House battery not being charged by engine

[DNMakinson]

Shore power will charge house battery
Engine on will supply voltage to refrigerator and to Leveler panel, but not to house battery or generator starter, pump or interior lights.

I have attached pics of battery connection, under hood relay and relay near battery.

2017 Greyhawk MV29

Where should I look to find problem and fix this?

[Stavman]

So u tested lines to the house battery...and no power going to it?
Is it charged?

Genny starts from house battery unless u use the emergency start in cab

Did u recently remove or change the house battery?

What's the goop on the terminals?

[DNMakinson]

I have not meter tested anything. Upon leaving home, house battery fully charged. After driving 300 miles, and staying overnight, then driving another 100 miles, house battery is dead. No charging from Engine. After on shore power over night, house battery is fully charged.

MH is new to me. I do not know for sure i the battery cables are correct (hence that picture). I don't know when the problem started, only what it is at this time. Battery is relatively new, and it supplied the coach for about 20 hours before depleting.

Goop is NCP2 corrosion preventative.

In my 2nd pic, I presume that the relay on left is the emergency start connection relay that you mention the button in the cab, and that the relay on the right is the charging circuit relay.

[DNMakinson]

Test to see if I can tag... @DNMakinson

[craigav]

Originally Posted by DNMakinson

I have not meter tested anything. Upon leaving home, house battery fully charged. After driving 300 miles, and staying overnight, then driving another 100 miles, house battery is dead. No charging from Engine. After on shore power over night, house battery is fully charged.

MH is new to me. I do not know for sure i the battery cables are correct (hence that picture). I don't know when the problem started, only what it is at this time. Battery is relatively new, and it supplied the coach for about 20 hours before depleting.

Goop is NCP2 corrosion preventative.

In my 2nd pic, I presume that the relay on left is the emergency start connection relay that you mention the button in the cab, and that the relay on the right is the charging circuit relay.

Do you have a voltage meter? To better understand what is happening it is important to know what the voltages are at the chassis battery and coach battery when the engine is running and when it is not running. It is possible that the coach and chassis batteries are charging as they should, but that there is a large drain on the battery. ~CA

[Stavman]

Like Craig reiterated

It's a must to know what is happening, and a simple start is a volt meter..they are $10-20 and a must have in an RV

Also.... Just because the meter in the RV says the House battery is charged..dosent mean it is. A bd cell can fool you and it discharges very fast

Test, test, test

[Yooper906]

Originally Posted by Stavman

Like Craig reiterated



Also.... Just because the meter in the RV says the House battery is charged..dosent mean it is. A bd cell can fool you and it discharges very fast

Test, test, test

True. I've had older batteries that showed 12.6 V on a VOM, but when a load tester was put on them, voltage dropped like a rock. And stayed there.

[Ann-Marie]

You will need a volt meter but you can also use a 12 volt light such as a portable spotlight to test for voltage with one side grounded and a test lead on the other side.

As I understand it, the charging relay is also the starting boost relay, just one relay. When the engine is running it is turned on by the ignition switch, and the boost button operates the relay manually. I think the red item with the 2 red cables is a safety fuse on the cable between the batteries (via the relay).

The cables to the house battery are incapable of carrying starter current, you would have to hold the boost button down for a couple of minutes to transfer charge before trying to start the engine.

You will need a volt meter to check that both sides of the relay are showing voltage. This will check the heavy current circuit is intact. If not, you will have to check for bad cable connections or that red fuse thing. Another check is with the engine off, when someone presses the boost button you should hear the relay click. When it clicks both relay power terminals should read very nearly the same voltage as they are connected together.

If that all checks OK you may have a fuse blown that connects the ignition to the relay. Somewhere there must be a small relay or a diode to isolate the boost button from the ignition circuit - I've not checked how that works because I just eliminated the (nearly useless) boost button when I installed an automatic Combiner 200 relay.

I also don't remember now if the master DC on/off switch on the house battery has to be on for the alternator charge to get to the house battery, I don't think it does but something to check.

[DNMakinson]

Originally Posted by Ann-Marie

If that all checks OK you may have a fuse blown that connects the ignition to the relay. Somewhere there must be a small relay or a diode to isolate the boost button from the ignition circuit - I've not checked how that works because I just eliminated the (nearly useless) boost button when I installed an automatic Combiner 200 relay.

I also don't remember now if the master DC on/off switch on the house battery has to be on for the alternator charge to get to the house battery, I don't think it does but something to check.

Will have a DVM this evening.

Ann-Marie, when you put in the Combiner, did you simply move the (2) heavy cables and add a ground... leaving the red thing as it was?

Can anyone confirm that the house battery is normally connected with (3) cables to the + and one to the - ?

Can anyone confirm that the red thing is some sort of fuse, and not a big diode? If not, I'll test it for Open vs Short vs Diode action.

