Dead battery and a busted earth lead?

From CEM to VEM, from LED to lightbulb and more. If you have an electrical problem, like a broken info-centre, search for answers in this category. This is also the place to be when you expect the problem to be of an electrical nature...

Moderators: jifflemon, coyote1980, Rachel

Post Reply
User avatar
ladyforatey
480 Newbie
Posts: 30
Joined: Wed Aug 30, 2006 7:00 pm
Location: Nottingham

Dead battery and a busted earth lead?

Post by ladyforatey » Sun Oct 06, 2019 2:13 pm

Hello everyone,

I've been really quiet since my last post but in that time I've had my rear arches redone, some other work and a respray and Bunny is looking glorious. The only problem after all that was the dash gave up completely, but thanks to the brilliant guides on this forum I have taken the dash apart, replaced the little gear in the odometer, resoldered the connections and replaced the bulbs, (as well as nearly all the interior ones) which was looking like a job done well until I came to start her after a week stationary and the battery was drained. I've taken it out to charge it but found this in the battery tray which I'm guessing is the earth lead.

Image

Firstly, I know this connects somewhere here in the car but can someone point me to exactly where as I can't work that out. Also, does anyone know how I can fix the clamp?

Could the lead be the reason for the drained battery? Or is it more likely I've done something when removing/replacing the dash/interior bulbs?

I'm sorry if I'm missing something obvious but I've been working on the electrics for ages now and I'm losing the will. Any help would be gratefully received.

jifflemon
480 Is my middle name
Posts: 987
Joined: Sat Dec 17, 2016 11:03 am

Re: Dead battery and a busted earth lead?

Post by jifflemon » Sun Oct 06, 2019 3:25 pm

Quite simply, replace it.

have a read of my post here

Its quicker to simply replace earthing cables than try to replace them.

Cut the end off that cable, roll it up and slot it into a new clamp. Add extra earths for good measure.

User avatar
jamescarruthers
480 Is my middle name
Posts: 1617
Joined: Mon Jul 07, 2003 3:19 pm
Location: Cambridge

Re: Dead battery and a busted earth lead?

Post by jamescarruthers » Mon Oct 07, 2019 9:57 am

If I'm reading this right, you've found an EXTRA battery negative terminal?

After the original broke it looks like someone has added an replacement already  and this is what you disconnected from the battery and can be seen placed over the air filter box cover?‎

If thi‎s is the case, you can just chop off the original one as it isn't doing anything now. 

However, if you have a battery that is going flat you've got a problem with either the battery (old and in which case replace it) or with the charging system (check the charging voltage as a first check). There's a chance that the problem could be high resistance where the new one is connected to the body?‎

(handing back over to Jifflemon, who is an actual electrician)‎
1987 Volvo 480 ES, 507274, 217 - Red (Ness)
2001 Volvo C70 2.4T convertible (Olivolvo)
2008 Mini Cooper convertible (Mau)

Previous 480's:
J123 CFU -- ES
J449 MNL -- ES auto
D864 CPV -- ES
L691 JFC -- Turbo
F70 MNR -- ES
H858 FGV -- Turbo auto
E981 KHM -- ES (509849)

jifflemon
480 Is my middle name
Posts: 987
Joined: Sat Dec 17, 2016 11:03 am

Re: Dead battery and a busted earth lead?

Post by jifflemon » Mon Oct 07, 2019 3:48 pm

jamescarruthers wrote:
Mon Oct 07, 2019 9:57 am
If I'm reading this right, you've found an EXTRA battery negative terminal?

After the original broke it looks like someone has added an replacement already  and this is what you disconnected from the battery and can be seen placed over the air filter box cover?‎

If thi‎s is the case, you can just chop off the original one as it isn't doing anything now. 

However, if you have a battery that is going flat you've got a problem with either the battery (old and in which case replace it) or with the charging system (check the charging voltage as a first check). There's a chance that the problem could be high resistance where the new one is connected to the body?‎

(handing back over to Jifflemon, who is an actual electrician)‎
By golly James, think you're right - just re-read and studied he picture and yes, we've got an extra earth lead in place already.

Looking at the how it's connected is giving me some nervous twitches though - It looks like an 10mm bolt shoved through the braid and bolted up tight? If you follow that black cable, where does it go? Follow the braided one too....

The standard volvo one goes from the gearbox, bolts to the body and then into the battery clamp.

A missing earth wouldn't lead to a drain of the battery. I'd say there's a combination of standing battery and electrical testing. But, lets get this resolved before looking at that!

jifflemon
480 Is my middle name
Posts: 987
Joined: Sat Dec 17, 2016 11:03 am

Re: Dead battery and a busted earth lead?

Post by jifflemon » Mon Oct 07, 2019 7:38 pm

the more I look, the worse it gets....

Small brown wires fudged into the bolted connection... :shock:

Please sort this.... Its giving me the shivers!

Alan 480
480 Connoisseur
Posts: 877
Joined: Sun Aug 28, 2011 9:03 am
Location: Aberdeen

Re: Dead battery and a busted earth lead?

Post by Alan 480 » Mon Oct 07, 2019 10:01 pm

Surely best option would be to run the 'new' earth lead direct down to the gearbox mounting or direct to the side of body rather than simply clamping to a rather corroded section of braiding? I doubt if you'd ever get the braid 'properly' clean :cry:

assuming that the flexible flat braid still exists between the gearbox mount and chassis?

To be honest I'm not a fan of the flat exposed braided earthing. I'd rather that the lead from battery to chassis was a decent copper (within PVC) then a short round flexible from chassis to engine etc and ideally before installing the round briaded version give it a good coating of water expelling material (AKA grease to keep the corrosion at bay)

even a decent PVC earth strap will work if it is in a 'pig-tail' to absorb the vibrations?

the 'live' lead also looks as if it has been 'got at'? surely the car didn't leave the factory with those screwed in terminals? they'd have been soldered/crimped? (I can't comment as with 20+ year old cars no idea who/what/when modifications have been done)
Alan

480 ES 2litre x 2, C30 1.8ES, SS1

Post Reply