Hi Jim,
Just to clarify, my gearbox came as part of my Propulsion Marine drive, but they are not too costly. Browning's warranty is only 1 year, but I remember their MTBF being somewhere around 100,000 hours.
I assume that you're talking about synchronous drive belt systems and the "asymmetrical" type that you bring up are like the Goodyear Eagle NRG products with HOT (Helical Offset Tooth) design.
If I were to build a belt drive system, those are the belts and pulleys that I would use, I think that they are perfectly suited to our application. First, they're not outrageuously expensive, and I think that the noise, efficiency, self-alignment and power rating factors justify the additional cost or regular belts. Second, your propeller can not collect nearly the energy that your motor puts out, so regen loads will never get that high (see Myles' post from earlier today). I would have no problem running an Eagle NRG system under all potential regen scenarios below 10 knots.
Lastly, I think that you might be falling into "analysis paralysis". None of this is rocket surgery, don't over complicate things. The regen part is such a small factor of a conversion, you should focus on the drive aspects, get enough motor for your boat, pick the biggest prop you can fit under the boat, add the right reduction to match the motor to the prop, work out your storage requirements (range/cost/weight/volume considerations) and get your boat going.
You can work out the regen part later, almost everyone here takes whatever regen they get as a bonus, but the regen value proposition doesn't appear to be worth spending too much time or effort to focus on that.
Fair winds and good luck,
Eric
1964 Cheoy Lee Bermuda 30, 5.5kW Propulsion Marine drive, 8kWh Lithium batteries
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "jim_ranger_26" <jim_manley@...> wrote:
>
> Hi Eric,
>
> I wound up conflating my response to this post in my reply to Mike, but, the bottom line on the prop is that "analysis continues" - or at least it will continue after I'm able to get into/out of my slip at all.
>
> A geared system is obviously the most efficient (and expensive, I'm guessing, but, maybe not by much, except perhaps lifecycle costs over decades/centuries - e.g., belt life vs. your 100,000 hour warranty) and should have no problem running in regen mode. There are asymmetrical-toothed gear systems that are only supposed to be run under load in one direction, but, those are exotic even for well-heeled boaters (yachters, really), and would have no use in our application (let alone budget).
>
> All the Best as I descend back under the rock,
> Jim
>
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