Generator not charging house batteries

[mlafleur]

Hello everyone,
This morning I stated my genny to top up my house batteries, only to realize the batteries were not being replenished. The battery indicator indicated only 1/3 and remained there the entire time.

Since the rig is in temporary storage, we're leaving in 2 weeks for warmer skiees, I don't have access to shore power.
I also wanted to take her out for a short spin, to test my new Blue Ox hitch, so I started the engine, stopped the genny and took a peek at the batt indicator. It was showing Full (the engine alternator provides charging). We drove for about 8 miles, came back, parked, stopped the engine and checked the batt again: Full.
I double checked to make sure the genny breakers weren't tripped (they were fine), and I also verified that 120V was available, and it was.



So that tells me that somehow the genny (or maybe even shore power) does not provide charging to the house batt.


My questions are: where do I start? what to check? I have a DVM and know how to use it.


Thanks everyone.


Maurice

 

[TitanMike]

My questions are: where do I start? what to check? I have a DVM and know how to use it.


Thanks everyone.


Maurice

Is converter circuit breaker on?

Check reverse polarity fuses on converter?

Make sure battery disconnect switch is in right position with house batteries connected.

Check for resetable circuit breaker between batteries and converter.

Make sure generator circuit breaker(s), if any, are on or need to be reset.

Check transfer switch to see if it's functioning when generator starts.

This is a start.

 

[mlafleur]

Thank TitanMike.
I’ll need to locate/indentify the elements you are citing (clues?). One thing I know for sure is that the generator breakers (2 X 30 A) are on: I reset them myself.
I will only be able to check things out tomorrow, and report then.
M

 

[TitanMike]

Thank TitanMike.
I’ll need to locate/indentify the elements you are citing (clues?). One thing I know for sure is that the generator breakers (2 X 30 A) are on: I reset them myself.
I will only be able to check things out tomorrow, and report then.
M

First thing to check is for battery power at power distribution panel. Do 12v lights, fans, Furnace, light in refrigerator, when not connected to shore power? If yes this means you are connected to the battery and issue is most likely at converter or 120v power from generator.

With generator running check for 120v power at outlets. If not look for transfer switch and check for voltage at the solenoid (signal voltage). If yes, and 120v power is present at gen input- but not output, transfer switch is bad.

Next check voltage at battery while connected to shore power and after checking converter circuit breaker in power panel to make sure it's ON. Battery voltage will rise to ~13 volts or more if converter is OK.

If not, look for a couple of 12v fuses in power panel labeled Reverse Polarity fuses. If converter is integrated into the power panel they're usually near the bottom of the 12v fuse column and slightly to the left with a printed label, not hand written.


If controller is a separate unit it could be behind power center or even closer to battery. Reverse polarity fuses are then generally on the output side of the converter near the 12v pos/neg wires.

Several years ago I was talking with a tech rep for a converter manufacturer who shared his frustration over converters often being installed under sinks where they frequently got "dribbled on" and failed. Don't know where yours is but just mentioning do you could look under sink area if the converter isn't located behind power panel or near battery. Wet converters don't work all that well

 

[bikendan]

Moved thread from the Tech and Repair section to the Motorhome section's Georgetown sub-forum for better help from other Georgetown owners and possible factory support.

 

[NXR]

Did you have the house batteries connected? If not, they will not charge from shore power or from generator power but will charge from the engine alternator.

Do you have an SDC-107A Battery Control Center? If so, this page has docs at the bottom that may help you: https://rvcustomproducts.com/sdc-107a

That company is supposed to have superb support as well.

Ray

 

[mlafleur]

I’m going to run a fee diagnosis today. Since I don’t have acces to shore power, can I use one of the 120V outlets to connect my shore cable, in a sense «*simulating» shore power from my own genny?

 

[Twinboat]

If you want to plug your shore power cord into a motorhome outlet, NO that won't work. Once the auto transfer switch senses shore power, it won't switch to generator power.
You need a portable generator to do that.

Generators don't charge batteries, they power converter/chargers that do that.

 

[Twinboat]

If your converter/charger is in the rear compartment like FR30DS are, check to see if that plug came out. It's up next to the charger.

 

[mlafleur]

(Responding to myself) I ended up finding shore power at the storage facilitied, and found the following:
When I connected to shore, batt rose to 14.3V, as expected.
With shore power still connected, I fired up the genny, the transfer switch clicked and went to the power provided by the genny, as expected. The voltage at the batt went to 12.6V.
I turned everything off, opened the transfer switch casing to make more measurements. The 120V switches from the shore to the genny, and back to the genny when connected to shore and turning the genny on/off. As expected.
I disconnected from shore, batt went down to 12.6V.
And now for the surprising end to this saga: still disconnected from shore, fired up the genny. Batts went back up to 14.3V!!!!
It appears to be working for now, back to normal, without any intervention (if only but divine �&#56832, or repair or fuse change.
I’ll be leaving for an extended stay in 2 weeks, with some apprehensions as to when will it fail again.
Thanks evetyone for your contribution, and maybe I’ll come asking questions again later.
Best regards,
Maurice.

