so, is 80/100 watt H4 safe for my euros with factory wires?
 

Here's the scoop. I have a set of W201 DEPO euros. I recently purchased a pair of Hella H4 bulbs rated at 12V 80/100w. I also have a pair of generic blue-tinted H3 bulbs rated at 12V 100w. After reading about the H3 bulbs, I have decided to go with a standard 12V 55w H3 (preferably the same brand as the H4 to keep it consistent). With this fear of overloading my factory wires with high wattage bulbs, I am now wondering if the 80/100w H4s are safe for my euros. In some posts, I have read that you can get away with this wattage without upgrading your headlight wires or adding a relay. However, in some posts, there is mention of "caution" in using anything higher than the standard 55/60w H4.

My main question to you all is it absolutely SAFE and OK to use 80/100w H4 bulbs in my euro-spec headlight units WITHOUT HAVING TO UPGRADE ANY WIRING OR ADD A RELAY?

Here is my setup: H4 12V 80/100w :: H3 12V 55w :: no city lights

ps.
reason I ask is that I really don't have the expertise or know-how to upgrade the headlight wiring or add a relay. And since I have the 80/100w H4, I don't want to go through the hassle of wasting more money and time buying another set of H4 bulbs if I know it is perfectly fine to use them without having to do the above.

many thanks!

I have a set of Euro lights that were nearly ruined from running high wattage bulbs in them. There really is very little to gain from high wattage bulbs. Most of the headlamp effectiveness with Euros comes from the improved reflector and lens shape. Using standard bulbs is definitely the way to go in my experience.

Good luck,

I wouldn't do it with the original lighting circuit. You'll need to run some relays. Here are some good instructions:

http://lighting.mbz.org/tech/relays/relays.html

I've had a burnt out bulb holder on my Euro becoz of these high wattage lamps.

Trust me, BAD...

I've run 55/100 watt bulbs on 2 different Benzes with Euro lights for a total of 4 years now. Also 100watt fog lamp bulbs. No problems with either. The relays, fusing and wiring are up to it. I also ran 80/100s for about a year but switched to 55/100 because they are far cheaper and more readily available. I also have daytime running lights so my bulbs are always on. The difference between stock 55/65 and 55/100 is like night and day. Literally. They take the fatigue factor out of night driving.

i'm using 100/90w H4 bulbs on my 123 sedan. From my experience, i would say upgrade your wiring. From the stock wires to thicker gauge wires, plus a pair of relays (or you could go overboard and use two pairs; 1 pair for low beam another for high beam - but why?.. eheheh) then definitely upgrade your bulb sockets to ceramic ones.. bosch makes these.. dont use the stock plastic bulb sockets.. as these will melt.

More light from H4 bulbs
 

I tried 100/90W (or 100/80W) H4 bulbs and concluded that most of the advantages were almost outweighed by additional voltage drop in the wiring caused by the higher current. Apart from concerns of damage to the headlights, wiring or switches, I also had concerns as to possible damage to the bulb failure unit in the W124.

Recently I have fitted Hella "Plus 50" H4 bulbs in the standard 60/55W rating. They are supposed to offer 50% higher light output presumably by converting slightly more electrical energy into light rather than heat. The difference in light output is quite noticeable and superior to the 100/90W bulbs I tried. The "Plus 50s" also maintain the correct light pattern which the 100/90W did not. Hella also market a "Plus 30" which I believe also gives a noticeable improvement over the standard H4s (although presumably not as great as the "Plus 50"). Bosch, Philips and Osram all offer similar higher output versions in the standard wattages. In fact, I think the Hella bulbs are manufactured by either Osram or Philips anyway. Check any of their websites to see what's available.

I will be using any of these in future rather than risking damage with 100/90 or 100/80 bulbs.