Keep in mind that the 12kw motor
rating is probably for its max rated voltage, which is likely 96V. And 12kw out of a 48v bank would be about 250 amps. Just sayin. Nevertheless the motor
should be sufficient for your intended usage.
It is nice to plan for switching to a bigger prop, but you may find that you just can't swing a bigger prop. You need a couple inches clearance with the hull
. But cleaning
the one you got will improve performance a LOT. You can do it in the water
, in minutes. At least knock the barnies off. With EP, you will find yourself more concerned with incremental improvements in efficiency such as clean prop and hull
FWIW my bank is also 48v on my electric boat
, and consists of 8 GC-2 golf cart batteries
from Sams CLub, now I think 4 years old, still going strong, at a cost of $85/each, giving me a 10.56kwhr bank. I am quite pleased with my return on that purchase
. I also eliminated the old 12v house bank. One bilge pump
, the higher one, is connected directly to the first two batteries
. The second, lower one, and all other 12v loads, come from a DC/DC converter.
You will appreciate the improvement in usability and maneuverability of the EP system. Instant on, instant torque, near instant reversing, no startup sequence or lucky charms or incantations or prayers when you hit a start button. No minimum idle speed!!! If you want to ghost into your slip at 50 RPM
, you can. No more bumping in and out of gear
at 700 RPM
Regen really doesn't offer much until you are regularly achieving double digit speeds. On my boat
, it was very small indeed, I think I was getting around 140 watts or so, max. Not enough to be concerned with. Better to just let the prop windmill with no load. An old school
two blade sailboat prop, locked down in the vertical position, would also be good. The original folding prop was too small but a bigger one might have been okay. Anyway prop drag will never slow you more than about half a knot
, on the typical sailboat. If you were in a hurry, you would have a different sort of boat altogether, I am thinking.
Another advantage to EP is "power tacking". Some boats are very stubborn tackers, particularly when you don't have crew to handle the headsails. In this day and age of fin keels and boats that pirouette on the head
of a pin, a whole new generation exists that think wearing ship instead of tacking through the wind
is comical and lubberly. And it is a PITA, too. So you flip one switch, turn one knob, and instantly you have mechanical propulsion
to force her across onto the other tack. Even singlehanded full keelers are very tackable if you give it a little push with the prop. Would you really want to start a diesel
for every tack? No? I didn't think so. Nobody does, AFAIK.
The portable generator
is a common means of extending the range of an e-boat. The Honda
2k is very popular. I have a 2k Ryobi that is very light and portable, has bluetooth connectivity, starts on the first or second pull, sips gas, and so far, knock on wood, has been very dependable. I use a Variac connected to the 120v output, to feed a welding rectifier for charging
batteries while underway on battery
power. Requires careful monitoring, yeah, but it is a cheap
solution. The variac and rectifier together were only a couple hundred bucks, at most. The Ryobi lunchbox genny was on sale
for $500-something, I think, at Home Depot. This is NOT an efficient way to run an EP system, but it will get you home if you overextend your battery
use. It will never be needed for day sails
or weekenders, for just ins and outs, anyway. Shore power
will take care of that. Cheap insurance
though. And if you have gasoline aboard, may as well hang a little Tohatsu long shaft outboard
on the stern, for additional backup.