Porsche Cayenne S Hybrid Battery got water, won' start

Discussion in 'VW Touareg, Porsche Cayenne, and Panamera hybrid' started by ike, May 21, 2016.

  1. ike

    ike New Member

    Hi everyone, first time poster here. I've had a 2011 Porshe Cayenne S hybrid for 3 years now. I returned from a weeks trip to find some water in my trunk area. Somehow, the rains got into that area.

    The water got in and reached about 3 cm of the compartment where the hybrid battery is. I used paper towels to cleaned the area dry and now when i try to start the car, i get a hybrid battery low fault on my dash.

    Right now, i'm a bit confused cos i don't know exactly how to go about troubleshooting the battery pack. I have tried to ascertain the voltage of the pack by pulling the high voltage lines from the sockets, enabling the locking bar, and safety connector while probing the high voltage connections (have a class A glove on) but no reading.

    Can someone point me on the next step to troubleshoot this situation. I live in Africa and have very limited support for the Cayenne S hybrid.
  2. voltron

    voltron Administrator and Defender of the Universe Staff Member

    Unfortunately, there is not much support for the Cayenne hybrids in general as most of these cars are serviced at dealers. The Ross tech VCDS diagnostic cable will have limited function on your car since it's a Porsche and VCDS is for VW/Audi/Seat/Skoda. The Durametric cable is for Porsche and could retrieve error codes but will have limited repair function.

    My best guess is that some error code has tripped and perhaps a safety fuse has broken or a sensor has tripped and is preventing charging. Can you drive the car normally without the battery and see if it charges? Please post any follow up repair if you find it.
  3. ike

    ike New Member

    At the moment, it shows ready on the dash which means tht the engine is ON, but the hybrid system is completely off ...Down without a charge, so it cannot start or provide power
  4. ike

    ike New Member

    Ok, made some significant progress with this project and wanted to share this for everyone who will be reading this later...or found themselves in similar situation. First off, if you ever have to do this, please note that you are dealing with a 288 volts battery pack and if you are not comfortable working on power systems and likes, i strongly suggest you get someone who is qualified to handle these batteries to take a look. However, if you must, please ensure that you have the right rated safety gloves because high voltage in hybrid battery packs can cause serious shock or death when not handled properly.

    In addition, this may not work every vehicle basically because of the level of water that got into the battery, length of time that water was there and corrosion generally. However, what worked for me was getting the hybrid battery assembly down, getting to the individual modules, cleaned and sandpapered module and contacts, charged and reinstalled modules and it worked.

    The steel case had very visible signs of water collection and infact had started to rust out, the modules had visible signs of water on them and the contacts to the dual connectors seemed to have started corrosion also. All of the plastics at the base of the pack where the water had collected where visibly discolored different from the other parts of the plastic that did not get in water.

    The battery was taken apart, the pack is made up of 60 modules in 2 banks of 30 module each. Each of the banks delivers nominal 140 volts totaling 280 VDC in all.

    One of the bank of modules can be easily detached from the frame housing and taken apart separately, the other bank is connected to the battery power terminals, and a battery computer unit which is harder to get through. Each bank of modules was taken apart, and since the bottom modules where the most affected, we had to reach them, and clean them out, sand papered then and used some contact enhancer on them before reinstalling them. Bank 1 read 29 volts and bank 2 read 58 volts before charging. Both banks where charged separately to 150 volts for about 15 hours period and then there were allowed to cool down for like 4 hours before re installation.

    Car has been fine since.

    Generally, i think that the decision to have the hybrid battery at the bottom of the trunk without any form of drainage system is not a very cool one because that location is the lowest part of the truck and should you mistakenly have water on any other liquid spill in that area considerably, then chances are that they will eventually collected right at that area where the hybrid battery is.

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