Classic charging

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norseman

norseman

Well-Known Member
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Essex - UK
I know this subject has been well covered but each case can be different, so may I impose on the vast experience of forum members?

Just fitted a brand new battery to my 3.5efi & thought it wise to check the charging rate, the figures below follow it's first run of approx. 25 miles following the battery replacement.

All power off except under-bonnet lamp. Output from battery terminals at both idle AND 2000rpm … variable between 14.14 & 14.16v
Exactly the same figures were obtained at the alternator terminal for the heavy brown wire.
The car has only recorded 57k in it's 31yrs years, so could well be the original genuine alternator.

Merry Christmas to all :)
 
If it's the A127 alternator the bits are cheap off ebay & not difficult to fit.
There's a few 'how to's' on various sites.

ETA IIRC check by taking for a short journey with everything off & on return leave running with everything off, (unplug your underbonnet light connector) raise rpm to 2-3000 & check battery volts. Should reach 14.4 as a minimum. Anything less suggests a voltage regulator fault.
 
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Ratae said:
If it's the A127 alternator the bits are cheap off ebay & not difficult to fit.
There's a few 'how to's' on various sites.

ETA IIRC check by taking for a short journey with everything off & on return leave running with everything off, (unplug your underbonnet light connector) raise rpm to 2-3000 & check battery volts. Should reach 14.4 as a minimum. Anything less suggests a voltage regulator fault.
Click to expand...
Earlier alternators had regulator set points of 13.8 volts or 14.2 volts, the voltage should be roughly the same off load to full load only dropping on an over load.
 
Many thanks for all the replies folks.
I'm not onto working on the car myself these days & with a 31 year old alternator (I'm thinking of bearing wear etc.) maybe a new unit would be the best long-term solution? In that event, as the car does such little annual mileage & I cannot charge the battery without removing it from the car, would there be any advantage in fitting a higher output alternator?
 
norseman said:
Many thanks for all the replies folks.
I'm not onto working on the car myself these days & with a 31 year old alternator (I'm thinking of bearing wear etc.) maybe a new unit would be the best long-term solution? In that event, as the car does such little annual mileage & I cannot charge the battery without removing it from the car, would there be any advantage in fitting a higher output alternator?
Click to expand...
A standard alternator should do the job if it has the higher charge voltage. I would fit a remote charging point to keep the battery topped up as no matter how big the alternator is it will never fully charge the battery unless you do long runs. I keep mine topped up via the 7S caravan connector.
 
I had diode pack fail on mine last year & considered just renewing the diode pack & voltage regulator but then gave the same consideration as you. I'm fortunate in that I have an alternator/starter motor/etc overhaul specialist nearby who I've used for years & got one from them.
Interestingly the voltage output on my old one was fine on their test rig but the diode pack had gone. The regulator is very easy to replace - its 3 retaining bolts are very small headed - but the diode pack requires some dismantling & soldering work with a big iron.

If it's very low mileage & seldom used then you might want to consider fitting a battery isolator.
On vehicles with a lot of electrical gadgetry that would need resetting after a battery disconnect that may not be an option due to being a PITA.
As I only have to reset the clock & reprogram the radio channels that's the option I went for.

Can't really see the benefit of an uprated alternator unless you have a lot of extra electrics fitted.
I've said elsewhere that the purpose of the alternator is to power the vehicle electrics & top-up a good charged battery. Repeated attempts to charge a deeply discharged battery is not good for either battery or alternator. https://www.optimabatteries.com/en-...nators-are-not-designed-charge-dead-batteries.

I do put mine on a charger from time to time on the car but I only need to run an extension cable to do so & as said, have the isolator fitted so don't need to undo a battery terminal.
 
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Its the amps that you really need to know, iy can give 14v but low amps usually due to bad earths. Common faults I have seen have been poor earth cables on the battery and other stuff, take them off clean connecting services and re fit, I have had one perfect looking braided earth strap that wouldn't pass current as the centre was badly corroded but externally perfect, I swapped it for a traditional earth wire from a Nissan.
I use a £12 Aldi intelligent charger very happy with it
 
winchman said:
Its the amps that you really need to know, iy can give 14v but low amps usually due to bad earths. Common faults I have seen have been poor earth cables on the battery and other stuff, take them off clean connecting services and re fit, I have had one perfect looking braided earth strap that wouldn't pass current as the centre was badly corroded but externally perfect, I swapped it for a traditional earth wire from a Nissan.
I use a £12 Aldi intelligent charger very happy with it
Click to expand...
The Aldi and LIdl chargers are very good, and for £16 cannot be beaten.
 
Interesting replies, giving me options.
By 'little use' I mean the car gets a run (min 20miles) at least every couple of weeks in winter, with more regular use in summer as I take it to classic car shows. Despite these less than ideal circumstances the two standard 72 AH batteries I've bought from my local factor have each lasted at least 5 years, bearing in mind it now looks like the alternator may have been losing some of it's poke for a while now. The car parks close to my home, but it is impractical to connect to a power supply for charging. Taking on board all the advice offered & applying it to my circumstances my best bet would seem to be replacement of the alternator with a standard spec. unit, together with a check of all connections (earths etc.) Any advice on source's for best value for money units (not the cheapest) would be appreciated.
Thank you all again.
 
norseman said:
Interesting replies, giving me options.
By 'little use' I mean the car gets a run (min 20miles) at least every couple of weeks in winter, with more regular use in summer as I take it to classic car shows. Despite these less than ideal circumstances the two standard 72 AH batteries I've bought from my local factor have each lasted at least 5 years, bearing in mind it now looks like the alternator may have been losing some of it's poke for a while now. The car parks close to my home, but it is impractical to connect to a power supply for charging. Taking on board all the advice offered & applying it to my circumstances my best bet would seem to be replacement of the alternator with a standard spec. unit, together with a check of all connections (earths etc.) Any advice on source's for best value for money units (not the cheapest) would be appreciated.
Thank you all again.
Click to expand...
If the car is parked in the open or inside with a safe exterior place, a solar panel will keep the batteries in a good state of charge, I have solar panels charging our old cars and the Transit.
 
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