Does anyone know the output of a C40 dynamo? Do you think I have will have enough output for some driving lights without up-grading to an alternator? I think the early MGBs had dynamos and factory fitted fog lights.
I'm sure some one has tried the question is did the battery go flat?
c 40 dynamo output
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RogerRust
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c 40 dynamo output
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MikeNash
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My BMC workshop manual says (at page n.4) that for the Lucas Model C39PV/2 dynos the output is 17 amps at 16 volts on a load of 0.8 ohms without regulator (total 272 watts). Presumably the C40 is equal or better. In practice, my C40 drove six 6 watt side lights inc number plate (36w), five 2.2w (11w) instrument lights, and two sealed beam headlamps of 60/45 w totalling 167w on mainbeam and 137w on dip. The ammeter showed the dynamo balanced it all at under 20mph when dipped.
I then fitted two fog lights each 55w (an additional 110w the lot balanced on dip at about 25mph with the total at 247 watt) and later an extra two spots each 55w (110w). To my surprise I had only a discharge of about 5 amps, and after while, presumably as the system voltage fell, we got a balance again - this for a total nominal consumption of 277 watt. The lights were glorious!
So go for it, and if you worry fit an ammeter. All this was done reliably without relays, the fogs taken off a sidelight bullet connection thro' a separate switch, and the spots permanently off a mainbeam bullet on the assumption that when you max light, you mean it. Regards, MikeN.
I then fitted two fog lights each 55w (an additional 110w the lot balanced on dip at about 25mph with the total at 247 watt) and later an extra two spots each 55w (110w). To my surprise I had only a discharge of about 5 amps, and after while, presumably as the system voltage fell, we got a balance again - this for a total nominal consumption of 277 watt. The lights were glorious!
So go for it, and if you worry fit an ammeter. All this was done reliably without relays, the fogs taken off a sidelight bullet connection thro' a separate switch, and the spots permanently off a mainbeam bullet on the assumption that when you max light, you mean it. Regards, MikeN.
Morris Minor, the car of the future. One day they will all look like this!
Lucas C40/1 (as fitted to the 1098) output is 22 amps at 2250 rpm dynamo speed. If you can get hold of one, the C42 dynamo is good for 27 amps. These outputs are quoted at 13.6v (battery voltage). The output you quoted is at 16v - off load - which is a theorectical maximum but of course in use you will not achieve it.
All the best - Nigel
All the best - Nigel
I used to run additional lomg range lights on my rally Minor - and on main beam both filaments were on in the special sealed beam 75/45 units I got at that time - I just tweaked up the regulator slightly and it worked ok. On the basis the extra lights won't be on very often - in fact it's rare to get on main beam for any time these days - you will be ok. Might be an idea to stick a new set of brushes in it. Really though - an alternator is the way to go.
