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Flat battery problems common?

obzi

Well-known member
Joined
13 Sep 2005
Messages
111
Hi all

On collection of my 996 C4S a few days ago, the seller mentioned that all 911's have a common fault of flattening the battery after a week.

I am out of the country for 2 weeks approx 6 times every year and was a little suprised by this, he claimed it is because of all the electrical equipment! I did notice a trickle charger on the Official website and thought it was unusual.

Is this a problem with 911's or was the seller just hiding something from me?




Migration info. Legacy thread was 34201
 
I have a 993 and had problems - a week and it was flat.
Had a new battery - after a few weeks went on holiday - battery flat.
Had a service and mentioned the problem - the techy connected a volt/amp guage to the battery terminals - switched off the engine - big drain until the system closes down completely - can take 40 minutes.Then it should drop to a very small drain - it didn't - so he rewired the Alpine replacement radio correctly and fixed the problem! It was permanently on and wired wrongly.

Moral of the story - get an auto electrician to check that all is as it should be.

Search for "battery" there are lots of other posts on this subject. Lots of people have problems because they use their cars only at weekends and then do 25 miles with the lights, aircon, stereo on full blast and never get the battery fully charged - which kills it.
So if you dont use it every day get a trickle charger.


Migration info. Legacy thread was 34202
 
From previous posts..
have a look at the Varta site for battery care.
eg....
Cleanliness is important for starter batteries
It's particularly important to keep the battery and its surrounding area clean. Dirty or moist surfaces may result in small continuous currents, 'flowing' from one terminal of the battery to the other. The contacts also need to be clean, dry and lightly greased, and the electrical connections need to be secure. Moreover, defective switches for lights in glove box or trunk can give drivers an unpleasant surprise. Even if the bulbs only take a small amount of power, they still considerably reduce the performance of the battery in the long term.

With cars that only do trips to the supermarket and the school run - often the second car in many households - it is also important to check whether the battery installed is powerful enough. A larger battery with higher capacity will often solve the problem of the alternator not recharging the battery sufficiently on short trips.

Last but not least, a specialist should also check that the V-belt between the engine and the alternator is in good condition and correctly tensioned before winter sets in. Otherwise the howling noise you get when you start off signifies that your battery will soon be flat.

What sort of battery problems can arise during use?
If a starter battery is poorly maintained, it can soon fail. Dirty terminals cause power trickles, causing the starter battery to lose energy. If you mainly make short trips in urban traffic with electrical systems running (air-conditioning system, ventilators, seat heaters, heated rear window and windscreen, etc.), the starter battery can become flat, even with the engine running. This can lead to starting problems, particularly in the winter.

see
http://www.varta-automotive.co.uk/


And from the Bosch site

Charging

For safety reasons, we advise connecting the battery to the charger before switching the charger on. If the battery has vent caps, remember to unscrew them and place them to one side (this is not necessary with Bosch Silver or Silver Plus, as they are maintenance free).

The charging current in amps should not be more than 1/10th of the battery's rated capacity in ampere-hours (Ah). For example, a 60 Ah battery should not be charged at a rate greater than 6 amps.

If the battery has become deeply discharged it will not accept a charge rate of more than 1/20 of the stated ampere-hour capacity. This is due to the excessive internal resistance that develops and means recharging at the appropriate rate can take 12-18 hours.

Any prolonged attempt to charge at a higher rate will probably damage the battery and will result in a less than complete recharge. The internal resistance will cause the current, which cannot be absorbed by the plates, to turn into heat instead. Using automatic chargers or boost chargers are not recommended for deeply discharged batteries. At best it will have no effect, and at worst it will terminally damage the battery (any charger will need to have a variable input with a minimum of 2 amps). Charging batteries can give off flammable fumes, so make sure no one smokes and there are no naked flames nearby, and if the battery is being charged indoors there should always be adequate ventilation.

After charging the battery check level and if necessary top up with distilled or de-ionised water. Do not use tap water.

http://www.boschautoparts.co.uk/pcBatt10.asp?c=2&d=1


Migration info. Legacy thread was 34204
 
Could someone tell me please what the amp hour should be for my '97. I think it's time to change the battery before it dies (I think it's the original) and all I can find is that a '95 would need a 75 amp hour - would the '97's (non-turbo) requirement be any different?

Migration info. Legacy thread was 34206
 
Obzi

The 996 has a "sleep mode" which cuts in after 5 days and shuts down some of the systems to conserve battery power. The most noticeable of these is the remote locking which means you will have to use the key to unlock it. I guess this was introduced to try to solve the problem. I'm not sure what other systems get shut down but I think the handbook tells you.


Migration info. Legacy thread was 34211
 
The replacement battery I have is a Bosch Silver 74AH which is a new type sealed battery which should stand low charges better than the old type according to their web site - it is also hugely cheaper than a Porsche battery. Its a direct snug fit in the battery space on the 993.
Local yellow pages will get you a dealers details.

Migration info. Legacy thread was 34230
 
Thanks Stevo. I got a Bosch Silver yesterday (75ah) from Eurocarparts for £52.50 plus vat. Fits perfectly.

Migration info. Legacy thread was 34279
 
I think you'll find the battery in a 996 should either be 80 or 90 A/Hr. The 90 should do a good job and have sufficient life in it to start the car after a fortnight. I replaced mine earlier in the year and have since been away on holiday for 2 weeks; started without a problem.

I would add that the battery was from an OPC, so for the £140, it should start the car!!!




Migration info. Legacy thread was 34282
 
anybody recommend a trickle charger/bettery conditioner to charge through the lighter socket??



Got a Helfrauds one on my Exige but it has to be attached directly to the terminals..........could be painful
. :lol:


Migration info. Legacy thread was 39078
 
the Porsche one is meant to be a good'un and IIRC if its a 996/997 its plug n play

Migration info. Legacy thread was 39080
 
Let's ask Robert. After all he did win one at the curry meet and now he has the most pampered battery in Oxfordshire :D

Migration info. Legacy thread was 39082
 
Sorry Robert, Berkshire :oops:

Migration info. Legacy thread was 39086
 
I have the Porsche charge-o-mat. Also found that my 993 didn't require any mods for it to work. Plugs straight in and works a treat.

Migration info. Legacy thread was 39088
 
Thats the one I bought a couple of weeks ago.

I think its excellent, and about £10 cheaper than I paid :evil:


Migration info. Legacy thread was 39130
 

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