2003 Adventurer 33V. Generator won’t start without jumping

[Dawn & Rich]

After thorough inspection at CW, all fine. Days later have to jump batteries off engine battery. Then after running for 2-3 hours, needs jump to start again! Are they not getting charged by gen?

 

[Morich]

Ok, time to get to know the beast and one area that is a common issue to know about!
We normally call the battery that starts the engine "chassis" battery as it comes as a stripped down chassis to Winebago where they build the house on top and we call that the coach battery group!
But the "simple" batteries are one of the harder things to get to know as they are simple but tricky!
Big thing to know about motorhomes is that there are those two battery groups and they work seperately and connect together at other times. So you get a confusing issue, both of what powers items and also how each gets charged or runs down!
Let me start with the very basics to clear some things there first.
The chassis battery operation is what we expect to have in any truck or car. They power truck things like headlights, horn, and wipers that a truck would have. They charge off the engine alternator just pretty much like a truck! But with some extra duty involved!

The coach batteries are what run the parts that make it an RV! That includes starting the generator, running inside lights, fans, and controls on furnace, etc. That group gets charged in different ways at different times. When we plug into power or run generator, there is a converter that changes 110AC to 12VDC to runs things and charge the coach batteries.
The first big hangup is that both chassis and coach have things that gradually run either set down, if given a chance and time. Ignition and radio presets are on the chassis and work to slowly kill it.
But it sound like your problem is the coach batteries are likely down and not cranking the generator, as a first guess! Those can get run down, even if we have the battery disconnect switch turned off! They want the safety items like CO and propane detectors left on, even when we turn the disconnect off. No filling the RV with propane and coming back to turn on the lights??
Is this RV new to you and you don't know history? That is when dealers often sell us RV that have had the battery abused while on the lot and they are often a big question if they are still good or damaged! UGLY story behind all that!

Some basics to see how it may work out?
This is a drawing of the main place where we need to know what is going on and how each group should connect to the other.
Somewhere in a compartment, there should be a label like this:

Under that cover, there should be this set of connections and items.

This can be a mind bender at first but not TOOO hard to follow and it is important to know to avoid long term trouble! The green line is how the chassis battery gets connected to a "mode solenoid". That name is just a relay or switch by a different name!
When the engine runs or we hold a switch near the drivers that has had different names at different times, this relay closes and connect left chassis battery to right coach batteries! That switch may be called/labeled AUX, boost, etc. but it is a handy thing to know about! When we push the switch, it closes this mode solenoid and we can do a "jump start" for a weak chassis/start battery! If the chassis battery is run down we get a jump start without getting cables out!
But the main important thing this solenoid does is connect the two batteries together as we dirve to the next site! Kind of slow and we need to drive quite a ways to get full charge as charging is really slow, but it helps!
Power from green line goes through solenoid to red line and then to disconnect relay. If relay is closed, power goes through to orange line and out to generator to start!

But to get the genrator to crank? We are far better if we first start the RV engine as it is more likely to start easier. That should connect the alternator and chassis battery to the coach batteris before we try to crank the generator. Since we don't start it as often, it often takes longer to crank enough to get fuel to it and let it start.

This is a place where many find a meter to test voltage is needed, but we can do some looking at what might be wrong without the meter.
When you are plugged in or generator running, either of those should power a converter that changes the 110AC to 12VDC. That should make the inside lights and such all good even if the coach batteries are dead! But the battery disconnect switch has to be ON, to make things work OR get charge to the coach batteries from the converter!
WHEW! Info overload??

Main points are starting RV engine should make the coach batteries get a little power and let you crank the generator off the alternator? If generator starts or plug in, the converter should then be able to slowly charge those coach batteries but it is a slow 6-8 hour process that can't be rushed.

Hope that is not too much at once but all important things to know for future!

 

[d58kerry]

Just bought a Minnie Winnie so first time with generator. )Not taken delivery yet) Reading what you said am I correct here?
1) The disconnect switch protects the house batteries from left on light or similar but not the propane or CO detector drain. If so then it takes about 2-2 weeks to drain the battery down.( I’ve been to my storage lot in the past and heard many a propane detectors going off on different trailer)

2) the disconnect switch doesn’t protect the chassis battery because it has a relay that disconnects chassis to house battery when rv engine is off.

3) The boost switch over rides the relay in 2) above so as to get house battery help. Chances are if left for a while that the house batteries would be dead first rather than the chassis battery so boost only useful if you have a bad chassis battery.

