLOSE to battery (OR DC Circuit Breaker---small box with 2 studs...small reset button on side)
IF BLown---no charging/no battery supply

Jacks/Slides etc are typically wired DIRECTLY to battery POS posts due to high amop draw...have their own in-line fuse protection
So not surprised they work when not connected to AC Power
Is it time for your medication or mine?


2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31

Matt_Colie
Explorer
Explorer
David,

Your scenario describes so many possible failures that nobody reading will be able to do more than maybe tell you where to start.

The fact that you loose 12V system when not AC powered means that the house bank has a problem like a bad connection.
The house battery bank should never be 18 volts.
The most converter fans do not run full time, only as required.
The fast voltage loss when loaded by the inverter says that the pair(?) of GC2s are not charged to full density.

You changed out the house bank? Are you sure you got it all put back together correctly?

If you can start the APU and run the jacks, then the house bank can't be that dead.

Can you get a real schematic from Forest River? Do you have a buddy that is juice smart? Offer to buy him dinner if he brings his meter.

Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.

2oldman
Explorer
Explorer
10David43 wrote:
my Go Power control panel says the batteries are sitting at 13.8v, but when I put a meter on the batteries they are now reading 18v.
It's hard to know where to begin, but, your batteries should *never* read 18v. Is is possible your converter thinks you have a 24v system? Is this during converter charging or do you have solar?
"If I'm wearing long pants, I'm too far north" - 2oldman

10David43
Explorer
Explorer
Yes it did. Can't say I love Forest River after buying this rig. For the price, there are a lot of poor quality parts.

2oldman
Explorer
Explorer
Did this nightmare system come this way from the factory?
"If I'm wearing long pants, I'm too far north" - 2oldman