Club 80-90 Forums

So when you got my van a few months back it was not charging and was diagnosed as bad alternator. New alternator and now getting 13.6v at idle cold, however when hot this drops to 13.4v. Hot and it's struggling to start hot and the battery is not charging on a run which then makes the hot start even more difficult. I'm going out with a spare charged battery and a jump pack and jump leads now!
I stick the Batt on a charger when I get home, so it's always fully charged again.
I'm guessing bad cables somewhere? Any suggestions

I do the foot to floor hot start proceedure, it starts OK especially with the fresh battery, it just struggles when hot.

The charge voltage should be a minimum of 13.8V at the battery or it will not fully charge. Check the connection where the alternator cable connects to the starter motor is clean.

I believe this is what the mechanic did which got it up to 13.6v from 12.8. So I'm imagining replacing the cables is going to be required, any idea roughly how long and what spec or does somebody make uprated ones ready made?

asterix_the_gaul wrote:I believe this is what the mechanic did which got it up to 13.6v from 12.8. So I'm imagining replacing the cables is going to be required, any idea roughly how long and what spec or does somebody make uprated ones ready made?

Cleaned the connection or replaced the alternator?

You know, I have no idea about the alternator on a van but my regulator for my car is set for around 14.4v.

13 point anything seems rather low - is that normal? Can you check the voltage produced on the alternator directly?


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I’m not sure about air cold, but on the water cooled petrols the short lead tween the alternator and the starter is a known problem , it deteriorates and often goes high resistance , rots internally with the constant hot cold hot cold of being just above the zorst . Often just replacing that one cable can solve the low voltage to the battery issue , and the slow starter motor when hot problem ....

Alternator or wiring?

Easy to establish
Take a voltage reading at the alternator ( using the casing as neg ) with engine off
Then again with engine running
If you have a difference of more than 0.5v between those readings and the readings at the battery it’s connections or wire fault
If it’s no different ( ie less than 14v at alternator it’s brush pack or alternator)

Brickwerks regulators are 14.2 volts

kevtherev wrote:Brickwerks regulators are 14.2 volts

Apart from the 14.5v ones
https://www.brickwerks.co.uk/voltage-re ... 14-5v.html" onclick="window.open(this.href);return false;

Mocki wrote:

kevtherev wrote:Brickwerks regulators are 14.2 volts

Apart from the 14.5v ones
https://www.brickwerks.co.uk/voltage-re ... 14-5v.html" onclick="window.open(this.href);return false;

Yeah it says that.. but in practice..

I found that the 14.5v one gave me 14.3v which is still better than the 13.8v offering.

So, an update, paid an auto electrician to come out and check and replace wiring as you guys advised would probably be the problem as most garages I have asked shyed away when I have said the word electrical or booked up for weeks, I'm off tomorrow for a long weekend in the van so want it fixed quick

Anyhow, auto electrician agreed that the wiring connections were bad onto the starter motor but it was so rusted on the nut that he'd likely snap it if he tried to replace it so told me to get a new starter motor.

It appears in the hour 15min of diagnostics(with an analogue voltmeter?!) he charged me for he didn't test the battery : I swopped out a brand new battery and hey presto 14v. So the battery looks like it had a tired or dead cell which would be most Of The issue.
Voltage drops to 13.5v with headlights on however so ideally need to look at the corroded wiring.
I'm going to see if I can get a look at this rusted nut and see if it can be soaked and eased off, what gauge and length wire and connections am I going to need? I see brickwerks do the alternator plug..

soak it with plusgas for a couple of weeks daily beforehand and clean the threads you can get to with a fine wire brush .....

just a side note,
the lower the battery voltage you start the test with the bigger the difference you will see if the connections or wire is the fault , so a fully charged battery will give you nicer readings

Even with a brand new 096 battery it's still playing up, it's sometimes giving much lower voltage, 12.5 -12.8 and that was from cold, been soaking the starter connection nut with plusgas so hopefully that can be got off. What gauge cable should be used to replace? There's the one cable alternator to starter, what delivers the power is it that one? I don't quite understand how the current gets from the battery to the starter motor

The power to the starter comes from the battery !
The big fat wire from the battery travels under the van to the starter , where it joins onto the starter solenoid along with the not so far wire from the alternator

That connection on the starter solenoid if it’s corroded and rusty and manky is the o ly connecruon between the alternator and the main battery , so if you are loosing charge voltage it will either be that connection or the wire

You need to get a multimeter ( digital or moving needle ) and take some readings to find your problem
It’s Easy to establish
Take a voltage reading at the alternator ( using the casing as neg ) with engine off - take a reading at the battery with engine off , compare them .
Then again with engine running
If you have a difference if more than 0.5v between the alternator and the readings at the battery it’s connections or wire fault
If it’s no different ( ie less than 14v at alternator it’s brush pack or alternator)

I’m your case also take a set of readings at the starter solenoid




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