Ya never know....some people are tinkerers.
I agree on the 20v line, I've been trying to convince my wife I should upgrade. Hasn't worked so well yet though.
Can't advise you there.
Rebuilding your battery pack is easy. Care should be taken to evaluate the build vs buy choice. If your build price is 90% of your buy price, then buy.
There are numerous websites that sell NiCads and other battery types. I use www.batteryspace.com
. They come in all sizes and types.
Step 1. CAREFULLY remove the screws that hold the case together, and CAREFULLY remove the top. Carefully document how the batteries go together. You will need this.
Step 2. With a cheapo voltmeter, discover which pin is positive and which negative. Document. (you always document, because some of us have CRS. (can't remember s t.))
Step 3. Measure the old battery cell. Decide what cell it is, e.g. A, or AA, and whole, half, 2/3, etc.
Step 4. Buy from the website the nearest size battery without going over the size. Choose the option with tabs.
Step 5. Carefully solder the tabs the same way as the original batteries. If there is space left over, fill with cardboard.
Step 6. Test with the voltmeter for proper polarity. Important!
Step 7. CAREFULLY put the top back on and screw it down.
Step 8. (don't laugh) Put on your face shield and gloves, and plug the newly rebuilt pack into the charger. You'll know right away if there's a problem.
Test in the appliance, and enjoy, until it, too craps out and you do it again.
Recycle the old batteries at a hardware store.
Hope some of you are daring enough to try this.
BTW. Li-Ion Dewalt battery pack, $49.95 to $99.95 at HD depending on the size. Batteryspace Li-Ion batteries, $3 - $5 each. You would need 5 to get 18.5V. $25 is 50% of $49.95. Build.