In this post I will show you how to replace the batteries of an Anki Overdrive car either to increase the capacity or to fix a broken LiPo pack. But first a warning: this process will most likely void your warranty. Only do this if you know what your doing and on your own risk
As I wrote in this post I recently won a Anki Overdrive race track. It is a really cool toy and with its SDK a wonderful opportunity to play with it on a technical level. But I was quite disappointed when one of the cars seemed to have a broken LiPo battery: after a few warm up rounds I would get a battery warning and after a few more rounds the car would just stop working. I decided to open the car and to see what might be the problem. After all I had won the race track and it might be complicated to claim warranty without a receipt.
This article on ifixit about the older Anki Drive cars made me believe that it wasn’t too complicated to take the car apart. After all the Anki system got a repairability score of 8/10!
The result of the replacement is promising: the pimped car is not only working again but has even increased capacity, since the new LiPo has 100mAh instead of the original 70mAh!
Replacement battery from ThingPulse. By buying the battery here you are supporting this blog
Taking the car apart
You can see three screws if you turn the car upside down and look at the bottom. But only the biggest one in front of the car holds the hood in place. Unscrew it and you will be able to take the hood off. That was easy, right? Now to the slightly more complicated part. The PCB is hold in place by two tiny latches on each side of the car and two hooks at the back. Carefully release the latches and take out the PCB. Make sure that you don’t rip off the tiny wires at the back of the car which lead to the motors. Don’t try to completely remove the PCB from the black plastic part: the engines will stay connected with the motor during our little operation.
Now you can see the LiPo battery and the two forked light barriers which measure the motor speed. At this point I also realized that the LiPo pack had a soft bloated top which indicates that it was past its best time and degrading quickly (and also becoming more dangerous).
Replacing the battery
Now let’s replace the batteries! Heat up your soldering iron and carefully unsolder the red and the black wire connecting the battery with the PCB. You might want to use a desoldering wire or a desoldering pump to remove the excess solder. Also make sure that your wires don’t accidentally touch a part of the PCB. This might destroy the car! To avoid this wrap a tape around the end of the first wire.
Once you have removed the old battery we can continue to add the new one. Here we have a similar problem: you don’t want the wires to touch anything but the intended patches. Don’t forget that your battery is at least partially charged! Use tape or a third hand to keep the wires in place after removing the plug.
Closing it up
Now either use the double sided tape which held the old battery in place or make a “tape loop” and attach the battery to the PCB. This will help you to fit the PCB back into the chassis. Make sure that the end of the battery touches the optical sensor. When everything is nicely centered and the wires are in place slide the PCB into the hinge at the back of the car and make sure that the engine wires are placed in the slots. Now carefully move the PCB down below the two latches. My new battery is slightly bigger than the old one which causes the PCB to not completely sink into the chassis but this appears not to be a problem. Now use the screw to put the hood back in place.
Now put together a race track and use your car with another one to test the capacity of the new battery. The first time I put the car back together everything worked fine from the start. Then I took it apart again for this article and after that the car behaved as if it couldn’t read the race track anymore. I think that the forked light barrier might not have been in place properly or one of the cables obstructed the light. In that case open the car up again and make sure everything is in place. The second time everything worked fine.
I choose “Battle” mode to test the cars since they run until one of the cars wins enough points or the batteries run out. While the untampered car ran and eventually showed a “battery low” warning on the smart phone the pimped car continued to run for 20 more rounds without any sign of batter warning until the normal car just stopped. I know this is not a scientific experiment but it seems that the pimped car really profits from the increased capacity.
My little operation Save-the-car was a big success. The USD $50 car which was dead on arrival runs now longer than the stock cars for a cost of USD $3.- But be warned: I would only recommend this operation if your car is broken anyway or you are quite handy with a soldering iron. It is very easy to destroy it completely.
Please leave a comment with your experience if you also decided to do the replacement to encourage (or discourage;-)) other readers.
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