JRo · Nov 12, 2023

Hi all,

As the title suggests, Earth and electricity newbie here.

Question: does temperature affect earthing?

Context: Been having some issues recently. I’ve cleaned up some of the earth connections and relays (previous owner installed loads), most of the problems with lights etc are better but the starter still needs a jump first thing. After that she’ll start first time all day.

Any advice/ideas very welcome.

Thanks

kermit_rr · Nov 12, 2023

What do you mean exactly, it needs a jump?
The cold will affect a battery hugely, is it's not in top condition then it can struggle to start a car

steve2286w · Nov 12, 2023

It’s worth cleaning up all the connections on/ near the starter motor you will be surprised the difference it makes, warm engines start easier , is the battery good

kermit_rr · Nov 12, 2023

Cold engine means cold, thick oil, harder to pump round the engine, harder to blow through bearings.. means more cranking effort required

Anaconda · Nov 12, 2023

Or maybe the starter is faulty.
The 2a had the same issue, starter would be very slow or nothing first try. Once it was going it would be fine for rest of the day, new one fixed it.

JRo · Nov 13, 2023

Thanks for jumping in everyone. I’ve tested the battery, seems in good shape. Sounds like it’s probably the starter - I’ll clean up the connections and go from there.

WoodyO · Nov 13, 2023

Tested how and for what? Voltage isn't necessarily an indication of a good battery.

kermit_rr · Nov 13, 2023

WoodyO said:
Tested how and for what? Voltage isn't necessarily an indication of a good battery.

voltage drop during cranking can be an indication of health

JRo · Nov 13, 2023

steve2286w said:
It’s worth cleaning up all the connections on/ near the starter motor you will be surprised the difference it makes, warm engines start easier , is the battery good

Will try that, thanks. Would a warmer engine be more forgiving to earthing issues?

JRo · Nov 13, 2023

kermit_rr said:
voltage drop during cranking can be an indication of health

WoodyO said:
Tested how and for what? Voltage isn't necessarily an indication of a good battery.

The nice man at Halfords got his testing kit out and assured me it’s not the battery. This was a month or so ago and I’ve since installed an isolator switch thinking something was drawing pre ignition. Pretty sure it’s the starter or earth.

kermit_rr · Nov 13, 2023

bad connections/bad earths can mean higher resistance in circuits, which mean less amps to do the required job.
a hot engine will need less power (amps) to the starter
a bad connection has higher resistance, which is why it will heat up, sapping more of the available power

kermit_rr · Nov 13, 2023

JRo said:
The nice man at Halfords got his testing kit out and assured me it’s not the battery. This was a month or so ago and I’ve since installed an isolator switch thinking something was drawing pre ignition. Pretty sure it’s the starter or earth.

in my experience, the average halford man is lucky to get kit connected to the right car, never mind tell you a battery is good or not.. their threshold is rather low

JRo · Nov 13, 2023

A further question - the earth from the battery, to the trans has a 2inch exposed section. Guessing that’s meant to be clamped to the chasis? It’s currently hanging free, collecting road juice.

JRo · Nov 13, 2023

kermit_rr said:
in my experience, the average halford man is lucky to get kit connected to the right car, never mind tell you a battery is good or not.. their threshold is rather low

Ha! I’m choosing to have faith in Gerald. For now.

CohPC · Nov 13, 2023

kermit_rr said:
in my experience, the average halford man is lucky to get kit connected to the right car, never mind tell you a battery is good or not.. their threshold is rather low

The average worker in halfords probably couldnt work out how to open the bonnet on a series - he'd spend half an hour looking for the bonnet release under the dash

JRo · Nov 13, 2023

kermit_rr said:
bad connections/bad earths can mean higher resistance in circuits, which mean less amps to do the required job.
a hot engine will need less power (amps) to the starter
a bad connection has higher resistance, which is why it will heat up, sapping more of the available power

Makes a lot of sense. Thanks Kermit!

JRo · Nov 13, 2023

CohPC said:
The average worker in halfords probably couldnt work out how to open the bonnet on a series - he'd spend half an hour looking for the bonnet release under the dash

This is almost verbatim. When I told him the battery was in the back, he nearly choked on his chuppa chup.

boguing · Nov 13, 2023

kermit_rr said:
bad connections/bad earths can mean higher resistance in circuits, which mean less amps to do the required job.
a hot engine will need less power (amps) to the starter
a bad connection has higher resistance, which is why it will heat up, sapping more of the available power

A curious side effect of a loose connection heating up is that it can sometimes improve the conductivity by closing the gap. That's what may be going on here.

boguing · Nov 13, 2023

JRo said:
A further question - the earth from the battery, to the trans has a 2inch exposed section. Guessing that’s meant to be clamped to the chasis? It’s currently hanging free, collecting road juice.

I don't think so, I can't remember how the chassis gets earthed, it's five years since I did my Lightweight and ten since I had these problems on an SIII, but I'm pretty certain that each earth strap only does one job.

Anaconda · Nov 13, 2023

Ours had an earth strap going to the chassis near the starter motor, might have been on the starter mount bolt.
Why is you battery in the back, what Series have you got?

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