I have confirmed that pressing the emergency button in the cab closes the relay. It seems to me that the (2) heavy wires connected to that relay would carry starting current, but the coach battery might not be able to supply much starting current, depending upon if it is a deep cycle only, or a combination.

I have wiring diagrams from JAYCO, but what is really needed is a schematic. I will ask them for one.

EDIT: I have confirmed that the red covered thing is a 20A fuse. I have also confirmed that the relay is closing when ignition switch is On (so either push button or ign will close the relay. When I get the meter I’ll be able to find out if the contacts are any good, and all the other items.

DNM

[Ann-Marie]

Yes, moved the two heavy cables to the Combiner 200.
The orange and white wires on the small terminals were abandoned.

The red thing was left as-is. It has to be a fuse because charging now works in both directions.

If it is a 20 amp fuse it sure ain't going to start an engine and too small for battery charging. Something is wrong there???

[craigav]

Originally Posted by DNMakinson

Will have a DVM this evening.

Ann-Marie, when you put in the Combiner, did you simply move the (2) heavy cables and add a ground... leaving the red thing as it was?

Can anyone confirm that the house battery is normally connected with (3) cables to the + and one to the - ?

Can anyone confirm that the red thing is some sort of fuse, and not a big diode? If not, I'll test it for Open vs Short vs Diode action.

I have confirmed that pressing the emergency button in the cab closes the relay. It seems to me that the (2) heavy wires connected to that relay would carry starting current, but the coach battery might not be able to supply much starting current, depending upon if it is a deep cycle only, or a combination.

I have wiring diagrams from JAYCO, but what is really needed is a schematic. I will ask them for one.

EDIT: I have confirmed that the red covered thing is a 20A fuse. I have also confirmed that the relay is closing when ignition switch is On (so either push button or ign will close the relay. When I get the meter I’ll be able to find out if the contacts are any good, and all the other items.

DNM

Check this link out and comment #2. Someone else shared that to me quite a while back, I don't remember who to give the credit too though. Also, this schematic is for a 2013 however the same schematic has been noted by many to be accurate for a lot of year models 2008~2018 +or - a few years, and even very similar to the newest 2022's.

https://www.jaycoowners.com/forums/f...-fk-90662.html
~CA

[DNMakinson]

Originally Posted by Ann-Marie

Yes, moved the two heavy cables to the Combiner 200.
The orange and white wires on the small terminals were abandoned.

The red thing was left as-is. It has to be a fuse because charging now works in both directions.

If it is a 20 amp fuse it sure ain't going to start an engine and too small for battery charging. Something is wrong there???

I believe that the charging goes through the large wires (either direction). The fuse is just supplying some other things by the #10 wires, They could have connected it to the fuse box hot just as easily, but used the chassis lead to the solenoid for convenience.

If my solenoid is bad, I think I'll order a combiner and be done. I like what you did.... if shore power is connected to keep the coach battery up during storage then the chassis battery is tended as well.

DNM

[DNMakinson]

Originally Posted by Ann-Marie

Yes, moved the two heavy cables to the Combiner 200.
The orange and white wires on the small terminals were abandoned.

The red thing was left as-is. It has to be a fuse because charging now works in both directions.

If it is a 20 amp fuse it sure ain't going to start an engine and too small for battery charging. Something is wrong there???

If you wanted to, you could connect the "Manual" input to the orange wire and retain the functionality of the emergency button. See the schematic that craigav posted. It shows the 20A fuse and the operation of the emergency button.

[Ann-Marie]

I just remembered, on our Greyhawk, one of the wires from the solenoid picks up starting battery voltage through a fuse and ships it back to the power entry step so you can still step in when the DC MAIN switch is OFF.

Why they routed all that distance instead of picking it up off the house battery 6 inches away involves deeper thought, - - perhaps backup in case the house battery was dead? But it isn't that critical.

[DNMakinson]

Solenoid is bad. It actuates either with button or the ignition, but the contacts remain open.

Temporary, I have hard tied batteries together, and will take them apart overnight when I want to be on coach battery only. Tie them back when on the road.

When I get home, will get a Combiner 200; and will post a picture of it installed.

DNM

[Justafordguy]

That's what I suspected because one of the boots that covers the battery cables looked burnt. Glad you found the problem and should be an easy fix.

[DNMakinson]

I cut the Yellow wire to the "Emergency Start" Button, so that the Combiner works in automatic mode from the alternator perspective. The Yellow wire is from the ignition. The end result is that the alternator will not charge the coach battery until the chassis battery is first charged. This can be reversed, if needed.

Pushbutton still forces coach battery to parallel the chassis battery to help with engine cranking, if ever required.


DNM

[don_kleinschnitz]

Having been flailing with parasitics and step problems.
Attached is an annotated version of the chassis schematic in case it is helpful to someone else.