Battery Explosion - How just turning the ignition key can ruin your day!

Part 2!

Part 3!

Hi, Tracy Wilkins, Boxster secretary, has had a number of these explosions reported on Boxsters all with Porsche batteries and trickle chargers and with help from Tony at Carrera Engineering wrote an article in the July addition of the PCGB mag, well worth a read[ ]

Hi Everyone, Just thought that I would share my day with you! Nice bright sunny day here in Cambridgeshire today so I thought that I would give my 996 4S a run and enjoy both the car and the weather. Unlocked the garage, took the cover off, unlocked the car and removed the Porsche trickle charger from the cigarette lighter; all as my usual routine. Turned the ignition key to the first stop and checked that the oil level was normal. All OK, turned the key to the starter position and there was an almighty bang from under the bonnet followed by white smoke coming out of the top of the bonnet. At this point there was no power so I couldn't unlatch the bonnet to see what had happened. Luckily I had a spare battery from my wife's A Class Mercedes knocking about so I connected it via the fuse box post and popped the bonnet. To my horror when I opened the bonnet I found that the battery had exploded, literally exploded! The top of the battery had shattered and all four sides had been blown out. Luckily the battery box cover had prevented any damage to the bonnet, the cover had taken the full force and had shattered. I have now removed the battery, washed the car down thoroughly and connected the Merc battery to see if the electrics still worked. To my delight everything fired up as it should. Talk about ruin my day! Has anyone else on here had anything similar happen to them? It was a genuine Porsche battery which I purchased as a replacement about 4 years ago. I hope that you have had a better day than me!!! Here are some of the horror photos!!!!!!

Looks as though this has been happening for some time Steve. Here's a report of a similar incident on a Boxster back in in 2010: http://www.porscheclubgbforum.com/tm.asp?m=574284&mpage=1&key=battery%2Cexplosion&#574330 As Brad has mentioned, it's worthwhile reading the article in the latest PP in the Boxster Register section. Glad it didn't cause any serious damage. A bit worrying though for us with an ageing (dreaded!) Moll battery. Jeff

Oh man! Moll batteries are not the best TBH, not that this makes the issue ok BTW. There are better batteries (Bosch as one example) but clearly where a Porsche warranty is in force this ties ones hands somewhat.

Batteries when not vented do explode and can be very nasty, what brand maintainer were you using?. Always switch off before disconnecting!!! Sorry just re read your post and saw its the Porsche charger is that not the basic ctek model? Bad day indeed.

Sounds like the Hydrogen gas generated by a charging battery.

Hi again everyone, An updated following my battery explosion today. I have just read the article by Tracy Wilkins in the July issue of Porsche Post (page 111). It seems that battery conditioners may have a part to play in batteries exploding! The theory is that if the conditioner is faulty then it may not switch off when the battery is fully charged. This will result in the battery being over-charged and getting hot which then leads to the production of extra gases within the battery. When the car is started this build up of gases causes the battery to short and explode; which is all very worrying. I am going to fit a new Bosch S5 battery tomorrow as the Porsche Moll batteries seem to have a question mark about their quality (and they are over £200 from your local Porsche Centre), the Bosch is £82! My car is a weekend and dry weather car and is stored over the winter, so I really need to use a battery conditioner but I don't want to risk the same exploding battery issue. So my question is how can I check that the battery conditioner is working correctly and cutting out when the battery is fully charged? I guess that I could undertake regular checks on the battery temperature or camp out in the garage for several days to see if the conditioner cuts out but I am looking for a more technically advanced solution. Any ideas? Any thoughts, comments or suggestions would be most welcome.

I don't really get this battery conditioner / charger use, yes I have one but very very rarely use it, my c4 is a weekend car mainly, but this year has seen very little use due to a building project, my car might sit for 3 / 4 weeks and it starts fine , the battery is 3years old and a Bosch . I reckon if I left it for longer it would loose charge but the simple answer is to drive the thing. Ps , glad the explosion didn't cause any damage. 75pno

Nice option, but not possible for everyone. Battery maintainers as Ive said before, especially the cheap ones will cook batteries because they don't cut out. Said it here to many peoples upset. Simplest answer for a healthy battery is a tiny solar panel," Obviously the Battery needs to be fully charged in the first place".

My Cayman has, for 4.5 (until Jan this year) of the 5 years I've had it, been the second car and will be again when the Macan arrives. Most recently I've been using a £40 Halfords battery charger and conditioner. I've wired it up once every two weeks, irrespective of whether we've been for a run in it. Run the charger for 4 hours (label says 3 hours is enough) Came back, battery fully charged and being conditioned. Switched off. Car lives outside year round, under a cover in winter. Not sure about which battery brand it is though. End of, no problems to date. David

Interesting reading here.. http://www.honestjohn.co.uk/faq/battery-explosions/

Make sure you clean up with lots of baking soda a water to Neutralize all that Acieeeeeeeed! [ ]

I bought a cheap digital voltmeter which plugs into the lighter socket, and keep an eye on that. I don't know if there is something odd about Moll batteries, but for some reason my Ctek doesn't seem to cut out (and the green light doesn't come on) on the Cayman, which has a Moll. On my Carrera, which has a Bosch, it works fine. I've also got a cheap one I got from Lidl, and that seems to work OK, and holds the Moll battery at 12.8. If I knew what the voltage was supposed to reach it would help, but when it was climbing over 13.7 and not cutting out I got twitchy. Not very scientific, and maybe I'm not giving it a chance, but I'm always wary of battery charging.

