Lights Slow to come on Bright

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Model T Ford Forum: Forum 2014: Lights Slow to come on Bright
Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Friday, December 20, 2013 - 05:26 pm:

Wired my 1915 so that only the headlights and tail lights are connected to the battery (12 volt). And of course a brake switch. It is an older battery but seems to hold a charge although I have not really tested it for a long period in this mode.

When I turn the lights on (new switch) the headlights come on slowly... almost like they are warming up and it takes about 2 seconds to come on fully bright.

Why is that? I used 12 gauge for the main ground to the frame (battery to frame) and 14 gauge for the other grounds to the frame.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Friday, December 20, 2013 - 05:38 pm:

Slow electrons....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Seth - Ohio on Friday, December 20, 2013 - 05:52 pm:

The lights know that there is no hurry to go to bright because the car can't go that fast.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie on Friday, December 20, 2013 - 05:59 pm:

Here's a wild guess:

The connection at the back of the bulb is loose or corroded, and when it tries to go on, it has to warm up and expand in order to make good connection.

Sounds far-fetched, I know, but I can't think what else it might be, other than a problem in your new switch.

If my wild guess is close to correct, this would only happen when you turn the lights on from cold. If you turned them off and then back on while still hot, they's come on bright.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Milton,WA on Friday, December 20, 2013 - 06:04 pm:

What "new switch" are you using ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Friday, December 20, 2013 - 06:07 pm:

Odd. Sounds like your bulbs are behaving like toaster filaments. Are you using 12-volt bulbs? Are the contacts in your switch clean? Are you using an original, 1915 pull-switch, which, from what I've been told, wasn't built to withstand the voltage of two 12-volt headlights, two tail lights + brake-lights?

My '15 was retro-fitted with a 12-volt system and instead of using an original, 1915 pull-switch, we went with a 1924-vintage rotary switch, which occasionally needs a little jiggling to get both headlights to fire up. I just think of that as one of the charming little idiosyncrasies of a horseless carriage.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Friday, December 20, 2013 - 08:36 pm:

I am using a re-pop 1915 push-pull switch (new).

Peter... you are correct. Once they are on I can shut them back off and immediately turn them back on and then they come on as I would have expected.

Problem is BOTH bulbs would have to have a loose connection as I wired them separately as opposed to what the 1915 wiring schematic shows. I didn't like the idea of having one bulb go out and loosing them both as a result.

Bob, ironically that is what I was thinking. But this aint no toaster!@!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom VanMeeteren on Friday, December 20, 2013 - 10:55 pm:

Cold weather, everything is slower when it's cold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert E. (Bob) Blackbourn, Gautier Ms. on Tuesday, December 31, 2013 - 04:02 pm:

Try this: preheat the switch with a hair dryer or heat gun before turning on the switch. If that "fixes" the problem then you have a bad switch.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Cascisa - Poulsbo, Washington on Tuesday, December 31, 2013 - 06:01 pm:

John,

Trade that antique electricity in for some new electrons :-)

Be_Zero_Be


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Tuesday, December 31, 2013 - 07:32 pm:

Sheesh... I KNEW I needed newer 'lectricity.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, January 02, 2014 - 04:19 pm:

John:

This is one case where a digital meter might be easier to use to figure out what is going on. With motor shut off so as not to interfere with your digital meter, measure the applied voltage at the bulb terminals when the bulbs are cold and you first turn on the lights. Make sure ahead of time that you have a good ground on your meter negative (black) test lead to the same ground that the bulb is using. Make sure you can watch digital meter which should be on a scale to read digital volts DC on hopefully about a 15VDC scale. When you first turn on the switch - look at the DC voltage on the meter and verify one of 2 things. Either the voltage on the bulb jumps right up to a steady 12.6 and then the bulb gets brighter later or the bulb voltage comes up slow as the bulb gets brighter. One or the other is likely to happen. If the voltage is coming up slow as the bulb gets brighter than likely you will then end up at a voltage that is somewhat below the battery voltage and that would indicate your wiring is not heavy enough or you have a high resistance connection somewhere in the series wiring between the battery, switch, and bulb socket. If the voltage jumps right up but the brightness is slower then you need to check the ground side of the bulb to see if there is a bad ground. The can be simply a measurement of the voltage present on the ground side of the bulb in an amount less than 2 Volts or so. That voltage on the ground side of the bulb indicating a bad ground will jump up to perhaps a couple of volts and then drop down to a smaller amount once the bulb is warmed up. If that is what you see then you have too light of a wire on the ground side or just simply a bad ground if there is no wire there but simply have a bulb terminal there. Finally if both side show full voltage instantly at the bulb socket terminals yet the bulb gets brighter at some later time then you have a bad bulb but I would still bet its a bulb to socket resistance problem then as a first guess.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Aldrich Orting Wa on Tuesday, January 07, 2014 - 07:32 pm:

Installed a new battery and guess what...

Problem gone.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Aaron Griffey, Hayward Ca. on Thursday, January 09, 2014 - 12:30 am:

I had a customer with a '25 speedster that overcharged all the time. Way too much. Seems to me it was a 12 volt system, it was several years ago.
Couldn't adjust the 3rd brush to go lower than about 10 amps.
That car drove me crazy until I changed the battery.
I got a new Interstate battery and set it to charge 4 amps. It stayed at 4 amps for many years and as long as I knew of the car.


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