Combination meter bulb replacement

Maybe this can speed up the process:

LED Resistor Calculator

Ten years is a long wait!

Next question, can you put the LED/resistor circuit in the OEM bulb base? That would make a clean installation.

 

I'm pretty sure Bob could calculate a resistor for an LED with his eyes closed. The trickier bit, as he points out, would be following back the printed-circuit traces to figure out which side of the light carrier should be the anode. Unless you just want to throw a bridge rectifier on it and call it good.

None of that's impossible, but when the replacement bulb 90010-06019 is all of $1.70 over at Village Toyota Parts and your time is worth something, and it uses all of 1.12 watts when it's on and it's off most of the time ... the question could come up, what would the LED save you?

Now ... if somebody wanted to figure out the right polarity for all the bulbs in the combo meter, and design little LED + resistor + base thingies to replace them (with due attention to matching light output and appearance and all that), and upload those to the thingiverse so anybody who wanted to could 3d-print and build them ... that might be a fun project.

-Chap

 

What happens if the LED polarity is wrong ?
If it just fries the LED then I say start with five and replace four

 

Sage, I had to try it, reverse polarity did not fry the LED, it just didn't pass current the other way like a good little diode. So it looks like you would be safe to prep some bases and if installed wrong and they don't light, just turn them around. "Polarity aspect" is now a new term in my vocabularity.
I tried it on some Chinese bare LED's on I had on hand- I am making a separate 12v circuit in my house for lighting so I can run bare naked LED's without the wasted energy and heat of the rectifier-transformer circuit in the bases of the 120v. led bulbs. Their price was awesome, enough bare LED's for the whole house, with a lifetime life expectancy- cost less than a pack of 4 incandescent bulbs!
Using these in hard-to-reach places like the combination meter could prevent ever having to pull that sucker out again.
On the efficiency side, you've got me thinking about changing my headlights and running lights to LED, reducing the load on the DC-DC converter and possibly extending its life, and it would be great for those hard-to-replace headlights, once and done. I see some headlights on Ebay for $2.42 each.

 

I'm pretty sure I can pop my combination meter out and back in again faster than I can usually decide if you're kidding.

There genuinely are some spots in my house I'm thinking of using LED tape that runs on 12V nominal. Underside of the bookshelves over my desk is one, and considering the stack of little chargers, peripherals, routers, etc. that all sit right there plugged into their own individual 12V wall warts, one larger 12V power supply would make good sense right there. Inside of the dark cabinet the stereo lives in would be another.

The LED tape isn't yet close to the lumens/watt you get with Cree's Edison-base bulbs at Home Depot, and the lumens/dollar could also still use some improvement, but all that's improving so fast....

For wiring the whole house with 12V circuits (and not just local areas like a desk or cabinet), I'd still have to think hard about wire gauge and current. Compared to all-incandescent, all-LED could use maybe a fifth of the power originally budgeted for lighting ... but at a tenth of the voltage, that's still twice the current ... I haven't yet looked at what wire gauge it would take to keep the losses down.

-Chap

 

Thanks Chap, I will look at ampacity. I am using all 120v LED now, Ariston micro hot water heater, induction cooktop, large convection oven/mic, threw out the cookstove. Got the power bill down to about 20 bucks a month, and enjoy cooking more. The waste heat from lights no longer causes the AC to kick in at night when I stay up to read.
35 years ago I set my camp in Maine up all 12v and it was great, but today there are such lower draw devices available. I didn't mind paying $8 for Cree led bulbs last year, and would have paid $100. for one 35 years ago.
I want to start using some solar panels and want to avoid the conversion losses of going dc-ac-back to dc at the LED. Same problem with inverter mini split air conditioner.