Charging questions

acadian said:

Worthwhile to invest $15 in one of these doodads.. fits right into the headlamp shell holes and shows under, correct, and over charge status...

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+1 on that LED goodie!
Mine just warned me of potential charging / battery problem.
Testing with voltmeter confirmed alternator not charging battery with headlight on and just weakly with it off.

The volt meter was checked against a Fluke, it was never more than .1 off.
Don't really see the utility of the LED warning light as the voltmeter tells
you more. I have one on my Enfield as there is no 'ignition on' warning lght.

I just took both bikes for a ride and they exhibit similar characteristics within
.2 of a volt.

Have ordered a modern replacement parts more to see exactly what difference,
if any, they make compared to the original Lucas bits. Over the years I must say
Ive had little trouble with the stock equipment other than one or two bad zeners.
That is over 40 years of brit bikes.
Hate descending into parts changing but sometimes it can replace guessing with
knowledge.
Sometimes.....

The Norton workshop manual has the same 13.5-15.3 volt specs. If you have an ammeter available and can insert it inline with the zener and measure voltage too, that'd tell you for sure if the zener is OK. I've never seen 15+ volts on a working system and I'd be leery about battery health. But if the factory said it's OK then it must be.

Onder said:

Don't really see the utility of the LED warning light as the voltmeter tells
you more.

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I do not like to ride with my voltmeter attached. :mrgreen:
The light tells you when to worry and check for a problem with the meter.

I dont have a good ammeter to hand just now. But Ill get one.
Amusingly the one NEW zener I have seems to let the voltage rise to
18 volts! Unfortunately I bought it two years ago and never used it so
Im stuck with it at this point.

Your comment that' the book says it is ok then it must be ok' is sort of
where Im at but want to check with a new reg-rectifier and see what
numbers I get.

Im learning from Jim Comstock: gather the data then make your
theories. Data first. Im not sure all my data is in yet.

In a week or so Ill be back with what sort of numbers I get with a modern
system.

maylar said:

The Norton workshop manual has the same 13.5-15.3 volt specs. If you have an ammeter available and can insert it inline with the zener and measure voltage too, that'd tell you for sure if the zener is OK. I've never seen 15+ volts on a working system and I'd be leery about battery health. But if the factory said it's OK then it must be.

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Maylar wrote: I've never seen 15+ volts on a working system and I'd be leery about battery health. I agree, and short lamp life as well.

However, with main beam on, your voltages are in the normal range. Most jurisdictions require "lights on", so you should not have battery/lamp life problems if you ride with lights on.

I have one of those three color LED voltage sensors. FWIW, the device goes into over-voltage warning at 15.2 volts and above (at least that is what the datasheet tells me, I have not actually seen it happen).

Slick

As an aside, I worked as an engineer for a company that made instrument light dimmers for military aircraft. The military had data that said life expectancy of an incandescent bulb was a twelfth power exponent of applied voltage. Which means that even a small increase in voltage over the rated value had a huge impact on service life. It's also why the bulbs in a typical car instrument panel seem to last forever - they're on a dimmer.

Onder said:

To make matters more interesting I also have a Triumph exhibiting the exact same problem!

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What's common? Same issues apply to all Brit bikes of that era; low charging system output. You now have two with over-zealous charging systems. Something fishy in Denmark...

You commented earlier that:
14.0 volts indicated at 3500 steady cruise with main beam on.
14.2 volts with low beam on. (beams include tail 1157)
15.1 volts to 15.3 volts with no head lamp on.
That seems reasonable. Modern charging systems run anywhere from 14.2 to 14.5 volts, and don't seem to eat batteries much. At the top, with nothing but the coils for a current sink, all excess current is now being dumped as heat from the zener. You may be seeing the edge of the saturation curve.

And:
If you turn off the beam, then turn it back on it may read .1 or .2
higher than it did previously.
Not surprizing, as you're momentarily supplying all excess current to the battery with nothing but the ignition pulling some juice. I would venture a guess that the voltage drops back down after a short period once the lights are back on.

Take a look at sparkbright-eliminate-the-assimilator-t23236.html#p305091 for a bit of noise about LED voltage indicators. As mentioned there I'm partial to the Sparkbright, but that's only because it's the only one I've tried (why mess with a good thing?) While running a 20W low-beam LED headlamp and all other bulbs incandescent, the indicator shows I'm better than 13.2 volts at anything above 1800 rpm. Plus, at a spirited ride at anything about a sustained 4500 rpm, the indicator is warning me that the voltage has risen above 15.2, so, based on that, it would seem yours is right in there.

You mentioned early that this began right after blowing a fuse. The blown fuse might be one of those chicken-or-egg things in that the fuse might have blown due to excess current into/out of the battery, or it blew because of age/vibration, so you're now scrutinizing your charging system more closely. I highly recommend installing an LED indicator that gives you a good range of voltage indications, and ride.

Nathan

Update, case closed:


I installed a regulator/rectifier and did away with the zener and stock rectifier. I get 14.3 volts with no head lamp load and 14.3
volts with the standard lamp on. Leaving the lamp on at rest for a while drained down the battery some and it then ran at
13.7 for a while until it charged up and leveled off 14.2 to 14.4 never going higher.

The cause of this whole event was a chafe in a hot wire in the harness. This probably caused the fuse to blow and may have
caused the zener to die. Or it could have been that the zener was fragile after upteen years and was dying and the short
circuit was just and unrelated event that happened at the same time.

Ive known that lucas equipped bikes run fairly high, 15.3v and above without the lamp on. My worry wasnt that there wasnt
enough power available but that the high voltage would kill my EI. So going to a modern regulator/rectifier isnt that expensive
and hopefully will ease and worries about the EI.

Moral of the story: carry a short jumper so you can disconnect the battery output from the bike entirely and use the jump
to power the EI. I almost never ride at night so that removes needing another jump up to the headlamp.

Thanks for all the input.

My recommendation is to ensure that your headlight, preferably high beam, is on during the daylight hours when you ride. It's all about safety and increasing the probability that some of the idiots in cars will see you. Running without a headlight during the day is not a good idea, IMHO.

cNwRestomod said:

My recommendation is to ensure that your headlight, preferably high beam, is on during the daylight hours when you ride. It's all about safety and increasing the probability that some of the idiots in cars will see you. Running without a headlight during the day is not a good idea, IMHO.

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+1000
To not do so is just begging for Left Turn Larry/Linda to have a successful assasination attempt. Harry Hurt told us about it....
https://en.m.wikipedia.org/wiki/Hurt_Report

@Onder

Thanks for the Update and Case Closed.

So many OPs seek answers, so many others lend their time and talents, only to be left hanging wondering if we made a contribution.

If everyone were to close out as you did, we would ALL learn more.

Slick

I did this for that reason. Many times Ive searched the list, found a similar problem to whatever I was experiencing and there might be many replies
but often it just peters out and one never really knows what effected a solution.

I run a headlamp daytime. But I want to know what is going on with the electrical system and not hand wave it and say "oh I dont know it is fine if
I leave the lamp on" that sort of thinking will bite you someday.

Again, thanks to all until my next event!