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Est. 2004

Car battery question

Without warning, my car battery seemed to have failed a couple of days ago. The car is a 2016 Seat Leon FR Technology ECO TSI (although I call it JeffThree). I started the car with a little charger pack, after initially putting the clamps on the wrong teminals “Doh!”. I took the car for good 30 minute run along a few junctions of the M25, keeping it in a gear of two lower than I would normally, so as to keep the revs high, on the understanding that charging is better with higher revs.

When I got the car back home, after about 25 miles of driving, and went to start it again, the panel stated “12v battery low. Drive to charger” or something similar. A couple of days later, it now states “12v battery almost empty. Infortainment system will be shut down”. When I turn the key, i just hear rapid clicking.

Now I don’t mind buying a new battery, and it is due for a service anyway. I just don’t want to get ripped off. Checking the prices for batteries ranges from £70.50 to £215.00. If it is the battery, what are the factors I need to consider please? I’ve noticed some stating 70Ah and others stating 110Ah, which I presume is Amp hours, but cannot remember what that means, or if a lower number is better than a higher number or vice versa.

£200 for a car battery sounds excessive. I’d rather buy an £80 battery with a 2 year warranty than a £160 battery with a 4 year warranty, or is that the wrong way to think?

Additionally, if I remember correctly, batteries don’t generally go wrong, but it is the charging system to them does.

There were no warning signs of the battery loosing power. I didn’t leave any lights on. The car is regularly used. I bought the car in may 2016 with 3580 miles on it, it has now done 35500 and I’ve had it regularly service only by main Seat dealers. This car is a “stop/start” one, where the engine cuts out most of the time when stationary, and quickly restarts. I’ve never had a problem with the restarting.

with modern vehicles high revs aren’t needed, you’ll have 14v from idle on all injected, and that’s what’s needed to charge

could be the battery, could be the charging system
do you have access to a multimeter?
check the Aux belt is still there

amp hours is how many amps per hour the battery can give
80Ah can give 1 amp for 80 hours, or 80amps for 1 hour (this is very simplified, theres more to it).
bigger number is a larger battery, the manufacturer will say what your car needs, get that size. you can get bigger if you want, and if it fits, but there’s not much of a gain for normal use (you’ll be able to leave your lights on longer while parked is pretty much the only gain)

dont forget the cost and inconvenience of it failing. in general I’d go for the longer lasting more expensive option

both can fail quite easily, and one failing can break the other.
test both before changing

stop start batteries are generally more expensive, as they are used a lot more (its the battery that does the starting each time)

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^^what he said

All sound advice, for my two penneth (lift the bonnet) check the Ah and EN CCA ratings of the original battery (label/printed on battery) against what it recommends in the (open the glove box) owners handbook. If they both tally go with that, if they differ go with the higher rating. I’d expect to pay £60 to £100 for a battery depending on the ratings. My go to off the shelf car battery supplier is Euro Car Parts (Lion brand) good on price vs specification/guarantee. Halfords (own brand) also good but tend to be more expensive, Kwik-Fit (don’t go there) more expensive and then some.

Typical batteries should last a minimum of 3-5 years some last much longer. Some fail just like that, others fail gradually. My original Ford battery is still good and its 12 years old. Worse car battery I’ve had come from the AA, it lasted 2 years and 51 weeks, replaced under 3 year guarantee and the replacement was still good when we sold the car 8 years later.

Driving around is not how you should be charging any battery, get yourself


Very sound advice.

I had a cheaper motobatt battery on my KTM for good few months. Always fine in summer/warm but a bitch in winter/cold days.

Turns out even though it followed KTM spec on every single thing, on CCA it did not. Once I replaced it (with a marginally more expensive Honda equivalent) never had an issue again.

Your battery is fuked

High revs can actually be counterproductive, the alternator will stop delivering charge in case it over charges the battery.

Yup you need a new battery. Buy the largest one that will fit. Modern cars put a lot of demand on batteries.

Agree with above advice re checking charging. For a battery try MDS Battery which is local to you in Brimsdown as well as Eurocar Parts who always seem to have discounts. Halfords are always overpriced in my experience.

A lot of cars now have a smart charge system that can push out up to 20v so don’t automatically assume its an overcharging scenario .

Smart charge alternators: everything you need to know - Garagewire.

Short town journeys put more demand on the battery …
Lights, steering ( most cars have electronic assist pumps) engine management , start stop .airbag modules, abs pumps , traction control
All of those are requiring power before you decide you want the aircon on or the heater and lights and entertainment …


Gentlemen, thank you all for your comments and advice, possible exception of Wise. I’ve learnt a lot, and have discovered a local dealer that also provides bike batteries.

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