Simple Mod for a Coast G20

I bought a few lights at Home Depot the other day and two of them were Coast G20 penlights. I like the looks of them and the fact that they were $9.95 each. I figured I could mod them and I did.

I figured I would share one way to mod it, in case anyone else wanted to try it.


Here's the stock light in the package.


Here's the tear down, along with a TIR optic. I couldn't get the head loose on the darned thing. Finally I heated the head to get it unscrewed. You will notice the original white plastic sleeve is warped from the heat. I don't care, I'm not going to use it anyhow. The original optic was a double convex plastic lens. The original led was a 5mm led with a board attached. I'm going to use a TIR optic from CNQG, along with a Nichia 219 on 10mm star.

The TIR optic is just a little too big in diameter, to go in the head, so I used sandpaper on a sanding block to sand down the outside lip, till it would slide in easily.

Once I put the optic in the head, I could do a little measuring and I found I had 20.8mm of room, so I figured the thickness of my led on star and found I could use a 1/4" copper coupling with a .250" thick copper round and come up with a workable stack height. I intend to use the black plastic end cap on the original stack, for the positive terminal, just as it was. I will need to cut it down to fit, but the stack height should be just about perfect.


Here's the copper coupling with the copper round soldered on and the center has been filled with copper shot and solder. It makes a very nice pill and a very big pill, for a penlight.


Stack up next to the head. The plastic end cap will bring it up to flush.


Here's the whole pill. The led is glued to the copper with AA and the plastic end cap has been cut down to be short and give just the right overall height.


The inside of the head already had grooves cut for the original driver that sat in the head. I just deepened one of them, so I could force the ground wire in, along side the copper pill.


Positive terminal, not pretty, but functional.


TIR fits like it belongs there.

Beam shots with a stock light and the modified light.









This is not a powerhouse. It's a penlight and it's not designed to scare the neighbors. I am using the two Alkalines that came with the light. NiZn or Primary Lithiums could also be used. Do they make AAA NiZns?

Anyhow, I think I like it better with the mod. The original light was blue white and I just hate that color.

That's all.

Dang great mod there OL! Makes me want a pocket protector to put it in!

The pep boys pen mod made me start wanting one and have been looking. Now this is probably gonna start my pen light collecting and hoping some day i can craft something this special!

Also - been looking for copper rounds on eBay nothing really comes up on the searches I have made, where do you get those at?

Thanks and nice mod



Search: Copper Disc

Looks like it… Ebay is your friend:

That stock TIR throws a sweet lookin’ beam…

What I would like to see is how this mod compares to Coast’s own ‘souped-up’ versions of the G20 the HP3 and HP4. I can tell you that my HP4 is ALOT brighter than the stock G20 I picked up the other day at Home Depot. But it’s hard to say how it compares to the modded G20.

Any reason this mod won’t work on the smaller 1AAA version the G10? Many of us got the G10 for free during the promotion ($3.50 shipping) and while the host is nice, the blue tint is off putting and it doesn’t pump out much light. A 219 and a 10440 in the G10 could make it a wonderful little light.

I could send you my G10 so you can try it out if you like. I’m not going to us it as is.

Single AAA won't run direct drive. They would need a driver. There are no aftermarket drivers for diameters as small as are needed in a single AAA light that normally has an ID of about 10 - 11 mm. Only DD, if a 10440 was used instead of the single AAA.

Nichias and most crees need at least 2.4v to turn on at all and that's nite lite territory. 2.8 - 3 volts to get them fairly bright.

but the two lites I just sent ya have a driver in them of 11mm. I tried a 10440 with it and it worked with the stock super-bright led. Although it’s prolly pushing it.

I’ll be posting some pics of it later on here soon. Here’s the original thread…….

Yes, there are lots of drivers in AAA lights all over the place. I just have not found any aftermarket drivers we can buy that have that small of an OD. Even if they did, they would not be able to push more than a few ma, so DD is still brighter with a single 10440, but of course, heat is the killer. These lights just were not meant to see high powered leds in them. These mods are for fun, but they hold no true value. If they are run on a single li-ion, the heat will kill the led soon enough. Using Alkalines DD gives enough voltage, to light the led up and it’s fairly brtight, but does not give the amps, so while the light is bright (compared to stock), it still doesn’t get hot as fast as a Li-ion would.

11 mm drivers. If you find any l would hate to be the one soldering to it. Those TIR's are fantastic. Thanks to your mods I've used a couple now and a real fan.

IS has 13mm 500 mA AAA drivers. As soon as I get home and can fix my iron one will go into that Utilitech AAA light but it is damn small.

What do you think of the AK-007 from DX?

The Coast G20 is on sale at Home Depot right now for $5.00 with free in-store pickup.

I like your after mod beam shot the best!! Danged nice!! Thats a great improvement over the stock output.

NICE!!! Dan

I think some of these single AAA lights could be done with 1 - 3 7135 chips. It seems to work in the two I’ve done(soon to be 3). :slight_smile: I have a G25 that I had to heat to remove the two head pieces. Both had adhesive on the threads.

At only 5$ others might try this mod too :P

twice as much fun as the G10..