 

[TitanMike]

(Responding to myself) I ended up finding shore power at the storage facilitied, and found the following:
When I connected to shore, batt rose to 14.3V, as expected.
With shore power still connected, I fired up the genny, the transfer switch clicked and went to the power provided by the genny, as expected. The voltage at the batt went to 12.6V.
I turned everything off, opened the transfer switch casing to make more measurements. The 120V switches from the shore to the genny, and back to the genny when connected to shore and turning the genny on/off. As expected.
I disconnected from shore, batt went down to 12.6V.
And now for the surprising end to this saga: still disconnected from shore, fired up the genny. Batts went back up to 14.3V!!!!
It appears to be working for now, back to normal, without any intervention (if only but divine ��), or repair or fuse change.
I’ll be leaving for an extended stay in 2 weeks, with some apprehensions as to when will it fail again.
Thanks evetyone for your contribution, and maybe I’ll come asking questions again later.
Best regards,
Maurice.

This sounds like the relay in the auto transfer switch may have dirty contacts or possibly a damaged wire/bad connection that "cured itself" when you opened it's case.

If it were mine I'd consider purchasing and carrying a replacement. At the very least start the generator and wiggle all the wires in and out of the case to see if the relay remains activated. Relays can fail and almost always at a time THEY determine, not the user's.

 

[Aussieguy]

if it is a relay style transfer switch
for testing swap the generator and Shorepower IN wires

you can also measure voltage on the INPUT side of the contactor then on the OUTPUT of the same contactor

there is a spring loaded contact in the middle of the contactor.... make sure it moves freely and is not sticky.... (it's what makes the click you hear)

use a well insulated screw driver to push it in... you might have to do that several times if it is sticky from non use... if it is tight and does not pull all the way IN replace the contactor... (push on it after it has pulled in electrically)

you can replace a contactor for a fraction of the price of a new transfer switch
use the contactor model number etc.... or take the contactor to local electrical supply store ..... they can match up a replacement .

 

[NXR]

if it is a relay style transfer switch
for testing swap the generator and Shorepower IN wires

you can also measure voltage on the INPUT side of the contactor then on the OUTPUT of the same contactor

Generally an automatic transfer switch has a 30-second delay built in before the generator contactor will kick in. This is to help assure the generator is stabilized before a load is placed on it. Swapping the wires solely for troubleshooting can help but it's just easier to use a voltmeter.

Forest River has used a Progressive Dynamics PD52 model transfer switch for many, many years in the Georgetown but I don't know about twenty years ago.

The PD52 uses two mechanically-interlocked contactors, not one. One is for shore power and one is for generator power. Using two mechanically-interlocked contactors assures that shore power and generator power can never get connected together in a failure condition such as a welded contact.

Ray

 

[mlafleur]

Thanks to everyone who contributed.
Today I went back to the rig and fired up the generator, after the 30 sec delay, 120V power came to the outlets, but the batteries were not charging. It was OK went I left Sunday, but today it is not.

The readings and experiments I have made Sunday indicate that the generator provides 120V to the outlets, that the converter gets its power and converts it to 12V. It also appears that when shore power is available and that the generator does NOT run, the transfer switch clicks to power the AC circuits from the 120V shore power. If the generator is started, the switch gives priority to the generator power.


In other words, everything BUT charging the house batteries is normal. I'm lost.

Any help is welcome.

Maurice

 

[NXR]

What Battery Control Center do you have? It's usually a box in the same place as the house batteries. The SDC-107A was common pre-2019.

If that's what you have there are some docs at the bottom of this page: https://rvcustomproducts.com/sdc-107a

RV Custom Products is also supposed to have great support.

Ray

 

[mlafleur]

Thanks.
From what I can gather (and remember from a conversation with an RV tech a few years back), it’s the Intellitec Battery Control Center that’s on board.
The RV tech had even given me the board number, and the guy at Intellitec had sent me a quote and technical details about the board.
I emailed him again today, and I’m waiting for an answer.
M

 

[Twinboat]

Don't waste your time looking at battery control centers.

If it charges on shore power and not generator power, with 120 volts coming from it, it has to be the auto transfer switch. Generator power is a substitute for shore power, for everything 120 volts.

Have you tried the air conditioners while on generator power ? Is your generator producing proper voltage ?

