Newish battery not charging.

HorseSea

Background. I rarely use the car and sometimes it would flat when I went to use it, so would charge and all good, then it would not hold the charge. AA put in new battery and said alternator needed replacement. Got alternator replaced and a few weeks later battery would not hold charge. AA replaced battery under warranty. All good for a few months until yesterday battery flat. Took battery out and put on charge, checked about 4 hours later and battery was extremely hot and there was an awful smell. Charger was still going, despite allegedly having 4 types of safety cut out. Disconnected battery.

What is likely to be wrong that is killing batteries? And I assume this battery is toast now?

Dirty Nails

What make is the battery?

Are you sure the charger wasn't connected in reverse?

HorseSea

100% sure connected correctly, just went back out to garage to check and the battery is still very warm and it's disconnected a couple of hours now.

The battery is Exide Premium EA640 027

mk7r

Check the car to make sure the voltage is not too high ( but it may just be the fact the batteries are going flat, each time the battery runs down to the point it wont start the car its getting damaged and charging it wont remove that damage so it doesn't take many ties to kill the battery.

newmember2

How rare is "rarely use the car"? What car or what age car?

Sounds like battery is getting overvolted (boiled).

greasepalm

Funny smell off battery like rotten eggs could be faulty battery.

Batteries do get warm when charging

Slow charging or fast charging and how small or big is your battery charger as the bigger you go the quicker it can get charged.

What type of car is it and does diagnostics need to be run to program vehicle again?

HorseSea

The battery was definitely more than warm, extremely hot and I think I heard it creaking.

I had been using an old charger but I bought this one in case the charger was at fault

https://www.amazon.co.uk/dp/B08MPKGJGQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

It says the current will drop as battery charges to about 0.3 amps, it was 8.9 when I put it on charge and the same when I disconnected. There is not fast charge option, I just set switches to Automatic and Ordinary Battery.

It's an old Renault Laguna 2001. Don't think diagnostics will need reset, but I haven't reinstalled the battery.

HorseSea

https://www.boards.ie/discussion/comment/120720718#Comment_120720718

Usually weekly but sometimes it would be two weeks and I give it a good run, an hour or two at least when it does go out.

greasepalm

No resetting on a Renault , but why did level not drop and no fear of it been on 24V as never had one.

zg3409

If a battery is left flat for any length of time it may never recover.

I suggest getting a battery isolator switch if car is used so rarely. Things like remote licking constantly drain the battery and the battery may not be full charged on short runs.

If you don't look after a battery it won't last. I also suggest a small jumper pack lithium for around 100 euro as another backup plan.

Batteries can explode and leak and vent sulfuric acid so not a good idea to keep a bad one. Recycling centers take them

HorseSea

Thanks all, I think I will order a new battery and an isolator switch and go with that. I will get the old battery to recycling centre over the weekend.

greasepalm

Supplier of battery will also take back battery.

If battery is new should be a warranty on it as faulty.

Get motor factors to check battery with their tester.

Make sure while transporting it in car it cannot fall over as acid is very corrosive.

Hmm Renault with electronic locking ? as you will need a metal key entry into car.

Possible to have something draining your battery over weeks or month.

Solar charger to get the sun to top up your battery ?

John.G

https://www.boards.ie/discussion/comment/120723041#Comment_120723041

If you already havn't got one, you can get a cheap multimeter in Halfords for around a tenner the last time I was in there. As soon as you start the car with your new battery check the terminal volts, they should not be more than 14.4/14.6 volts ( car idling) and should not fall below 13.5V with head lights + heated rear screen on (car idling). If you do use that charger again ensure that the amps do fall back to a trickle charge level of 0.1/0.3A when the voltage rises to ~ 14/14.4V. Looks as if that battery was damaged before you put it on charge as charging a flat battery at 8.9A for 4 hours = ~ 36AH so would't be unusual to still charge at that rate, did you notice the voltage (displayed on the charger) before disconnecting?.

HorseSea

https://www.boards.ie/discussion/comment/120727134#Comment_120727134

New battery fitted, old battery gone and isolator switch to hand, but not fitted yet. The old battery was at 5.2 v when fitter tested it!

The battery is charging at 14.63v which fitter said was too high, he said should be 13.8-14.2, and that over time 14.63 would damage battery. He blamed the new alternator fitted about 1 year ago, said it was likely the wrong one of resistors were set wrong.

If I fit and use the isolator switch will that keep me out of trouble, unlikely the mechanic that fitted alternator will accept there's an issue that, avoiding phone calls atm.

newmember2

https://www.boards.ie/discussion/comment/120734332#Comment_120734332

Bring it back to him and get him to test the output voltage from the alternator to the battery and tell him you've gone through two batteries since he installed it.

Dirty Nails

https://www.boards.ie/discussion/comment/120734332#Comment_120734332

14.7 v is normal but I'd question it if it was more than that. It won't damage your battery. Did he test for Amp output & Amp drain with the car turned off?

Amps will do more harm than volts if it's not regulating correctly. As for setting resistors,he was trying to impress you with his knowledge. There is no such thing. Who done it for you? Halfords or Bestdrive :)

As far as the isolator goes - dont fit it. Every time you use that is akin to turning off your desktop computer by yanking the plug out. All the ECUs need to shut down by themselves

John.G

In most cars now, the battery management (charging) is done by the ECU which varies the voltage as required, even if the old fixed voltage type then 14.63V shouldn't have resulted in any battery damage. Quite alot of cars with smart alternator charging (and stop/start) reduce the charging voltage to 12.8/13.4V while driving and increase it up to 15.0V on overrun when the throttle pedal isn't being pressed.