Battery charging issue

[Mathemagic-1970]

Hi all,

I'm hoping someone can offer some advice.

My father-in-law has a 2017 C4 Picasso petrol automatic and as a result of various medical reasons, the car hasn't been driven much in the last 6 or 7 months at least. I've taken it for one longer run and borrowed for a few short runs, the last being probably last November. We haven't been able to take it for a good run since as we have had to tell my father-in-law that he should no longer be driving which is upsetting for him due to dementia.

Anyway, about 10 days ago or so I convinced him to let me take it for a run. Unfortunately, it wouldn't start and we had a lot of various dashboard warning messages. Shortly afterwards, the battery charge must have been so low that we couldn't even lock the door without problems.

I started it a couple of days later with a booster pack and took it out for an hour run (probably about 30 miles or more). I immediately hooked it up to a battery charger and left it for a day or so. The charger was showing 1 bar (so only 20% charged when I starter). Eventually it was showing 5 bars so I disconnected and left it on his drive locked up for about 5 days.

When I went today I hooked the charger up again and it was showing 1 bar again. I left it charging and went back about 5 hours later and full 5 bars. But then one thing seemed to drop the charge back down - I think it was me locking the car with the bonnet still slightly open which caused the alarm to go off. Back down to 1 bar again. The car started 1st time quickly when I tried.

The battery isn't the original, it is a Yuasa 9096 one (correct spec) so he has had it changed at some point but his dementia means he can't remember when (the stop start system was working fine back in October).

Anyone got any ideas of what to look for? I've just ordered a multimeter and a different charger (I have to give the one I borrowed back). My next plan would be to disconnect the positive, charge the battery fully and leave for a few days to see if the battery is losing charge itself or whether it means it is a circuit draining (or even misleading readings from the charger). Could a battery deteriorate like this after not being used for months?

Any other things to try would be very much appreciated.

Tony

[bobins]

It may be that the battery just got discharged too much to be recoverable. If the battery voltage drops below around 10.5 volts then it's in the realms of being permanently damaged. Although various battery chargers will happily charge it to show full, the battery may still fail when asked to deliver cranking amps. It's possible to get a relatively cheap battery tester that'll do a diagnostic test on the actual battery (Topdon BT100 for example), but it's debatable whether it's worth getting one and then finding out the battery is duff so you need a new battery anyway. If you want to go down the route of testing the battery, then a competent garage should be able to run a diagnostic on a battery with some testing kit.... and then no doubt tell you they'd recommend a new battery ..... and then try and sell you one You may be better off just getting a new battery yourself - Eurocarparts, carpartsforless, GSF, Halfords, Tayna may variously have offers on that make the price a little cheaper.
I'd do basic tests first - charge the battery off the car with an 'intelligent' charger if you have one. Refit it to the car and start the car and drive it a little then check the charging voltage with a multimeter.

[PaulC5]

Definitely sounds like it needs a new battery. Get a volt meter, they only cost about £10 and check its voltage - should be 12.7 volts if fully charged, below about 12.5 and it needs charging. This does not give the full story though, the battery will have gone flat due to lack of maintaining its charge all those months, so then it will have lost capacity and the slightest use will flatten it again after you charge it up but it will appear to fully charge in a short time. If the car is not going to be used much then you are better disconnecting the battery or at least charge it up now and again.

When you come to disconnect and reconnect the battery do not do it too quickly or you can cause odd electrical problems. You need to give the car electrics (bsi) time to shutdown. Best to follow something like this bsi reset procedure but the bit about initialising keys is not usually needed. viewtopic.php?f=51&t=61997&p=601679#p601679

[Mathemagic-1970]

Thank you PaulC5 and bobins for the kind advice.

I've ordered a multimeter that should be here tomorrow. I suspect I'll end up replacing the battery. Thankfully, I have a diesel 2015 C4 Grand C4 Picasso and changed my battery last year thanks to some fantastic guides on this site.

Tony

[bobins]

Halfrauds will do you a free battery health check - you need to book your appointment for it first I think.
I'd put money on it that they say it's bad and they can sell you a replacement one though <spoiler alert - they're bloody expensive for your battery>

https://www.halfords.com/car-repairs/ca ... TTERY.html