PV headlamps

[morwenna240]

Guys, it’s a 12 v dynamo! But yes, Ron, I will investigate first, before going out on a 200 mile night trip, a dying after 60 miles. . .
I did have alternator failure on the 240, 50 miles out, in dark. Battery got us home, just on side lights an coil.

[Laird Scooby]

Originally Posted by morwenna240

Guys, it’s a 12 v dynamo! But yes, Ron, I will investigate first, before going out on a 200 mile night trip, a dying after 60 miles. . .
I did have alternator failure on the 240, 50 miles out, in dark. Battery got us home, just on side lights an coil.

If it's a Lucas C40 dynamo, you should be able to substitute an ACR series alternator. By extension, you could use an A127 instead (more modern design, same style of brackets) which would give a much higher output.

In addition to what Ron has correctly quoted about the current consumed by the 145/100W halogen bulbs, have you considered the switchgear was only designed to cope with ~8A (@12V) for the headlamps? You're at least tripling that on dipped beam (145W Vs 45W) so your switches won't last long!

A better option would be an LED option from this :

https://www.classiccarleds.co.uk/sea...prefix%5D=last

Current @12V (12-14V) nominally would be in the region of 2.0-2.5A each but give superior light output even to a standard 60/55W halogen. There is an option of "Warm White" to preserve the "classic" look if that is your hearts desire but whichever you choose, it would be kinder to your switchgear and electrical system in general. No problem with legality either, cars older than 1986 aren't subject to the ridiculous laws on LED headlamp bulbs.

If you explore that site i linked to, you'll find they do complete car kits to upgrade to LEDs, much kinder to your electrical system in general and much more reliable than filament bulbs. Alternatively, give them a call, it's a freephone number and Duncan is very knowledgeable and helpful.

Disclaimer - i'm in no way affiliated with Classic Car LEDs but have used them many times and always had excellent service and reliability from their products. Don't be tempted by the cheap Chinese stuff on ebay, they design their LED bulbs to run on 12V at maximum current. This means that with the alternator (or even dynamo) running, more than 12V is supplied, normally above 13.8V resulting in seriously excessive current (~50% over maximum) through the LED element and the premature failure of the LED or flickering on/off or both!

[morwenna240]

That’s all very interesting, thank you. I have replaced the stock switch with one for tractors, as mine died. I did strip the latter, an found it to have quite beefy internals, but I couldn’t at the time repair it, as it involved “unrivetting” various bits, an needed lights the next day. I shall return to it, as is a nice switch an is original.
I NEVER buy Chinese, for, with a few exceptions, is always very low grade rubbish, complete waste of materials as should never have been made, particularly not in these times. As for china itself. . .
Alternator fitting being investigated, in interests of long term reliability, anyway. Tho, a healthy dynamo is good kit, but I worry about the control box thing, when on the Continent. The car is the only classic I’d trust as an everyday driver, seen so many Brit classics of the period on tow trucks or by side of rd. I asked an RAC chap what is commonest fail point in moderns, he said “ the computer says no!” Cheers.

[Laird Scooby]

Originally Posted by morwenna240

Alternator fitting being investigated, in interests of long term reliability, anyway. Tho, a healthy dynamo is good kit, but I worry about the control box thing, when on the Continent. The car is the only classic I’d trust as an everyday driver, seen so many Brit classics of the period on tow trucks or by side of rd. I asked an RAC chap what is commonest fail point in moderns, he said “ the computer says no!” Cheers.

You can do away with the regulator (control) box if you convert to an alternator.
The troble with so many British classics is that people remember then when new and were sent for servicing and were generally reliable. Now when those simlar/same people own a classic, they look at a modern service schedule which in many cases is simply oil/filter change (if you're lucky!) and think the same applies to a classic. That leads to plugs, points, condenser, timing etc being neglected which can cause rough running/breakdowns and in some cases, severe overheating. Couple that with the fact many people don't even look at the coolant level which on a non-sealed system such as the majority of British cars pre 1990 ish and that's another recipe for overheating/breakdowns.

