Key Fob 24hr Battery Drain - My biggest mind boggler yet!!!!

For nearly 18 months now I've had an issue with my key fob munching batteries. I refurbed my key back in January last year, fitting a new outer case and soldering new buttons on to the circuit board using one of those kits off eBay (like in the link): Pardon our interruption... Since then the battery would only last a couple of days maximum. Even if I only used the fob once, the next day the battery would be flat. I checked out the 3 new buttons and also everything else on the circuit board I was able to check (dry joints, etc.) and didn't find fault with anything. I decided the best option was to either get a new fob from Porsche and have it coded or book it in with pixelsfixed. I decided to book it in with pixelsfixed but then ended up cancelling the appointment due to a front suspension spring snapping. Anyway, the last couple of week I thought I'd revisit sorting it out. By chance I fit a new battery in the fob, but left it at work and didn't fit it back in the key housing. Returned to work after the weekend and the battery is still up over 3V. This is strange I thought, so decided to use the fob without it in the key case to see how long the battery lasted. a few days later and all OK, so pop it back in the housing. Next day battery is flat again. I still had my original key case with the original rubber case buttons (genuine Porsche and not the plastic after market ones) so thought I'd try fitting the upper part with the buttons on the case of the aftermarket one. Battery is now still up over 3V after vigorously using the fob since Monday. So it looks like the aftermarket plastic key (upper) housing is for some reason draining the battery on my fob. The only explanation my electronics mate can come up with is there may be carbon in the plastic (to make it black) and that is causing a micro short on the fob and draining the battery. Either that or the plastic case is somehow putting pressure on the circuit board and causing it to somehow drain batteries. Fortunately Design911 sell the genuine upper part of the housing with the rubber buttons (see link), so I've just bought on of those (£25 delivered) and will see if it's cured the problem. If it has, I'll be a happy man as I was looking at at least £250 to have the fob repaired. Will feed back in a week or so if it's not worked. Porsche 996 986 Boxster Key Head Remote Control Upper Part 99663735100 - 99663735100 | Design911 Porsche 996 986 Boxster Key Head Remote Control Upper Part 99663735100. Design911 supply car parts, spares and accessories, to both retail and to the trade. Our car product and accessory range includes brakes, exhausts, tyres, wheels and panels and interiors. www.design91.uk

Sherlock Alex on the case

Pricey but another alternative that D911 now stock is a much nicer upgraded key fob where you swap over the innards Dedicated to your Porsche needs Design 911 supply car parts, spares and accessories, to both retail and to the trade. Our car product and accessory range includes brakes, exhausts, tyres, wheels and panels and interiors. #Porsche #ServiceCentre #Essex www.design91.uk I did something similar with an “ARID” designed fob. Does make a difference in the look and feel

I look forward to hearing the result. I also have this same problem, but haven’t yet replaced my switches.

Over 1 week in and still works fine.

Thank you very much for checking back in. I hope this will solve my problem too!

So my battery lasted till Wednesday, just short of 2 weeks. Although the problem isn't fixed, I know know that the case has played a huge part in draining the battery. I'm now wondering if the blade holder base is also playing a part as it's the other half of the part causing the problem. I have a spare from years ago so will swap that over and see if it makes a difference.

Its funny the things you come across like this isn’t it, they’ll probably be a Tefal Head in a lab somewhere that’ll know exactly what’s happening ..

I assume that you’re not using bulk purchase eBay batteries as I’ve often found them to be moody and not match OEM performance?

Duracell. So I changed the back yesterday and the battery has lasted 16 hours!!

I've swapped my key case to this https://www.ebay.co.uk/itm/38746586...teid=0&campid=&customid=&toolid=10001&mkevt=1 (which I have no reason to believe is any different to the one you bought) and the fit was so horrific that I delegated that key to the spare, and am now using the OEM spare key as the main one. The key blade is moving up and down inside the ebay case. Not sure it's even worth "fixing" tbh

I might've joined the club, key ate through a battery, thought fine, replaced it with the one from the spare, ate it in a day. This is in the OEM housing, no chinesium interference. To have a proper look I need to desolder the battery holder from the PCB. Failure into closed (short) might be a capacitor which is somewhat fixable