Community Forums

Doc Vegas · 11-09-2014, 12:30 PM

Hi Folks: I am hoping someone can help me with my 2007 Itasca Sunova. I got this used a year ago and the previous owner replaced the three batteries (under the steps). However, I am sure that it drains all three batteries equally, thus the chassis battery and the two house batteries seem to be connected. The chassis battery is also an identical marine deep-cycle battery, which seems odd to me compared the the owners manual which shows a smaller, more conventional looking battery. Does it matter?

Lastly, it seems to me that all three positive leads are connected to a common post. Is this why all three are draining equally and the chassis is not separated? Any help would be greatly appreciated, pictures even better.

Thanks!

vsheetz · 11-09-2014, 12:52 PM

For clarification, you have three batteries (house) under the entry steps and a forth battery (chassis) in the engine compartment - correct? And all four are the same battery, a 12vdc marine type -correct?

grtharris · 11-09-2014, 05:42 PM

Doc Vegas, below is a link to the battery wiring in you coach look at sheets 3 and 4 for the Ford chassis.
http://www.winnebagoind.com/diagram/...ire_157187.pdf

Hikerdogs · 11-09-2014, 05:45 PM

Quote:

Originally Posted by vsheetz

For clarification, you have three batteries (house) under the entry steps and a forth battery (chassis) in the engine compartment - correct? And all four are the same battery, a 12vdc marine type -correct?

If it's the standard configuration there should be 2 deep cell 12 volt house batteries, and 1, 12 volt starting battery. There could be several reasons the previous owner linked them all together. Among them might be:

1. Solenoid to allow house batteries to be charged from the alternator when the engine is running failed and the previous owner didn't replace it.

2. The charger for charging the house batteries when plugged into shore power failed.

3. The previous owner did a lot of boon docking and wanted a larger battery bank.

The first 2 scenarios would require some repairs beyond just rewiring the batteries. The 3rd would be an unusual case specific to the previous owners needs. In any case I would return to the original configuration, which would include separating the house and chassis batteries, and replacing the chassis battery with a normal starting battery.

You can go to the "manuals" section of the Winnebago website to get the schematic of how the batteries were originally installed and wired.

Wiring Diagrams

Doc Vegas · 11-09-2014, 10:45 PM

OK, I much appreciate the responses! So, please look the link kindly provided by grtharris. Definitely my positives are wired this way, I should check the negative. But here is what I do not get, looking at that schematic, how could the chassis battery possible be isolated?????????? It has a common positive and a common negative....! Am I missing something?

Thanks again.

Hikerdogs · 11-10-2014, 07:07 AM

If you enlarge the diagram you can see the labels on the battery cables going to the isolation stud.

One goes to the chassis battery

One goes to the chassis battery electrical box

One goes to the leveling system pump

One goes to the chassis external power

The Positive wire from the House batteries also goes to the chassis electrical power box. In the box there is a solenoid that connects all the batteries for charging by the alternator when the engine is running.

When the ignition is on (or the "Battery Boost" switch is activated) the solenoid is engaged tying all the batteries together.

Page 3-8 of the owners manual http://www.winnebagoind.com/resource...7/07Sunova.pdf

When the ignition is off the chassis and house batteries are isolated from one another. The solenoid looks like the old Ford starter solenoid. The big difference is that it has a 100% duty cycle as it's engaged anytime the ignition is on.

These solenoids do fail from time to time. When they do the house batteries aren't being charged, and the "Battery Boost" switch cannot manually connect them. A new solenoid costs about $25.00 - $35.00. Ours was mounted behind a removable plate at the back of the top inside step.

grtharris · 11-10-2014, 07:21 AM

Doc Vegas, Look at sheet 2 this is were the isolation take place. The chassis battery connects to the left side of the left relay and the coach batteries connector in the center between the relays. The left relay is for charging the coach batteries when the engine is running and the right relay is used to disconnect the coach batteries from the coach.
http://www.winnebagoind.com/diagram/...ire_154491.pdf

Doc Vegas · 11-23-2014, 09:22 AM

Thanks again guys! I will check out the selenoid. I am also curious if a deep-cycle marine battery is the correct battery for the chassis (to start the engine)? The manuals consistently show a "regular" car battery in that spot, but mine has three deep-cycle batteries. Could that be the issue?

Thanks

Hikerdogs · 11-23-2014, 11:25 AM

The deep cell marine battery isn't the optimum for a starting battery. However it could be a hybrid deep cell/starting battery. They are commonly used as dual purpose batteries for outboard engines. See if it has a CCA (cold cranking amps) specification printed somewhere on the battery. The group 31 starting battery in our 2013 Adventurer has 570 cold cranking amps. The group 29 that was in our 2001 Adventurer (both were on the F53 chassis with the 6.8 liter V10) had 550 cold cranking amps.

If you don't live in a cold climate or travel to those areas in the winter I would think something in the 300+/- would be sufficient if the battery is in good shape. If it's getting tired I would replace it with either a Group 29 or a group 31 starting battery.

Doc Vegas · 11-27-2014, 04:32 PM

OK fellows, thanks again for all the info. Today, we were going to take a short trip, but alas, the coach would not start again - battery too weak. So, I decided to use the day to pull it apart. Here is what I discovered. The coach battery is reading 11.5 volts while the house batteries were reading 12.6. I pulled the coach battery out and the house power was fine - of course the motor would not turn (no power at all). I removed the leads on one of the house batteries and connected it to the ignition and she fired right up.

I should have started by saying that holding the "battery boost" button does NOTHING! With or without the coach battery connected. So maybe it is the selenoid. I am guessing I can crawl under the rig and find it somewhere, it is not obvious top-side.

My remaining question though, is why is the coach battery draining when it is on shore power??? I thought the shore power would also power up the coach battery...? Is this the same reason the battery boost button does nothing?

Thanks!!!!!!!!!!!!

grtharris · 11-27-2014, 06:04 PM

Doc Vegas, coach battery disconnect relay and the boost relay are in the compartment just in front of the batteries behind a removable panel. If the coach battery disconnect is in the disconnect mode the boost relay will not work.
When on shore power only the coach battery is charged by the converter. On your coach without additional equipment the chassis battery is only charged when the engine is running. BTW the coach battery is charged through the boost relay when the engine is running.

Doc Vegas · 11-28-2014, 12:19 AM

Thanks Grant. I checked that the coach batteries were "on" with the switch, so that is not the issue. Good to know that the house power does not charge the chassis battery (I am very surprised by that, any idea why not?).

grtharris · 11-28-2014, 06:35 AM

Doc Vegas, I think it is left over from the days when chassis engines did not have all of the electronic drains that have now. They are lots of after market solutions to keeping your chassis battery charged, I like the Trik-L-Stark.
Sounds like you boost relay may be bad.