The relay is there just to protect the BCU!

Also the wires may be overloaded without relay. I mean same wire which carries 35W now has to carry 35+35W load!

@ abhijeet080808 & rahuldevnath

Iam confused with the terminals now. Which is correct?
Anyhow iam again going to hunt Hyd for the relay that is used on PCB's. Is there any current limitation for it? Looking at the pic i dont understand what its current limit is. 7A or 10A?
The relay which i took is of 15A. I guess its too much and will not justify the job of protecting my BCU. So which one shall i go for? I would be running 2 55W halogens. It would be drawing 9.2A from my poor battery. I think i need to take a relay of 10A. Now iam thinking of why taking so much risks.
The thing is iam a student and if i ask my parents for money for HID's they for sure will start to shout at me. They wouldnt understand the need to spend around 7k just for the bike's lights.

@ Shreeni0403 & abhijeet080808

Here is my version of why high beam and low beam cant be shorted. If they are shorted they both would run simultaneously no matter if the high beam or low beam is on. I maybe wrong also.
I think using a diode is simpler and easier. Give the +ve of diode to high beam +ve and -ve of diode to low beam +ve and another diode in similar fashion for connecting -ve terminals aswell. When the low beam is on the diode would be reverse biased and wouldnt conduct. Hence only low beam. When high beam is on the diode would be forward biased and it would conduct and hence both the beams would be on. But i think the current flowing through the diode would be too much and the diodes would blow. We can use a resistor in parallel for limiting the current through the diode. But i dont know how to calculate the value of the resistor. If iam not wrong its resistance should be lesser than the forward resistance of the diode to allow more current to flow through it.
Please shed some light on this setup. Its easier than using a relay.

abhijit ,u seem to be the resident expert here.can u pls. help with the following:

can anyone please list some websites in US ,where one can source 35W bixenon 6000k HID kit.
also what would be the approx. cost in USD.
i tried google but there was a lot of mis information as well as price difference across various websites
one website says $144
http://www.xenonhid.org/motorcycle-bixenon-hid-kits-p-38.html

with 1 HID bulb & 1 ballast

wheras the 2nd says $60 only

http://www.housinghouse.com/goods-521.html

with 2 xenon bulbs & 2 ballast

now I am totally confused as what to do.

Answers in bold.

@darkknight - I have never brought anything online, so no idea there! BTW, why import it when HIDs are available easily in our country? Nowadays, even manufactured right here and thus have warranty too.

Price starts from $15 on ebay but quality no idea, all from Chinese brands, tryout some reputed sites like listed under after ebay. Go for slim ballasts as its the advanced tech.


Try this:

hid conversion kit, buy and sell Motorcycle Parts on eBay Motors

The Retrofit Source (U.S.) - HID Projector Retrofit Kits, Retrofit and HID Componenents, Projectors Lens, Wiring Harnesses, Shrouds and more!

Hid Kits | Your Xenon Hid Conversion Kit Source

i was only looking at a cheaper option.
what wud be the approx. price here in india for a 35W 6000k bixenon HID

The whole concept of RELAYING is all thanks to the BCU. What Shreeni mentioned, is the basic idea behind using both beams simultaneously, say in Fazer. In 220, the reverse current, activates the BCU short circuit/overlaod protection and hence does not allow any of the beams to work.

Abhi, the circuit still puts 35+35W on High Beam, just there's no reverse current in this case.

Oops, I see. I forgot that. Had to refer to the diag again. The 35+35W load does not overload the BCU? Whay not use another relay to battery? As you know HID start up current spikes upto 9A. 2 HID is 18A.

And, maybe I have asked this before too! In which case ignore it.

What i meant was if something goes wrong and the whole unit is drawing more current i wouldnt be protected if iam using 15A relay. Thats why gotta use 10A one.

Even if we use a relay the whole current has to pass through the BCU right?

Why will there be reverse current and where will it be towards? Please explain.

Well, chinese ones for 2-3k. With warranty, price is around 7-8k for a pair. Not sure if available separately.

Got the Relay finally !!

Understood. But there should be reverse flow to the BCU even if there is a relay right? Or is it because the low beam socket +ve has been given to the relay and from another point in relay a wire goes to the bulb, that there isnt any reverse flow in this case?

Let me give it a try. The HID's during starting take upto 9A. Two HID's sum upto 18A. I dont think the BCU would allow 18A to flow (incase both the beams are turned on at once). It would be a wiser decision to switch on low beam first and let it fully glow and then after a few seconds turn on the high beam (or both beams). If both the beams are turned on at once even a relay wouldnt be of much help as the BCU itself may cutoff the flow. Perhaps i maybe wrong.

Got a Relay today. Searched a few electronic shops and got hold of a miniature (looks very cute to me ) PCB mountable relay. It cost me just 10rs. I must have been a fool to spend 50rs for the last one. This is similar to the ones which automobile shop guys were showing saying that it is used in Pulsars. The only difference being this is PCB mountable and wires have to be soldered and they were the normal ones.

Yeah, the relay prevents reverse current the way you said. This relay will do the job. And the Pulsar relay is a electromechanical relay, even if similar in size. This one is a semiconductor relay.

Perhaps the BCU will limit the current or perhaps the BCU will overheat. As I do not have a P220, I can not say. But, it I were to try out this circuit, I would have used a car h/l relay too direct from the battery, supposing the BCU allows this and does not interfere. I expect Rahul to answer this!

Abhi I do'nt think you asked it, though a very valid point.

Now why did I refrain from using a relay directly to battery? Well...

(1) The 220 BCU is either very stupid, or over smart! There's a nifty feature of chaning over to other beam if one fails. For example if I'm riding in Low beam, and suddenly the filament goes off, God forbids at 121Kmph? I will not have a time to think and switch over to other beam, but our dear 220 does that for me, and even check upto 5 times, if the bulb is working.

This feature goes bonkers in case I use a relay, or even a 35W HID (the default load is 55W). It happens as I switch on the low beam HID, it sometimes does'nt glow, and automatically turns to high beam, and within 3 seconds again try the low beam, which may glow this time or again go into loop!! Cool isn't it!

(2) My assumption, but I could be wrong, that it's good to take power directly from the charging system, rather than battery. As, the coil after 2K RPM takes over the job of powering up the bulbs directly!

So that's answered

Rahul, your idea is what exactly I had in mind before I made this mod. And it's supposed to be used that way, though both the beams can be switched on if you are more past 3K RPM. But's it's better to switch on low beam, wait at least 10 Seconds before you move to high beam.

Ok, so the BCU has load sensing. So, it needs a load (bulb on the BCU o/p). A relay from the battery may be too low a load and may trip this feature.

So I guess what you did is the best way to do this.

About 2, the charging system is connected to the battery and then to the loads. So, it is the same thing.

True. These H7s don't come with their own relays like h4s, and if cars with 60/55 stock can take a load of HIDs so can our 220s with stock 55W, and yes I have saved 10Ws with LEDs.