Hello everyone! Hope all is well; I was looking through my battery compartment as I was testing the relay for the rear defroster. I noticed there was condensation in the battery compartment; on the actual battery, everywhere in the compartment. ( Luckily not in the fuse box ) It's not just in the battery compartment though. I also notice it in the truck where a few items get condensation on them as well.

Perhaps of the cold mornings and the heat of the battery? ( If that's possible? )

I will check for leaks, ect tomorrow are there any culprits that could lead to leaks? Should I be worried about rust forming because of it?

Thanks everyone and happy holidays.

- Pilotman

 

Condensation forms on cold surfaces so you're not really looking at heat from the battery.

I suppose check the level in each battery cell in case something's wrong and water is being driven out. (I don't know if your battery is vented as mine is via a tube to the outside air.)

Otherwise it's just a sign of damp air. Or... maybe water getting in - check the seals etc if so.

 

Do you have the correct battery? With the vent tube connected?

They normally don't vent very much -- I did have an overcharging situation with a MB many years ago that caused excessive battery moisture.

If everything in the trunk is coated i would start looking for a leak. Make sure the trunk seal is clean -- I have had pine needles get jammed under under the lid.

 

+1 water leak; adjust the stops to the boot lid, lightly lube the seals with silicon spray. Look for rust in the trunk: under the battery and spare.

 

Will check later. I just had a new battery put in 3 months ago. Where's the vent tube located?

 

One end should be connected to the battery, the other passes to the outside at the front right of the battery compartment.

 

There's no water leak. All of the seals are perfect; no cracks, all clean. No evidence of any leaking. However I did notice that the floor of the spare tire has condensation; same with the battery again. Doesn't seem like acid at all; especially if the battery is brand new. I did notice rust on the bottom of the battery ( pictured ) is this common?

I think the condensation might be from Northern CA's freezing nights and warm days. Overnight the battery gets down to the ambient temperature and then next day when the heat rises quickly, the cold air stays on the battery.

Maybe I'm wrong still.

 

The trunk is ventilated and dried with air passing thru the ventilation of the vehicle while moving and it exits in the rear of the trunk. You need to check for obstructions at the parcel shelf where the air enters the trunk and the rear area where fresh air exits the trunk. The condensation would prove the trunk seal is in good shape but the vent path is obstructed.
I have attached a cut sheet from the x308 tech manual showing the trunk venting.

My first guess is the exit flaps are stuck closed or obstructed.

 

Thanks Avern. Is there an easy way to check the flaps?

According to the doc you need to have fresh mode on; not recirculation for the air to pass through. I usually always have recirculation on because I'm always stuck behind traffic. Tomorrow I'll check the flaps but I'll also leave recirculation off and see of there's condensation at the end of the day.

Thanks again.

- Pilotman

 

In case it's from the battery (which it pretty much can't be if vented correctly and battery cell caps installed) it would be almost pure water, not acid.

 

Pilotman in the trunk on the fender sides you should find a slot in the liner with a plastic vent duct. Mine sometimes fall out and are laying behind the trunk liner. I haven't gone further than putting them back in place. I would imagine you would find the vent flaps mentiioned in the cut sheet in the area behind the liner at the rear fender area inside the trunk.
It says they exit near the rear exhaust.

 

Found the vents behind the liner. I don't think the vents are getting enough air flow through with the liner being in front of it. I know they support the trunk floor but could those pieces that are block the vents be cut out?

Also I could not find the vents for the air to go outside. What I did find was two holes near the side of the battery that's taped up. Are these the vents?





I think the condensation is coming from three problems: 1) Almost always using recirculation mode 2) the trunk liner being in the way of the vents. 3) the outboard vents might be blocked?

I really appreciate the help;

- Pilotman

 

Great info thank you