Headlights Revisited

[rv_safetyman]

Brian, if you consider a 12V system and 4 ea 55 watt bulbs, that is 220 watts or about 18 amps (half that for a 24V system).  That is not a huge load.  

The typical bus wiring runs a very heavy cable (6-8ga?) to the front and that will carry a lot of amps.  I see no reason to run a special wire direct to the batteries.

There are three major places you get voltage drop in the headlights circuit (not considering bad connections):  headlight switch, dimmer switch, and any fuse in the system.  If a bus has breakers then they probably do not create much of a problem, but Eagles use oversize fuses with clips on each end and they are terrible after many years of service.  In the previous sentence it may seem that is dismiss bad connections.  Not the case, I just wanted to sort out component issues.  Bad connections are probably the major issue.

When you install relays, that reduces the current load on the headlight switch, dimmer switch and fuses to less than 1 amp (only has to pull in the relay coil).  That really makes a drastic difference!!!  The headlight switch and  dimmer switches could now be micro switches if you wanted, rather than the huge switchs that have to carry all of the current load for the headlights.

Jim

[bevans6]

Everyone probably knows this but when you are doing all your measuring of voltages and such, do it with the lights attached and on...   The load will capture any voltage drop due to bad connections which won't show up if you pull the bulb to get at the terminals easy...

brian

[Len Silva]

Everyone probably knows this but when you are doing all your measuring of voltages and such, do it with the lights attached and on...   The load will capture any voltage drop due to bad connections which won't show up if you pull the bulb to get at the terminals easy...

brian

Yes, absolutely.  And measure across the lamp, not from hot to chassis ground.  Bad grounds are probably the worse offender, rather than wire size or fuses.

[rv_safetyman]

Sorry, did not complete my thought in my last post (whats new? ).  

When you wire in relays, you use the current headlight wires to trigger the relay (activate the coil).  You then run a wire from the main power supply terminal (the one that the 6-8 ga wire runs to) to the hot side of the relays.  You will need to put a resetting breaker as close to the main power supply terminal.  That breaker should be consistent with the wire size you run to the relays.  I used a 30 amp automatic resetting breaker and 10 ga wire to supply the relays.

Jim

[artvonne]

  Cibies are awesome. I had a set years back, you really do not need high wattage bulbs, 100 watters have a reflective range of "miles", and anyone out in front of you will hurt if your on high. They are incredibly bright.

  If you place high quality relays near the lights, and have good grounds, you wont have any voltage drop. 55/60 bulbs are more than sufficient.

  What I noticed however, was a loss of light output over the years, regardless of what wattage bulb I out in them. The problem was pitting in the glass, from the many miles of driving and sandblasting them. I was able to restore a lot of the output with some serious polishing, but the point here is that headlights, even the best on the planet, lose a great deal of output with just minor pitting. So beware buying used ones off eBay, I found cheap Sylvania halogens had higher output than my "worn" out Cibie's.

  In that regard, the Hella's may offer better value, and offer better availability out on the road. But ive never had Hella's, so I cannot comment on their performance. As stated above, the sharp cutoff of the Cibie's is remarkable, and it owes those qualities to the engineering of lens and reflector. It would be nice to see the two brands side by side.

[bioVenture]

I don't want this to sound like a broken record but as others have stated, check the voltage at the light. That can't be stressed enough. Mine was only getting 8 volts. I used the feed to run relays and added a 12 volt sydtem to the bus and couldn't believe the difference.

Also checking the voltage while the light is on will be a better indicator of the condition of the circuit.  You can have good voltage in a poor circuit when no work is being done.   

[Ericbsc]

My 05 eagle has the large square ones like a model 15. Not bright at all. Someone gave me a p/n for some bright ones but I lost it. Anybody happen to know the number? Don't want to add more lights. Thanks!!

[Lin]

Okay, I finally got around to testing the voltage.  It was 25.5 at the battery and 23.5 at the left (furthest) headlight.  I did expect it to turn out to be something like that.  It certainly would be useful to reduce that loss.  However, it seems unlikely that that will make enough of a difference to make these lights acceptable. 

