The Stovebolt Site Forums The Shop Area The Electrical Bay Headlight solenoid installation

I just installed a kit to move the power to the headlights off the headlight switch to straight from the battery and I have a question. Would it be acceptable to get the power for the headlights from the top post of the voltage regulator as opposed to the positive terminal of the battery? Mostly I like that it will be a shorter run, but it will also show as a load on the ammeter (with the way it is wired now, the ammeter load returns to zero when switching from the parking lights to the headlights).

Thanks,

Lee.

I'd be inclined to mount the solenoid under the dash near the switch to connect the original wire through to the headlights. It will keep your headlight switch from wearing out.

... but one of the reasons to put in a headlight relay system is to get a nice fat wire from a well supplied source (like where the battery cable connects to the starter (or starter solenoid) to the relays mounted near the headlights.

I'd suggest using the battery cable connection at the starter as a voltage source for the relays, with a 30 or 40 amp self-resetting circuit breaker inline. In case of a short, the headlights will flicker on and off instead of simply going out like a blown fuse would cause. You definitely DO NOT want an unfused straight battery voltage source with a heavy wire anywhere on the vehicle. That's setting the stage for a vehicle-destroying fire.
Jerry

The real question is why are you doing this? For an original style 56, it is 100% unnecessary. Playing with electrical for no reason will get you "burnt".

Yes, only a fool would eliminate several feet of wire barely adequate to carry the current load, specified by a bean-counting corporate accountant, and a bunch of voltage drop from connectors in series, to get brighter headlights. The horror!
Jerry

A little education is necessary here to to prevent hyperventilation that seems to be causing some folks to faint. As I said, if this is a "original" style 1956 electrical system, then the following applies.

1. The headlight switch is not protected by a built-in 30-40 amp thermal overload breaker, It is protected by two separate built-in 13 amp thermal overload breakers. One breaker for the park and headlamps, another for the rest. The overload protection was reduced because Chevy went 12V in 55.2, less amps.

2. The stock headlights draw 5 amps on Hi beam, X2= 10amps....about the same as a radio or heater fan. Protected by a 13A breaker.

3. The wires can handle this.

4. The headlight switch is designed to handle this.

5. In 1956, a small fuse was added to the H/L switch for the instrument lights.

6. In 48-49 Chevy was 6V and the headlight switch was protected by a 30 A breaker.

7. In 1950, the breaker was up'ed to 42 A

8. In 1955.2 Chevy went 12V and amps came down. Better system.

9. Lee is not a fool for wanting to be safe. I don't know his issue.

10. I am simply asking the question as to why and explaining there is no reason for a relay if the system is stock. Lights seem dim because of our age or the truck's age.

11. It's foolish to suggest that the electrical system was designed by accountants. It was designed by engineers. Not shop teachers, not back yard mechanics, bean counters or insurance appraisers. The lighting designs we are discussing have held for 70 years +. No fires, no need for relays or shorter wires.

12. To answer Lee's question without prejudice: Chevy wired from the battery to the starter solenoid, solenoid to ammeter, thru ammeter to, I think, a terminal block or some common spot, then to Ignition switch, headlight switch, voltage regulator. Should add a fusible link/big fuse or two in that scheme.

When my brother with the master's degree in electrical engineering and the doctorate in plasma physics was designing and computer simulation testing electronic parts for GM, Chrysler, Ford, and Nissan (and getting paid $1k per day to do it) the bean counters definitely had priority over whether or not to put his designs into production. He calls me for car repair advice, BTW.
Jerry

Yes, as designers and engineers we must keep an eye on costs, efficiency, machinability, manufacturability, materials, safety, serviceability, reliability and profit for the company. The team does include marketing, cost management and bosses to remind us not to get carried away while we are trying to make the thing work. Glad to be retired.

Most of the headlights we get now draw more current than the originals. I turned on the lights on a truck I had before & ran a jumper wire from the bat. to the term on the lamp. The lights got considerably brighter. I went ahead & put relays on them & got brighter lights. I would do the same with the truck I have now but I want to preserve the originality. It still has the original sealed beam bulbs in it.

