Open the lid, remove the silicone screw covers and undo the screws.
Watch the silicone covers! Don't loose them.
Be careful not to damage the plastic during this step! Using a plastic opening tool instead of a screwdriver may be advisable.
Watch out, the hinges are spring loaded. They tend to fly away when tension is relieved.
As said in the previous step, be careful when removing the springs. They tend to fly away!
Pull out the connector, be careful and only pull the connector and not the wires to avoid damaging them in the process.
The battery is fixed in place with double sided tape. Make sure not to bend and damage the battery when taking it out.
Please note the correct type of battery! These batteries are easily available but failing to use the right one may result in damage to your Waka Waka!
Now put your Waka Waka back together in reverse order. Please note that it may take some time to figure out how to deal with the loaded springs of the hinge when putting it back together. It depends on how you hold it what works best. There is not one 'right' way to do it.