There are now chargers for electric cars at Cabin John Park near Cabin John Ice Rink and Shirley Povich Field.
The chargers are run by Pepco and branded "EVsmart Life, Fully Charged". They don't have the power level on them, and Pepco's website doesn't list it either. I think they are 50 kw DC fast chargers. That may seem like it isn't very powerful, but, I think they are geared for people who are going to be around for a while enjoying the park facilities. Not only is the ice rink and baseball field (where Bethesda Big Train plays) just across the parking lot, there are also tennis courts and the Cabin John Trail right there.
There are two charging pedestals, each one has a CCS plug and a CHAdeMo plug. You need to use the SWTCH mobile app or RFID card, or call a phone number to start the charger.
For those of you who want to charge more slowly, or who can't charge with CCS or CHAdeMO, there are also two Level 2 J-1772 chargers available. The Pepco website lists the cost of the Level 2 chargers at $0.18 per kWh which is a reasonable price. It doesn't give the power of the chargers, but based on the information they do provide, they appear to be 7.25kW chargers.
There are four parking spots reserved for charging, 2 for the DC fast chargers and 2 for the Level 2 chargers. The DC fast chargers cost $0.34 per kWh which is cheaper than most fast chargers (but they are also slower than most fast chargers). Based on information on their website, these fast chargers have a power level of 45kW, but the nameplate capacity is probably 50 kW.