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99 SLK230 Sport
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818 Posts
Discussion Starter #1
1. ok.. so who's got em on their car?
2. what type? (plug n play w/o relay or with relay wires going to the battery)
3. how long have you had it on your car?
4. any reliability issues?

the reason why i'm asking is somebody just told me that aftermarket kits without relay can damage my computer?? i have the type of kit without relay.. so i disconnected mine for now...
 

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SLK in brilli silver
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854 Posts
I can answer a few of ur questions.
16months used aftermarket HID kit, no relays that u spoke of

No problems or isssues

No problems related to the HID w/the computer. I don't see how it could possibly damage the computer since it has a seperate ballast that fires each HID bulb and actually pulls less energy than the traditional lights.
 

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99 SLK230 Sport
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818 Posts
Discussion Starter #3
thanks for the input mike! the guy told me wrong. i did some research and found out that long time use of the aftermarket HID without relay can fry the stock wires, i guess those are the wires coming from the power source to the headlight assy for it might be too thin and will just serve as a fuse on heavy laod when you plug the ballast. relay kits are about 30-40 dollars and contains all the wires, plugs, and fuses that you need. you can also make your own relay and cost you $10, there's a bunch of diagrams on how to do it on the net, just search on google. also maybe because you're not having problems is because the SLK's wiring is good enough to handle such laod.
 

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SLK32, ML430
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I have been running aftermarket HID for about a year. The only issue I have had is that one of the lights has turned bluer than the other and is a little dimmer.
 

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SLK in brilli silver
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hmm im not sure what you mean by load exactly. The only time there would be a higher demmand would be when you instantly turn them on and the ballast discharges to fire up the xenon. Other than that my understanding is that the xenon actually use less power than the standard bulbs. The Kit I purchased plugs into the stock receptical and then goes to the ballast then to the hid bulb. I must be missing something because I dont see how it could fry the factory wiring.
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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As long as the proper fuse is in the line how would you fry wires ?

The fuse should go long before the wires get hot, let alone get damaged.
 

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99 SLK230 Sport
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Discussion Starter #7
not an electrincian or even close to an electician..but from what i read from a couple of forums and aftermarket HID stores... the number one major problems with these kits are burnt wirings and the relay seems to solve that problem, well the only solution they have for the problem. in my opinion, it's better to have the relay than taking the risk of having the problem in the future.
 

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99 230 SLK Sport
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42 Posts
Im thinking about doing this myself, can you guys tell me which kits you are running and how long you've had them installed?

From what I've read, there is a much higher draw of current when they are first ignited, then they actually use less power to stay lit. Since MBZ offered stock HID lights for this car, I wonder if that was a different wiring harness or if ours is strong enough to handle both types?

Jaye
 

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2000 Designo SLK-05 C230WK-05 E320CDi-2010 GLK 350
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714 Posts
The reason some people reported wiring problems is because the start-up current draw of HID ballasts may be as much as 33% higher when the lamps are first powered up than the OEM halogen lighting, and this high current demand diminishes slowley as the lamps warm up and come up to full brightness. You will notice this warm up period because even the stock 4200k lamps appear to have a very blue tint as the first come on. You need to fuse these fixtures allowing for the increased starting current and time.

The need for relays is most common on cars built with the US DOT lighting standards of the early 90's. Most DOT spec cars of that era used the 9004 lamps which were 45 watt lamps and had their wiring and fuses sized for that low current rating.

The other compounding problem was that some cars of that era had DRL's running at reduced brightness. The reduced brightness was achieved by reducing the operating voltage to the lamps through a switched resistive element. HID ballasts are self regulating and will compensate for reduced input voltage by dwawing more current. The added current needed will cause the ballasts to run at higher than normal temperatures and cause early failures.

As near as I can tell, no Benz ever had reduced brightness DRL's and no R170 ever used 9004 lamps so there should be no problem retrofitting HID to it. Just remember to up the fuses for the lamps to the same rating the cars with OEM HID's use. The best solution although the most expensive is to retrofit the OEM HID fixtures to your car.
 

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99 SLK230 Sport
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Discussion Starter #10
makes sense now why they highly recommend the relays on economy cars.. so would a 20 AMP fuse do?
 

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2001 SLK 230
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Why not just buy replacement OEM assemblies. You get the whole package, ballast, wiring, correct lens and reflector. The price is not much higher, if you shop around. I looked at aftermarket and decided to go with OEM.
 

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SLK32, ML430
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Geoff - 4/5/2005 12:29 AM

Why not just buy replacement OEM assemblies. You get the whole package, ballast, wiring, correct lens and reflector. The price is not much higher, if you shop around. I looked at aftermarket and decided to go with OEM.
Not much higher? One of us is shopping in the wrong place. Last time I looked OEM was $1k+ and a much more involved install. Aftermarket HIDs can be had for ~$275 and are a couple minute plug and play operation. If I could get OEM for anywhere near the aftermarket stuff I would hop on it.
 

