Battery problems now

macblack

Member
Joined
Jun 21, 2020
Messages
43
Reaction score
0
Points
6
Location
Merseyside
I came out to a flat battery last week, assumed it was just the short journeys (although I do 20 miles a day).

Breakdown guy said it’s the original battery and lucky it lasted this long (car is 2011). Took it out for a 30 min spin but then dead again (no low battery warning).

Got a new battery fitted on the drive (Halfords - yes I know :|). A week later the battery is dead again.

I’ve ordered a charger, but I’m concerned it’s either a) not being recharged properly b) something is draining the battery or c) the new battery is a dud.

Any advice on finding what’s wrong?
 

Carpo

Member
Joined
May 29, 2018
Messages
118
Reaction score
1
Points
18
Location
Bouce, France
You need to find out if its charging or not. I've got one of those cigarette lighter plug-ins that shows the voltage, you'll find them in your favourite car parts store. It should show around 12.6v for a fully charged battery (engine off, ignition on). Less than around 12.2v, the battery is not up to speed. When you start the engine the voltage should show around 14.7 which will indicate your alternator is OK. This should point you in the right direction for the least initial cost.
 

jberks

Well-known member
Joined
May 10, 2014
Messages
2,804
Reaction score
32
Points
43
Location
Leeds
Don't rely on the red charging indicator - I fell for that on my Dad's Merc. Wasn't charging at all, yet no warnings until it died.
I'd also check the red battery connector bolt behind the OS front wheel (behind the cover) as apparently that can fill with muck and corrode, leading to charging issues.
But yes, first basic check is what's the voltage when it's running. The go from there.
 

macblack

Member
Joined
Jun 21, 2020
Messages
43
Reaction score
0
Points
6
Location
Merseyside
OK thanks, the car is dead at the moment (central locking works, the infotainment system comes on and then goes off, there is no attempt at starting the engine).

When I came to start the car I noticed something odd which happened the last time the battery was dead and that was the brake pedal was really stiff? Does this indicate anything?

Also, I have a smart charger coming today with an AGM mode. Can I charge it by connecting the charger directly to the battery in situ? I think I read mixed views on this, just looking for real world experience...
 

jberks

Well-known member
Joined
May 10, 2014
Messages
2,804
Reaction score
32
Points
43
Location
Leeds
The brake pedal being stiff is perfectly normal and unrelated.
Yes you can connect the charger directly. They generally advise to connect the earth strap to the bodyshell rather than the battery directly but that's normal too. I've never removed a battery to charge as it shouldn't be necessary.
 

Lenticular

Member
Joined
Feb 18, 2011
Messages
243
Reaction score
0
Points
16
Location
Mid Wales
OK thanks, the car is dead at the moment (central locking works, the infotainment system comes on and then goes off, there is no attempt at starting the engine).

When I came to start the car I noticed something odd which happened the last time the battery was dead and that was the brake pedal was really stiff? Does this indicate anything?

Also, I have a smart charger coming today with an AGM mode. Can I charge it by connecting the charger directly to the battery in situ? I think I read mixed views on this, just looking for real world experience...

Yes, but only connect positive directly to battery. Connect negative to point where battery tie down is attached to body above the battery.
Get a fly lead to permanently attach in that way, and leave the end above the boot carpet
and you don't then need direct access to the battery.
 

macblack

Member
Joined
Jun 21, 2020
Messages
43
Reaction score
0
Points
6
Location
Merseyside
Sorry, I am a dumbass and know very little about this stuff, however needs must! I can see the two terminals but everything else is covered by trim. I can get to the positive terminal easily enough, and there is a metal loop on the left of the boot (I think for strapping luggage down??) can I use this for the negative?
 

Billy2Jags

Senior member
Joined
Mar 14, 2016
Messages
5,448
Reaction score
39
Points
63
Location
Midlands, UK
I use the stud to the side of the battery on the wheel arch, but you can use any metal that is attached to the vehicle body.
 

chris9369

Member
I Have Donated !
Joined
Jan 13, 2014
Messages
572
Reaction score
7
Points
18
Location
Wymondham, Norfolk, UK
Sorry, I am a dumbass and know very little about this stuff, however needs must! I can see the two terminals but everything else is covered by trim. I can get to the positive terminal easily enough, and there is a metal loop on the left of the boot (I think for strapping luggage down??) can I use this for the negative?
The tie-down loop is usually painted black so will not be a good point to use as an earth.
 
Top