Hello,
I saw the thread about the battery maintenance. This was helpful. Thanks!
But what else do I need to look for? I see some claims of “maintenance free”. Is this really the case?
In the battery related thread someone mentioned W40 for the jet engine. Is this just for salt water or also when riding on lakes?
Sorry for all the questions, but if you pay 10k bugs or more you want to make sure the toy will last for a while 
Thanks in advance!
EP (no, not the real one 
)
Most electric boards are maintenance free until they break 
If you use it weekly there is not much else to do rather than clean it properly and charge. As all electric boards are sealed and waterproof, there is really not much you can do for maintenance inside the board or control.
The petrol board - you can open the hull and clean inside, put W40 to protect from corrosion, change grease etc, it’s more work but more chance that you can fix smaller issues yourself.
Copying this from the battery maintenance thread for reference:
https://forum.e-surfer.com/t/battery-maintenance-winter-storage
How do you know that the battery is charged 40%?
You probably have to make an educated guess.
Given that the charging process is faster at the beginning I would charge an empty battery may be 20% of the time compared to a full charge.