My v4s sits idle most of the time so maintaining the battery became an issue. I needed a safe & effective yet simple solution. I bought a FLOAT charger. A TRICKLE charger of 1-2 amps is NOT good left on unattended , however, it should be used for charging a dying, weak, or new battery. A float charger IS the correct way to MAINTAIN a good battery.
I ran 2 wires, red & black ( poss. & neg. ) from the battery to a convenient location and added a 2 prong female plug. I cut off the 2 clamps on the float charger and replaced them with a mating male plug, job done. NOW it's simple, plug in/ plug out, I don't bother unplug the low drain transformer from the wall outlet.

Parts I used:
trickle charger- harbor freight #42292 about $6
plug connectors- radio shack #27422 about $2 or/270-025 about $6 nicer
wire, wire ends, solder, electrical tape, shrink tubing,liquid tape, what ever you have on hand or like using. picture posted.

I did it my way- Buyingchina