Charging problem

[Peter in Aus]

Your right there John 6V needs a 220 ohm 1/4 or 1/2 Watt resister and 12V a 560 ohm resister
Peter

[duTch]

They wont last long like that 

They are diodes not bulbs so need resistors to limit the current through them

and....

Your right there John 6V needs a 220 ohm 1/4 or 1/2 Watt resister and 12V a 560 ohm resister

 Thanks for the tip- as they are two 3.2V diodes wired in series for 6V I figured they'd work ok  (3.2+3.2=6.4). I'm not sure of their max rating, I'll check up- but if they blow, I'll look into adding a resistor; should it be one resistor in parallel over the two in series?
  My bodgy Volt meter connected to battery shows ~7.0v-7.8 V whilst riding sometimes spikes to a bit over 8V (daytime- no lights, dunno about night/lights on, can't see it. I could turn the lights on in daylight to check it, but the daylight might leak in and contaminate the result - just jokin')

[KiwiGF]

Isn't 3.2v for LED diode the minimum volts needed to light the LED? If that 3.2v rating figure is what is called its "forward voltage"?

But maybe the LED you have have a resistor built into them

From what I just googled  an LED diode has very little resistance once it reaches its forward voltage so if you put a 3.2v LED across a 4v battery it would short out the battery and probably blow the LED, conversely if you put it across a 3v battery it would not light up at all.

[edboy]

curse modern technology.  left behind ages ago but now creeping up on the old bsa of all things. my old tip is to bypass the ameter and put the charge wire straight into the lighting switch. but how do i worry about charging ? you ask. well rev the old girl with all the lights switched on and see if the bulbs go bright. no brighty- no lighty.  when its dark and i need to know how my lights are charging i watch the speedo light bulb. if it goes very dim or out then i know i m in trouble.

[coater87]

curse modern technology. no brighty- no lighty. 

 Quote of the year, right there.

[Triton Thrasher]

curse modern technology.  left behind ages ago but now creeping up on the old bsa of all things. my old tip is to bypass the ameter and put the charge wire straight into the lighting switch. but how do i worry about charging ? you ask. well rev the old girl with all the lights switched on and see if the bulbs go bright. no brighty- no lighty.  when its dark and i need to know how my lights are charging i watch the speedo light bulb. if it goes very dim or out then i know i m in trouble.

The production racers' trick was to bridge the ammeter terminals. The ammeter would still work, a bit, but if it's coil fractured it didn't isolate the battery.

[Peter in Aus]

curse modern technology.  left behind ages ago but now creeping up on the old bsa of all things. my old tip is to bypass the ameter and put the charge wire straight into the lighting switch. but how do i worry about charging ? you ask. well rev the old girl with all the lights switched on and see if the bulbs go bright. no brighty- no lighty.  when its dark and i need to know how my lights are charging i watch the speedo light bulb. if it goes very dim or out then i know i m in trouble.

The production racers' trick was to bridge the ammeter terminals. The ammeter would still work, a bit, but if it's coil fractured it didn't isolate the battery.

That is not a bad idea, it has often worried me that the coil would become open circuit in the amp meter especially with these cheep amp meters coming out of India and gods knows where.
It could be catastrophic if it did, and  you are using AC generators "like me."
Peter

[mikeb]

dutch - finally something on a BSA forum that I know about. your LEDs won't last long as they are. they need a current limiting resistor in one leg. also, as you have a red and a green they have different forward voltages so need different values. assuming you are 6v system then with max volts of 7.2V and 20mA per LED best idea would be  put a separate resistor in line with each one - a 220 Ohm series with the green and a 270 Ohm with the red. then put those in parallel, like the pic. if 12v system use 680 Ohm for both (or 560 Ohm for the green if you can find similar). all 1/4W.
but it is modern technology, an acetylene lamp would be more authentic

[duTch]

 Thanks guys, a few things I can respond to there, but first- I forgot to say on the way back from the swappie when I picked up the S/H +/- 8A meter, I stopped in a the young fellas and forgot to turn off the lights, no big deal- figured it'll charge up on the rest of the trip (at dusk). That was not to be as I found out later, my trusty +/- 30A Fergie meter musta gone on strike at possible redundancy .
 I didn't realize until I went out for a test with the new setup, and couldn't get a charge. Ok it was in the daylight so I figured the daylight was pushing the Lucas-light back in , but the LED's worked ok, and even came on with the brakes .
 So I stuffed around a bit and got the charge happening again and went out today with lights on and charging- the whole bit and yep the LED's failed fairly soon.

 I did figure out that the 5mm green LED could be a 3.2 or 3.5 V, but red ones are only rated for 1.7 / 2.1V. Only the green one blew, red still works from a 3V (2.98v) button battery.

 Mike, (and all) it should be obvious I only know enough to be dangerous...I had them in series (as in pic) but you suggest to run them in parallel?
  KiwiGF;

Isn't 3.2v for LED diode the minimum volts needed to light the LED? If that 3.2v rating figure is what is called its "forward voltage"?

But maybe the LED you have have a resistor built into them

From what I just googled  an LED diode has very little resistance once it reaches its forward voltage so if you put a 3.2v LED across a 4v battery it would short out the battery and probably blow the LED, conversely if you put it across a 3v battery it would not light up at all.

 The rated voltage is a 'typical voltage', but I think they fire up lower but they also have a 'VDD'-Maximum V that I haven't determined- others'll know.

  Edboy;

Quote from: edboy on 30.06. 2016 22:12

    curse modern technology.  left behind ages ago but now creeping up on the old bsa of all things. my old tip is to bypass the ameter and put the charge wire straight into the lighting switch. but how do i worry about charging ? you ask. well rev the old girl with all the lights switched on and see if the bulbs go bright. no brighty- no lighty.  when its dark and i need to know how my lights are charging i watch the speedo light bulb. if it goes very dim or out then i know i m in trouble.

 I don't disagree, but every now and then I make an attempt at being 'civilized', and this is one of those moments- it don't come easy
 TT

The production racers' trick was to bridge the ammeter terminals. The ammeter would still work, a bit, but if it's coil fractured it didn't isolate the battery.

 
 So I don't know what I did to fix my charging issue, but I retuned the reg and it's within specs I think- maybe had a loose wire

[mikeb]

dutch - leds have a forward voltage but require a certain current through them. the resistors act like a crude current limiter. they aren't like lightbulbs that have a voltage rating. if you put leds in series you still need a resistor but it would be smaller value with more current variability across the 6-7.2v range of your bike. either google it or just follow that pic (yes - in parallel)

[duTch]

 I thought I had some of the recommended resistors but no-go, so went and bought some at Jaycar, and also a regulator that I thought might do the job.
  It's a LM 2936 2936 3.3, but I'll play worth the resistors first and see what damage I can do.

 On the other note, that's something crazy happening with the charge system;  it works and then doesn't and then does again. ..ammeter keeps goin' spazzo. Might put the old meter back in and see what it does, but being less sensitive may not say much.