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SLK in brilli silver
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lol, yeah id love to know where u got a full oem setup for under 1k thats new. The cheapest I have found the oem for is 800 used on ebay. I got my setup for 400 bucks and I am very happy w/it. It couldnt of been easier to install.
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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makes sense now why they highly recommend the relays on economy cars.. so would a 20 AMP fuse do?
Don't do that....[:0] Fuse rating is controlled by wire size and insulation type. A 20 amp fuse is normally for a 12 gage wire if you were to put it on a typical 14 gage wire the circuit could overheat and cause a fire, or at least soften the insulation and cause a short circuit.
Seriously, working with the electrical system is a lot like working with your brakes. It's easy enough to do, but if you are not sure of exactly what you're doing, get help, and watch what they're doing.
 

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1999 SLK230 Sport
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2,713 Posts
Something doesnt make sense....

given Ohms law V=iR
and
12 Volt Supply voltage

Most current ratings for wires (except magnet wires) are based on permissible voltage drop, not temperature rise. For example, 0.5 mm² wire is rated at 3A in some applications but will carry over 8 A in free air without overheating. You will find tables of permitted maximum current in national electrical codes, but these are based on voltage drop (not the heating which is no problem in the current rating those codes give).

Here is a small current and AWG table taken from the Amateur Radio Relay Handbook, 1985.

Code:
AWG  dia    circ  open   cable  ft/lb   ohms/
     mils   mils  air A  Amp    bare    1000'

10   101.9 10380    55    33    31.82   1.018
12    80.8  6530    41    23    50.59   1.619
14    64.1  4107    32    17    80.44   2.575
Mils are .001". "open air A" is a continuous rating for a single conductor with insulation in open air. "cable amp" is for in multiple conductor cables. Disregard the amperage ratings for household use.

To calculate voltage drop, plug in the values: V = DIR/1000
Where I is the amperage, R is from the ohms/1000' column above, and D is the total distance the current travels (don't forget to add the length of the neutral and hot together - ie: usually double cable length). Design rules in the CEC call for a maximum voltage drop of 6% (7V on 120V circuit).

Usually the choice of fuse rating is to protect the equipment to which it is connected from getting too much current and hence, blowing. Normally the connecting wires are rated for MUCH higher current ratings than the equipment they supply.

So how can the choice of a 20 AMP fuse be linked to the specific reason that it is 12 ga wire? Educate me please.[:D]
 

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2005 SLK350
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316 Posts
I've had my Mecca Tune set for about a 1.5 years. The only thing i have found was that the "light out" lamp stays on constantly. However that could be fixed with a load resistor. I just used a tiny piece of electrical tape to cover the light. It blends in with the display and doesn't bother me. On my kit, i have each balast running to the battery, and into the factory harness with relays. Everything was plug&play, and easy to put in. I rebalanced the headlights to lower glare and get a nice beam pattern. If you want, check out my other posts, there are pictures in there of the setup. I have a slight tint of blue hue to mine, but i tired to get them as close to stock as possible. Overall i would say i am very happy with my results.[:D]
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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Household wiring and automotive wiring both have something in common, they are not in free air. Typically they are at least partially enclosed, and often in fairly tight locations. The NEC is conservative, and likely the wire can carry more power then their rating would indicate as you have stated, but do you want to take the chance ?
Your data is actually not far off from what the NEC states:
23 amps. for a 12 gage wire (NEC states 20 amp breaker.)
17 amps. for a 14 gage wire (NEC states 15 amp breaker.)
I believe the NEC is more concerned about protecting the wiring then the equipment, otherwise you wouldn't have multiple receptacles on a given circuit. I believe NEC is more concerned about the wire because if the equipment fails you buy a new radio or blender. If the wire fails you or the insurance company buys a new house. Automotive is not much different, much of the wiring is hidden and in bundles packed tightly in inaccessible areas. There are few areas that can be considered free air.
If you want me to go into this further, tell me what you want, I have the current NEC book at work. We use it on almost a daily basis. I also have three Master Electricians that I work with and two Electrical Engineers that I can ask anything you might want to know.
I'm not trying to be a smart a$$ with any of these comments, believe me, but :
( 1 ) The Amateur Radio Relay Handbook doesn't have anything to do with what we're talking about.
( 2 ) When voltage goes down, amperage goes up in DC current. ( I'm sure you know that.)
( 3 ) Automotive wiring isn't in free air, and seldom is run as single wires. They are bundled in a wire harness.
( 4 ) Aircraft wiring is rated the same way, with exceptions for specific insulation types. That's generally a weight saving measure, to allow for use of a thinner wire at a higher amperage draw, and the resultant higher wire temperature.
( 5 ) I believe both ASME and ASAE use the same standards as NEC, but I don't know that as a fact.
None of the above is to say any of these wires are going to run hot enough to feel any heat at their "rated" load, but as you start to bump up the load, that may very well change.
If I'm wrong, please show me where, I'm certainly willing to learn. [:p]
 
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