New owner - battery question

Hi All, After years of looking at 996's on the internet and always coming up with reasons not to buy one, I finally jumped in last month and bought a 99 C2 which I couldn't be happier with! As other new members have said on here, this forum is a great source of information for anyone looking to buy their first 911. I actually bought the car from a forum member who was a pleasure to deal with. So I have a question about battery life and jump starting. The car is kept in a garage away from home with no power so unfortunately no option for a trickle charger. I've read about the solar chargers but the garage is in a block of rented garages so probably wont be allowed to fix one to the outside and would most likely get nicked anyway or advertise the fact that there is a car in there. With what is going on in the country at the moment the car won't be driven for a while now and i'm resigned to the fact that the battery will probably go flat. So wondering what other people do in the same situation; just expect to have to jump the car when it's not been used for a period of time? Or are there any other tricks or gadgets that i've missed? I assume there is no other way to keep the battery topped up without a mains power supply? Best guess at the moment is to buy a portable jumper along the lines of the one below. https://www.machinemart.co.uk/p/clarke-jumpstart-1100/ Thanks in advance. Olly

Welcome! Great to hear you are enjoying your new car and can get out in it soon! Letting batteries go flat generally shortens their lives, so best avoided if at all possible though I appreciate easier said than done in the circumstances. How secure is the garage? Could you disconnect the battery or fit a hidden isolator switch? If your car has an electric bonnet latch (as opposed to the levers on the early cars, which yours may be if it's pre 2000 MY) then bear in mind a flat battery will prevent access to the battery to remove and charge it without a fair amount of faff.

Hey Olly, I am in a similar position and am just having to jump it when it goes flat, instead of the one you posted (I used to use one of those too) I switched to something like this which is much lighter, versatile, and easier to manage. https://www.amazon.co.uk/UTRAI-Star...qid=1585515863&sprefix=DBpower,aps,151&sr=8-5 Good luck :thumb:

:welcome: Olly :thumb:

Thanks for the info. The garage is secure so I could disconnect battery. Hadn't thought about an isolator switch so will investigate this. It has the bonnet lever so no issues with access if it does go flat.

Good to know. I assumed these smaller chargers wouldn't be up to the job but sounds like they are worth investigating. Would you recommend this brand?

They are definitely up to the job. I am not sure about the brand I posted, it just an example but the reviews looks good. Unfortunately the one I bought from Amazon is no longer available, it was called a 'BPOWER 600A Peak 18000mAh Portable Car Jump Starter Battery Booster". I bought it in 2017 and it still works perfectly. DBPOWER 600A Peak 18000mAh Portable Car Jump Starter (up to 6.5L Gas, 5.2L Diesel Engine) Battery Booster Phone Power Bank with Smart Charging Port, Compass & LCD Screen and LED Light (Yellow) https://www.amazon.co.uk/dp/B077HSX127/ref=cm_sw_r_cp_api_i_tHxGEb1A4MEFY

And do make sure you check and double check the terminals when jumpstarting. The consequences to the ECU and your wallet can be large! Some owners stick tape round the negative lead as an aide memoir.

I highly recommend a NOCO Genius GB20 jump starter - rated up to 4.0L petrol, so well suited to a 996 - example link below - can typically be had for ~£75 I had some starting issues (now all resolved) and this got me through no issues. Jump starting tech has definitely come on some in the last few years(!) These compact starters also have a polarity check inbuild so there should be no risk of frying your ECU https://www.ebay.co.uk/itm/NOCO-GEN...533824&hash=item3d949c2991:g:LtMAAOSwOmBeXnNv And remember that you jump start a 996 from the engine compartment, NOT the battery! - there's a positive post in a black plastic "box" top right, just above the air con compressor - the negative/ground post is the bolt used to hold the airbox down right next to the catch for the lid (hence its a slightly odd looking bolt...!)

Thanks for the recommendations chaps. I'll buy one of these and hope for the best :thumbs:

If secure enough, I would just disconnect the battery and leave the bonnet on the latch. You would need a determined thief to take it when they can so easily pinch a keyless entry car. You will need to leave the bonnet on the latch, and won't be able to lock the passenger door, so park against a wall. MC

Afternoon all, I'm hoping to get the car out of the garage soon and after two months or so of being parked up i'm expecting to have to jump start it. Quick question, I bought a portable jump pack and on closer inspection it seems to have very short jump leads, so I don't think they will stretch between the two terminals in the engine bay. Does anyone know if there is a negative point closer to the positive that would still work? Also assuming jumping straight off the battery is a no go? Thanks, Olly

I often jump start cars and use the battery terminals .. it's very rare for anything to go wrong .. possible but very rare .. you are also limited as to where else you would jump start it thats any different ... Engine jump start is connected direct to the battery so no real difference ... use it if you wish though . There is the alarm siren bracket and bolt close to the positive you could use .. it would however mean both jump leads are very close together which concerns me .

Thanks demort, much appreciated. I've heard people saying you shouldn't jump straight from the battery terminals but I have no idea why. With the manual also saying to jump from the engine compartment I guess there must be a reason? However if the cable doesn't stretch in the engine I'll try from the battery and hope for the best :thumb:

It is to do with the electronics concerned with the battery on cars that have auto stop-start systems in traffic. Jumping from the battery terminals can expensively ***** things up with some of those, so the general advice has become one of if in doubt - don't charge the battery or jump the car from the terminals of an installed battery. This is certainly not a problem with 996/997 Porsches - I've jumped both vintages from the battery terminals many times without issue and as many people use the battery terminals as the ciggy lighter socket to charge/maintain them too. One reason not to nominally jump from the battery with a 996/997 is that you actually need rather long jump leads to do it from another car (which means higher quality ones too as a consequence). Clearly if using a jump pack that isn't a factor. If you wanted a little more reassurance - I once had a dead battery on the 997 sorted at a random OPC in Belgium halfway through the journey home and they used a jump pack straight on the battery terminals too.