Battery health?

Cap2019

Suzuki swift (65 plate) struggled to start yesterday, battery light and engine light flashed up briefly but went away once the car was running and haven’t returned. Car has started fine two times since. Got the multimeter out this morning after letting the car settle overnight and checked the voltage. Resting voltage seemed to settle at 12.29v, dropped to 10.36v when cranking and climbed to 14.45v when running. I will test again once the car has had a charge. From these readings it would appear the battery is approx 67% charged but I’m getting conflicting information online regarding how concerned I should be. Any one with a little more knowledge able to shed some light? 

EDIT: Further question asked on Page 2; Out of curiosity I had a look at the resting voltage of my car (63 plate Hyundai i30) and it was 12.10!! It starts quickly and convincingly every morning without fail (touch wood) and has given no indication that it is on the way out. My girlfriend and I both drive appox 20 mins to work and back each day and only occasionally further, could this be why the lower resting numbers? insufficient time for the alternator to charge the batteries? Would it be worth charging the batteries with a smart charger to restore them to full charge every once in a while or am I going to have to pick up two new batteries this month? I can replace the battery in my girlfriends Swift myself (will have to use a memory saver tool) but my car has stop/ start technology so i'd rather leave that to the professionals to program correctly. I was of the impression that battery chargers are only useful when batteries are flat but could I benefit or is that just putting off the inevitable?

Car_54

Voltage readings do NOT indicate the %age charge. You need a hydrometer for that.

Rodders53

Voltage readings do NOT indicate the %age charge. You need a hydrometer for that. 

Nonesense.  See http://www.batteryfaq.org/ Section 4 where there a SoC vs Voltage charts.  Voltage will depend on temperature and chamical make-up of the battery. So OP will need to know what is fitted originally and what is there now (in case it has been replaced)
Modern batteries are often essentially sealed so you cannot use a hydrometer on them anyway
Suzuki forums are maybe a better source of information as owners/expert posters will know what type battery and alternator systems are fitted, among other things like regenerative braking via engine/alternator.  These may affect what is considered a 'normal' charge state?
OP Consider asking your Suziki dealer service techs as well?

Cap2019

Rodders53 said:

Voltage readings do NOT indicate the %age charge. You need a hydrometer for that. 

Nonesense.  See http://www.batteryfaq.org/ Section 4 where there a SoC vs Voltage charts.  Voltage will depend on temperature and chamical make-up of the battery. So OP will need to know what is fitted originally and what is there now (in case it has been replaced)
Modern batteries are often essentially sealed so you cannot use a hydrometer on them anyway
Suzuki forums are maybe a better source of information as owners/expert posters will know what type battery and alternator systems are fitted, among other things like regenerative braking via engine/alternator.  These may affect what is considered a 'normal' charge state?
OP Consider asking your Suziki dealer service techs as well?

Thanks for this, I’ll have a look tomorrow for any information on the battery age and life expectancy. If the car fails to start or begins to struggle regularly I will have it looked at straight away but in the meantime I will get on to the Suzuki forums to see what the other owners have to say!

ElephantBoy57

Suzuki swift (65 plate) struggled to start; a newish car, you would think would start at first turn of the key.

Is it a petrol, does the car have the eco-mode where it switches the engine off when stationary? That might put more of a strain on the battery. Four years old is early for a battery to fail, but not unheard of.

[Deleted User]

The only way to properly test battery health is with a special meter. A basic one is about £15.

marlot

>> Resting voltage seemed to settle at 12.29v, dropped to 10.36v when cranking and climbed to 14.45v when running..

Other than the battery being a bit flat, those don't seem too bad.  Give the battery a decent charge and see how it goes.

Cap2019

ElephantBoy57 said:

Suzuki swift (65 plate) struggled to start; a newish car, you would think would start at first turn of the key.

Is it a petrol, does the car have the eco-mode where it switches the engine off when stationary? That might put more of a strain on the battery. Four years old is early for a battery to fail, but not unheard of.

No the car doesn’t have anything like that, no stop start technology. I’m putting it down to a couple of below freezing nights in a row paired with my girlfriend doing a string of short journeys in the days before. Will keep an eye on it and report back!

Cap2019

[DELETED USER] said:

The only way to properly test battery health is with a special meter. A basic one is about £15.

Thanks for responding. What should I look for? does it have a name?

Cap2019

marlot said:

>> Resting voltage seemed t o settle at 12.29v, dropped to 10.36v when cranking and climbed to 14.45v when running..

Other than the battery being a bit flat, those don't seem too bad.  Give the battery a decent charge and see how it goes.

That’s what I was thinking, thanks for the response 

forgotmyname

Was the 12.29v under no load?   You should load the battery to test the voltage.
With no load that is slightly low, but maybe the battery is just getting on, small
petrol engine it may last a while yet. Get an external charger.

Its possible for a battery to test at 12+ but drop way below 11v when just turning on the
headlamps.

Switch on the headlamps for a few minutes and then test the voltage, with the headlamps
still turned on. That will give you a better idea of the batteries health.
Do this test with a cold engine, not after it has just run.