My idea for my first mod...

[Walrus]

It's going to be bulky, heavy, unattractive, impractical, and altogether satisfying if I can pull it off (and I do mean if... I no longer have a steady hand.)

I'm planning on running two 18650 batteries in series, with an UCC383TDKTTT-5 low dropout regulator. Imagine 5v at 3000mAh capacity.

I've ordered the regulators and a custom 18650 battery holder. Next to look at project boxes at Radio Shack. I have no plan, I'm making this up as I go along.

 

[Kewtsquirrel]

Linear regulators run at about 40% efficiency and require a vin 3 volts higher than regulated vout. The extra voltage isn't saved, its bled off via heat from the voltage regulator chip.

tl;dr You need 8v to run a 5v regulator and your batteries will only last 40% as long as they did unregulated.

 

[planetofthevapes]

Oh well, all in fun. How big are those batteries walrus?

I did my first project with a regulator on saturday, worked out beautifully. I used a 9v in an altoids tin. Fun fun fun! Of course 9v batteries have like 120 mah, so it doesn't last long...but what the heck right?

 

[Laredo7mm]

Linear regulators run at about 40% efficiency and require a vin 3 volts higher than regulated vout. The extra voltage isn't saved, its bled off via heat from the voltage regulator chip.

tl;dr You need 8v to run a 5v regulator and your batteries will only last 40% as long as they did unregulated.

You need to read the spec sheet of the chip he is using. It is a low drop out voltage regulator. The drop out is 0.45 volts at 3 amps. I am using the same chip from TI on one of my mods with two 1200 mah 18350's. I can vape for 3.5 days on a fresh set of batteries.

18350's are shorter versions of 18650's. They are 35mm long as opposed to 65mm.

Walrus- You will be happy with your mod. It will probably go for over a week on a single charge. Keep us informed and up to date on how it goes.

 

[Laredo7mm]

Oh well, all in fun. How big are those batteries walrus?

I did my first project with a regulator on saturday, worked out beautifully. I used a 9v in an altoids tin. Fun fun fun! Of course 9v batteries have like 120 mah, so it doesn't last long...but what the heck right?

Yeah, I saw your post on that. One thing I noticed is that the voltage regulator you used is rated at 1 amp. Not a problem with the 9V battery you are using, but if you up the battery capacity, you may start drawing more than the one amp that the chip is rated for.

Go to Texas Instruments web site and search for the part number that Walrus gave. Then order yourself some free samples. The wiring will be about the same as you are using now.

 

[kinabaloo]

The beauty of starting with a higher voltage and regulating it to a lower value is that one gets stable performance (for a period) rather than slowly diminishing performance.

Good luck Walrus. Be interested to see what you come up wth ...

 

[Kewtsquirrel]

You need to read the spec sheet of the chip he is using. It is a low drop out voltage regulator. The drop out is 0.45 volts at 3 amps. I am using the same chip from TI on one of my mods with two 1200 mah 18350's. I can vape for 3.5 days on a fresh set of batteries.

18350's are shorter versions of 18650's. They are 35mm long as opposed to 65mm.

Walrus- You will be happy with your mod. It will probably go for over a week on a single charge. Keep us informed and up to date on how it goes.

I stand corrected on the chip, all of the regulators I was looking at were at around 3v drop. It does seem a bit large though, 10.9mm x 15.6mm x 4.9mm according to the spec sheet. Shouldn't be a problem for a box mod, but trying to cram it in something screwdriver or magnum sized wouldn't be fun.

Sorry if I caused you any confusion Walrus, best of luck with your mod.