Battery Tender?
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From: Virginia
Battery Tender?
There is another thread about how long a battery holds full charge. This got me thinking. Our new (to us) '96 is not driven every day. It has an Optima yellow top model D750S in it. The age is unknown. And after long periods, say 4 or 5 days, the car is slow to start. Today, it required a jump. FWIW, I now have a standard charger on it.
One of the posts in the other thread mentioned using a battery tender as routine practice for use such as what we do. Is this normal? Is there a circuit on these cars that draws down the power?
One of the posts in the other thread mentioned using a battery tender as routine practice for use such as what we do. Is this normal? Is there a circuit on these cars that draws down the power?
Three Wheelin'
Joined: Apr 2006
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From: somewhere on a twisty road...
I can tell you from my experience, that my 993 often sits for 8-10 days while I am out on business trips, and I have never needed one. In fact, (Knock on wood) it always starts right up on the first attempt. My guess is that your battery is getting old and/or weak. On the other hand, for my motorcycles, I use the "Battery Tender Jr." because they often sit for much longer periods. On my street bike, I only use the tender during the winter months, but on my dualsport/dirt bike, the tender is always on when the bike isn't being used because it has one big cylinder and a very small battery with no gear reduction on the starter.
Burning Brakes
Joined: Mar 2007
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From: Flagstaff, AZ
I've used a battery tender on a 03 M5 that gets driven very little and the battery tested as good as a new unit when I sold it.
I plan to use one on a recently purchased 97 C4S when it arrives.
I plan to use one on a recently purchased 97 C4S when it arrives.
Racer
Joined: Nov 2003
Posts: 436
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From: NC
I use the Porsche battery tender as the worst thing you can do to a battery is let it sit for long periods. One thing I found interesting though is it is not for all cars. When plugged into the Porsche you don't even know it's there, but I plugged it into my Tundra once and it lights up most of the instruments on the dash! 
Intermediate
Joined: Sep 2006
Posts: 47
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From: Fox Point,Wisconsin
starting issues
i have a new optima red top in my 98 993.. it is almost dead after one week . i have put the porsche trickle charger on it and it's ok but i don't think that's the way it should be ....there must be some abnormal electric draw on that thing.. i know it is not related but my my speedster starts after six months with out a charge...
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From: Virginia
Originally Posted by endodoc
i have a new optima red top in my 98 993.. it is almost dead after one week . i have put the porsche trickle charger on it and it's ok but i don't think that's the way it should be ....there must be some abnormal electric draw on that thing...
FWIW, I put my yellow top Optima on a charger for the last 3 hours and it started up as strong as I ever remember. I guess a better test will be to see how it does in the morning.
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From: Colorado Mountains
Have been using the battery tender religiously for years.
The car alarm consumes enough power that generally after 10 days the battery is too low to start the car.
This type of repeated drawing down of the battery is the worst thing for the battery and considerably shortens battery life.
The quick connect that comes with the battery tender makes it super easy to hook-up on a routine basis.
The car alarm consumes enough power that generally after 10 days the battery is too low to start the car.
This type of repeated drawing down of the battery is the worst thing for the battery and considerably shortens battery life.
The quick connect that comes with the battery tender makes it super easy to hook-up on a routine basis.
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From: Miramar Beach, Florida
Originally Posted by killsbugsfast
Have been using the battery tender religiously for years.
The car alarm consumes enough power that generally after 10 days the battery is too low to start the car.
This type of repeated drawing down of the battery is the worst thing for the battery and considerably shortens battery life.
The quick connect that comes with the battery tender makes it super easy to hook-up on a routine basis.
The car alarm consumes enough power that generally after 10 days the battery is too low to start the car.
This type of repeated drawing down of the battery is the worst thing for the battery and considerably shortens battery life.
The quick connect that comes with the battery tender makes it super easy to hook-up on a routine basis.
I have them on both cars. Drop 2 extension cords from the garage ceiling.
