I have never said 14.8 is correct for a P38, I have said that up to 14.8 is OK with lead calcium batteries. I've never seen even 14.5 on a P38 but it wouldn't worry me if the alternator is OK.

Somebody thinks you did. See posts 17 and 18. The poster is post 17 attributes the comment to you. Then in post 18 you attribute it to me. Maybe he has misread a discussion on calcium batteries. :);)
 
Ran it all day yesterday with a multi meter connected so I could watch it while driving..
It seems to charge at 14.2/14.5 after start up then settles back to 13.8 and slowly drops as I drive. Was reading about 12.25 V when I switched off last night. Switching headlights on dropped the voltage a couple of points.
It does seem to be dropping slowly. Very difficult to get it tested properly here.
 
Ran it all day yesterday with a multi meter connected so I could watch it while driving..
It seems to charge at 14.2/14.5 after start up then settles back to 13.8 and slowly drops as I drive. Was reading about 12.25 V when I switched off last night. Switching headlights on dropped the voltage a couple of points.
It does seem to be dropping slowly. Very difficult to get it tested properly here.
So as said many times, the alternator is fecked. The voltage should remain pretty constant.
 
Ran it all day yesterday with a multi meter connected so I could watch it while driving..
It seems to charge at 14.2/14.5 after start up then settles back to 13.8 and slowly drops as I drive. Was reading about 12.25 V when I switched off last night. Switching headlights on dropped the voltage a couple of points.
It does seem to be dropping slowly. Very difficult to get it tested properly here.

Change rate should be high just after start up. Then drop off as battery is replenished but rise when headlamps are on to balance drain.
 
Change rate should be high just after start up. Then drop off as battery is replenished but rise when headlamps are on to balance drain.

Thats exactly what I thought......Datatek says it should be constant yet in another thread agrees that it changes....
It was sitting on 12.4 this morning after being stood overnight. Started first touch and charged at 14.2 then slowly dropped back as the engine ran....it really seems like its working ok but trying to find somewhere to fully test it tomorrow.
In the meantime Im running it locally to see what it does.....will check out the headlights on running too.
This car has given me so many problems....I must like it or I would never have stuck with it!!
 
Thats exactly what I thought......Datatek says it should be constant yet in another thread agrees that it changes....
It was sitting on 12.4 this morning after being stood overnight. Started first touch and charged at 14.2 then slowly dropped back as the engine ran....it really seems like its working ok but trying to find somewhere to fully test it tomorrow.
In the meantime Im running it locally to see what it does.....will check out the headlights on running too.
This car has given me so many problems....I must like it or I would never have stuck with it!!

Each cell is 2.1 volts so a charged battery after being stood and rested for a while should be 12.6 volts. 12.4 is not shabby as EAS systems and alarm systems will have been active over night. But if battery voltage drops below 12.00 at any time you have a battery problem or a system current draw problem. Battery needs shunt testing first of all to establish it's condition. I have had brand new batteries drop a cell or go weak within a couple of weeks of first usage.
 
Thats exactly what I thought......Datatek says it should be constant yet in another thread agrees that it changes....
It was sitting on 12.4 this morning after being stood overnight. Started first touch and charged at 14.2 then slowly dropped back as the engine ran....it really seems like its working ok but trying to find somewhere to fully test it tomorrow.
In the meantime Im running it locally to see what it does.....will check out the headlights on running too.
This car has given me so many problems....I must like it or I would never have stuck with it!!
The alternator voltage should be fairly constant, that's what the regulator is for, it's the current that changes as the battery voltage rises towards regulator set point reducing the potential difference between battery and alternator. When battey voltage reaches alternator set point there will be virtually no charge current. Alternator voltage should only drop as full load is approached.
Battery should not be below 12.4 after resting overnight.

At no time when the engine is running should the alternator voltage be below the regulator set point unless the load is more than the rated output of the alternator.
 
