When my DeWalt 18 volt 1/2 inch drill broke, I sprung for a 20 volt L-ion replacement, then got a 20 volt skill saw. They were so impressive I though I should replace my 18 volt saws-all too. Instead I found a cheap 18 to 20 volt adapter on Amazon. Cost less than $20. Worked great - my saws-all runs about 4 times as long with more power. I recycled the old nicads and invested in a bunch of knock-off 20 volt L-ion batteries (which also work just fine at a third the cost of DeWalt brand).