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From: NE Florida
Originally Posted by Hal
There is another thread about how long a battery holds full charge. This got me thinking. Our new (to us) '96 is not driven every day. It has an Optima yellow top model D750S in it. The age is unknown. And after long periods, say 4 or 5 days, the car is slow to start. Today, it required a jump. FWIW, I now have a standard charger on it.
One of the posts in the other thread mentioned using a battery tender as routine practice for use such as what we do. Is this normal? Is there a circuit on these cars that draws down the power?
One of the posts in the other thread mentioned using a battery tender as routine practice for use such as what we do. Is this normal? Is there a circuit on these cars that draws down the power?
To answer your question, you should not have to be recharging your battery after only 4 - 5 days, it sounds like your battery is near the end of it's life. Of course you may get 6 - 12 months of use with it like this but why take the chance? Do you wait until your spark plugs don't fire anymore until you replace them?
Edit: ...unless there is something putting a significant drawdown on your battery, in that case get that fixed.
Last edited by Slow Guy; Apr 4, 2007 at 10:08 AM.
Three Wheelin'
Joined: Apr 2006
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From: somewhere on a twisty road...
Originally Posted by 993BillW
...To answer your question, you should not have to be recharging your battery after only 4 - 5 days, it sounds like your battery is near the end of it's life. Of course you may get 6 - 12 months of use with it like this but why take the chance? Do you wait until your spark plugs don't fire anymore until you replace them?
Pro
Joined: Oct 2006
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From: Belgium
As you can gather from the other thread I've been struggling with this as well. When I first gor the vehicle the battery, which was very old, kept it's charge no probs for a few weeks. With the new battery fitted, it seems to loose the best part of the charge after a week or so, after two weeks it's a non starter. I've been backtracing the stuff I did to the car since the battery replacement, and have discoverd that in fact the ONLY thing that's changed is the fitment of a Kenwood radio/cd player. For the sake of experimentation I will now remove it and see what happens. I'm gonna do a substantial audio upgrade anyway, so I want to get to the root of this.
I am considering fitting a battery switch, but I don't know if the car electronics are up to it. I may fit it in the earth circuit instead of the + circuit to reduce arcing then I throw the switch.
Edit : I've been doing some simple maths on this. If the drain from all sorts of electronics (alarm system, immobilizer, car stereo) is just 0.25 amps (3 watts to you and me), that would mean a 70Ah battery runs dry in just 280 hours, or short of 12 days. That's not even two weeks. I would gather that after a week and a half there's not even enough juice left to start her up.
Peter R.
I am considering fitting a battery switch, but I don't know if the car electronics are up to it. I may fit it in the earth circuit instead of the + circuit to reduce arcing then I throw the switch.
Edit : I've been doing some simple maths on this. If the drain from all sorts of electronics (alarm system, immobilizer, car stereo) is just 0.25 amps (3 watts to you and me), that would mean a 70Ah battery runs dry in just 280 hours, or short of 12 days. That's not even two weeks. I would gather that after a week and a half there's not even enough juice left to start her up.
Peter R.
Last edited by Peter R.; Apr 4, 2007 at 06:50 AM.
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Originally Posted by Peter R.
I am considering fitting a battery switch, but I don't know if the car electronics are up to it. I may fit it in the earth circuit instead of the + circuit to reduce arcing then I throw the switch.
Edit : I've been doing some simple maths on this. If the drain from all sorts of electronics (alarm system, immobilizer, car stereo) is just 0.25 amps (3 watts to you and me), that would mean a 70Ah battery runs dry in just 280 hours, or short of 12 days. That's not even two weeks. I would gather that after a week and a half there's not even enough juice left to start her up.
Peter R.
Drain from the battery with the car at rest is ~20 to 30 mA, (or, .02 to .03), not 250 mA (.25A) and a 70 AH battery is useless when it's at less than half charge, so multiply your number by ~5 and we come up with about 60 days of life under ideal conditions. In real application, 3-4 weeks is about what one could expect before the battery won't be able to start the car.
The Battery Tender (or similar) is the simple solution.
-Jim