[BOB968]

Folks: I haven't used my '95 Cab much this year--Covid restrictions, weather, etc. Frequently the car will sit 3 weeks without use. When I want to use it, the battery does not have enough power to start the car. The battery is new this spring. For sure, no lights or anything is left on. A friend offered advice that the alarm system is a heavy drain on the battery and suggest disabling it ( even though the system is not active as I don't lock the car when in my garage). Is there any merit to this recommendation? If so, what is the best way to disable it. 

 

Thanks to all that reply.

 

Bob

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[John]

Measure the static drain: with ignition off, remove the ground cable from the battery, and check the current with a multimeter (many auto parts and battery stores will do this for you). You should see about 12ma. (on a coupe anyway). That should cover the clock and the alarm system. If the current is higher, check to see if any of the glove box, under hood, or hatch lights are on. To go beyond this, start pulling fuses one at a time and note what happens to the current. If it goes down, that would be a clue. Finally, does your rear wiper work? If not, it could be jammed and drawing current (search the forum for more on this problem).   .. good luck, John

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[Waylander]

The battery lasts about 3-4 weeks with the alarm off, 2 weeks with it on

Best thing is just put it on a conditioner on it, that will keep it topped up

I have no power in my garage with the car, so I just drive it at least once a week for 20 miles or so, much better for the car anyway

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[Rap]

I’ve only driven my 968 once since the fire last thanksgiving. It is on a battery tender. I run it for 20 minutes occasionally then put it back on the tender. Works like a charm.

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[ds968]

I’ve only driven my 968 once since the fire last thanksgiving. It is on a battery tender. I run it for 20 minutes occasionally then put it back on the tender. Works like a charm.

 

Same here . 

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[tejon007]

Keep it on a float charger or it'll kill the battery. Not so unusual as the 955 (which has a really large battery) dies in about the same amount of time as the 968.

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[ds968]

There are a bunch of parasitic draws on any car’s battery … newer cars loaded with electronics are much worse than ours . 

I think the longest time I left the 968 parked WITHOUT a trickle charger on is about six weeks and it was ok, I’ve also left  it many times for three to four weeks and never had a problem, but any longer than that you’re taking chances ..

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[J.Elenbaas]

I sometimes had it months without starting or trickle charging, and always started unless the battery went bad over time.

I also had one time after not correctly reinstalling the glovebox compartment that after a week the battery was more or less empty, anyway not enough juice to start.

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[ds968]

Yup, the glove compartment light contact is an issue with our cars,  I remember quite a few battery drain discussions on this forum where the first question was “ did you check to see if your glove box light is on “ ..   As to why Porsche didn’t engineer  those to make sure everything turns off when you remove the key, is a mystery..   Same with the hood / bonnet light contact , I think ..

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[tejon007]

Yes...have killed the battery with the glove box light and the light by the front hood latch (owed the car for several years before I noticed the burned out bulb there...replaced it with an LED bulb and killed the battery a month lafter, by leaving the hood open overnight).

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[BOB968]

Thanks to all. I will measure the drain on the battery, check the glove box light. But it sounds as if I have to keep a trickle charger on it. I am skeptical of those chargers that claim to be 'smart' and know when to turn on and off. However, the units I have are all old economy models and they could cook the battery if left on too long. Probably time to invest in a new high tech unit. I am looking at a 2amp NOCO that claims to be smart, battery maintainer and trickle. Has anyone had experience with this brand or other brands?

Thanks.

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[ds968]

I have used this for years and it’s been great  :  it is “smart“ ( and that’s not just marketing hype ).   I believe they have two or three different models , at various price points , depending on the features / options  .   



 

https://www.amazon.com/CTEK-40-206-5-0-1...2030&psc=1

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[J.Elenbaas]

Few years ago I bought the CTEK MXS 5.0, I find it a very good charger and has different functions too.

It can charge, maintain and recondition your battery. 

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[Waylander]

I would expect a drain of about 250-300ma

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[ampegboy1]

I've also got a CTEK MXS 5.0, it's brilliant - aside from keeping the battery topped-up on the 968, I've used it to resuscitate four utterly dead batteries that wouldn't take a charge from anything else, saving a good few pennies - it's well and truly paid for itself.

 

Michael

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[sstman]

I’ve not got access to power in my garage, so I bought a solar panel ‘trickle charger’ it certainly keeps the battery from draining completely, and I can leave the car for 6/8 weeks at a time.

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[ds968]

I’ve not got access to power in my garage, so I bought a solar panel ‘trickle charger’ it certainly keeps the battery from draining completely, and I can leave the car for 6/8 weeks at a time.

I have a solar charger connected to the two cars we park on the street , one or the other which sit for weeks or months .. but I thought you need several hours of “direct” sunlight or at least daylight on those units , every day , in order for them to work .. I never thought it’d ever work in a garage or carport ..  :o ..  good to know it does ..

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[dlearl476]

I bought a cheap ($39?) solar charger on Amazon with no electronics (just straight from the cells to a cig lighter plug) and it cooked a $150 battery in one of my MLs. It was kind of an old battery, but Ive been hesitant to use it since.

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[Waylander]

Think you need to read that again Dan

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[ds968]

Think you need to read that again Dan

 

Which post ?   Surely you don’t mean the one from dlearl476 which was posted the day after I had responded to sstmans’s post  ..?! 

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