Jzh_perth wrote: The Wavejet surfboard produces 20 lbs of thrust (2kw i believe) and is sufficient to propel a surfer along at 10mph apparently.
It seems that both power and battery voltage escalade are very likely to occur.
Found in the general performance specifications of the 2016 WaveJet Model A power pod:
• Maximum thrust: Model A: 20 lbs
• Minimum run time: Model A: 30 minutes of continuous run time
• Re-charge time: 3.5 hrs
• Nominal voltage: 21.6 volts (V nom)
• Nominal capacity: 27 amp-hr (I nom)
• Nominal Watt-Hour: 583.2W (= V nom x I nom)
• Normal voltage operating range: 19.5 to 24 volts = 21.6 +/- 11%
So 583 W <=> 20 lbs OR 9kg of thrust can supposedly move a 80 kg mobile over the water at
8knots for 30 minutes wih Lithium Ion batteries, a longer run time if you accept 5 or 6 knots.
Obviously, it's not the type of performance we're after.
At least twice this power combined with the HF performance factor (minimum wet surface) should allow to reach approximatively 2 to 2.5 times this speed.
So choosing a minimum power of 1.5 KW seems to be a reasonable tradeoff and a good start, that is 12-15 knots for 45 to 60 minutes run-time. It's just a guess.
There is a lot to learn from the e-surfboard world. They use Li-Ion batteries to maximize the very short run time....Although the lithium-ion polymer (LiPo or LiPoly) battery is sleeker, thinner (10% better energy density) and very popular in the R/C world, lithium-ion batteries cost less to manufacture.
The Carver board
from aquilasurf.com = onean.com (Aquila group) , 4400W Water JET, 19 to 22 knots for 20 min max depending on water surface , rider 80kgs
- cost 5000eu incl VAT
they have the type of water thruster we're after !!
The extreme in terms of power and price:
The Boost board
from lampuga.de from Hamburg, 11Kw (15HP) water Jet, claims 34mph or 30 knots during 20 min, 52V Li-Ion battery and cost €13.000 or €18.000 if carbon Edition !!