 

[Aussieguy]

Hello everyone,
This morning I stated my genny to top up my house batteries, only to realize the batteries were not being replenished. The battery indicator indicated only 1/3 and remained there the entire time.

Since the rig is in temporary storage, we're leaving in 2 weeks for warmer skiees, I don't have access to shore power.
I also wanted to take her out for a short spin, to test my new Blue Ox hitch, so I started the engine, stopped the genny and took a peek at the batt indicator. It was showing Full (the engine alternator provides charging). We drove for about 8 miles, came back, parked, stopped the engine and checked the batt again: Full.
I double checked to make sure the genny breakers weren't tripped (they were fine), and I also verified that 120V was available, and it was.



So that tells me that somehow the genny (or maybe even shore power) does not provide charging to the house batt.


My questions are: where do I start? what to check? I have a DVM and know how to use it.


Thanks everyone.


Maurice

going back to original post...

a) OP using factory supplied battery level indicator it was 1/3rd full
so much is wrong with that... it works OK for lead acid but it is still a system that can read pretty bad based on wiring size, age, corrosion and condition of the battery connections
Voltage losses can be all over the place ..

If you want to know your battery "TRUE" voltage use a meter and read it at the battery

b) used generator / alternator etc to charge .. for a short period
at this point OP is reading charging voltage?
even after turning off charging .......... it is recommended to allow battery to sit before looking at the resting voltage

if the battery was truly 1/3 SOC at the beginning and assuming it is a lead acid
then running generator and/or alternator even for an hour is no where near enough time to recharge a house system

a typical house battery bank lead acid will take at least a day to charge connected to shore power is best.
the voltages /soc you are reading may be misleading

follow the first 2 posts by Titan ... start by checking what is actually working
get a multimeter and read voltages at key points battery , disconnects, fuses 120v breakers and converter (inverter/charger?)

learn how to test converter (charger)
disconnect the battery and any solar...
use multimeter to test voltage OUTPUT on the converter
if you are NOT getting around 13.6 (OR more) then converter may be bad
but first check converter's reverse fuses...


got to start at the beginning and work in logical steps


and remember lead acid takes a long time to charge... while in storage with no power make a schedule to test everything is working...

when getting ready for a trip take the rv to a place you can load and fully charge with shorepower .... at home you can use a good extension cord and run the converter , fridge even test the a/c

-------------------------------------------------------------------
if you storing outdoors look if solar might be feasible to keep battery charged

no trickle charger or solar... and only storing for a month ... disconnect the battery so you are only dealing with self discharge

longer than 2-3 months best to remove battery and take them home or someplace so ...... you can trickle charge them.

 

[NXR]

Don't waste your time looking at battery control centers.

If it charges on shore power and not generator power, with 120 volts coming from it, it has to be the auto transfer switch. Generator power is a substitute for shore power, for everything 120 volts.

Maybe. But if you put a voltmeter on your FR3 chassis battery and power the motorhome from generator power or shore power you'll notice something interesting: the charge voltage to the chassis battery comes and goes while the house battery charge line remains constant.

The Precision Circuits BCC monitors the chassis battery voltage by temporarily disconnecting it from the charge. Once it thinks the chassis battery is fully charged it disconnects the chassis battery from charging and goes back to monitoring it.

When the charge (as determined by who knows what algorithm) starts to go below 12.6 VDC the Precision Circuits BCC resumes charging the chassis battery.


The SDC-107A I mentioned has a known issue as it ages where a particular contactor fails. When that failure occurs, the house batteries no longer charge front the engine alternator but do still charge via the converter. That's the opposite of this problem.


The Precision Circuits BCC had a contactor that was installed in 2020 and early 2021 that had a defect. After a while that contactor failed and stopped charging the house batteries but everything else worked.


I'm sure a twenty year-old motorhome does not use electronics to do monitoring and control like that but people were using voltage monitoring and contractors to do the same tasks for a long time. I have no idea what the designers of a two decade-old motorhome were thinking. Heck, it might even be a single stage converter still.

Lots of moving pieces in these things.

I asked about the BCC because I figured if we had more pieces of the puzzle we could, you know, complete the puzzle.


Mlafleur, in your original post you said you had no shore power available at the storage facility. In later posts you mentio using shore power. What changed there?

Ray

 

[Twinboat]

The OP states his house batteries are not charging on generator power. That has nothing to do with the chassis battery, nothing !

House disconnect open or tripped 80 amp breaker could be an issue.

There are 2 charging systems, house and charging. Each handles the battery it's named after. Any cross charging or bridging is between each system.

One other point, his battery charge is FAIR not 1/3rd. You use the letters ( L= low, F =Fair, G =Good, C =Charging , not the fractions on the panel. His batteries started the generator, they aren't discharged to bad.