Does car battery voltage drop when it gets colder?

[Fordulike]

Checking over the fluids, tyres, battery etc.. on the little Micra, I tested the voltage of the battery.
It had been charged fully the night before, but left overnight to settle. Think the outside temp wasn't much above freezing though.
The voltage read 11.8 volts, which I thought was a bit low. I tested with two different multimeters.

The car starts fine and the reading goes up to 14.5 volts when the car is running.

Does car battery resting voltage drop slightly when the battery is very cold and can anyone confirm whether 11.8 volts is ok, or should I think about replacing it soon?

 

[Fordulike]

Sorry folks, think I made a schoolboy error

I stupidly measured the battery voltage at the DC socket, which only activates when the key is turned to position '1' on the ignition. It is cold outside lol.

Obviously, the radio and whatever else drags the voltage down doing it this way.

Checked the voltage directly on the battery and it reads 12.4 volts, which I'm happier with.

If someone could still answer my original topic question, that would be grand.

 

[flecc]

Yes it does, it's one reason why one often hears a starter motor labouring in cold winter weather. The starter motor drain further reduces the voltage, resulting in reduced spark voltage in petrol engines.

That said, 11.8 volts is rather low. I've just this moment checked the voltage on an old battery that could no longer start a car three years ago (kept charged for other uses). It's currently at 10.6 degrees C and it reads 12.4 volts. It only drops to around that 11.8 volts area two months after the last charge, but if at much lower temperatures than 10 degrees as yours might be, I'd expect it to drop much sooner.

As yours is starting ok, I'd carry on using it and wait until the first signs of the start getting laboured before thinking of renewing.
.

 

[Fordulike]

Yes it does, it's one reason why one often hears a starter motor labouring in cold winter weather. The starter motor drain further reduces the voltage, resulting in reduced spark voltage in petrol engines.

That said, 11.8 volts is rather low. I've just this moment checked the voltage on an old battery that could no longer start a car three years ago (kept charged for other uses). It's currently at 10.6 degrees C and it reads 12.4 volts. It only drops to around that 11.8 volts area two months after the last charge, but if at much lower temperatures than 10 degrees as yours might be, I'd expect it to drop much sooner.

As your's is starting ok, I'd carry on using it and wait until the first signs of the start getting laboured before thinking of renewing.
.

Thanks for the reply flecc. As you can see, I made a silly mistake

 

[eBoy]

Glad to see you're a fellow Microbe driver, chief! From your name I imagined you would be...a Ford aficionado! LOL! I've had my little Micra for fifteen years now, and it's never been a jot of trouble. Nearly as much fun as an e-bike! Johnny

 

[Fordulike]

Glad to see you're a fellow Microbe driver, chief! From your name I imagined you would be...a Ford aficionado! LOL! I've had my little Micra for fifteen years now, and it's never been a jot of trouble. Nearly as much fun as an e-bike! Johnny

Owned a Ford Mondeo many years ago and created the ID coz I liked the car so much. No surprise there

The Micra only gets used to take me to work and back, so I didn't need anything flashy or ultra comfortable. It's a 2002 model and has been pretty reliable. Had to recently replace the starter motor, but that was peanuts to fix.

I like the fact that it costs very little to run and is very easy to work on. Plenty of room in the engine bay to swing spanners about.

I'm keen on engines with timing chains too. Why on earth some manufacturers moved to belts is beyond me. I'd rather have an engine that is marginally more noisy, than one that has the potential to send the valves into orbit at any time.

 

[flecc]

I'm keen on engines with timing chains too. Why on earth some manufacturers moved to belts is beyond me. I'd rather have an engine that is marginally more noisy, than one that has the potential to send the valves into orbit at any time.

Timing belt engines are simpler to design and cheaper to make, with no enclosed chamber in the castings or lubrication needs. And of course even timing chains can fail, hence some designs using a train of gears to the overhead camshaft.

Another consideration for the manufacturers is providing a sufficient service work flow for their dealers to give them an adequate income since sales never will. As service intervals have been forced to become longer by a public increasingly realising that low mileage or annual services aren't necessary, the addition of a belt change interval helps.
.

 

[Fordulike]

Another consideration for the manufacturers is providing a sufficient service work flow for their dealers to give them an adequate income since sales never will.
.

Bingo

 

[eBoy]

Yes, I much prefer the idea of a cam-chain, Mr Ford. I've heard that Micra engines are good for 150,000 miles with regular oil-changes. My daughter's cambelt snapped, causing £1,000 worth of damage - and it was never the same afterwards. It was a low-mileage car, but she'd gone over the recommended 5-year change period. Johnny

 

[Fordulike]

As yours is starting ok, I'd carry on using it and wait until the first signs of the start getting laboured before thinking of renewing.
.

I did end up buying a little device that plugs into the DC lighter socket on the dashboard, and gives a real time voltage reading. Only cost a few quid:
It shows the voltage of the battery when the engine isn't running, and the voltage of the alternator when the engine is running.

It should give me early enough warning if the battery or alternator is on the way out.