PowerEx MH-C9000 Battery Charger Problems From Maha Energy
I bought a Maha Energy PowerEx MH-C9000 battery charger and eight PowerEx 2700 AA batteries. The batteries lasted longer than the charger!
I paid what I felt was a premium for this charger. I used the charger once or twice a month to charge batteries for my camera. After three years and six months, the charger failed. It charged and reconditioned the battery in the first slot but did nothing with the batteries in the other four slots. The warranty is three years.
I emailed Maha Energy support and got a response from Eric Cheng asking me to reset the charger and try again. I did so with the same results and he determined the charger was broken. Eric indicated the warranty had passed and the best they could offer was a 25% discount, "The discounted total is $52.46 plus shipping. Let me know if you are interested."
I think I might have let things go if it were not for this last offer. I was disappointed the company would not stand behind the product and fix or replace my unit at their cost. The warranty had just recently expired. However I did not expect them to make additional money off of me. Worse, it was not clear if the replacement would also fail!
I looked on line to see what the current price of the charger was. Much to my surprise the first four shopping links on Google offered the charger for less than the 25% discount offered by Maha Energy! Why would I pay more for the replacement than I could get it online. Why is Maha Energy charging me so much?
So visitors to my Sands Mechanical Museum know I like to take things apart, see how they work, and sometimes fix them. The battery charger was a lump and I decided to take it apart.
This shows where the corrosion was on the number two position battery contact. The blue devices appear to be temperature sensing and should prevent the battery from over heating. Some of the corrosion has already been brushed off so I could see where the problem might be but some of it remains. The yellow arrows are pointing to two black holes. Originally they were also covered with corrosion but they are supposed to be shiny like the other holes.
The reason the battery charger failed is that the corrosion etched away the conducting material around the right hole. This caused the trace conducting electricity to be broken. There is supposed to be contact from one side of the right hole to the other side.
Here are the same two holes on the reverse side. The resistor at RT2 was also covered in corrosion but did not seem to suffer and was still connected to the metal trace at the hole. I cleaned the area around the hole on both sides, stuck a wire through the hole, and soldered it on both sides.
This is the inside of the base of the PowerEx Charger, showing the corrosion. Note the material must have traveled down onto the circuit board, through the tiny holes, and pooled on the plastic in the base! I suggest future designs have a tray to catch the corrosive material before it reaches the circuit board.