I thought you were talking about Single Xenon
In that case low is halogen and hi is xenon so was wondering

Cmon man, low beam will be always on to power up HID, and the high beam wire is connected to HID solenoid to move the bulb to High position. I hope u know in a bixenon HID, it acts as H/L function by a solenoid. I think its the right selection of switches between H/L rather than the whole supply is bypassed thru the switch. Each time u switch between H/L on the other method, HID is eating a good chunk of batt. Its useful for ur proposed mod, all the lights on pass/high beam. There r people still staring on the bulb due to its intense brightness, so imagine if I put on the High beam always. U want me to receive those wild greets from all trcukies?

Did u see the focus adjusting mechanism in stock beams on the other thread?

Does it mean, when u switch to LOW beam even the HIGH will remain ON ???

Shree almost all HID kits r coming with a built in relay in the control box. U dont need to change, it takes only very little curent to operate. Otherwise, since u wired through a relay, and if u've little space to accomodate to all, avoid the control box messy long wires and connect the power to the ballast from the low beam and the high beam to the solenoid in case of H4. bridge the low beam power to the main light switch. I've done this way, the benefit is, ur HID will not get off while switching to H/L and ineffective, bulb and batt life can be increased. This is done with spdt relays for each beams.

Does that mean H4 HID's come with relays ?? I have already installed relays so will i have to remove them if i put a H4 HID

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.

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.

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.

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!

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.

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

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.

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.

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.

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