Flat Battery advice

[g7jhp]

Battery on my wife's Golf GTI Mk5 went flat.

Managed to jump start via leads and a second car and get it home.

Put it on a C-Tek trickle charger for 24 hours to try and rejuvenate it.

It seemed to have topped up, but then dropped off and now won't start.

Presume battery is dead as it's not holding charge?

I could check the alternator is working.

What else would you check?

Edited by g7jhp on Tuesday 26th September 09:44

[Vsix and Vtec]

Silly things like the glove box or boot light staying on and draining the battery. Some cars have permanent live cigarette lighter sockets, so check there's nothing plugged in drawing power there either.

[g7jhp]

Vsix and Vtec said:

Silly things like the glove box or boot light staying on and draining the battery. Some cars have permanent live cigarette lighter sockets, so check there's nothing plugged in drawing power there either.

Thanks that's a good call.

[paintman]

How old is the battery?

[g7jhp]

Not sure at least 3 years I think.

[g7jhp]

Think I'll just stick a new battery in.

[Vsix and Vtec]

g7jhp said:

Think I'll just stick a new battery in.

I would. Generally speaking unless the battery is 12 months old or less, I'd always put a new one on once it's gone repeatedly flat like that.

[PositronicRay]

g7jhp said:

Not sure at least 3 years I think.

Worth checking many batteries have a 5 yr warranty.

[A500leroy]

Less the alternators not charging it.

[vikingaero]

If you need a new one try Tayna. They do next day delivery.

Just avoid overpriced stuff at Halfords and ECP and their endless fake discounts. And never a Lion battery from ECP.

[Red9zero]

vikingaero said:

If you need a new one try Tayna. They do next day delivery.

Just avoid overpriced stuff at Halfords and ECP and their endless fake discounts. And never a Lion battery from ECP.

Another vote for Tayna. I ordered on a Sunday afternoon and it was delivered on the Monday morning.

[Vsix and Vtec]

My go-to is usually Yuasa, they're not cheap, but the quality is high.

[donkmeister]

Vsix and Vtec said:

My go-to is usually Yuasa, they're not cheap, but the quality is high.

Echo this.

Alternatively an OEM battery - sometimes not actually any more expensive than an aftermarket one.

OP, does the CTEK have a repair feature? My NoCo has a repair mode that, judging by what I saw when I kept a multimeter across the terminals, does some higher voltage pulsing to desulphate the plates.

[Sticks.]

The Ctek 5.0 has an indicator of the battery is defective. You have to decide whether the battery is faulty or is fine but being drained by something not working properly.

[TimmyMallett]

Sticks. said:

The Ctek 5.0 has an indicator of the battery is defective. You have to decide whether the battery is faulty or is fine but being drained by something not working properly.

It does, but only in the sense that it monitors the battery voltage float over time and if there is a parasitic drain, that doesn't necessarily mean the battery is faulty, so best to test with it out the car.

[Pica-Pica]

Vsix and Vtec said:

My go-to is usually Yuasa, they're not cheap, but the quality is high.

A couple of years ago my wife’s Fabia just would not turn over. Clearly the battery was gone. I collected a Yuasa from Halfords and fitted it. Seems good.

Note:
The car was 8 years old, bought new.
I then read the handbook, and that said, ‘replace battery after 5 years’.

My 335d is coming up for 7 years old, with an AGM battery (stop-start is usually switched off). I am wondering how long they are good for?

[Sticks.]

Pica-Pica said:

A couple of years ago my wife’s Fabia just would not turn over. Clearly the battery was gone. I collected a Yuasa from Halfords and fitted it. Seems good.

Note:
The car was 8 years old, bought new.
I then read the handbook, and that said, ‘replace battery after 5 years’.

My 335d is coming up for 7 years old, with an AGM battery (stop-start is usually switched off). I am wondering how long they are good for?

They last about 8 years on my Z4. First sign will be an electrical fault/warning light which is intermittent or makes no sense.

[Belle427]

I'd say 7 years is about the norm for a quality one to last these days under normal operating conditions.
I usually go for Varta from Tayna.