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New Battery


Well-known member
10 Jul 2004
Technical question. Can a new battery improve performance? Just had to put a new one in my 993 and she seems to be going better - increased power and more eager. Or is it just my imagination?

Migration info. Legacy thread was 26807
When our one got a new battery it sounded better too...

Migration info. Legacy thread was 26809
what a load of bull nonny stick to your pedal bikes

Migration info. Legacy thread was 26810
Sensors on the engine send info to the ECU which expects a certain voltage - poor battery output gives lower control signal voltages which affects performance. Same effect if you have poor earthing or corrosion in wiring contacts or those old bullet fuses. Corroded bullet fuses caused misfiring on my 3.2 Carerra.

Migration info. Legacy thread was 26812
Previous poster said:
Quote: Originally posted by ferrari's rule on 09 April 2005

what a load of bull nonny stick to your pedal bikes
Shut it.

Like I said, when our 993 got a new battery it sounded stronger/better. Not sure about performance.

Migration info. Legacy thread was 26813
Previous poster said:
Quote: Originally posted by Stevo on 10 April 2005

Sensors on the engine send info to the ECU which expects a certain voltage - poor battery output gives lower control signal voltages which affects performance. Same effect if you have poor earthing or corrosion in wiring contacts or those old bullet fuses. Corroded bullet fuses caused misfiring on my 3.2 Carerra.
I always thought that batteries was there to start the engine, after that, the alternater will take over the job of supplying electricity as well as charging the battery. That's why you can jump start a car with flat battery and then it can keep going without the external electric supply. Am I missing something?

Migration info. Legacy thread was 26822
Previous poster said:
Quote: Originally posted by ferrari's rule on 10 April 2005

why is your 993 electric nonny
I'm just stating my observations when our old 993 got a new battery. Now shut up!

Migration info. Legacy thread was 26823
Good point Mick! - Stevo?

Migration info. Legacy thread was 26826
have a look at the Varta site for battery care.
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.


Migration info. Legacy thread was 26828

There is a manual for the 911 3.2 Carrera printed by Bentley Publishers which contains this paragraph
regarding the electronic ignition on the 911.

Page 200-13 Engine management
"All the cars covered by this manual use engine management systems that rely
on precise electrical signals for proper operation. Some of the DME circuits
operate on very low current and are sensitive to increased resistance due to
faulty or corroded wiring or connectors. If any of these signals are
distorted, incorrect or missing the car can develop major driveability

Migration info. Legacy thread was 26829
And from the Bosch site


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.


Migration info. Legacy thread was 26833
And this site is superb for battery information and explains the 993 battery problems very clearly.....

There are ways to greatly increase battery life and performance. All the products we sell are targeted to improve performance and battery life.

An example: Let's say you have "toys"; an ATV, classic car, antique car, boat, Harley, etc. You most likely don't use these toys 365 days a year as you do your car. Many of these toys are seasonal so they are stored. What happens to the batteries? Most batteries that supply energy to power our toys only last 2 seasons. You must keep these batteries from sulfating or buy new ones. We sell products to prevent and reverse sulfation. The PulseTech products are patented electronic devices that reverse and prevent of sulfation. Also Battery Equaliser a chemical battery additive has proven itself very effective in improving battery life and performance. Other devices such as Solar Trickle Chargers are a great option for battery maintenance.

Parasitic drain is a load put on a battery with the key off. Most vehicles have clocks, engine management computers, alarm systems, etc. In the case of a boat you may have an automatic bilge pump, radio, GPS, etc. These devices may all be operating without the engine running. You may have parasitic loads caused by a short in the electrical system. If you are always having dead battery problems most likely the parasitic drain is excessive. The constant low or dead battery caused by excessive parasitic energy drain will dramatically shorten battery life. If this is a problem you are having, check out the Priority Start and Marine Priority Start to prevent dead batteries before they happen. This special computer switch will turn off your engine start battery before all the starting energy is drained. This technology will prevent you from deep cycling your starting battery.

see here


Migration info. Legacy thread was 26834
Thanks Steveo for the info, now I know why I had the problems I had with the batteries over the years.

Forgive me for being a bit slow, and I don't mean to be diffecult, I've read your post a few times now and still don't understand how a good (or new) battery would make any difference to how the engine runs once it's started.

Sure it would make it easier to start and all, but after the battery has done its job, providing the alternator is in working order, how would the condition (or even its presence) of the battery make any difference? Do you mean the battery actually contribute electricity to the running of the engine (?may be tempory, like a capacitor kind of way may be?) beyond starting?

Migration info. Legacy thread was 26842
I know nothing!

However from the web information I have formed the following opinion

The 993 is the only car I have ever had with persistent problems with flat batteries.

The 993 I have has a master switch to disconnect the battery from the car to preserve the charge.

This 993 had at least 3 batteries in the first 4 years.

It suggests "infrequent use" based on the battery manufacturers sites definition.

I use the car often, but also leave it for 4 or five days occasionaly - which is when I get the problems.

Like now - its on charge and will take all night to get to fully charged with the charger maintaining a full charge.

So lets say you do 25 miles to work with the radio and aircon and alarm and heated rear window on - you are not putting as musch into the battery as you are taking out - so every day is a net negative - so you are effectively running on the battery.

eventually this will weaken the battery which will eventually be unable to be charged up by the alternator - slippery slope!

This comes back to - did Porsche give enough room under the hood for a battery big enough to cope? I paid 120 quid for my last Porsche purchased battery! And its being charged again NOW!

So the answer appears to be that we have to use a battery conditioning top up device like a solar cell system to keep the battery in a well charged state to prolong its life and reduce the chances of a strained and flat battery.

Meanwhile we have a nice electronic engine management system which likes voltages from the battery/alternator system to be within certain boundaries. So if your battery is undercharged and you are using alarm/radio/heated seats/lights/heated rear window etc etc - you are not giving the DME electronic computer the voltages it needs through the sensors to run the engine at 100percent efficiency.

So a new battery restores the system to full efficiency.

Until you flatten it!

Migration info. Legacy thread was 26846

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