I changed my mind - I wanted to get the charger going so that I could keep the battery pack easily filled up. I started with a plastic cover plate, and drilled a hole in it to match a marine outlet that I had purchased earlier:
The cord for the charger comes out in an outlet box in the former gas tank filler opening:
I threaded the cord through the plate, and attached the wires:
Finally, I completed it by attaching the plate to the box:
Here it is, plugged in and charging:
To avoid damage to the batteries, I am only charging to 330V for the pack (this is roughly 12.7V per battery). I will charge the individual batteries to equalize. This will only be necessary until my battery management system shows up (I already have a PakTrakr installed for monitoring purposes).