Things you'll need:
Old Twist type EGO battery
The cheapest Multimeter you can find. ( You can pick one up for $6.99 at Harbor Freight . I got mine free with a coupon in my weekly ads. )
Soldering tools ( I have only soldered 2 or 3 times in my life. It's not too difficult. )
Pliers or Channel Locks
Step 1: Multimeter Wires.
Cut the Probes from the ends of the Multimeter wires and dispose of them. Drill a hole in the bottom Power Dial just large enough to fee the wires through. Strip the ends of the Multimeters wires so you can feed them through the bottom Power Dial, then the empty tube. Solder or twist them together to connect them to the EGO wires at the top section with the button.
(This will come toward the end of the project)
Step 2: Destroy, and Properly Dispose Of, Your Old/dead Battery...
Grab the button assembly (at the section where the button protrudes) with some large pliers or channel locks and rock it back and forth with some muscle to remove it from the battery tube. You'll want to do this slowly to avoid ripping the wires from the board. (like I did)
Carefully pull the battery from the tube.
Pull the VV twist mechanism from the bottom end of the tube using the same technique used for the top.
Step 3: Prepare the Top End
Send the Multimeter wires through the bottom hole you drilled and connect them to the boards positive and ground wires. Carefully, push the bottom dial back into the tube. Then, carefully push the wires from the button assembly with board into tube and push the button assemble back into the tube at the top.
Step 4: ...and... You're Done!
Connect an atomizer (An EGO or a 510 atomizer or tank should both work)
EGO will screw onto the male threads of the button assembly, or, a tank with a 510 connection into the female threads of the button assembly.
Turn on your Multimeter and set it to Ω "200" setting. Connect any cartomizer or tank to get a reading.
I added a photo of my eVic mod to find the accuracy. Just remember you'll need to set the multimeter to Ω 200 setting and jump the positive and ground connections to check the resistance of your meter. example: if you cross-connect and your meter reads 0.2 Ω's, you'll need to subtract that number from your results to get an accurate reading.
Hope this will help someone.
Steve in Ohio