poor headlights!

robertglines1 · December 01, 2014, 11:30:54 PM

observations and conclusions from my bus..Test all batteries @ 12.86 V light switches turned on .I tested at headlight socket = 10.5 volts which = 510 lumens Lots of voltage drop within switching and the prevost wires are 18Ga. examples of other voltage results would be 12.8V = 1000 lumes and if engine running we could get clean 14volt = 1356 lumens ------- danielsternlighting ----- provided me with the relays and hardware to upgrade my voltage and headlight system to Cibie Notable restoring stock voltages were accomplished by installing 12 ga stranded feed wire from 12volt stud in front electrical apartment to a cube relay-this relay get it signal to close from the original headlight socket. one for low beam and one for ground. Example of low voltage to bulb at 12.54 volts your bulbs will be 95% efficient at 11.88 they would be 67% efficient. All voltage is measured at headlight bulb socket all wiring in circuit in now 12ga stranded I was surprised by my test results A 10.5 v /might be good thing to check if you feel your headlights are weak. weak switches-wiring size and connectors--ground all contribute to low voltage at headlight. FWIW Bob

belfert · December 02, 2014, 12:51:59 AM

I had similar issues with my bus and the headlights. I was getting pretty low voltage to the headlights. My problem was the 12 volt feed from the batteries to the electrical panel at the front of the bus. I wasn't getting full voltage due to the manufacturer using too small a feed to the electrical panel. I ended up running a dedicated 8 AWG cable from the batteries to the headlights.

bevans6 · December 02, 2014, 04:07:40 AM

I am curious if your buses were both 12v headlights stock, or changed to 12v headlights, and if the rest of the bus system is 12v or 24v. 18 gauge is way too small for any 12 volt headlight and Prevost should have known that.

Brian

belfert · December 02, 2014, 04:46:37 AM

My bus is a 1995 Dina so it had 12 volt headlights. I actually switched to 24 volt headlights when I rewired everything. I went back to 12 volt when I installed the 90mm HID headlights this summer. The HID headlights take less amps than the halogen headlights did.

I don't think the wiring to the headlights themselves was the problem on my bus. The problem is the 12 volt cable from the battery compartment to the front power panel is not big enough and causes voltage drop.

robertglines1 · December 02, 2014, 04:48:24 AM

lights always 12volt--yes wire size was a surprise and has prevost ID #s on them. There is about 10 yr span they uses same set up and everyone has fought with them. I had always thought it was the lenses. This is just test of my own along with research of affect of voltage on brightness. Bob

bevans6 · December 02, 2014, 05:02:02 AM

As you know I am going back to 24 volt with the headlights you sent to me, to try to fix my 12v light problems! Seems that after all this time they would have figured it out. On my MCI the wire from the battery to the 12V stud was 10 gauge fused at 30 amps. Normal headlights would draw around 20 amps so within the capacity of the wire, not counting other 12v loads of course. Voltage drop should have been around 1 volt or less. Goes to show that overkill is best when it comes to headlights!

Brian

robertglines1 · December 02, 2014, 05:38:24 AM

Jim Shepard(rvsafetyman) did a article on how to boost voltage a few years ago. Makes more sense to me after my new findings. At the time I though his was just a upgrade to different headlight system but can see now that it boosted stock system up to the voltage levels it should have been. Bob

uncle ned · December 02, 2014, 05:35:42 PM

I have wonderful headlights on huggy and do not have any thing special,just common halogen lights.

The reason is that I run the voltage at 14.2 because I have a diode bridge that lets me charge my house battery's and engine batters at the same tie.There is a 1 volt drop across the bridge and the battery's see 13.2 volts.

The diode bridge keeps me from running my start battery's down.

Boy are they bright light up the world on bright but incoming car do not like if i forget to dim.

uncle ned

ros · December 02, 2014, 06:07:07 PM

Hi, Uncle Ned

You didn't ask and probably know all about this and I don't know what batteries that you are using but just in case:

I would feel very uncomfortable charging them at 13.2. If typical lead-acid, they will never be charged to their maximum capacity.

As a general rule, dependent on the type of diode/s, one can count on approximately .7volts drop per diode/junction.

Have you considered using a dpst heavy duty, porcelain, switch to first charge one and then the other, directly from the charging source?

Ros

Quote from: uncle ned on December 02, 2014, 05:35:42 PM
I have wonderful headlights on huggy and do not have any thing special,just common halogen lights.

The reason is that I run the voltage at 14.2 because I have a diode bridge that lets me charge my house battery's and engine batters at the same tie.There is a 1 volt drop across the bridge and the battery's see 13.2 volts.

The diode bridge keeps me from running my start battery's down.

Boy are they bright light up the world on bright but incoming car do not like if i forget to dim.

uncle ned

PP · December 02, 2014, 06:10:33 PM

I just had to replace a low beam on the bus and was surprised that the socket read 12.23V. I was expecting it to be 24V. This is the first headlight I've had to replace on the bus. Everything else I've replaced has been 24V so I expected the same on the headlamps. Learn something new everyday.
Will

uncle ned · December 02, 2014, 06:24:58 PM

Ros been working very well for quite a few years. have 3 group 31 for start and 4 big fork lift battery's for coach

uncle ned

B_K · December 02, 2014, 06:33:08 PM

Quote from: uncle ned on December 02, 2014, 06:24:58 PM

Ros been working very well for quite a few years. have 3 group 31 for start and 4 big fork lift battery's for coach

uncle ned

An a 6V92 for the SMOKE! (lol, sorry Ned the Debil made me do it! Beside we all know if you let the smoke out of electronics they don't work no mo!)

BK

ros · December 02, 2014, 07:27:45 PM

uncle ned, I don't doubt it a bit on how long they have been working. The fact (not my opinion) remains that they have never been fully charged.

That they have been charged 'enough', to satisfy your needs, is just fine. However, being not fully charged is one of the reasons for 'early' plate sulfation and premature failure of the battery.
Now, guessing how long they will last being undercharged is a black art that is anyone's guess.

For me, I always charge lead-acid cells at their factory recommended voltage and nothing less.

I wish you well

Ros

Quote from: uncle ned on December 02, 2014, 06:24:58 PM

Ros been working very well for quite a few years. have 3 group 31 for start and 4 big fork lift battery's for coach

uncle ned

Dawgs · December 02, 2014, 07:40:45 PM

In the world of aviation, a 12 volt system is called 14.....still uses a 12 volt battery.

belfert · December 02, 2014, 08:10:58 PM

Quote from: bevans6 on December 02, 2014, 05:02:02 AM
As you know I am going back to 24 volt with the headlights you sent to me, to try to fix my 12v light problems! Seems that after all this time they would have figured it out. On my MCI the wire from the battery to the 12V stud was 10 gauge fused at 30 amps. Normal headlights would draw around 20 amps so within the capacity of the wire, not counting other 12v loads of course. Voltage drop should have been around 1 volt or less. Goes to show that overkill is best when it comes to headlights!

I used 8 AWG wire because my battery compartment is some 35 feet from the headlights. I used one of the online voltage drop calculators to figure out what wire size I needed to limit voltage drop to an acceptable amount. The 24 volt headlights when I had them I think drew around 200 watts when on high beam.