jdeas

jdeas

Well Known Member
Can anyone give me a practical current or wattage range for interior/gauge lights?
My guess is the worst case would be a steam gauge setup with traditional bulbs.
I am looking for a general rule. Is a 3amp circuit enough? 5amp?
 
jdeas said:
Can anyone give me a practical current or wattage range for interior/gauge lights?
My guess is the worst case would be a steam gauge setup with traditional bulbs.
I am looking for a general rule. Is a 3amp circuit enough? 5amp?
Click to expand...



Incandescent will draw more current then LED's. You will really have to decide what u want to use and check the specs. 5 amp is more than enough, but once again you have to check specs.
 
It needs to handle 1/2

jdeas said:
Can anyone give me a practical current or wattage range for interior/gauge lights?
My guess is the worst case would be a steam gauge setup with traditional bulbs.
I am looking for a general rule. Is a 3amp circuit enough? 5amp?
Click to expand...

The hardest position for the dimmer is when it is taking 1/2 the load of the system. If you system/wire will be supplying 10 watts without dimming then the dimmer will need to be able to handle 5 watts at least.

Kent
 
Not a Linear dimmer

One of the reasons for my request is that I don't like generating heat just for a dimmer. A proper "high side" PWM will do the job without the excess heat.

The worst case is assumed to be lamps in steam gauges.
If I knew the bulb type and number of gauges it would give me my answer.

A 3amp solution would be better as there are single chip solutions in that range. If 5amps is needed then a descrete solution would be needed.
 
I measured my Wheelen post lights: 70 miliamps each @ 14 volts, full bright. They use a GE330 bulb. I am thinking a Van's 1 amp dimmer will be plenty for me. (airspeed, altimeter, Garmin CDI). I have a second 1 amp dimmer that will power two red LED map lights, 40 miliamps each http://steinair.com/lights.htm
 
I made one

jdeas said:
One of the reasons for my request is that I don't like generating heat just for a dimmer. A proper "high side" PWM will do the job without the excess heat.

The worst case is assumed to be lamps in steam gauges.
If I knew the bulb type and number of gauges it would give me my answer.

A 3amp solution would be better as there are single chip solutions in that range. If 5 amps is needed then a discrete solution would be needed.
Click to expand...
Its impossible to guess how much your lights will draw. If you plan on post lights (with incandescent bulbs), +3 amps is a real possiblity.

I made a PWM with a NE555E timer, discrete TO220 FET transistor (forgot the part number). It easily handles 5 amps with a modest heat-sink of the alum hobby case. It was fun to make but would not do it again; I'd by a LC40.

Most have gone to LED lights. Some panel avionics/ gauges use LEDs, other incandescents, right. I think its mostly LED now a days. The LED's and 'bulbs" might not be so compatible on the same dimmer circuit. As a suggestion, consider making two 3 amp dimmers. Two dimmers gives you flexibility in dimming and eases a possible incandescence / LED's compatibility issue.

As I said I made my own PWM dimmer; it was fun, learned a lot, but this was before the LC40 was available. Frankly the LC40 is better and would have bought it, if available at the time. It gives you 4 channels; you can choose to use one or all of them. Each is 1.5 amps, 4 channels can be ganged together for a master. If you have map light, cabin light you can put it on the LC40 as well. By the time you make 4 PWM dimmers it might be cheaper to buy the LC40.

http://www.fdatasystems.com/LC_40.htm
 
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LC40

The LC40e is very close to what I am building and at a good price. In the under 3Amp there are several high side drivers designed for the automotive industry that will do the job. I do want mine a bit more stout than the LC
I am planing to build a 4 channel 3amp system where the last two channels can be ganged for more current if needed. I am also planning two different response curves to deal with LED vs lamps issue.
 
Neat Chip

Neat chip. Only problem is I will have a mix of bulbs and LED lamps. I also wanted to stick with through hole components so the average joe could build it as well. Surface mount is tough if you don't have the right tools!

Check out this chip.
http://www.national.com/mpf/LM/LMD18400.html

This chip along with a pic or lpc processor would be a two or three chip 'through hole' solution for a 4 channel controller. I have already ordered the parts and have software written for the control logs of the LED and lamp circuits in a single lpc controller.

If you really want to see a 'safe' design check out:
http://www.national.com/mpf/LM/LM9061.html

If the first chip turns out to be underrated the this would be my choice. Really a hardened controller for unfriendly environments and can be purchased from JamesCo. Surface mount only, but may be worth it.
 
EL lights

Kinda off-topic for this thread but I have to ask.
In my work I have found EL to be less than optimal in an industrial enviroment. Given the power supply issues and life span I would shy away unless I knew that panel model could be purchased again.
Is there even a standard panel size or form factor that could be purchases year after year? The inverters seem to have common traits but what about physical size, light output, and interface issues?
 
jdeas said:
Is there even a standard panel size or form factor that could be purchases year after year? The inverters seem to have common traits but what about physical size, light output, and interface issues?
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Not sure what you mean - are you talking about replacing the inverter or the EL strips? Inverters are common. EL sources - the only one I'd use now are light rings, and I think the only ones are made by UMA.

TODR
 
Yea, light rings?

The inverters I have used are 400hz jobs and can be used across several types of EL.
The EL panels are what worries me. I have low confidence that I would be able to find the same panel twice!
In addition, I have had several instances where clients are straining to see their displays. Mostly due to the slow decay of the EL. Until they get eye strain they don't notice the lowering light level:rolleyes:

Now I admit I have not worked with the 'newest' technology here but given what I have seen and the environment of the cockpit, is it a good fit? Manufactures can pay for or stock pile what the use. We can't.
 
jdeas said:
The inverters I have used are 400hz jobs and can be used across several types of EL.
The EL panels are what worries me. I have low confidence that I would be able to find the same panel twice!
Click to expand...
I don't think I'd use EL strips or wires. LEDs should be able to do what you want with fewer problems. EL works well for light rings because of the thin nature of EL.

TODR
 
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