Chassis Battery Charing When Camping Questions 2011 Vista 36D

[dallasrules]

I have a 2011 vista 36D motorhome. I have had it for about 2 years now and I am trying to figure out some battery issues. I thought my chassis battery and my house batteries were separate, but the way things are functioning, I can't get it to make sense. My main issue is that if I leave my chassis battery turned on while I am not driving, it gets drained very quickly and can not start the mh. If I shut it off immediately after shutting off the engine, it stays charged fine. Even for months. The house batteries show full charge when the engine is running or it is plugged in, but drain rapidly as soon as unplugged or the engine is shut down. They appear somehow to also drain the chassis battery if it is not shut off. I am coming to the conclusion that I need to replace my house batteries, but why would they drain the chassis battery. They are behaving as if all 3 batteries are linked. Can anyone explain how the system is supposed to work?

Also, can I replace my house batteries, which appear to just be lead acid car batteries with 12v lithium batteries? Is there any issues with the current charging systems, or anything I would need to know or do? If all 3 batteries are linked, I don't think i could replace the house batteries with lithium and that be linked to my lead acid chassis battery.

I need to get this figured out because currently, I can't take a trip without needing a jump at least a couple of times. However. I can have the mh parked at my house for months plugged in to electric and the chassis battery shut off and have it start right up.

BTW, there are 2 house batteries and one chassis battery.

 

[Morich]

Okay, this is a frequent source of problems/questions and I am somewhat familiar with it!
So are you a drawing reading info guy that would like to look at those or is that a mind blowing mess? How much explain what I "think" I know or would you rather have links to the drawings and like to check? I can go either way, so trying to cut down time wasted if it is not of interest?
Main group of wiring diagrams is here:

Wiring Diagrams

Sheet 2 of this group is the setup of the battery disconnect relays and the mode solenoid that connects/disconnects the two systems when driving or parked and lots of good stuff to know there!

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/2011/11_wire_174399.pdf

But it sounds like there may be some basic ideas being missed as they DO get tricky!
One big one is that the name battery disconnect is misleading as it only cut off a large part of the drains but also LEAVES some to run either set of batteries down!
Safety items like the CO and propane detectors, etc. are on the coach side even when disconnect is off! Check for a little green LED on them to see it stays on?

Then on the chassis side, there are also things left on! Radio preset buttons for stations, any automatic door locks and some ignition parts, are suspect but we get less chassis info, so I'm not well trained on exactly which! Anything that works before you start the engine, is suspect?

One big confusing pointthat can snag a lot of people is the battery disconnect switch. When we store and want to save power, it seems smart to turn the battery disconnect switch off to cut power drains. The problem is when we think we have the RV plugged in and it will keep the coach batteries charged.
ARRGH! WE find the disconnect switch cuts the drains off but ALSO the charging! So we can come back after a month and find the coach batteries are dead because the charge was cut off. But only MOST of the drains were cutoff and the safety items ran it dead!

Batteries are so simple they can drive us crazy!

But I can pass along a hint that may save you some grief until you get a final solution!
Rather than doing a jump start to get the engine going, you should have a built in system to use the coach batteries for that without cables!
Somewhere ion the dash, there should be a momentary toggle switch. Labels /names change but look for "boost, AUX"or a switch that you don't know about?
Pushing and holding that switch, while cranking should let this mode solenoid connect the coach and chassis for a handy jump start without getting out the cables!

Multi function item that closes when you hold that switch but also closes when you have the ignition on as we drive. That connects the coach batteries to the chassis where it gets charged off the engine alternator . We get "some" charge back into the coach side as we drive!

One first thought to check on the chassis side running down is the battery condition but also there is a tricky switch in lots of RV that may need a check??

This switch can switch power to radio from chassis to coach or back! It seems a trouble source to me but if we use it on chassis while driving, no problem as it works off the alternator. But if we leave it on the chassis battery and that is not powered by alternator when stopped, we can run down the battery if we use the radio.
Maybe review if that is what might be happening?
When we stop and want to use the radio, it needs to be switched to the coach side to avoid running down the start battery!
I kind of disagree with even having this option!
If we want to sue the coach when stopped, why not just leave it on coach if the coach is connected to the chassis through the solenoid while driving??? Seems a setup likely to cause more problems than it solves?

Exactly why and how the chassis is running down may need a whole long discussion, though!
Some RV have an extra part that you may need to look for as it may be OEM or it may be added. An item called Trik-L-START was very popular and added to some RV but is now gone from the market. It was a small electrical box that let the coach converter that charges the coach batteries sneak a bit of charge over to the chassis while we store with the coach plugged in. Small silver box with 3 small wires. One to chassis, one to coach and one to ground. If you have one of those, keep it as it does nice things!
A change to lithium is great but it also is a real head scratcher to get right as it takes several things changed to get it right. Perhaps better to put it off for right now?

