Joined: Aug 2017 Posts: 3,247 Threads: 360
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I've got a 6V Chinese 21W flasher relay and the winkers - all tungsten - work fine on ignition.
But don't function correctly when car running.
Its got a CFR2 with a diode replacing the resistance wire behind. All charging fine on both positions.
I know there are sometimes issues with LEDs not flashing when their Wattage is so low, but what are the variables to test here please when all bulbs are at least 3W? Does the combined wattage need to be closer to 21W?
Or shall I just try another flash can first?
Joined: Aug 2017 Posts: 254 Threads: 3
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Location: Shropshire, UK
Jon, the answer is probably in the name "21W flasher". It is obviously designed to operate with 21W load and I wouldn't expect it to perform correctly with anything less that 15W.
I don't know what the 3W bulb issue is other than totally abnormal for any flasher.
Joined: Aug 2017 Posts: 217 Threads: 19
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Looks like your total wattage is too low. Put a higher wattage bulb in to test, if still no good must be the new chinese junk.
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Location: N W Kent
Do you know if your flasher unit is electronic? If the flashers work OK when the motor's not running, but misbehave when it is, it's could be because the electronics in the flasher unit are suffering from interference from unsuppressed/insufficiently suppressed plug leads.
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26-03-2021, 12:28 PM
(This post was last modified: 26-03-2021, 01:04 PM by JonE.)
Ian and Peter - it was because it worked fine on ignition that the lower wattages passed the first test, with an odd combination of units!
But yes, I will up the wattages first and see if that sorts before moving on to Stuart's point. Thanks all.
Need to find highest wattage small globe and those weird long festoon bulbs...
Interesting to find I can get 21W festoon rather than 15W currently. Good.
The sidelight units at the front are BA15S and you can get small globe versions at 6V up to 15W, which I can paint with amber. I can't get a standard size bulb in.
I see they DO a 21/5W dual pole in the 6V (small bulb) - I wonder if I can bodge that so it all works via the single wire... or insulate/isolate one of the pins for the sidelight.
Joined: Jul 2019 Posts: 186 Threads: 41
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Car type: Austin 7 RN 1931
I had exactly the same problem ,I found by trial and error that it was the HT leads. A suppressor cap on each solved it
Buy an Austin 7 they said, It's easy to work on they said !
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aha - that's good to know.
In which case it may be that the 21W x 2 = 42 W is presently working on 15+ 10 = 25W perfectly well.
Will report back.
Joined: Aug 2017 Posts: 528 Threads: 17
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Location: Hampshire UK
Hi JonE
The electrical noise on all the wiring of an unsuppressed Seven when the engine is running is enormous. An old tech thermal flasher will be immune. A typical electronic flasher will go haywire. On the other hand, thermal flashers are a bit fussy about total bulb wattage, electronic flashers less so. Both types are supposed to flash rapidly if the load is much less than normal (= blown bulb warning).
Try 5000 to 10000 ohm suppression resistors (suppressor caps) at each spark plug, and/or try adding capacitors between the input and output of the flasher and ground. A value between about 0.1 and 0.5 microfarad with fairly short leads is best. The things that used to be sold as radio suppression capacitors are more convenient to connect to than wire ended ones intended for circuit boards, but either will work. Even an ignition condenser is worth a try.
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Location: The delightful town of Knaresborough, North Yorkshire
So will my unsuppressed ignition system upset all the electronic flashers in the modern cars sat at the traffic lights?
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I'm not an electronics boffin , but just wondering if an earthed "Faraday cage" around the flasher unit could isolate it from the ignition electro-magnetic effects of the H.T. Any ideas anyone?
