Engineering analysis of charging pod problem
I bought the $13.50 charging pod on clearance at Staples about a month ago. Glad I only paid $13.50, as it has not been very reliable. As others here have also reported, I would often get the "lightning bolt" charging symbol but no actual charge.
I later bought the Battery Guru app, which has the cool feature of indicating both the charger type (which is responsible for displaying the lightning bolt) as well as the word "Charge". Finally, I could fiddle with the thing until it would seat properly and actually charge.
This morning I was reading about other users lamenting about the same thing, so I got off my duff and decided it was time to take a close look.
In one sitting, I inserted and removed my PB fifty times, using Battery Guru to indicate whether the seating was successful (27 times) or unsuccessful (23 times). Of the 23 unsuccessful attempts, 3 even failed to register the lightning bolt.
The high-current magnetic charge connector consists of three pins. On the PB, they appear to be made of stainless steel. On the pod, much softer brass. This choice of metals makes sense from a durability standpoint---much better for the less expensive pod to wear out first. The pod's pins are spring loaded to minimize wear and maximize contact.
The choice of metals also determines which will corrode. When dissimilar metals are in contact, all it takes is some moisture in the air and some electricity to start the oxidation process. Metals are ranked on the "galvanic series" by their respective electronegativities. Interestingly, all the corrosion occurs on the less "noble" metal---in this case, the brass.
Indeed, the PB's connector was spotless, but the pod's connector was tarnished and pitted. I used a center punch to mechanically remove the corrosion. Afterward the success rate increased to about 75%---still way unacceptable.
Someone suggested resoldering, but I feel that's a bit extreme at this point. So I'm planning on first trying two things:
1. Caig DeOxit. This is a chemical that you apply to electrical contacts to remove corrosion. I don't have any right now, but I'll be adding a $7 tube of the stuff to my next order from amazon.com.
2. Sacrificial anode. One clever way to remove corrosion---commonly employed in water tanks and automobile radiators---is to introduce an even less nobler metal into the circuit. This again forces all the corrosion onto that metal, which is eventually discarded. Normally such "sacrificial anodes" exist in a liquid electrolyte, but my idea is to simply fashion some aluminum pins hooked to some resistors, which I will plug into the pod when it's not in use. In theory, any corrosion on the brass will be magically drawn to the less noble aluminum. We'll see if we get bright shiny brass as a result.