Author Topic: Fitted 60W Halogen, dynamo then moved!  (Read 365 times)

Offline t20racerman

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Fitted 60W Halogen, dynamo then moved!
« on: 23.10. 2017 12:02 »
Hi

Anyone else run a 12V system with 55/60W Halogen headlamp for long? Possibly a coincidence, but I uprated my headlamp to a H4 halogen a week or two ago. Ridden a fair few miles without  the headlamp on much, but then went for a 20 mile ride yesterday with lights on.... and the dynamo slipped round so that the belt drive became too loose to spin it!

Did I just not tighten up the dynamo strap enough in May when I changed a (20 year old) snapped belt? Or could those extra watts of light really have caused too much strain? Personally, I think it very unlikely its the 55Wdip, but thought I'd ask....

Incidentally, for the record, its an SRM belt drive, that keeps the ammeter at or above zero at only 1800rpm, and the dynamo was rebuilt with nice new bearings a couple of years ago, so its not that, as it still spins nicely now.

Adrian
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
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Offline t20racerman

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #1 on: 23.10. 2017 14:14 »
I've been in the garage investigating, and my dynamo strop locknut wasn't as tight as I'd have expected - so 'problem' solved. I do wonder how it became loose though - its never happened before. Perhaps its been like that since when I changed the belt, and the extra oomph needed to power the H4 was just enough to make it move? Hard to say. but a little embarrassing nonetheless!  *red*

Will now have a two-nut locking system on it!

1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Online groily

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #2 on: 23.10. 2017 17:13 »
I've run 55/60W up front, 12v, for long periods on one bike, and not had problems with overloading or with the drive train (but that bike is steel-gear-driven not belted).
However, that was always using original spec armature and field, ie the '6v' versions, which are heavier gauge but need more revs to cut-in (as has often been discussed). DVR2 regulator in recent years, prior to that a JG unit after they were launched way back when.

The only time I ever converted to '12v' bits (UK-made, so not crap parts in theory) also with a DVR2 - it threw the solder off at the commutator after not many months with 'just' a 45/40W halogen. With tail & speedo (no LEDs) it was being asked to deliver 80%+ plus of its current rating all the time - bit too close to the limit maybe, or I was just unlucky. That machine now runs '6v' parts at 12 and hasn't had any further problems. Lately it's been running an LED up front so the dynamo is a pretty idle beast - but that will have to change for winter if I want to see anything before I hit it as the LED version I have isn't any good.

On my A, I have had occasional belt/pulley slippage troubles over the years. The SRM kit did quite well but died in the end (lost its fit on the taper on the driving pulley after slippage). The Dyn Regulators kit that is now fitted seems bullet proof so far, even with an extra 35W of 'Hot Hands' on the 'bars and a total load therefore of around 75-80W continuous on occasion. Wider belt and easier to get on and off too owing to provision of threaded holes for extraction.

So I'd say the loads you mention shouldn't be a problem, but there's nothing quite as unpredictable as an old bike (except the memsahib of course).
Bill

Offline u28909z

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #3 on: 23.10. 2017 17:23 »
Hi

Just to back up what Bill says, I run an original E3L 6volt dynamo at 12Volts on a Triumph, and that copes well with a full fat halogen headlight, and has done for some years. It is even ok on a K-Tech control unit which I know have not had the best reviews in the past, but have worked just fine for me.

Arthur
Arthur

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #4 on: 23.10. 2017 17:38 »
Using a 6V dynamo with a 12v solid state regulator was fine until the solder on the commutator melted. This happened more than once. Since then I invested in a proper silver soldered 12v spiral-wound armature and field coil (made in USA) and have had no further problems.
I stick to a 50/40W BPF bulb which is very effective plus an LED stop/tail. That should keep the loading to something sensible. It's not a good idea to run a dynamo near max output all the time. 
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Online JulianS

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #5 on: 23.10. 2017 19:05 »
Similar positive experience using 55/60 H4 and 6 volt armature and field coil and JG regulator. Did many years shift work commuting with the setup. Only real problem was short life of speedo bulb until it was replaced by an LED.

Now there are a number of high output 35/35 HS1 bulbs which just need the top locating tongue thinning to fit an H4 light unit. I now use an Osram Night Racer 35/35 which gives excellent light intensity and pattern using an original "old" Lucas H4 flat headlamp (found the "new" Lucas H4 domed units have a poor beam pattern)

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Re: Fitted 60W Halogen, dynamo then moved!
« Reply #6 on: 23.10. 2017 21:22 »
Using a 6V dynamo with a 12v solid state regulator was fine until the solder on the commutator melted. This happened more than once. Since then I invested in a proper silver soldered 12v spiral-wound armature and field coil (made in USA) and have had no further problems.

Goes to show then - no perfect answers!

But it is slightly counter-intuitive to me, assuming that the US-made armature is comprised of finer wire than you'd find in a std Lucas winding (which it must be), that it has done so much better than the heavier gauge jobs. It will presumably be running closer to its limits with 50W on than a standard wind, in current terms at least.

I'm just surprised that a std wound armature of reputable quality would throw its solder in normal use at 12v, as assuming a system voltage of no more than 13.5, that's only 4.4 A draw for just under 60W of power. But I have certainly seen failures on some of the lower-cost armatures made in far-away places. So I guess  high quality construction and materials are at the root of it - along with a decent regulator.

More of life's ponderables, or are they imponderables? But I'm sticking with std windings, despite the late cut-in penalty, as it's what's served me well for a long time and I'm a creature of habit! 
Bill