You might do a search here of the forum to find several postings as it is a whole big idea! Can be good to do but mayor thought needed!

Welcome to a whole new world of fun ----- and headaches!!

 

[Morich]

A bit more looking at drawings here for where a Trik-L might be found, if it has been added?
There should be a fuse/breaker panel outside left somewhat near the front?

maybe they made it easy to get behind the fuses?

BUT if you can get a look, this is a common place for TRik-L to be added due to access to both coach and chassis battery? Normal OEM is this, so spot any small box added?

Good place to look around and study when bored and getting to know a new RV?

Interactive parts catalog here to see through walls without crawling around:

Parts Catalog

No telling what we might find hiding in there !

 

[creativepart]

First, it's very likely that both your Chassis Battery and your House Batteries are in need of replacement. They are not "connected" at least the way you are suggesting.

First, your chassis battery needs to have a charging source anytime the chassis disconnect is ON. Even when you are on shore power at a campground. Newer coaches solve this with a device that takes some of the house battery's charge and shares it with the chassis battery. That device is either a "BIM" or a "Mode Solenoid."

As Richard mentioned above some older Winnebagos came with a device called a Trik-L-Start that did the same thing.

You can simply buy a small battery maintainer and attach it to your chassis battery when the RV's on shore power and the problem will be solved. A more elegant long term solution is to buy a device that does the charging automatically. Trik-L-Start is no longer available after the death of the company's owner. But Xantrax makes a similar device called an Echo Charger. It does the exact same thing.

Now, your house batteries. House batteries that can't reliably hold a charge and are a few years old are very likely damaged and ready for replacement. Simple as that.

Oh, there could be other issues that cause this but start with the easy most likely answers and go on from there.

Heck, both problems could even be related to each other... but that's pretty much a long shot. Go for the easy things first. Take the house batteries to an Auto Parts store and have them load tested. If everything keeps failing then get an RV Tech to come do the deep dive into what the problem could be.

 

[dallasrules]

Thanks for the information. I know about the battery boost switch, but it doesn't work since I am pretty sure the house batteries are bad. I am equal amounts sure that the chassis battery is good and has been replaces in the last 12-16 months.

I plan to start with testing and replacing the house batteries and see what happens from there.

One more question. Do you know if the slides and the leveling Jack's work from the chassis or the house batteries?

 

[creativepart]

One more question. Do you know if the slides and the leveling Jack's work from the chassis or the house batteries?

Chassis battery.

 

[Morich]

One big one that can help a lot on battery power is starting the RV engine first before trying to do the heavy power users like slides and jacks or starting the generator! That does two good things for us. One is that it helps avoid working a weak battery really hard, so we are more likely to get the job done.
But it is also true that a motor will last better if we avoid setting up a situation where it has to work using voltage that is lower than best. When faced with low voltage it creates more heat in the motor and that heat is why we say things "burn out"!

Another p[oint that is often overlooked is how much quicker the RV engine starts than the generator which may need some time to get fuel if we have not run it recently!

Avoid abusing things like this to make them last longer!

Start the RV engine, that connects the two battery groups together and also has the alternator and you will get much better power for longer life!

A small easy thing to do on RV that have the batteries next to each other may fit for you to avoid a second battery charger? Something to consider on how you want to operate?
When you are storing the RV and you find the onboard converter does a good job of charging the coach batteries by leaving the RV plugged in and the coach battery disconnect switch on, you may want to let it charge the chassis battery as well!

On your RV, if you find it works for you, a simple strap from a positive post of one of the coach batteries to positive of a chassis battery will make them act as one larger battery! They are both already connected to ground so one strap is all that is needed. power will flow from the converter to the coach and on to the chassis battery! No need of a second charger if happy with the way the converter does it?

But be aware that most things come with both good and bad points! Be aware that IF you put this strap on manually when you store it, you also need to take it off manually when using the RV.
IF you FAIL to take this strap off and one battery runs down, the second start battery will also run down and you are then dead!
But that may be where you are now if the boost switch is not working.


It can be a question of which you prefer? A second charger to keep the second battery up or the effort to put the strap on/off each time. I found it more convenient for me to add the strap and just a piece of 12 gauge was handy. I added alligator clips at each end to make it handy and left it in the battery compartment.
I didn't even want to have to go find the strap! A #12 is plenty if you put it on when getting home from a trip because the two batteries will be near the same voltage as they have been connected all the time driving. That makes the current flow very low as the converter takes over the charging.

 

[dallasrules]

Thanks. That all makes sense. I am going to check the batteries to see if someone may have connected them and that could be what is dragging the chassis battery down.

 

[Morich]

Humm?
Yes, that WOULD explain why they seem connected!
Had not thought of that idea but part of getting into a different RV is learning what others may have done before!