Solutions, inspired by our surfoiling friends, exist:
1 - don’t use your battery for take-offs which draw a lot of energy
1.a - use the backwash of a shore wave
1.b - use a pontoon
2 - pump to fly
When/if you can do that with a 30kg board, you can probably sell the efoil 
One can’t do that with a normal propeller, need a low drag one (folding, jet drive (?) )
You need a trained heart to pump efficiently (draws a lot of… energy)
@tamarua_mahina from Tahiti, you rock !
Vid: use a wave backwash and pump:
https://www.instagram.com/p/BteBnGxgSNt/
Vid; use a pontoon and pump:
https://www.instagram.com/p/BuUl5ntgc4L/