Battery RIP?

[ik9000]

My car battery has gone completely flat. Jump starter won't turn it enough to get it going. Is it a lost cause? Time for a new battery? If so any good brands/places to get one from? (and how do I go about working out which is the right one for my car - the current one is obscured by a massive plastic cap that prevents reading any markings on it. (and I'm not entirely sure how to remove it atm). If it's not a lost cause and can be salvaged what should I try instead?

[CAT-THE-FIFTH]

Trickle charge it overnight?? You do that already?? It's what I would do for any new battery - fully charge it up first before using it.

[Saracen999]

At the risk of teaching grandpa how to suck eggs, are you sure it's the battery?

Last time that happened to me, it turned out to be an alternator fault and battery was flat because it wasn't getting any charge.

[CAT-THE-FIFTH]

TBF,if like a number of people,you are using your car,less then the battery will discharge over time when not used,and if you are doing shorter journeys than normal, the battery will probably get less charge. It is why sometimes you might need to charge it up again using an external charger.

Edit!!

Halfords batteries are made by Yuasa,so are not too bad IMHO.

[Saracen999]

Good point. And we have one of those Halfords Yuasa batteries in the wife's car. It's been fine.

[CAT-THE-FIFTH]

Good point. And we have one of those Halfords Yuasa batteries in the wife's car. It's been fine.

Strangely cheaper than than the Yuasa branded Yuasa batteries!

[jimbouk]

I generally just use one from euro car parts, can get them cheap in the sale. When they're half to a third of the price of Halfords then you don't worry if they might not last quite as long.

Re your battery, trickle charger as has been said. If it's fine completely flat then they don't always recover so even if it does start again be prepared for trouble if you're not using it regularly or when it gets cold.

[ik9000]

Thanks I fear I'm in that camp. It went flat circa August and we used our starter jump pack thing. It got it running. Was happy for a bit. Now it's flat as a pancake as no use for last three months+. With the external jump pack You can hear the starter motor trying to turn but the jump starter throws up a warning and smoke starts coming off the clamps. Warning is problem with battery.

[Helios451]

Thanks I fear I'm in that camp. It went flat circa August and we used our starter jump pack thing. It got it running. Was happy for a bit. Now it's flat as a pancake as no use for last three months+. With the external jump pack You can hear the starter motor trying to turn but the jump starter throws up a warning and smoke starts coming off the clamps. Warning is problem with battery.

Definitely need a new battery then! Others have pointed you towards a replacement, but also remember the lead in your old one will get you a few quid at a scrap merchant.

[watercooled]

Thanks I fear I'm in that camp. It went flat circa August and we used our starter jump pack thing. It got it running. Was happy for a bit. Now it's flat as a pancake as no use for last three months+. With the external jump pack You can hear the starter motor trying to turn but the jump starter throws up a warning and smoke starts coming off the clamps. Warning is problem with battery.

Jump packs often aren't enough to power the starter by themselves so this isn't uncommon if it's completely flat. As others have said, if it's gone completely flat and particularly if it's been left this way for a long time, it could have permanent damage even if you get it started again.

It's far from an ideal way of checking battery health but do you have a multimeter to check what the resting voltage of the battery is? Ideally this should be done with no load on the battery (i.e. disconnected from car) and left to rest for a few minutes for the voltage to stabilise, but beware that carries the risk of losing various settings/radio code etc in car if that's not already happened.

If it's anything like mine, the battery compartment lid pulls off with no tools to expose the positive terminal and the negative is deliberately hidden to force you to use the car body as a ground, partly because it doesn't want you bypassing the BMS system attached to the negative terminal.

A decent battery charger is well worth having for when you're not using the car for extended periods.

[watercooled]

Oh and just a little trick I use when giving the battery a top-up charge - I plug the extension lead into a power meter in the house, that way I can see when the charge has finished by the lower power draw without having to go out and lift the bonnet to check.

[ik9000]

finally got in there to have a poke around. After much research the reason I couldn't get the cover off is a hidden plastic clip (or rather a pair of them) that you have to release by shoving a long flat-head screwdriver down a slot in the housing, that if you didn't know what it was for you could easily overlook (like I did for a while). Now that the thing is off it turns out the battery is still the one factory fitted in 2010. Is it even worth trying to charge it? It would cost me as much for a decent charger as for a new battery. (circa £60).

[watercooled]

Do you have a way of checking the terminal voltage on the battery e.g. a multimeter? It's not an ideal way bit might give some indication how dead it is.

Also, do you have a bench power supply? Lead acid batteries are quite simple to charge if so, and you can gains some insight into the dead-ness by the battery's charge acceptance i.e. how much current it will accept at charge voltage.

