Car battery charging from deep discharge

Use this board for general non-cycling-related chat, or to introduce yourself to the forum.
Samuel D
Posts: 2894
Joined: 8 Mar 2015, 11:05pm
Location: Paris

Car battery charging from deep discharge

Postby Samuel D » 10 Nov 2019, 6:24pm

Sorry to bring cars into this fine cycling forum, but I don’t know anyone else to ask.

My girlfriend left the interior lamp on in our car while it was parked … for about two weeks.

A few attempts at bump-starting didn’t work, perhaps because I couldn’t get enough momentum in the space available in the underground garage. No downhill run was available. There wasn’t a flicker of life. Clearly no spark happening.

A garage nearby wants €30 to charge the battery or €60 to come and charge it in situ. Typical Parisian prices.

If I can get the thing started, would the alternator eventually fully recharge it? The web is a maze of obvious misinformation on this topic, but I’d need a week of digging to learn whose account to trust.

If so, I’ll look into jump-leads and the lend of a friend’s car.

Otherwise, what should I look for in a cheap charger to do the job? I’m willing to remove the battery and carry it home to charge it. This is the second time in a few years I’ve needed a charger so it might not be the last.

Thanks!

philvantwo
Posts: 764
Joined: 8 Dec 2012, 6:08pm

Re: Car battery charging from deep discharge

Postby philvantwo » 10 Nov 2019, 6:40pm

From past experience I'd say get a new battery.
[color=#FF0000][/color]

rotavator
Posts: 279
Joined: 6 Jun 2016, 9:50pm
Location: North Wales

Re: Car battery charging from deep discharge

Postby rotavator » 10 Nov 2019, 6:44pm

I would buy a charger, take the battery home, charge it up, return it to her car, start it up. Then, all being well, the alternator should keep it charged as normal. Unless there is actually another problem, like the battery is near the end of its life, or the alternator was failing to charge it properly before this incident, or current is "leaking away" when the car is stopped not just because of the interior light being left on.......

Carlton green
Posts: 552
Joined: 22 Jun 2019, 12:27pm

Re: Car battery charging from deep discharge

Postby Carlton green » 10 Nov 2019, 6:55pm

If you have a friend who will be happy to jump start from then that is the simplest way forward, beware that there are right and wrong ways to jump start. Detaching a battery from a car can have electrical complications - it would be my last resort but it’s still worth investigating.

60 Euros sounds a lot but garage time is expensive in most places ... if all else fails then there comes a time to ‘pay-up and look happy’.
Last edited by Carlton green on 10 Nov 2019, 7:03pm, edited 1 time in total.

Will
Posts: 192
Joined: 16 Jan 2007, 6:39pm

Re: Car battery charging from deep discharge

Postby Will » 10 Nov 2019, 6:56pm

I have been in a similar situation to you, though mine was caused by under use (too much cycling instead). I purchased one of these, and it worked really well:

https://www.halfords.com/workshop-tools ... mp-starter

All you need to do is connect it to the battery using the leads, switch it on and wait a minute, and then start your car. The car should run when it is switched off, and you can then take the car out for 30-60 minutes to charge the battery.

The good thing is that you do not have to rely on a second vehicle being available (as you do with jump leads). I still keep it in the boot of my car (and occasionally recharge it) it case of emergencies.

Note: There is probably a small charge still in the battery, and if you remove it from the car (in order to charge it) then you may experience problems with some of the electronic systems (such as the alarm).

Will

mercalia
Posts: 12812
Joined: 22 Sep 2013, 10:03pm
Location: london South

Re: Car battery charging from deep discharge

Postby mercalia » 10 Nov 2019, 7:15pm

philvantwo wrote:From past experience I'd say get a new battery.


yes likely one or more cells have had it. In the long run best get a new battery. You might be able to revive it temporarily but it then let you down some where out in the sticks ( has happened to me). lead acid batterys dont like being run down.

Samuel D
Posts: 2894
Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: Car battery charging from deep discharge

Postby Samuel D » 10 Nov 2019, 7:22pm

rotavator wrote:Unless there is actually another problem, like the battery is near the end of its life, or the alternator was failing to charge it properly before this incident, or current is "leaking away" when the car is stopped not just because of the interior light being left on.......

No other problems. The battery is a good Bosch bought in December 2016 to replace the factory battery.

Will wrote:I purchased one of these, and it worked really well:

https://www.halfords.com/workshop-tools ... mp-starter

Looks good but more than I’d like to spend. Is there anything cheaper if I can cope with slow charging from the mains?

Will wrote:Note: There is probably a small charge still in the battery, and if you remove it from the car (in order to charge it) then you may experience problems with some of the electronic systems (such as the alarm).

Even if the lamp was left on for two weeks? I’d have thought that would make the battery dead dead dead.

I installed the Bosch battery in 2016 myself with no ill effect, so I know the car (a 2009 Citroën C1 with minimal electronics) doesn’t mind having no power for a while. I think the ECU self-calibrates the injection and ignition timing from scratch and the radio forgets its stations. That’s about it. No alarm.

