Does A Good Car Battery Make Your Car Run Better Or Worse?

We had that thought at the back of our minds before – a better battery makes a car run more efficiently in more ways than one.

And we did not realize actually how apparently it improved a car that used to have a bad battery that we did not think much of it, until one day… When we got a call from the owner of a VW, an old gent whom we just two days back helped replace the car battery for his Golf.

Two Days And Called For Warranty Claim!

In our minds we were thinking that is just not possible, at all. Battery fault? But his car can start. And his complaints were, quite non-specific and seemingly unrelated to car battery replacement at all.

So what did he complain of?

  • Car aircon is way too cold compared to before the battery change (Note: he was an older guy and this was December weather)
  • Engine Idling Is Too Fast and the car sounds louder and boomier at idling. Also, car wants to move forward when stepping on brakes.

Because of the above, he mentioned maybe it was because the battery was too powerful (??) for his car or not suitable and wanted to change back to his original old battery.

This Car Battery Problem Could Confound Elon Musk

This Car Battery Problem Could Confound Elon Musk? Erm, just kidding

His old battery was weak but it still was able to start the car, he had done the change because the battery was already quite old. Since the old one could still start the car, he wanted it installed back to solve his “problems”!

We could not figure out at first what the issues were, and he was not very clear when explaining his symptoms. So we told him we would call him back after we scratched our heads and thought about his issues and after we tried to figure out what happened.

Car Aircon Too Cold After Car Battery Replacement

The car aircon working a little too well?

“Problem” No. 1: Car Aircon Way Too Cold

It could simply have been the weather on that very cold December period of 2020?

But there is always a choice, since there is a thermostat knob / switch in the car where he could adjust the temperature. He swore he didn’t change any settings, but we asked him “why not?”, change to a warmer setting since it is now so cold!

Lightbulb went off in our head! When the compressor works more efficiently, it always becomes colder! 

During a car charging system test, we always test the car alternator (the charger for the battery when the engine is running) and we test for the voltage drop when headlights and aircon are switched on. 

Why? Because these items take power from the system and cause a drop in voltage, and we want to know that the minimum voltage of the alternator is still able and healthy enough to charge the car battery in order to give you a report of the car alternator system health.

With the new battery, the entire system was running smoother because the alternator had no need to put so much effort into trying to charge an old battery that is not working well. And, since the alternator uses engine power to make voltage, this means less power sapped from the engine, which enables the aircon to work more efficiently!

Which partially explains the next “problem”.

VW Golf Speedometer at Idle

“Problem” No. 2: Engine Idling Too High

Because of the above, where the alternator is placing less of a load on the car engine, the idling of the engine is freer and so idling RPM is higher. But that is only partially the answer.

Engines run on three things that enable combustion, air (oxygen), fuel and spark!

The other thing that happened is available electric power to the spark plugs has increased.

Have you seen the ads that say stronger acceleration with better spark plugs and spark plug cables? 

Yes, a stronger spark ensures faster and more complete combustion in the engine, which produces more power each stroke of the piston and each squirt of petrol into the cylinder. 

So while the amount of air and fuel probably remained the same after the battery change (we doubt the old gent would go mod his car suddenly), the spark has become stronger as the car battery is newer and providing more stable base from which other electrical from within the car can drawing power without voltage drop – voltage is not weakening as much when power drain items such as radio (or in some cars hifi!), car driving camera and aircon blower fan, radiator fan, headlights and others come on.

You know the feeling in some old 25 year old cars which can feel like the car engine is dying when idling if aircon or high beams are switched on?

With a new car battery, this gives more available power and greater spark to the plugs which in turn provide better combustion at idling, raising the idling RPM.

New Car Battery Is A Great Way to Make Car Run Better

We got back to the old gent and told him “Your car is actually working better than before, that’s why it was showing these signs of higher RPM at idle and colder air-conditioning.”

Customer Still Unhappy!

Sadly, he didn’t quite understand nor agree!

We persuaded him to adjust the thermostat to a higher temperature and bear with the extra RPM at idling, which he said made the car surge forward when brake was released.

In the end, quite unwillingly, he agreed to try drive with this new battery for a longer period to try it out more, to keep his foot more firmly on the brake when stopped at traffic lights and adjust his temperature setting.

Car Aircon Control Knobs

We suggest twisting one or two of these if its too cold

We have had not any more complaints since the weather turned so sunny!

And we are also sure he will become happy with this new and more powerful car battery, eventually. 

Eventually, because, some years down the road when the battery becomes old and weakend, it will be the same weaker aircon and lower idling for him again!

Happy motoring, and if you are looking for a good car battery replacement for your car’s old failing one and more info about our focus on quality service and the car brands we work with!

happy customers that already replace their car battery

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