I think you see where i'm going with this..........

As for moderns, my most modern car is 2002 Honda CR-V and that has more computing power than the 1969 Moon mission at NASA. Come to think of it, so has my mobile phone! Put that into a harsh environment in a car and it won't remain reliable for long!

[morwenna240]

The dynamo seems to cope with 145w main beams. On switching on lights, ammeter goes up to max then drops to 25 amps.

[Laird Scooby]

Originally Posted by morwenna240

The dynamo seems to cope with 145w main beams. On switching on lights, ammeter goes up to max then drops to 25 amps.

The 145W is the dipped beams which are always more powerful to give extra light output because the reflector/lens design restricts light output.

Either way, most dynamos of the era your car is will be a maximum of 22A and if you're pulling a genuine 25A from it then it'll burn out in fairly short order, not to mention leaving nothing to charge the battery.
The reason the ammeter shoots past 25A at first is because the control regulator is trying to maintain the voltage, when it can't do this, it maintains maximum current instead.

You'll have to do that alternator conversion sooner rather than later or switch to LED hedlamp bulbs as i suggested before.

[morwenna240]

Yes, realised an agreed. Thank you.

[Derek UK]

145w is mains. First number is always mains. High watts need for distance and lesser needed for dip as it is pointing down. Lens pattern defines the dip pattern. Original PV lamps were symmetrical and relied mostly on the filament position to change the beam angle.
Perhaps stick to 60/55. LEDS legal pre 1986 so you could go down that route but you still really need an alternator for them.

[Ron Kwas]

LS;

I must take issue with a couple of statements you have made...

"dipped beams which are always more powerful" ...that is not consistent with the wattages given for main (45) and dipped (40) beam in for instance, this factory wiring diagram for an 1800: http://www.sw-em.com/Wiring_Diagrams...Wiring_Diagram

"dynamos of the era your car is will be a maximum of 22A" ...Bosch dynamos installed on Volvos were rated for 14V30A, and while this is at optimum measuring conditions (new brushes, clean commutator, elevated RPMs), drawing a momentary max of 25A falling to something less continuously will not kill the Dyn, but operating it at the max it can give for the long term is not doing the Dyn any favors either...

I do agree that installing lighting with a much higher electrical load will tax the stock Chg Sys to possible failure...not to mention the wiring and components all would need to be checked if suitable...

Cheers

[Laird Scooby]

Originally Posted by Ron Kwas

LS;

I must take issue with a couple of statements you have made...

"dipped beams which are always more powerful" ...that is not consistent with the wattages given for main (45) and dipped (40) beam in for instance, this factory wiring diagram for an 1800: http://www.sw-em.com/Wiring_Diagrams...Wiring_Diagram

"dynamos of the era your car is will be a maximum of 22A" ...Bosch dynamos installed on Volvos were rated for 14V30A, and while this is at optimum measuring conditions (new brushes, clean commutator, elevated RPMs), drawing a momentary max of 25A falling to something less continuously will not kill the Dyn, but operating it at the max it can give for the long term is not doing the Dyn any favors either...

I do agree that installing lighting with a much higher electrical load will tax the stock Chg Sys to possible failure...not to mention the wiring and components all would need to be checked if suitable...

Cheers

You missed one important word when you quote me Ron "Most" - i said "Most dynamos" meaning it was a generalisation. I was vaguely aware some models may have had higher output dynamos but they're not commonplace on all the machinery i've seen.
To enlarge on your point, the ammeter indicated a constant 25A so even on a 30A dynamo, this only leaves 5A to charge the battery and cover everything else which it won't do. May just about cover on a good day if you're lucky but won't replace what's been taken out during starting.

Unless i got it wrong when i checked a bulb to determine the current through the dipped beam filament (60/55W halogen, very many moons ago) then the larger number first is the dipped so it reads dipped/main for the reasons i cited above, that some of the light output is masked by the deflector present in H4 bulbs under the filament (not normally present in P43t 45/40 basic tungsten filament bulbs) and also by the reflector pattern and also the lens deflecting the light.