[actofgod]

I used three SPDT switches, a 4"x2"x1" project enclosure, an Adaptaplug hobby leads plug, and of course the resistors. I scavenged a bit-size charging pad from a Cannonball charger, and also added a charging plug for my Micro 4x4. BTW, check out that 4x4 if you haven't seen it already.. it rocks.

Wiring was simple enough. The negative wire from the hobby lead plug (black) went straight to the negative bit charging post and negative wire of the 4x4 charging plug, all soldered together. The positive wire from the hobby lead plug (striped black and white) split into two paths across each switch. If you can visualize a SPDT switch, it has three terminals. The middle one is always being connected to either the top or the bottom terminal. Incoming current will go from the middle (input) terminal to one or the other (output) terminals. The positive hobby plug wire went to the middle (input) terminal of the first switch, the one that would control the 10 Ohm resistor. From there, it would have two choices: run through the 10 Ohm resistor, or bypass it. If it was to run through the resistor, the bottom output terminal was connected to one end of the resistor, and that resistor went on to the 2nd switch's middle (input) terminal. If it was to bypass the resistor, the top output terminal was connected directly to the 2nd switch's middle (input) terminal directly, with no resistor inline. So the 2nd switch would have two wires attached to its middle terminal from the 1st switch, one with resistance and one without, but it is only possible for one of them to be used at a time. The 2nd switch would repeat the process, sending one output with no added resistance (just the resistance from the previous switch, if any) and one output with an added 22 Ohm resistance. Both outputs would connect to the 3rd switch's middle (input) terminal. It would then send both final outputs (one without resistance and one with the 68 Ohm resistor) to the charging base's positive terminal, which is also connected to the 4x4's positive plug wire.

A diagram might help:

START                    to car
 ||                      [-][+]
 ||                       ^  ^
 ||                       |  |
 ||                  [charging base]
 \/                    neg-   pos+                
                        |      |  \<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-<
hobby lead             /        \                                 \
neg- -----------------/          \<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-   \
                                                                \   \
pos+ ->->                                                        \  |
         \     [switch1 top]--\  [switch2 top]--\  [switch3 top]-/  |
          \->->[switch1 mid]   ->[switch2 mid]   ->[switch3 mid]    |
               [switch1 low]\  | [switch2 low]\  | [switch3 low]\   |
                            /   \             /   \             /   \
                          (10 Ohm)          (22 Ohm)          (68 Ohm)

If you follow the top path across the switches, you see you'll encounter no resistors. A path across the bottom will hit all three resistors; six other combinations are possible. Attached is a closeup of the wiring, but it's hard to make it out.

Hope this info is useful; I learned a lot doing it. If you already knew all of this, then you're the perfect person to correct any errors I may have made. Comments welcome.

Happy modding.