If what I said is true why not have a house battery disconnect for when you leave or does this make it risky if you start the rv to drive from a propane leak. Does the propane tank have an off valve at the point of connection? When leaving the coach you could turn that off for no risk.

Thanks in advance for a response to a newbie on motorhome generator stuff

 

[Dawn & Rich]

I have to have Aux battery switch on in stairwell to keep alarm on. It is direct wired.
Since I posted, I honestly think I left something on that drained it. Been fine since.

 

[Zoohelp]

Yes to No 1 except propane and co2 alarm are passive and always on. Don't need to be sounding to draw power. But drain will be pretty slow. Leaving battery switch on will drain house batteries alot faster as you never know what might be drawing power
No 2 is correct
No 3 Boost switch should not stay on once released. It's only active when being held. It's is also useful if house batteries are to weak to start generator

 

[Morich]

Been out of country for a bit!
Several points, One is look carefully at both the CO and propane detectors for a small green LED on the face. If that stays on while disconnect is off, that tells you it is drawing power full time!
Normal business is try to avoid liablility like killing the customers! So WE know we could turn the knob off at the tank and the propane fill guys do this on filling. They can also forget to turn it back on, so maybe take a look to know where to solve that as it is pretty common for me!
But the RV builders don't want to trust us to do it right every time so they keep the alarm alive to avoid liability!
But the way this is factory wired shows on the drawing above.
Look just above the mode solenoid on left for wire ID "GJ" for a small wire that goes across to connect on the right side of the mode solenoid and meets coach battery there? ? See how that doesn't go through the contacts on that disconnect relay? But most of the coach RV power has to go in the disconnect relay (item on right!) at left side through the contacts if they are closed to get to all the wires on the right side!
As built the safety items are getting power on GJ, whether the disconnect is open or closed!
If we look at the wire ID list, we see it described as "upstream" of the disconnect. Their way of saying disconnect not involved!

So on a dark night, you can go out and spot the little green LED, no matter where the switch is set and it is slowly working to drain the battery!

If the LED is going off when flipping the switch off, there may have been changes made by previous owners??? Probably not that uncommon if folks find it a nuisance, but it may also leave them at risk for surprises if they ever do have a leak that fills the RV??
On running batteries down, compartment lights are my main nuisance for this as they are hidden. Another to consider is when you leave the steps out, is there a light bulb under them that you may not notice in daylight? That can be a different battery killer that is easy to miss!
Disconnecting the chassis/coach connection when we turn the engine off is handy, especially if we have anybody onboard whl like to listen to the radio! Many RV have a switch to change power from coach or chassis to the radio. If that switch is left on chassis and somebody listens to the radio too long while camped, it runs the chassis battery dead! Got any teens that might get near the radio? Have to watch them close!

So the connection has two functions. One to let us charge coach as we drive, but also to let us do and easy jump starty if we do happen to get a weak chassis/start battery.
They tried to cover us for a number of "dummy" moves but, being human, we do a good job of shooting our foot at times!

 

[DancinCampers]

I owned the same coach for 8 years. The engine battery is used to start genset. The engine battery is only charged while driving. The converter only charges the house batteries. I ran a wire between my house and engine batteries with a toggle switch. If I was sitting stationary for awhile I flipped the switch so that both sets of batteries were charged.

 

[klook]

I installed a battery disconnect switch on the chassis battery.

 

[Morich]

One point that can often trip us on battery use? When dealing with a discharged lead acid battery, we have to keep in mind that charging for just a coule hours is likely just teasing them! It takes more like 6-8 hours to recharge them if they are actually really low.
How this can mess with our mind is when we look at the voltage after charging for a few hours, we may see a good 12.8 or even way higher. But that is a trick as it is only "surface charge" and will go away if the battery is given time to become stable after the charge is removed.
We have to think of lead acid more like filling a barrel with syrup? While we are filling the barrel it takes a long time and the syrup tends to pile up at the point where it enters. In batteries, that is also where we test for voltage!
If we look at voltage while filling or too soon after, we are likely to see that pile that has not yet spread out all through the battery or barrel.
The way this can work is that we may run the batteries for 8 hours and charge for 2, then when we look at the voltage too soon, we may see a voltage of 13+, even though we know lead acid will only hold a charge of 12.8 or so. We may think we got a super good battery and run it the next night but find it quits after 4 hours?
Messes with our mind if we are not fully awake!