Richard, I've been using a CTEK in combination with a Moll battery for more than 4 years on my Cayman. The only problem I experienced after about 6 months of continuous use was an intermittent charging problem when using the cigarette lighter socket, with the battery lights on the CTEK flickering between the red and green. Reverting to direct connection to the battery, I've not experienced any problems since then. I note that the Moll has a small integral vent. I seem to recall that in "the good old days" we always used to remove the cell caps when recharging a battery to allow any gases to escape. Jeff

My 996 4S is connected by CTEK Comfort Indicator via mains most of time when not being used for a few days (weeks in winter) without tempting fate.... Moll battery & been ok for 4+ years Could it possibly be lack of battery fluid? Paul

Hi again everyone, I thought that I would provide an update for those of you that are still following this thread. I have split the update into two sections, one for those of you who just want a quick update on the exploding battery issue and a second section for those that are more interested in the technical discussion surrounding this issue. 1. Update - The Porsche Moll battery (or what is left of it!) has been taken to my local Porsche Centre for them to discuss with Porsche. As this was a catastrophic failure, not just general wear and tear, Porsche may consider supplying a replacement battery. There is also the damage caused to the battery cover which disintegrated and damage to the plastic cover below the windscreen, the blast broke one of the fixings. I have given the car a thorough wash down to remove any remaining acid deposits and luckily the only acid damage I can find is to the battery tray. I have removed this, rubbed it down and re-painted it with anti-corrosion red primer, grey filler primer and two coats of black paint. Now looks as good as new. A new Bosch S5 008 battery has been fitted and I have ordered the replacement battery cover and windscreen cover from Porsche. The battery is now on charge using a new Cteck charger/conditioner. I have checked all the electrics on the car and everything seems to be working normally, the car starts and runs fine but I have not taken it for a spin yet due to heavy thundery showers here today but I don't anticipate any further problems. I have been in contact with Tracy Wilkins (the Boxster Register Secretary) about her article in the July 14 issue of Porsche Post about exploding batteries. She has now started a log on this issue and has so far had 1 x 996 (mine), 3 x Boxsters and 1 x 993 reported with the same problem in the last month! Incidentally all the car were kept on some sort of battery charger/conditioner. 2. Technical Discussion I have done a lot of research regarding exploding car batteries (not just Porsche) and it is a much wider problem than I thought. There are lots of theories but not much hard technical evidence so I shall throw out a few theories to those interested and see what comes back. Theory A. If the battery conditioner is not working correctly it may continuously charger the battery. This could cause a build-up of hydrogen gas in the top of the battery and could also lead to the electrolyte evaporating over time to below the plate level in the battery. When a heavy load is applied to the battery (i.e. starting the car) the plates arc inside the battery causing a spark which ignites the hydrogen gas. My comments - I have never checked the battery electrolyte level on my battery but it has been regularly service by my Porsche Centre. They have confirmed that a battery level check is part of the service and this was done on my car in April 14. My battery conditioner is the early Porsche type which is a black plug-in type with just one red LED light. I had noticed that the red light is always on, could this mean that the battery was being continuously charged? Theory B. Modern batteries have a much higher demand due to all the heated seats, air con, etc, etc in modern cars. So the battery manufacturers are trying to get more power out of the same size battery. They have done this by putting more plates into the battery but at a much closer spacing. If the battery overheats during charging or any of the plate welds within the battery are not 100% it is possible that the plates could warp and touch each other causing a catastrophic failure. My comments - not sure about this one but I thought that this is what happens when you get a dead cell in battery rather than a catastrophic failure i.e. explosion? Theory C. The alternator is faulty and overcharges the battery causing the same problem as in Theory A. My comments - my car only gets very occasional use and I have not been on an extended run with it for about 3 months so the possibility of this being the cause is remote but to be on the safe side I will get Porsche to check the output from the alternator. Theory D. The breather tube on the battery is blocked causing a build-up of hydrogen gas in the battery. My comments - I have checked the breather pipe and it is clear. Incidentally my new battery is a 'sealed battery' so I am not sure what happens to the hydrogen gas that is given off during charging? Any ideas? Well that is about it, sorry for the length of this post! I look forward to receiving your comments or adding any other theory that you may have.