Samuel D
Posts: 2894
Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: Car battery charging from deep discharge

Postby Samuel D » 10 Nov 2019, 7:23pm

philvantwo wrote:From past experience I'd say get a new battery.

mercalia wrote:yes likely one or more cells have had it. In the long run best get a new battery. You might be able to revive it temporarily but it then let you down some where out in the sticks ( has happened to me). lead acid batterys dont like being run down.

Will a new battery come charged? I have a vague feeling the Bosch I got in 2016 needed charging. Can’t certainly remember.

rjb
Posts: 3636
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Car battery charging from deep discharge

Postby rjb » 10 Nov 2019, 7:38pm

Ive had a similar incidence and the battery was so low that a modern charger wouldnt work as it kept detecting a faulty battery. The solution was to connect another battery in parallel and start charging straight away. After 5 minutes you can disconnect the donor battery and the charger carries on as usual. An older non electronic battery charger will also work without using a 2nd battery but they are not so common these days. If you have jump leads and a friendly car nearby you should be able to get it started then run the engine to charge the battery. :wink:
New batteries come fully charged generally, ask before you buy if you are about to purchase one.
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

merseymouth
Posts: 1530
Joined: 23 Jan 2011, 11:16am

Re: Car battery charging from deep discharge

Postby merseymouth » 10 Nov 2019, 7:44pm

Hello Samuel, With an alternator, as all ccars since the 1960's have been fitted with, the system will not work unless a battery is at least 1/2 charged!
It is an anomoly of such systems, whereas an old fashioned dynamo would happily come into life on the turn of the starting handle.
Even Jump Starting it from another car won't sort it out, as stated to actually create and store electricity the alternator needs a reservoir of current.
It is quite common for hidden lights to drain a battery, boot light or under bonnet light, so folk can return from holiday to suffer the same fate as you.
Not enough power cranked out by dynamos, too many demands on modern cars, so alternator is what you are stuck with. TTFN MM

gbnz
Posts: 1688
Joined: 13 Sep 2008, 10:38am

Re: Car battery charging from deep discharge

Postby gbnz » 10 Nov 2019, 7:45pm

Samuel D wrote:
I installed the Bosch battery in 2016 myself with no ill effect, so I know the car (a 2009 Citroën C1 with minimal electronics) doesn’t mind having no power for a while. I think the ECU self-calibrates the injection and ignition timing from scratch and the radio forgets its stations. That’s about it. No alarm.


I hadn't driven the car for 13 months so sold it two weeks ago. A Citreon C1, c/w a tiny battery.

No issues jump starting it, but the battery was "dead" I.e. Insufficient power for the central locking and barely enough charge for the spark plugs (NB. Stalled on 3-4 occ's on the one mile drive to the garage, having to be jump started each occasion). Sold it to the garage, their inclination was simply to replace the battery (NB. I'd have thought your's would be fine, subject to a reasonable length drive afterwards)

merseymouth
Posts: 1530
Joined: 23 Jan 2011, 11:16am

Re: Car battery charging from deep discharge

Postby merseymouth » 10 Nov 2019, 7:50pm

Hi GBNZ, See above reply! I used to be a motor mechanic, but despair at modern rubbish. :twisted:
MM

User avatar
Mick F
Spambuster
Posts: 48241
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Car battery charging from deep discharge

Postby Mick F » 11 Nov 2019, 8:18am

We left the interior light on in our Clio when we went off on holiday.
We'd put it on in the carpark at Exeter airport to retrieve the tickets and passport etc as it was in the early hours of the morning .......and went off the Malta for a fortnight.

Flew back, walked to the car to find the central unlocking not working, so opened the doors with the key. No power whatsoever. Totally flat battery.

I walked over to the carpark attendant office and asked about someone to come and jump start us.
The chap said it happens all the time, and he'd be round in a jiffy.

Jump start battery across ours, and the car bust into life, and we drove the 60miles home.

The battery was fine. We had that car for many years afterwards, and had no battery issues at all.
Never left the interior light on again though! :lol:

So, to the OP, get a jump start from someone, and go for a drive.
Mick F. Cornwall

reohn2
Posts: 37920
Joined: 26 Jun 2009, 8:21pm

Re: Car battery charging from deep discharge

Postby reohn2 » 11 Nov 2019, 10:28am

Samuel D wrote:Will a new battery come charged? I have a vague feeling the Bosch I got in 2016 needed charging. Can’t certainly remember.

I'm fairly sure they do have enough juice in them to start the car at least,but you can always check with the supplier.
I future if you don't use the car for long periods I'd give it a 20min run weekly to keep things operational :wink:
-----------------------------------------------------------
I cycle therefore I am.

User avatar
mjr
Posts: 15032
Joined: 20 Jun 2011, 7:06pm
Location: Norfolk or Somerset, mostly
Contact:

Re: Car battery charging from deep discharge

Postby mjr » 11 Nov 2019, 11:12am

reohn2 wrote:
Samuel D wrote:Will a new battery come charged? I have a vague feeling the Bosch I got in 2016 needed charging. Can’t certainly remember.

I'm fairly sure they do have enough juice in them to start the car at least,but you can always check with the supplier.
I future if you don't use the car for long periods I'd give it a 20min run weekly to keep things operational :wink:

Just get a solar trickle charger and say no to pointless pollution creation.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.