Headlights: strength and excessive draw

[Durabil]

Just purchased an older DP that in most respects is wonderful and nominal in performance. The only glitch has to do with headlights and any suggestions would be much appreciated.

1. headlight beam - the headlights (sealed beams) are relatively new and yet their effectiveness is marginal after the sun sets. In fact, the day-time running lights appear more powerful as far as illumination than the regular headlights as well as high beam setting. Any experience with headlights that I should know about to address this issue?

2. when the headlights are turned on the voltmeter takes a significant hit as indicated by the needle leaving the center position and dropping to the approximate 1/4 level ... still within the "normal" designation of the meter. Before the headlights are turned on, the mere use of the turn signal causes the volt meter to fluctuate with each blink of the turn signal.

In addition, even without the headlights or any other draw on the system, the volt meter indicator registers a gradual erosion from mid-normal to lower and lower normal ... I've always stopped before the needle enters the red zone (not normal).

Sure would appreciate any advice or recommendations.
Thanks in advance

DuraBil
Triple E 3126 Cat DP

[DieselTech39]

First I would check all the grounds on the batteries and repair as necessary.

Or, it could be the voltage regulator in the alternator needs repair. IMO take the alternator to a reliable automotive electric repair shop and have them test it. If not working correctly and unless you feel mechanically inclined to do it yourself, have them rebuild it.

[Peterd503]

The first area I would look is wiring connections with special attention paid to grounds. At the same time check for conductor condition. The symptoms point to an unwanted series load which usually happens in the grounding circuit. Good luck.

[falconman]

Everything you want to know about headlights;
Daniel Stern Lighting Consultancy and Supply
Email him, very responsive/ helpful

[jauguston]

Poor headlight performance with motorhomes is not unusual. There is often long runs of too small gauge wire and poor grounds.

First thing to do is take your digital multi meter (Don't have one-get one-they are cheap and everyone should have one) and do this test. With the motor running check the voltage across your chassis batteries with the lights on. Now do the same thing at the plug that goes into the headlight with the headlight plugged in and on. Compare the numbers you get. If there is a big voltage drop you have found the trouble.

A good fix is a aftermarket relay kit that runs heavy wire from the batteries to the headlights and uses the original headlight power wires to simply activate the relays. If your chassis batteries are in the back find a heavy gauge wire in front to use.