Hi guys, I’m trying to find a pair of latching relays but my limited knowledge has left me a bit stranded!
I’m creating a custom switch setup for the handlebars on my motorcycle. Once I have it figured out I would look at selling pre-wired kits to the custom bike community.
Space is limited inside the handlebars so I need to go with small momentary switches.
This however means I need to replicate some latching functions using a relay housed elsewhere.
One is for hi/low beam which would toggle between two active circuits.
The other is for the kill switch which would just break that circuit. This could be the same type as above I guess, I would just not connect anything to the remaining poles.
The closest thing I could find was this:
But from what my research tells me it will not simply reset using a pulse from the same switch due to polarity? It will need signal from a second switch to reset?
Bike runs 12V DC and 5A max for the headlights. Other funcitons would only need 1A.
For background I briefly worked as a tracer for my dad’s electrical drafting business years ago and have been soldering and wiring audio equipment for a long time but have no official electrical training.
Thanks for any help in recommending the right relays, or correcting me if my above assumptions are wrong!
Yes, you generally need two independent switches to set and reset a latching relay.
I would not use latching relays in any device I expect to be buildable over the next 5 years. In this century latching relays are very expensive devices with limited usage because of the normal alternative. More and more of them go out of stock every year and get discontinued by the manufacturers.
The normal alternative, for half to one tenth the cost, is to use a less than $1US microcontroller driving a regular low cost relay to replace any function provided by latching, time delay, and other unusual relay types.
You could use a full on easy to use and program microcontroller platform with a relay output accessory to prototype the system. Like these Adafruit Featherwing series parts:
The Adafruit learning pages linked from their product pages has a lot of details.
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Hi Paul thanks for getting back to me!
I see what you’re getting at and it’s exactly what’s been happening in the motorcycle world - everything being replaced by PCB microcontrollers.
That’s what I’m trying to avoid though! There is already an ECU on my bike where all these wires end up going, it has time delay functions for the indicators etc.
I’m just trying to replicate the mechanical switch function as simply as possible so the existing ECU gets the signal it’s expecting.
This one from Hella will work as a killswitch but from what I can see is only SPST and won’t switch between hi and lo beam headlights like an SPDT would.
These might do the trick but as you mentioned at significant cost these days.
The SAR 9200 as above seems to have been used on old VW beetles and kombis for this function.
I’ve been looking to find replacements for it like this perhaps
Am I on the right track or should I really be looking at replacing with a microcontroller for one simple function? I don’t think the custom bike community would go for it if I wanted to make them for others though, they want everything period correct on custom builds.
Guys I’ve found a retail product that does exactly what I want.
Hi/low beam and kill switch both in one simple, small module. No more, no less.
I have no idea how it took me literally two weeks of digging every day to find it but thanks for your help at least I have a solid grasp on how it all works now!
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