Bests & Worsts Reviews from Amazon

The adapter works great with any 20v MAX battery, and with most all 18v tools. And, it will also work with any 18v tool, if you modify the adapter (note it will void any warranty), but it is just a $50 adapter. There are notches that stick out on two sides of the adapter that will need to be cut off or ground down, see my picture. I used my bench grinder, takes less than 20 seconds to finish the job. After the modification, it will fit in any 18v tool. Please note since all 18v dewalt tools are actually running on 20v, there is no harm in using this with any of the dewalt 18v tools. The only tool I have that does not want to work correctly is my 18v finishing nailer, which will turn on the yellow light indicating low voltage when using this adapter (and I thought the new battery's had higher voltage than the old 18v battery's). All my other 18v dewalt tools work with my modified adapter, and I have almost every one of the 18v tools. One big negative to this is it will drain your 20v MAX battery if you leave it plugged in to the adapter. I have 4 of these DCA 1820 adapters, and they all show resistance when using an ohm meter on the terminals. I've left the 20v battery's in fully charged for a couple of days on all 4 of the adapters, and they all gave me 2 lights (indicating the battery is being drained) in that 2 day time period. It is a pain to leave the 20v battery out of the tools during storage (to keep the battery's from being discharged), so that is why I gave it 4 stars, but overall it is a good way to use the new battery's with the old tools.