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Battery life when car is left unused

Gents, it might be time for changing your batteries?
Normal current draw in a Porsche 964 or 993 with ignition off is about 25mA. (0.025A) An aftermarket alarm or other equipment can introduce an additional 5-50mA.
Theoretically, a fresh 75Ah battery would keep a 25mA current alive for about 100 days. Taking into account the needed power for cranking the engine, self-discharge and battery age, one could expect the battery to support at least a month of standing still and locked.
This is also my experience, my 993 starts fine after three-four weeks of storage. However, this of course require that the battery is fully charged when parking.
Cheers,
Tore
 
Battery Drain

Been away for a long time so good to be back reading the threads.

Have always disconnected the battery when leaving car for a while. I have no electricity where its stored so purchased a solar panel , placed on the garage roof wires run to car.
Then a battery cut out switch on the neg earth side. Clip solar wires to the battery side of the cut out switch (not the wires to the car) that way the battery is receiving the charge and there is drain out.
This has no ongoing costs and seems to keep the battery up on charge OK. Once cut out fitted it stays there all the time just screw turn the cut out to reconnect when Solar wires disconnected.
Solar panels are available at Halfords large were about 40.00. Lots of people use them on campers etc. Cut outs cost 5.00/7.00 and can be fused.

Steve
 
Re: Battery Drain

Prattie said:
Been away for a long time so good to be back reading the threads.

Have always disconnected the battery when leaving car for a while. I have no electricity where its stored so purchased a solar panel , placed on the garage roof wires run to car.
Then a battery cut out switch on the neg earth side. Clip solar wires to the battery side of the cut out switch (not the wires to the car) that way the battery is receiving the charge and there is drain out.
This has no ongoing costs and seems to keep the battery up on charge OK. Once cut out fitted it stays there all the time just screw turn the cut out to reconnect when Solar wires disconnected.
Solar panels are available at Halfords large were about 40.00. Lots of people use them on campers etc. Cut outs cost 5.00/7.00 and can be fused.

Steve

Do you have any problems with the alarm going off?
 

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