George

What is an example of "headlights we get now"? It's mostly about the watts......and of course lumens. 7" Sealed beam "originals" are 50-60 watts. Give me a part number of what you like to use.

Aftermarket headlight relays were a VERY popular addition to cars in the 1940's and 50's, particularly on 6 volt systems with slightly corroded connectors and rusty ground circuits. Dad's mechanics installed dozens of them durng that time. People were amazed at how much brighter their headlights got. I'm sure a few of our peers and subordinates are glad some of us are retired now.
Jerry

It's still popular, because the manufacturers (Ford in particular) use overly small wires from the fuse box, to the headlight switch and back up to the headlights. That causes a significant voltage drop and the headlights see lower voltage than they would if sufficiently large wires were used. Also, the switches are less likely to burn the contacts if all they're switching is a relay coil. I can tell you that headlight relays work.

Lots of info here! To answer a couple of your questions: I replaced all the wiring and installed a fuse block (Hot Rod Wires) a few years ago and have an 8 gauge wire running from the starter to the amp gauge (I am aware of the arguments for and against the use of a amp gauge, no need to repeat here) then to the fuse block. Same size also from the generator. Wire gauge is plenty big for my needs as I have added no additional loads to the system (heater fan, lights, ignition, and horn is about it). My main reason for installing the solenoid for the headlights is because one of my headlights burned out and the only local replacement I found has a wattage rating 60 watts for the high beam, but the specs for the truck say 50W. I did not wish to be always worried about what that extra wattage/amperage might be doing to the headlight switch (all the wiring is newer and larger than original, so that was not my concern), I decided to put in the solenoid to bypass that switch. Maybe it is necessary, maybe not; but I feel better about it. My question is about the main feed to the relays from the battery. The wire for this part is way too short to make it to the battery without adding in a section of wire. So would it be better to run a longer piece all the way to the battery, or a shorter section just to the top pole of the voltage regulator. It has 12 volts all the time and is a 8 gauge wire. I can’t think of what would be wrong with it, but maybe somebody here knows of a reason.

Thanks,
Lee

"Voltage regulator"? I assume you're running a DC generator, right? That BAT wire should run directly to one side of the ammeter, so as long as the conductor from the regulator to the ammeter is sufficiently heavy, it's virtually the same as going to the battery cable at the starter. You should be good to go. With the engine running, the current from the generator will meet all the demands of ignition, lighting, and accessories before sending the remaining amperage through the ammeter to recharge the battery.
Jerry

That is correct Jerry, I am still running a generator. I had some issues with it a few months ago, but they cleared up after some adjustments were made by our local generator/motor repair shop. I still may eventually go with an alternator, but not yet.

Lee.

The original 1956 headlight was 50W low beam and 60W hi beam. (T3 sealed beam bulb). The extras stress on wires and switches you are worried about between 50W and 60W is 0.8A. Lots of messing around for nothing. The super correct 1956 headlight form factor is a one year only design.

Dim lights was not your issue like I thought. It was thinking the headlight replacement was out of spec, which it is not.

Commentary:

If loose terminals, loose crimps, cold solder, corrosion or rust is making it hard to see the road, with 520 million more street lights than back in the day, is corrected by putting in a relay, all is well.
It's a band aid. Not a fix. If it fixes the problem, it's a crutch. It's temporary unless it works. Duct tape magnitude.

Both my operators manual and wiring diagram show 40 watt for the low beam and 50 watt for the high, and like you say only a difference in amps of .9 (the new lamp has a upper beam load of 60 watts). I have not had any issues with what I felt were dim lights; they are not as bright as my 2016 car, but I am fine with that. I just don’t over drive my headlights at night. My only concern was what the higher load was doing to my headlight switch; .9 amps does not sound like much, but this was an easy fix and relatively inexpensive, so I am okay with that.

Lee.