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Stock rheostat with LED bulbs?

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Pats54 Avatar
Pats54 Gold Member Mark M
Maynard, Mass, USA   USA
1979 Triumph Spitfire 1500
2012 Volvo C70 "The Weekender"
Can I use the stock rheostat with LED bulbs or will it cook the rheostat.
Or will the bulbs work but I would not be able to dim them?
I want to try them in my gauges, perhaps the Break lights if there is a easy swap.

I know there is a lot of talk about the LED bulbs or the lack of light on the gauges
I think unbalanced light is mor my issue where the speedo is not clearly lit but the temp gauge is.

Not that I plan to drive a lot at night but just want thing to look the best they can.
Can I put in the BA9S and E10 bulbs and not burn out the rheostat or is there a rheostat for the LED Bulbs.



Thanks guys
You light up my life.
Mark

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spitfire50 Avatar
spitfire50 Paul Mugford
Rochester, N.H., USA   USA
Mark,
It isn't a matter of burning the rheostat out. It will simply not give you enough range to dim the LED bulbs. At one setting you will have full brightness, at an almost identical setting the bulbs will turn off. Dimming LED bulbs works much better by using pulse width modulation. That turns the power on and off so many times a second you can't see it and the more off time there is, the dimmer the LEDs are.
Other applications of LED bulbs such as brake lights don't use dimming, and you only have to make sure the new bulbs spread the light properly for the use. LED bulbs can be extremely directional in their light output, so some bulbs don't show up at an angle. That could be very bad in a brake or tail light. Color should also be considered. Amber bulbs behind red lenses or vice versa don't shine as brightly. Badly mismatched reds could also be a problem.
All the best,
Paul

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
In reply to # 1496065 by spitfire50 Mark,
It isn't a matter of burning the rheostat out. It will simply not give you enough range to dim the LED bulbs. At one setting you will have full brightness, at an almost identical setting the bulbs will turn off. Dimming LED bulbs works much better by using pulse width modulation. That turns the power on and off so many times a second you can't see it and the more off time there is, the dimmer the LEDs are.
Other applications of LED bulbs such as brake lights don't use dimming, and you only have to make sure the new bulbs spread the light properly for the use. LED bulbs can be extremely directional in their light output, so some bulbs don't show up at an angle. That could be very bad in a brake or tail light. Color should also be considered. Amber bulbs behind red lenses or vice versa don't shine as brightly. Badly mismatched reds could also be a problem.
All the best,
Paul

https://www.ebay.com/itm/PWM-Pulse-Width-Modulator-DC-Voltage-6V-12V-24V-28V-3A-Motor-Speed-Controller/292287930008?hash=item440db7de98:g:0bsAAOSwOS1Z3I1Z

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Pats54 Avatar
Pats54 Gold Member Mark M
Maynard, Mass, USA   USA
1979 Triumph Spitfire 1500
2012 Volvo C70 "The Weekender"
Thank you Paul,
I will look into the pulse with modulationis.
Is this something I can add on the load side of the rheostat?

Thanks for the info on the break lights ( I did not want to dim them ) I will also research them.
It seams to me this is a very common question,both brake lights and instrument panel lights
I would have assumed it would be a simple modification.

Pats54 Avatar
Pats54 Gold Member Mark M
Maynard, Mass, USA   USA
1979 Triumph Spitfire 1500
2012 Volvo C70 "The Weekender"
Thanks Tony.
Just pick one up
Do you use LED bulbs?

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
I use ebay LED's in the stop, turn signal and side lights. Also the interior map light.

I have yet to convert the instrument lights, but I no doubt will.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
The stock dimmer will not work.

Check this out:

http://www.triumphexp.com/journal/Doug+in+Vegas/15361

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Pats54 Avatar
Pats54 Gold Member Mark M
Maynard, Mass, USA   USA
1979 Triumph Spitfire 1500
2012 Volvo C70 "The Weekender"
Thanks Doug
I bought one on EBay just waiting for it to arrive.
I am still not sure how I am going to wire it up, I will review when I get it

Tony
You did your breaks and turns?
Got them on Ebay did you go with white bulbs, if you have any more info that would be great

Thank guy's

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
Wiring is fairly easy.

You have a pair of wires to hook to the power and a pair of wires for the LEDs.

It's a pulse width modulator. (PWM) The wider the pulse the brighter the LEDs.

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
In reply to # 1496466 by Pats54 Thanks Doug
I bought one on EBay just waiting for it to arrive.
I am still not sure how I am going to wire it up, I will review when I get it

Tony
You did your breaks and turns?
Got them on Ebay did you go with white bulbs, if you have any more info that would be great

Thank guy's

I bought a bunch of bulbs to try differant styles, some like the COB inthe picture were very directional. I think I used those for back up lights. Others had lenses or side led and were more defused. All were very inexpensive (less than a $1 inc shipping) the # 1157 and 1156 are the type you need, one has 1 element the other 2 for combo side and brake light, I forget which is which.

All sorts of designs out there
https://www.ebay.com/sch/i.html?_osacat=0&_odkw=12v+led+brake+light&_from=R40&_from=R40&_trksid=p2334524.m570.l1313.TR0.TRC0.H0.X12v+led+brake+light+bulb.TRS0&_nkw=12v+led+brake+light+bulb&_sacat=0


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IMG_20171107_151703.jpg

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
I'm considering LED running lights myself. Those are interesting.

Pats54 Avatar
Pats54 Gold Member Mark M
Maynard, Mass, USA   USA
1979 Triumph Spitfire 1500
2012 Volvo C70 "The Weekender"
Thanks Tony
I will let you guys know how I make out
And try to track where I get the bulbs and what type
For the others thinking of converting to LED.bulbs

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