When does a car battery need replacing?
Discussion
All,
When is a car battery in need of replacing?
I've had it checked and, as you'd expect "yes sir, that needs replacing", but at what point does the PH wisdom think the battery needs replacing? When the car doest start? When the lights dim/bright depending on revs?
I was given a % reading of the charge in the battery - what is an acceptable level? 90% 75%? 50%? The car has never let me down but I'm keen to know at what point you stump up for a new battery.
Cheers
When is a car battery in need of replacing?
I've had it checked and, as you'd expect "yes sir, that needs replacing", but at what point does the PH wisdom think the battery needs replacing? When the car doest start? When the lights dim/bright depending on revs?
I was given a % reading of the charge in the battery - what is an acceptable level? 90% 75%? 50%? The car has never let me down but I'm keen to know at what point you stump up for a new battery.
Cheers
clabcon said:
If it's not broke then don't fix it. How do you know that the same equipment will give a new battery a full 100% rating?
Totally agree. The alarm has gone off a couple of times in the night over the last few weeks and I'm told (on some forums) that this can be as a result of a tired battery.....but I dont know what constitutes a tired battery!Thanks for the reply.
If you are worried about it get it 'drop' tested, this imo is the only test worth doing as it is the one that means your car won't start. A % of charge left doesn't really mean anything if you've just started the car
Alternator output should be checked at the same time to make sure that is working properly.
Testers are pretty cheap too if you want to buy one for future use; http://www.justoffbase.co.uk/Battery-Drop-Tester-6...
Parents left their car at mine whilst they went on their summer holiday last year. Tried to start the car 3 or 4 weeks later and it wouldn't start. Called the AA out and the chap charged it then hooked up his computer to see how much charge the battery is retaining.
Was told 'sorry sir, the battery needs replacing - its not holding any charge at all'. Thanked him for his help and he went on his way.
Anyway 6+ months later and the battery is fine and the car always starts first time.
Sorry I know that doesn't answer your question but I really wouldn't trust the devices used to check batteries.
Was told 'sorry sir, the battery needs replacing - its not holding any charge at all'. Thanked him for his help and he went on his way.
Anyway 6+ months later and the battery is fine and the car always starts first time.
Sorry I know that doesn't answer your question but I really wouldn't trust the devices used to check batteries.
TSCfree said:
Is it holding charge over a couple of days. Charge it up then measure the voltage with a multimeter after a couple of days. Charged should be 13-14V. Did the same on mine, recently dropped to 7V after 3 days, which means knackered.
Not necessarily, it could be that there is a drain occurring whilst the car is 'off' and have nothing to do with the battery.Quick tip........ DON'T buy a battery........ when you do replace...... from Halfrauds....
You can normally save 50%-100% of Halfrauds prices by visiting a trade counter....and you still get the warranty....probably a better one than Halfauds as they would try & get away with replacing... example..... 068 for my Jap camper... Halfauds...£96 ....Trade counter with a Japanese battery...£41... Sons Fiat Cinq... Halfrauds... £56 ....trade counter £26... nuff said
You can normally save 50%-100% of Halfrauds prices by visiting a trade counter....and you still get the warranty....probably a better one than Halfauds as they would try & get away with replacing... example..... 068 for my Jap camper... Halfauds...£96 ....Trade counter with a Japanese battery...£41... Sons Fiat Cinq... Halfrauds... £56 ....trade counter £26... nuff said
HellDiver said:
Replace it when it stops reliably holding a charge. Didn't think it was rocket science.
Its not. When does it stop reliably holidng charge? What I want to avoid is it not starting one day due to a tired battery, kind of preventative maintenance, and batteries not being my area of expertise, I was asking how I work when this is going to happen. It seems to hold charge, but not enough. I use the train to get to work and walk to the station so the car isnt used every day.Thanks again for the replies.
Some facts. At room temperature a car battery which has been disconnected, fully charged and then allowed to stand for a few hours (preferably overnight) will show the following voltage
12.65V - 100% good
12.45V - 75% condition
12.24V - 50% condition
12.06V - 25% condirion
11.89V or less - utterly dead
If your battery shows anything less than 12.4 volts it's time to replace it.
12.65V - 100% good
12.45V - 75% condition
12.24V - 50% condition
12.06V - 25% condirion
11.89V or less - utterly dead
If your battery shows anything less than 12.4 volts it's time to replace it.
My approach is generally fairly practical. If you have to jump-start the car twice, because the battery was too low, it's time to change it!
Also, as was mentioned above, try other sources like the official dealer or a motor factors. The batteries are usually a lot cheaper than Halfords. Halfords wanted something like £130 for a battery for my M3, and the BMW dealer charged me £90 for the official BMW battery.
Also, as was mentioned above, try other sources like the official dealer or a motor factors. The batteries are usually a lot cheaper than Halfords. Halfords wanted something like £130 for a battery for my M3, and the BMW dealer charged me £90 for the official BMW battery.
I'd second the bit about jump starts but say consider why the battery was flat first, my car has had to have the battery out on charge twice this winter both times the car wouldn't start. 1st time -12 outside and a diesel engine that has sat for a week or so, so will be hard to start, 2nd time i stupidly left my satnav plugged into the permanent live for 3/4 days so a lowish battery isn't too surprising. My assessment may be clouded by the fact the car has an Optima sealed battery fitted on its side under the passenger seat and looking at prices they are £100+ so if I can get it to last longer I'm happy.
Pork said:
clabcon said:
If it's not broke then don't fix it. How do you know that the same equipment will give a new battery a full 100% rating?
Totally agree. The alarm has gone off a couple of times in the night over the last few weeks and I'm told (on some forums) that this can be as a result of a tired battery.....but I dont know what constitutes a tired battery!Thanks for the reply.
varies. I had to replace the original battery in my Corsa recently. at the time it was 4 1/2 years old with 30,000 miles. if I played the radio for 5 minutes it would refuse to start, and was sluggish. the car had been doing low mileages on short trips until I had it, I put it down to that. never getting proper exercise. and also 4 1/2 years seemed reasonable enough
I have one of those jump start packs, if the battery starts getting a little weak I just carry the jump pack around with me for a few days, if a trend starts developing like battery not holding charge then I replace.
Saw a mag at Tescos yesterday (cant remember the name of it, it s a technical fix it mag) they have a test of about a dozen new batteries, from budget to expensive.
Saw a mag at Tescos yesterday (cant remember the name of it, it s a technical fix it mag) they have a test of about a dozen new batteries, from budget to expensive.
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