Given questions I've been asked, I thought I should add this posting about the main theory of how the boat is powered.
The propellor is driven directly by the electric drive motor with no clutches or gears or pulleys. Details of the mechanics of this are in a separate posting.
The electric motor is (hard-wired) powered from the electronic control unit which itself is hard-wiried to the drive batteries via a high current "off" switch (in reach of the steering position) that isolates the motor control electronics entirely from the drive battery input - both to meet BSS requirements and to isolate the drive batteries entirely from any current drain when away from the boat.
The generator output (coming via its necessary internal diodes since its output is DC) is hard wired to the drive batteries. The solar cell output is (via a diode preventing reverse current flow) hard wired to the batteries.
If the generator is not running, the drive motor simply draws current from the drive batteries.
If the generator is running, this accelerates (controlled by the VCS="Voltage Control System") after starting until it provides a steady 70A (Amps) unless the batteries are coming near to full re-charge and so the charging voltage across the drive batteries starts to rise above a (pre-set on the VCS) maximum value (approx 87.5V) in which case the VCS slows the generator maintaining this voltage but reducing the re-charging current. This effect only comes in to play when the batteries are within about 2% of full recharge, so for virtually all normal "running along" conditions the generator basically supplies 70A when on.
If the boat is stationary, the batteries recharge at 70A.
If the boat is going along at normal canal cruising speed (as an example) the motor draws 40A effectively provided by the generator whilst the remaining 30A recharges the batteries. As a general statement, if the drive current is less than 70A, the generator drives the boat (but crucially via the "smoothing" effect of the batteries since the actual currents are not steady things!) and the ramaining current goes to re-charging the batteries.
If the boat is being driven using more than 70A, the generator provides 70A and the batteries the extra needed. For example, if one is using 90A, the generator provides 70A and the batteries 20A.
Note that no special switching devices are needed for this to happen - it's a basic physics rule (Kirchoff's first law.) Nor do things have to be "steady" - current flow will adapt instantly - and, indeed, in fact the output from the generator is not a "steady" 70A but "wavy" whilst the drive current drawn is not the least steady - because of the electronic speed control the actual flow is high speed short pulses at (approx) 18kHz (18 thousand pulses per second) - but overall the average figures remain pretty much OK. Luckily, as a boat operator, one needn't worry about the detail!
There is a slight pragmatic effect. Recharging whilst also running along is slightly less efficient (compared to recharging whilst stationary - but not drastically.) In everyday terms one needs a short time of stationary recharging at lunch time or the end of the day to be sure to be fully recharged. In practice, one would in any case be needing to recharge the last bit of "pure electric" usage of the batteries, and in practice the loss of efficiency for recharging whilst running along can mean you need 30 minutes of "generator on" rather than 15.
This loss of efficiency is only fractional and at no time possibly puts one at risk of reduced power available, let alone anything drastic like a "flat battery" - one merely needs to run the generator a little bit longer (we are only talking 10 minutes or so - at lunch time or end of the day) until the charging current falls to 20A (as controlled by the VCS) to indicate one is definitely back to effectively near full recharge.
This system relies upon its simplicity to work without problem. Generator, batteries and motor must all work at the same nominal voltage and so be able to be hard wired - electronic voltage conversion units would not be able to average and suppress the effects of the actual currents being in fact highly complex. They would also have to be terribly high power - for example, at least 6kW if the generator had a different working voltage.
The system also relies on the fact the batteries can withstand vast currents in either direction - actual currents flowing zing around very violently at high speed where because the electric motor is a heavy duty inductive load there are short-lived secondary effects of reverse currents through the batteries pretty much nearly as great as the current drawn.. in our case, maximum out is 200A, but the flow "rings" so there are also very high frequency reverse spikes of very nearly the same - very, very brief, but if the batteries could not cope with this kind of effect, would be disaster.
Overall, because the system is Generator -> Battery -> Motor control ->Motor with nothing complicated in between, all possible disastrous so-called secondary effects are eliminated. Where all these potential secondary effects are to do with suddenly disconnecting a heavy inductive load which can produce incredibly high voltages ... can blow electronics and punch through insulation. The simplicity of our system is utterly essential!
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