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**rahuldevnath** · 05-20-2009, 12:45 PM

That is a very clear diagram. These two heatsinks will result in a short circuit if they come in contact with each other or with the frame of the bike. So, installation should be secure!

Yes installation has to be secure. But some heatsinks have a insulation coating, on it.

And to be doubly sure, it's best to put only the cathode, to loop around Heatsinks. This way it wo'nt matter if it comes in contact with the body as well.

The above diagram, is what I have adopted, there could be loopholes!

**Shreeni0403** · 05-20-2009, 05:14 PM

Sorry if this question sounds childish.
Should we connect the diode to heat sink (orange line given in diagram) with a wire or anything else

**abhijeet080808** · 05-20-2009, 11:04 PM

Originally posted by Shreeni0403 View Post

Sorry if this question sounds childish.
Should we connect the diode to heat sink (orange line given in diagram) with a wire or anything else

We need to conduct heat from the diode legs to the heatsink. Normal copper wire is used as it is a good conductor of heat.

**rahuldevnath** · 05-20-2009, 11:24 PM

Originally posted by abhijeet080808 View Post

We need to conduct heat from the diode legs to the heatsink. Normal copper wire is used as it is a good conductor of heat.

Yes, exactly. And these hard copper wires will also hold the heatsink in place. I haven't used anything to hold the heatsinks to the casing, it's just these wires. In fact, I haven't used copper wires either, just extended the diodes points and soldered. These bigger diodes have thicker points, so they hold the heatsinks as well.

**Shreeni0403** · 05-21-2009, 11:24 AM

Originally posted by rahuldevnath View Post

Series 5 diode used in this case.

4700uf capacitor is of how many volts?? 12v??

**rahuldevnath** · 05-21-2009, 11:54 AM

Originally posted by Shreeni0403 View Post

4700uf capacitor is of how many volts?? 12v??

25 to 35 volts

**Shreeni0403** · 05-21-2009, 07:07 PM

I completed the circuit and connected to headlight wire. But before connecting to battery i checked the voltage coming out. And there i got puzzled

When bike is in idling the voltage coming is 10-14v but when i rev the bike the voltage i am getting is 40v

Isn't that too much..!!! Or is it normal because there was no load.!!

I connected a LED strip which will work on 12v, to my surprise they worked fine and din't blow up

**rahuldevnath** · 05-21-2009, 08:53 PM

Don't worry, even if it goes 100 volts, it just the higher amps. As the load comes, it will drop. Current going to headlamp is not constant, that's why you need a big capacitor.

**Shreeni0403** · 05-21-2009, 09:06 PM

Originally posted by rahuldevnath View Post

Don't worry, even if it goes 100 volts, it just the higher amps. As the load comes, it will drop. Current going to headlamp is not constant, that's why you need a big capacitor.

I have put 25v 4700uf capacitor with 6A4 diodes with 2 heat sinks too..

But my doubt is.. How to make it water proof..

I ve covered it with plastic non sticky tape and also insulation tape but still i doubt that water will enter. Capacitor is completely sealed but diodes.. Are diodes water proof by default

**abhijeet080808** · 05-21-2009, 09:40 PM

Originally posted by Shreeni0403 View Post

I have put 25v 4700uf capacitor with 6A4 diodes with 2 heat sinks too..

But my doubt is.. How to make it water proof..

I ve covered it with plastic non sticky tape and also insulation tape but still i doubt that water will enter. Capacitor is completely sealed but diodes.. Are diodes water proof by default

If the two heatsinks are connected to the two diodes respectively, make sure that they don't touch each other or the frame. And put it all inside a plastic box! If you don't get anything you may use the box used to mount plugs and switches at home. Else, put it under the seat or below the meters in the headlamp assembly. That way it will not get wet.

Edit: How did you check for 40V? Used a multimeter? Was it set to DC? And it the capacitor connected properly?

**rahuldevnath** · 05-21-2009, 11:42 PM

Water won't enter easily, in some parts of the bike. Everything should be inside a plastic case, with the heat sinks outside. If you wish, buy a normal relay, and use it's casing!

Cover it many folds of insulation tape. Under seat space is best. The heat generated by the diodes, will take care of moinsture.

Edit: How did you check for 40V? Used a multimeter? Was it set to DC? And it the capacitor connected properly?

Well, yeah. Was the current checked after installation of capacitor? If yes, then the Voltage should be equal to the value of capacitor, in your case 25V.

**Shreeni0403** · 05-22-2009, 12:08 AM

Originally posted by rahuldevnath View Post

Water won't enter easily, in some parts of the bike. Everything should be inside a plastic case, with the heat sinks outside.

Well, yeah. Was the current checked after installation of capacitor? If yes, then the Voltage should be equal to the value of capacitor, in your case 25V.

I have not kept anything inside plastic casing, will see what best i can do to save from water.

Yes after connecting capacitor also its showing 40v+ around 42v and i tested it with analog multimeter not digital.

**rahuldevnath** · 05-22-2009, 11:20 AM

Originally posted by Shreeni0403 View Post

I have not kept anything inside plastic casing, will see what best i can do to save from water.

Yes after connecting capacitor also its showing 40v+ around 42v and i tested it with analog multimeter not digital.

Nevertheless put to battery, and try riding the bike for at least 2 hours, to check the battery drain.

**Shreeni0403** · 05-22-2009, 02:47 PM

Originally posted by rahuldevnath View Post

Nevertheless put to battery, and try riding the bike for at least 2 hours, to check the battery drain.

I tried connecting a indicator bulb, in idling it was fine but when i revved a bit the bulb blew off

The bulb went so white like a lightning and blew off. Now i think that voltage is too high.

I removed the capacitor and checked the output and its varying between 10-14v. I somehow feel that 15v capacitor is also too much bcz 25v capacitor is boosting to 40+ v. So 15v means it ll be 30v

I am totally puzzled what to do.!!! I don't want to connect it to battery with such high output.

**Shreeni0403** · 05-22-2009, 02:53 PM

Ok i changed the capacitor with the same 25v 4700uf and this time the output voltage was 25v so i believe the circuit is fine.

This time i tested it connecting to a bulb for 5mins and then i was unable to touch the capacitor. It was extremely hot.

Does it mean i should connect capacitor also to heat sink or something else is wrong??

Or is it normal?

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