Hi Steve, Mines on a Ctek conditioner especially when I am in OZ and the red light goes out and the green one comes on so it seems to be working. I also have a £13 one from Lidl which I also use and this also goes from red to green when charged. I have had no problems to date - YET

As a long-term Ctek user (alternating over three cars as necessary) I too have wondered about the above. Perhaps it is time to put this and other questions to a battery manufacturer?

As mine always is plugged in to a Ctek 3600 when in the garage, I have followed Richard's example and bought a voltage tester (cigar lighter plug in). With the green Ctek light on the voltage read 12.7 - phew! Will keep an eye on it in future though rather than just assume it's doing a "proper job". I think "gassing" is only a problem when the charging voltage exceeds 14.3?

Battery Explosion Update: Thank you for all the responses, comments and suggestions both on this forum and through email and personal contact. The consensus of opinion seems to be hydrogen build-up due to over-charging. As suggested in this thread, it seems a very good idea to purchase a cheap volt meter that plugs into the cigarette lighter socket to keep an eye on what is going on with both the external charger/conditioner and the alternator. My Porsche battery conditioner is currently plugged into the cigarette lighter socket so I plan to replace it with a CTEK conditioner that connects directly to the battery, then I can use a plug-in volt meter to check that both the conditioner and alternator are not over-charging. I will keep this thread updated with any further information that comes to light regarding this subject.

For those that are still interested in this subject, here are a couple of links to reports of exploding Porsche OEM batteries in the USA; one was actually being carried when it exploded! [link]http://www.6speedonline.com/forums/gt3-gt2-gt/240920-exploding-porsche-batteries-warning-2.html[/link] [link]http://www.6speedonline.com/forums/997/277976-oem-battery-exploded.html[/link]

Theory E Porsche Battery & Electrical engineering sub-assys department have squeezed so much cost out of the Battery Unit Cost that they have become unstable and dangerous. They are the only Co I am aware of who have not seen battery technology progress in recent years. Theory F That dept are now responsible for Procurement & Testing of Con Rods Theory G A GTR Nissan electrical system would not drain its battery if parked for 6 weeks.Why does a Porsche do this? Good to see you have no lasting damage George

Never used a battery conditiioner in my life, never had a battery blow up. The battery in my 996 was just "nearly new" when I bought it in March 2012. I have just replaced it with a bosch 110t for £102 inc. considering the price of the C-Tek conditioner in the first place and the potential for damage and personal injury I an happy to fork out 102 odd every two years or so. Mind you I am lucky in that the car can be locked up in a garage with a huge hasp and staple set into the concrete, so I only lock it when I am out in it. I have to say that no matter what electricla systems exist in a car they do not put extra strain on the battery. The battery is just a giant capacitor/buffer to supply 350 amos in a short burst to turn the engine over where upon the alternator takes over and supplies the current for all the appliances, unles you do what my Step cousin Stanley does on a cold winter's day which is to turn on the heated screen and seat about ten minutes before he tries to start the car. Sometimes he has to take the train due to a flat battery, I wonder why? If the battery is producing more hydrogen (and oxygen don't forget) than can vent away then perhaps the trick is to disconnect the conditioner the night before, i.e come home Friday disconnect ready for a Saturday blat to allow the excess gas to dissipate. If the Battery can't hold a charge for those 12 hours or so then it has had it anyway. How many journeys last three weeks? The plates can only arc if they are not covered by the electrolyte surely so there is the question of whether being contiually charged discharged and generally being in use for durations much longer than the average car journey, even if the current is low, can lead to the water content of the sulphuric acid solutioin being gadually boiled off and in thse days of maintenance free batteries you have no way of knowing.

The system uses slightly less power when locked than unlocked, and Porsche state about 40mAh with everything shut down. In my experience, it is more like 50-60mAh. That equates to about 18 hours per amp, so in 3 weeks it will lose around 30 of its 80 amps, and will struggle on the starter. Most likely it will drop a fair bit below 12 volts, which is likely to trigger the alarm. I also think my Cayman consumes more than my 996s did, so in the summer when I'm using the 3.2 most of the time, a conditioner helps a lot. I can leave the 3.2 for weeks on end without a problem, but do plug it in when it is off the road for the winter months.

From practical experience my 996 t can go longer than three weeks, I remember posting something to that effect on here somewhere.

What capacity/make do you have?

I would recommend a more sophisticated CTek charger than the Porsche one, the other additional drain is if you have a Tracker system fitted as, depending on type, they will be continuously in contact with the base station.

I use a CTEK MXS 5 and MXS 7 and have never had a problem although I'm using a Bosch S5 in my car.

I have been following this thread with interest as I have come across battery explosions before on boats where no regulator has been fitted to solar panels. Usually set off by an arc from the battery switch contacts. I bought a 2000 Boxster S a couple of weeks ago and I thought I would check the battery. It is a Bosch S5 and has a vent tube leading from the battery to underneath the car. When charging a battery, I always leave the bonnet open to vent any gases.