[luvrbus]

Len pretty well covered it all about voltage I am not a MCI person but in my Eagle bible it calls for 13.1 to 13.3 volts at the head lights most all the 24 volt head lamps I have seen are 28v if you go to NAPA you need to ask for 28V or they just look at you

good luck

[Len Silva]

Okay, I finally got around to testing the voltage.  It was 25.5 at the battery and 23.5 at the left (furthest) headlight.  I did expect it to turn out to be something like that.  It certainly would be useful to reduce that loss.  However, it seems unlikely that that will make enough of a difference to make these lights acceptable. 

That's not insignificant, almost 8% loss.  I would consider anything over 0.5 volts to be too much.

[Lin]

I agree that an 8% loss is not insignificant and I should deal with that to.  Interestingly, I checked the voltage at the dash switch, and it too is only 23.5 volts.  However, my point is that an 8% increase in illumination is still going to be inadequate.  By the way, Hella e-code H4 7 inch rounds are available for about $35. each.

[Lin]

I just wanted to let people know what we finally did.  We bought the Hella E-code lamps for about $80. for the set.  They came with 12v H4 bulbs which, of course, we did not use.  Instead, we bought a couple of 24v H4's.  The installation was easy.  It only required a little widening of the hole in the pan for the lamps to fit nicely.  During the process, we cleaned up whatever contacts were in need; the grounds were marginal and the contacts on the high beam foot switch were seriously corroded.  I suggest that anyone that is losing headlight voltage to check that switch.  They are generally very old, could get wet sometimes, and they are easy to get to.  I hope we picked up a bit of voltage, but I have not checked yet.  I have not driven with the new lights, but they do a great job of lighting up my yard.  I would guess that they put out a couple of times the light of the old sealed beams.  I did not change the high beams out yet and may eventually do the same with them, but may just put some halogen sealed beams in.

[JohnEd]

I have had the 7 inch Hella's since 95.  They are superb.  I hear the Cibies are better but I can find no reason to go further.  I bought a second pair for my Winnie.  $35 dollars is a really good price.

John

  Cibies are awesome. I had a set years back, you really do not need high wattage bulbs, 100 watters have a reflective range of "miles", and anyone out in front of you will hurt if your on high. They are incredibly bright.

  If you place high quality relays near the lights, and have good grounds, you wont have any voltage drop. 55/60 bulbs are more than sufficient.

  What I noticed however, was a loss of light output over the years, regardless of what wattage bulb I out in them. The problem was pitting in the glass, from the many miles of driving and sandblasting them. I was able to restore a lot of the output with some serious polishing, but the point here is that headlights, even the best on the planet, lose a great deal of output with just minor pitting. So beware buying used ones off eBay, I found cheap Sylvania halogens had higher output than my "worn" out Cibie's.

  In that regard, the Hella's may offer better value, and offer better availability out on the road. But ive never had Hella's, so I cannot comment on their performance. As stated above, the sharp cutoff of the Cibie's is remarkable, and it owes those qualities to the engineering of lens and reflector. It would be nice to see the two brands side by side.

[JohnEd]

The light output is not linear with the voltage applied.  8% voltage loss may yield 25% loss of light output.  Your wiring should drop less than .5 volts and that is easily done so don't askert.

John

Okay, I finally got around to testing the voltage.  It was 25.5 at the battery and 23.5 at the left (furthest) headlight.  I did expect it to turn out to be something like that.  It certainly would be useful to reduce that loss.  However, it seems unlikely that that will make enough of a difference to make these lights acceptable. 

That's not insignificant, almost 8% loss.  I would consider anything over 0.5 volts to be too much.

[Lin]

John,

I know that there is likely to be voltage losses.  The grounds and the dimmer switch contacts were so bad that I would be surprised if I did not pick up some of the loss there.  Actually, I just might replace the dimmer switch itself.  Even though it still works, I could imagine the the insides are compromised.  It would seem that many years of use by drivers with wet or snow covered boots would make those switches easy victims of corrosion.  However in the end, although I know that this might run against the perfectionist grain, the goal here is to have adequate lighting.  If it is necessary to rewire to get there, then that is what must be done.  If taking care of the easy to reach bad spots and putting better lights in place of the old ones works, I see no reason not to solve the problem that way.  Bus maintenance is time-intensive and costly enough even with compromise.