VW Grand California: Instructions for preventing water damage to the body battery in the engine compartment
The camping body battery is installed in the engine compartment of the VW Grand California. In this detailed report, our customer Joachim describes how he protects the body battery from water damage.
In this report, our customer Joachim explains how he prevents water damage to the body battery in the engine compartment of his VW Grand California.
Table of contents
Guest article: Instructions for preventing water damage to the body battery in the engine compartment
In the Grand California, the camping body battery is installed in the engine compartment.
I have replaced the factory AGM battery with a Supervolt lithium-ion battery
180Ah (SX 180P).
After 3.5 months, the battery suddenly switched off and could no longer be activated or switched on. When the battery was removed, water was found on the battery and on the stand plate under the battery. The cause of the battery malfunction turned out to be water damage.
The battery had failed due to corrosion of 2 of the 3 RJ45 sockets (Fig. 1).
The battery itself is hermetically sealed (IP65), but the RJ45 sockets were susceptible to moisture on the model at the time.
As a further development, Supervolt has added a blue cover flap for the 3-way socket in addition to the small “plugs” on the newer model (Fig. 2).
For certain functions, however, an RJ45 plug must be permanently plugged into one of the RJ45 sockets (e.g. for communication with another battery). In this case, the new cover cannot be closed.
I didn’t want to run the risk of water damage again for the replacement battery that Supervolt supplied without any problems, so I took the following measures to prevent water in the RJ45 sockets and on the surface-mounted battery:
Note
For the Grand California we recommend our Supervolt Ultra – 12.8V 150Ah High Power LiFePO4 high-performance battery with Bluetooth, heating and integrated balancer. This has no RJ45 ports and has IP65 protection. This means that 100 percent waterproofness can be guaranteed. If you have any further questions, please contact our technical support:
Measures on the battery to prevent water in the 3-way RJ45 socket outlet
(1) Cover for the RJ45 sockets
(as these may still be susceptible to moisture damage):
Image 3 Butyl tape: I used so-called aluminum-laminated butyl tape to “glue” the RJ45 sockets. This tape is also used for roof sealing, for example (10 cm wide, 10 m from approx. € 23).
If necessary, it can be removed like a rubber compound and then reused.
The butyl layer is permanently elastic. The water can run off to the side of the battery. I deliberately left the cavity of the “3 RJ45 socket” open at the bottom to ensure that the air pressure is always equalized.
If you try to seal such a cavity completely airtight, the air will expand when it is hot (and find a way out through overpressure) and when it cools down, the “vacuum” draws cooler air and water into the cavity.
Figure 4, alternative A: additional plastic cover over the RJ45 sockets:
Another option for covering the RJ45 sockets would be to stick a small plastic cover (gray in the picture) over the sockets like a roof with a slope so that the water can drip off the side of the battery.
Figure 5, alternative B: large plastic cover that covers the entire battery:
A large plastic cover that covers the entire battery would also be conceivable and would have the advantage that the other battery connections would not float in the water. The cables at the positive terminal of the battery and the control unit located under the battery should always be kept dry.
However, it is actually VW’s primary task to prevent water from entering the engine compartment, especially above the body battery:
(2) Prevention of water ingress into the engine compartment in the area of the body battery
How does the water get into the engine compartment of the Grand California?
Above the engine compartment towards the windshield is the large “water ditch” that collects the water from the windshield and drains it to the side towards the fenders.
Fig. 6 Cause of the water in the engine compartment of the VW Grand California:
If you look at the rubber seal on the upper edge of the “water ditch” (= boundary to the engine compartment), you can see that dirt is accumulating and drying there.
Between the lower edge of the closed hood and the upper edge of the rubber, dirty water apparently flows into the engine compartment when it rains and drips onto the engine and the body battery.
Presumably the pressure of the hood on the rubber is not strong enough ex works to provide a sufficient seal.
Fig. 7 Measure against water spilling into the motor room:
I have glued an additional barrier made of butyl tape to the hood in the area of the body battery so that the stiff butyl tape protrudes into the “ditch”. The butyl tape does NOT stick to the contact surface for the rubber seal, but to the side of the hood facing the “ditch”.
If water is pressed into the “water ditch” when driving on the hood in the direction of the windscreen and flows down over the edge of the hood in the area of the “water ditch”, it no longer reaches the rubber seal at all due to the “butyl strip lip”, but instead drips from the protruding butyl strip into the “water ditch”.
When the hood is opened, the rigid aluminum-laminated butyl strip lifts out of the “ditch” with the hood. When closing, it lowers back into the “trench” without touching the rubber seal. This water-repellent lip made of “adhesive tape” (butyl tape in my case) must have a certain rigidity to prevent it from being bent in any direction when the wind blows.
The solution with the butyl tape is not particularly elegant, but it is easy to fit. The butyl tape is not glued under the hood, so it does not lie on the rubber seal when the hood is closed, but it sticks to the side of the closed hood that points above the rubber towards the windscreen.
Result
Since then, there has been no more water on the body battery, the rubber seal and the
contact surface for the rubber seal on the hood remain clean on the driver’s side (= area
of the butyl lip).
On the passenger side, however, there is again dried dirt on the top of the sealing rubber and on the rubber contact zone of the hood. I am considering protecting the entire length of the rubber with additional butyl tape (or underlayment, see below), as there are a lot of other cables and plug connections in the engine compartment that could still corrode.
Remark
The solution with the additional lip made of butyl tape will not seal the engine compartment if the “ditch” completely fills up during heavy rain or if the drains are blocked. Therefore, the RJ45 sockets of the battery (see above) should also be sealed.
Alternatives
Alternative A Figure 8: PVC angle or U-profile
Of course, the rigid butyl tape does not necessarily have to be used. A conceivable solution would also be a PVC bracket or a PVC U-rail, which is glued to the hood from below to make it watertight, and which is then lowered onto or over the rubber when the hood is closed.
However, fitting a U-profile is much more complicated, as the rigid, immobile U-profile does not match the curved lines (in 3 planes) of the rubber or the hood.
Alternative B Fig. 9: Lift the existing rubber
Another alternative that you can make yourself is to remove the rubber between the engine compartment and the “water ditch” and line it so that the rubber is raised in the direction of the hood and this leads to the hood pressing more strongly against the rubber when the hood is closed.
For this, I would choose butyl from the cartridge, which remains permanently elastic and can be removed together with the rubber, for example. I have not tested whether this method produces a sufficient seal.
VW measure desirable
It would of course be desirable for VW to give the hood an additional rubber profile that forms an additional lip in the direction of the “moat”. This could then also prevent water from entering the engine compartment in heavy rain, if both rubbers are correctly matched. Another conceivable VW measure is a higher rubber that is compressed by the hood by at least 5-8 mm when it is closed.
I hope everyone enjoys a dry engine compartment!
Joachim
Acknowledgments
We would like to take this opportunity to thank Joachim for his very well written and honest report!
With the new battery, nothing stands in the way of your next vacation. We wish you a safe journey and unforgettable trips at all times.
If you are also planning to convert your vehicle yourself, please write to us ([email protected]). We will be happy to give you a discount on the purchase of your battery for a report.
Supervolt LiFePO4 batteries and accessories
In our store you will find the complete selection of LiFePO4 batteries – ideal for motorhomes, boats or solar systems. Thanks to their versatility, our batteries can be used reliably in a wide variety of applications.
Suitable installation accessories such as solar controller, charging booster or inverters are of course also available directly from us – for a perfectly coordinated system from a single source.