[ik9000]

Do you have a way of checking the terminal voltage on the battery e.g. a multimeter? It's not an ideal way bit might give some indication how dead it is.

Also, do you have a bench power supply? Lead acid batteries are quite simple to charge if so, and you can gains some insight into the dead-ness by the battery's charge acceptance i.e. how much current it will accept at charge voltage.

Forgive my ignorance but what do you mean by a bench power supply? The only thing I might have of any relevance is an Eventec KPS3010D 10A 10-30V DC supply for electronics work.

I have a multimeter. I will go and check now.

Edit it's reading 2.78V

[watercooled]

Yeah that's what I mean, an adjustable power supply.

From that voltage I'd say it's more than likely toast. I suspect a load of car battery chargers wouldn't even attempt to charge that. However if it's easy enough to try charging it, there's no harm in doing so.

Obligatory safety warning: Lead acid batteries contain lead. And acid. And when charging they can release hydrogen gas so it's always advisable to charge outside or in a ventilated garage for instance. Also it's worth switching off the power supply's output before removing leads to avoid sparking at the terminals.

Set the power supply to 14.4V and current limit to about 3A and see how much current the battery accepts - even if it's recoverable it might need to be left connected for a while before current starts increasing. At some point, a healthy battery should put the power supply into constant current mode as its internal resistance drops, lowering the voltage until it more or less finishes the bulk charging stage. If you see no increase in current after say a couple of hours, I'd say the battery is pretty much dead. However if it starts accepting a charge, it will take many hours at 3A to finish.

At some point, if it gets this far, the voltage will reach 14.4V again and the current will then start to taper off. What constitutes 'full' depends on the battery but don't expect it to reach zero on this type of battery. However at some point the current ramp will level out, at which point it's near enough full and should be fine to put back into service. However, even if it charges to this point, there's no guarantee it will work or last as it may be heavily sulphated, lowering capacity and/or CCA capacity.

Edit: If it is toast, various places online have battery finders where you put your registration in and it will show a compatible battery. This one being an example: https://www.yuasa.co.uk/ Don't gasp at the prices on that site though, just get the model number and shop around as they seem bizarrely high for some.

Halfords also have one https://www.halfords.com/motoring/ba...car-batteries/

[philehidiot]

Now that the thing is off it turns out the battery is still the one factory fitted in 2010. Is it even worth trying to charge it? It would cost me as much for a decent charger as for a new battery. (circa £60).

No. Just replace it. At that point the cost of retrieval is the following:
- Cost of a decent charger which may or may not engage in desulphation which may or may not recover the battery
- False hope when it starts and runs a few times
- Usually runs until winter and then strands you somewhere cold and where you can't stay in the car
- Recovery
- New battery

It has already failed, it is going to fail again. You might get another few months out of it, but it will fail again. Consider how important your vehicle's reliability is to you and whether you want to be calling recovery for an entirely preventable problem.

My bike's battery was showing signs of deterioration during my routine electrics test just before lockdown. It is also circa 2010. When I realised the age I immediately bought a new battery ready to swap out. I held off as there's no point putting the new one in and letting it sit there for 3 or 4 months.

A car battery can be expected to become unreliable after around 7 years on average for a standard OEM. They are servicable parts like anything else. Ten is good. Take your 3 year winnings and leave the betting table as the cost of a failing battery can be high.

Even if there are other issues with the vehicle (alternator, etc), it is still worth replacing the battery at this point due to age and trauma. If it's stop-start then the odds are you'll have noticed that function is no longer working as the lower battery voltage will result in suspension of that system. It is definitely worth looking for contributing factors (corrosion on connectors, parasitic drains, poorly fitted alarms, alternator, interior light stuck on, etc) but at ten years and with failures, it is time to send that battery to be made into little bits of lead I can send at high speed down a range (probably doesn't happen).

Do not go for an expensive battery unless you have specific needs or plan on keeping the vehicle for more than 6 more years. In my view, AGM batteries are essential only for people with specific needs like motorcycles or poorly designed / early stop-start systems (JAGUAR). I would simply check the specified amp hour rating and size and ensure you match them. As above, many websites have automatic size detection things inbuilt so you can find the size and then start googling for a cheaper price.

Yuasa are excellent batteries. I didn't know Halfords were using them. I used to use them before finding a better brand for bikes.

I really would not go down the route of trying to recover the battery unless you are utterly skint. If you must, borrow a charger and buy a portable jump starting kit (ensure it can deliver enough chooch for your engine as some of them really struggle with high compressions).

If you're near Leeds, UK, I may be able to help or put you in touch with someone who can help.