Indicator Relay

[Trigger]

The big question is: Are the flasher relays for LED the same as a normal 2 pin indicator relay. There does seem to be a big price difference, with the LED being a lot cheaper. Can any electric guru's please advise.

[SteveD CB500K0]

The original flasher relay works with a bi-metal strip. That's two different types of metal bonded together, each with a different coefficient of expansion (ie when a current is passed through them they expand at a different rate). This causes the metal strip to bend and make (or break) the contact. That's why when a bulb blows or the earth wire falls off, the indicators don't flash (there's not enough current flowing through the metal strip to heat it up).  That's also why you can hear them "ticking" when they are working properly.

LED indicator relays are not relays at all and are solid state electronics, make by the gazillion in China and hence really cheap.

Steve (BSc Electronic Engineering, back when integrated circuits hadn't been invented)

[Trigger]

Cheers Steve, that now makes sense. 

[AshimotoK0]

There are two types of indicator 'relays' fitted to classic Hondas. The ones with the round cans have an electrolytic capacitor in the end of the can and rely on the timing  duration of the flash (using a relay inside the can) using the RC time constant where the C is the capacitor value and the R is the internal relay resistance. These have three wires. The other type is rectangular can and as described by Steve and use the heating of a bi-metallic strip just like the rectangular units used in 60s/70's British cars (eg original minis). These are rectangular and have two  6.3mm 'Lucar'  style blade terminals on them and have 'Signal Stat 142' printed on them. I think they are fitted to USA CB750 SOHC models. My UK K0 was fitted with the capacitor type.
The Aftermarket  LED ones will probably be a low frequency oscillator using solid state IC and constant current generator with a power 'MOSFET' Transistor to switch the LED current.

The cool thing would be to build the LED electronics for the flasher into the can of the standard flasher if original look is required.

Cheers  AshD

[Trigger]

Ash, i maybe reading the last bit you wrote wrong but, you can buy 12v 2 pin Led flasher in a cylinder shape.

[AshimotoK0]

Hi what I meant was for restorers looking for originality it may be possible build the LED flasher circuit into the original Honda part 'can' . For just a retrofit yes there are round ones with two pins.... can't believe how cheap they are!!!

Cheers.... AshD

[Trigger]

  see what you mean now. So if i plunged a Led into my 550F , what would happen?

[AshimotoK0]

see what you mean now. So if i plunged a Led into my 550F , what would happen?

Don't know much about led lightsfor bikes  but I am fairly sure the standard Honda  relay  would not work properly with LED's.

Cheers ......AshD

[Lobo]

Whilst the cheapo / modern 2 pin relays work fine it just didn't seem right (!) the silent flashing / lack of a nice relay "tick-tick-tick..."  making / breaking... had to go back to ebay & spend a few more quid on my old girls...

Shamelessly copied from elsewhere...

"A standard relay uses the Amp draw from an incandescent bulb to create heat causing the flasher relay to blink. Since LED lights draw such a minute amount of Amps, they don't create enough heat to trigger a standard relay. That is why a LED specific relay is required. It is digitally controlled and does not require the normal Amp draw that a standard relay uses."

In other words..

A (suitably rated) LED flasher unit will run either LED or filament bulbs......
A traditional relay will not flash LEDs as the 'trigger' mechanism (ie current load) is missing.

Take a look at the below page & note the lower most product. (one's a 2-pin)

http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/flashers.php

...or you can 'frig the system' and keep your old flasher relay & add in the below 'extra load'
(Lower most product)

http://www.vehicle-wiring-products.eu/VWP-onlinestore/lighting/round.php

Cheers,
Simon

(& whilst I'm here... Steve, keep meaning to say what a bloody great website - thank you. And  OddJob, you miss nothing in all the bloody photos! You work for HM reconnaissance?)

[SteveD CB500K0]

Don't you just love it when people refer to electrical current as "Amp draw".

😄


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[Lobo]

...mmm, Amp draw, somewhere you keep your amps, aka 'battery'?

Dear god, let's not muddy the waters further!