Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Relay issues when motorcycle idling

Status
Not open for further replies.
The relay is rated to 30 or 40 A as a maximum current through the contacts. The coil is designed for DC and is rated for 12 V. It will take around 100 mA to run the coil.

As the headlight is run from the alternator directly, it is likely to be run from AC, and that is what is making the relay flicker.

You can use those very cheap diodes, and you would need 4 arranged as a bridge rectifier, so it would be easier to buy something like **broken link removed**
There are 4 wires, labelled +, -, ~ and ~.
Connect ~ and ~ to either side of the headlight bulb.
Connect + and - to the relay coil.
 
You still haven't said what motorcycle you're working with either, knowing that, we can look up technical data and give you answers appropriate to your bike. Honda has a different system than Yamaha and if you're working on a Bultaco, it could be a whole new deal.
 
Could it be that when the bike is at idle, the alternator is putting out AC at quite a low frequency which is why the relay is chattering ?
 
Could it be that when the bike is at idle, the alternator is putting out AC at quite a low frequency which is why the relay is chattering ?
Yes, I think that is the case. Running the coil from a rectifier will improve the situation, because the inductance of the coil will keep the coil current flowing in the parts of the cycle when the supply voltage is low. With the coil running from AC, the current will reverse each cycle, and if the frequency is low, there will be a long period when the current is small.

Running a coil from a bridge rectifier used to be common practice for 50 Hz circuits.
 
The diodes you linked to would be fine, four of them being used to make a bridge as Diver mentioned in post #21. It might also help to connect a 1000uF or so, 25V-rated, capacitor across the relay coil to hold up the voltage during AC troughs.
 
The relay will certainly draw considerably more current than is reasonable for your system. I wouldn't bother with it.

The circuit alec_t provided is a far better solution. There are other, similar ways to do this as well.
 
Thanks for all the amazing feedback guys this is a fantastic forum! We will try to source the gear we need for the N-MOSFET solution Alec_t suggested...

May I throw this thread in another direction? And ask what people think of a standalone lightbox with a solar power strip 10 x 140 cm along the top powering rechargeable lithium batteries and maybe a light sensor or timer switch to turn the thing on at night. This way the light could remain on even when they are not driving and they wouldn't be concerned about their battery going flat. Is this feasible? Any thoughts would be appreciated..
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top