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The alternator voltage should be fairly constant, that's what the regulator is for, it's the current that changes as the battery voltage rises towards regulator set point reducing the potential difference between battery and alternator. When battey voltage reaches alternator set point there will be virtually no charge current. Alternator voltage should only drop as full load is approached.
Battery should not be below 12.4 after resting overnight.

At no time when the engine is running should the alternator voltage be below the regulator set point unless the load is more than the rated output of the alternator.

OK......The battery isnt below 12.4 overnight. I understand its the charge current Im measuring but if the alternator isnt working surely there would be nothing to measure?
May have located a place to test/repair it in the morning...Im happy to put a new alternator on it if it really is the problem- It runs for days with no problem... lights on makes no difference...then suddenly dies. I would rather get it right here than have problems in the middle of Serbia in a day or 2.:)
 
OK......The battery isnt below 12.4 overnight. I understand its the charge current Im measuring but if the alternator isnt working surely there would be nothing to measure?
May have located a place to test/repair it in the morning...Im happy to put a new alternator on it if it really is the problem- It runs for days with no problem... lights on makes no difference...then suddenly dies. I would rather get it right here than have problems in the middle of Serbia in a day or 2.:)

Many a time re facing the slip rings and fitting a new controller sorts alternators.
 
Many a time re facing the slip rings and fitting a new controller sorts alternators.
+1, and it's not uncommon for semiconductors to become heat sensitive, failing as temperature rises and recovering when cool. The diode pack has 6 or 7 diodes plus you have the regulator components.
Badly worn brushes can also cause intermittant problems.
If you are going to Serbia, a spare alternator wpouldn't go amiss.
 
+1, and it's not uncommon for semiconductors to become heat sensitive, failing as temperature rises and recovering when cool. The diode pack has 6 or 7 diodes plus you have the regulator components.
Badly worn brushes can also cause intermittant problems.
If you are going to Serbia, a spare alternator wpouldn't go amiss.

Driven it for many miles today and it does seem to be a heat related issue....found a guy who does this sort of work and seeing him tomorrow morning.
Coming home(to hotel!) tonight it was showing 12.45 but 12.23 with lights on....My next escape ship is Wed at 13.00 so must surely get to the bottom of it by then...I hope
 
The alternator was checked out by an "expert" ..no faults found. Later in the day it stopped charging completely :-(
Waiting for one to arrive by DHL...they wanted 700E for one here....and we should be on our way on the Friday ferry...
Thanks all.
 
The alternator was checked out by an "expert" ..no faults found. Later in the day it stopped charging completely :-(
Waiting for one to arrive by DHL...they wanted 700E for one here....and we should be on our way on the Friday ferry...
Thanks all.
Hope you didn't pay for the Alternator test by this expert!
 
The alternator was checked out by an "expert" ..no faults found. Later in the day it stopped charging completely :-(
Waiting for one to arrive by DHL...they wanted 700E for one here....and we should be on our way on the Friday ferry...
Thanks all.
Some expert:rolleyes:
You would have saved time and money if you listened.
 
Yep, determined to do things the hard & expensive way.:D

Thats bollox! I did it the only way I could. Its ok for you to sit there and say "I was right" but there was no sign of you being right when the car was running and tested. Also they say they cant repair them here.....you and I know thats not the case but life isnt the same here as in the UK and if they wont repair it or order parts what can I do?
In the uk you just pop round the corner and get what you need. It isnt like that here and if you grasp that fact you will easier understand why I had to go this route.
Im not without some knowledge of these things having been in the trade most of my life and have made a good living from rebuilding Smart engines and repairing the cars....they also have quite a complicated electronic system so dont be talking to me like Im a schoolboy. Thanks for your input. Adios
 
Hope you didn't pay for the Alternator test by this expert!

No, didnt pay but to be fair it didnt show any faults when he tested it....Big workshop doing only auto electrics so he might have a bit of knowledge.
Im hoping it will be good to go tomorrow.
Thanks
 

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