Battery Runtime & Charging Planner

The method, in one line

Runtime ≈ usable battery energy ÷ average power draw. Run it the other way and a runtime claim becomes a wattage: a 5.5 kWh pack quoted at 45 minutes implies roughly 7.3 kW of average draw, while an 11.2 kWh pack quoted at 3 hours implies about 3.7 kW. Same category of boat, twice the assumed pace — which is why the number on a spec sheet is meaningless without the condition attached to it.

Published in our motor power and payload guide and our performance data article. We use the same conversion in the open because it is the conversion we ask every supplier to make.

What has not been published

Every figure on this page carries an evidence level, and these are the ones that are missing. None of them is filled in with an estimate.

• —No model in the range publishes a measured runtime under a stated test condition. Every runtime on this page is a published claim, and the claim does not state the speed, payload, water temperature or the state of charge at the start and end.
• —Seven of the eleven models publish amp-hours without a pack voltage, so their energy cannot be derived and their average draw cannot be calculated. The four that do publish energy are the only four this planner can normalise.
• —Charge time is not published as a general claim for the range. The figure comes from the factory or the supplier for the configuration you are buying, which is why the planner asks you for it instead of guessing it.
• —Cycle life at rental duty is not published. A pack quoted at 800 cycles is a figure for a test regime, and a fleet that runs two shifts a day ages its packs differently.
• —No public source quantifies how much salt spray shortens pack life. We are not going to put a percentage on it.

We publish configuration-specific battery numbers with the test basis stated in the quotation. That is a deliberate choice rather than an omission: a number without its condition is the thing this industry keeps getting wrong.

The battery data to demand in writing

Our published position is that sustained cruise draw, cycle life at rental duty, charge time at your fleet voltage and the salt-spray hours of the coating system all belong in your request for quotation. This is the list, in the order we would send it. Ask any supplier for the same, and compare the answers.

• Pack voltage

  Amp-hours alone cannot be turned into energy. "100 Ah" is 1.2 kWh at 12 V and 7.2 kWh at 72 V, so without the voltage the runtime cannot be checked.

• Usable pack energy in kWh, and the state-of-charge floor it is measured against

  Energy ÷ average draw is the whole runtime calculation. We retire packs at roughly 15–20% rather than running them empty, so the usable figure is the one that matters.

• Sustained average power draw at your operating speed, not peak motor power

  Peak power is a headline number. The average draw over a session is what decides the runtime, and it is the figure almost nobody publishes.

• Charge time at your fleet voltage, from empty to full

  Our published planning baseline is one charger per two boats, and a full fleet turnaround only works if the charge time fits the closed window. That arithmetic needs this number.

• Cycle life measured at rental duty, with the duty cycle stated

  A pack that ages visibly faster in a two-shift operation is a replacement cost you have to budget, and a bench figure does not describe it.

• Pack weight

  It decides how many packs one person can swap in a session and how much of the hull payload the battery takes.

• Salt-spray hours for the coating and enclosure system

  We do not publish a salt-water endurance figure for any model, and we are not going to invent one. Ask the supplier for a tested figure or a written warranty boundary.

• The test conditions behind the published runtime

  Average speed, payload, water temperature, and the state of charge at the start and end of the run. Without these, a runtime figure cannot be compared with another one.