Henry964

Back from New Zealand after 10 days there, I am planning to drive my 964 this weekend, but I didnīt connect the original Porsche battery charger because I share the building parking lot with others and wanted to avoid complaints.
Is enough to leave the battery charger on for one night to recharge the battery?
For all I know the battery could be still alive....
Or maybe I should leave it on for 2 nights and drive the car on sunday?

ilko

Are you talking about the Porsche Battery Maintainer? If you plug it in, it will automatically shut itself off once the battery voltage reaches a certain number. Then it turns itself on automatically once the voltage has dropped below a certain number. I've left a car for a couple of months at a time plugged in with no problems.

The Porsche Battery Maintainer is to maintain voltage, not to charge it. It doesn't produce enough power to charge a depleted battery. So it depends on how flat your battery is really.

Henry964

Yes Ilko I have the Porsche battery maintainer,thanks for your help

I plan to use it just as a precaution, my daily driver started today perfectly after 10 days and it didnīt surprise me at all, it is a normal/modern car, but the 964 is a different story altogether,lots of electrical issues in the past, so I want to be sure it will start

Indycam

Charge it till you can start the motor .
When you start the motor the alternator will finish charging the battery .

Henry964

thanks Indy!!!! I will do that, try to start the engine tomorrow and if it doesnīt start, leave the charger and try again on sunday

darth

I recommend to charge the battery fully with a battery charger rather than have the alternator charge it hopefully prolonging the life of the alternator. Just because a battery can start a car does not mean it is fully charged and although the alternator can charge an almost dead battery, it was intended to just keep it topped up as the demands from the use of car accessories call for it. It's a lot easier to removing a cable to hook up a charger than having to replace an alternator.

Bill

TahitiSweetie

+964,993

Indycam

Darth , lets say that the alternator is a stock 115 Amp rated unit , ie , it can put out 115 amps without hurting itself . The battery in the Porsche 964 when discharged yet still able to crank and start the engine will not take a charge current anywhere near 115 amps . The charge current going into the battery after the battery was able to start the engine will not be anything that the alternator will have any problem producing . None what so ever . Recharging the battery that has just cranked over and started the engine is exactly what the alternator was designed for . It will not hurt the alternator or shorten its life .

darth

Wow they have the potential of putting out 115 amps and with the assumed over engineering Porsche tends to put into most everything they build - say 10% conservatively, thats 126.5 amps. I wish these cars had a real ammeter in the dash rather than a voltmeter which I view as being little better than an alternator idiot light. Whenever I see a meter pegged at the max whether it be the tach at redline or an ammeter for any period of time, I get a bit concerned - but I digress. Say it's putting out 100amps (i.e. for the sake of simplicity), the diodes at 0.7 volt drop would be at 70 watts, again they're prpbably over engineered and can handle 100 watts. I probably havn't kept up with battery/electronic technology but no one can argue that the laws of physics still apply (i.e. I hope) and power still creates heat. I was taught that heat is still the main reason for electronic component failure and anything one can do to minimize this will contribute to the longevity of the component, like the battery, (i.e. unless it's one of those deep cycle batteries and have a yellow top which like to be charged quickly) carbon brushes etc. not to mention the insulation around wires which tend to deteriorate when exposed to heat (i.e. like I've said before in the immortal words of Chico Escuela - "Not rubber! Rubber break! But I can't talk about it. Back to you, Hane". Not sure about the Porsche battery maintainer but it will have been on the battery for a few days so Henry should be OK.

Sorry for be long winded
Bill

Henry964

Just an update, today I started the car after it being attached for 12 hours to the battery maintainer and... it started perfectly!!! (after 2 weeks standing ) then I drove it for a 15 miles relaxed drive( not so relaxed ) to prepare it for tomorrow "leg stretching" in the highway

What it was amazing is that my tires pressures increased 3 lbs each after the "relaxed drive" I controlled them before with a digital meter and after in the gas station (I get same measures in both meters when I drive directly from home to the gas station - 3 blocks away)