Good for You Jason, you "hit the Nail on the Head" .
From: Jason Taylor jt.yahoo@jtaylor.ca [electricboats] <electricboats@yahoogroups.com>
To: electricboats <electricboats@yahoogroups.com>
Sent: Mon, Oct 24, 2016 10:08 am
Subject: [Electric Boats] When things fail away from home - the need for remote CANbus support.
basically just some musings on the reliability of electric propulsion
systems and how to keep going when "something fails". Mike on Bianca
recently lost a season due to issues with a battery and his controller.
Some (not electric) boats at my yacht club recently lost valuable
sailing time due to engine issues. I had an issue with water finding
its was to my battery. I have even had a minor issue with the key-start
(water again). My issues were quickly and easily resolved, but it got
me thinking...
One of the features which drew me towards electric was the ease with
which individual components can be replaced compared to diesel. But
judging from some recent component failures I have 1st and 2nd-hand
experience of, I don't think that's quite the case. Both technologies
are fraught with expensive, hard to find parts, requiring sourcing from
the vendor. I still wouldn't go back to diesel, but these past couple
of years have opened my eyes somewhat.
How would you compare season-debilitating problems you have suffered (or
could suffer) to a diesel boat? We had two boats at our club have
engine troubles mid-season. One actually had to replace his engine (he
followed his mechanic's advice and did not go electric) and the other
had a fuel pump fail towards the end of the season. Yes, around these
partrs, end of October is pretty much end of the sailing season. It
makes me sad, but it just means boating has a more project and
maintenance oriented aspect.
The boat that replaced their engine was out for about 9 weeks (mid July
to end of September).
The boat with the failed fuel pump was out for about a month.
Both boats suffered delays from parts and mechanic availability.
I have been thinking about this a lot as regards my boat's electric
propulsion setup. What are the parts that could really play havoc my
season? How could I get back on the water as quickly as possible?
Personally, I am not about to stow a spare motor, controller, charger,
and battery for those "just in case" situations. That's a lot of
capital tied up in contingency. But how can I salvage a holiday (or
even the entire season) if any one of those fail?
Battery:
I think the most difficult part to replace is a Lithium cell. Because
they have a shelf-life, and lithium prices have fluctuated recently,
nobody stocks them which means that any replacement would have to come
directly from China. I can probably get around this issue by have a
house-bank made up of 4 identical cells. Should a propulsion bank cell
fail, I could scavenge from the house bank and short-term replace the
house bank with a wet-lead deep cycle from Sams or Costco.
Motor & Controller:
Since the motor is brushless, it relies on the controller to operate.
Being brushless, there is very little that can go wrong with the motor
itself. No contacts to wear out or short. So long as it isn't given an
over-current situation and is kept reasonably cool, it should outlast
most of the boat. To get the most out of the motor, the controller
needs to know everything about the motor and how it should be used. I
can't just swap out a dead controller for another one. Not even a same
make/model one. It needs to have the vendor-supplied motor profile
installed. This makes me reliant on my vendor exclusively for
controller issues. I either find a way for the vendor to do remote
config support on a new controller or I ship it to him and wait. I am
convinced that a RaspberryPi (tiny, low-power computer) with a CANbus
controller would be perfect for a vendor to do onsite support of the
motor controller from their location. If anything, they could
overnight-express ship a module to the customer and guide them in
connecting it and then upload the new firmware remotely. It's a matter
of time before all the vendors do this, or just build it into the
installed system directly for telemetry.
Charger:
The charger is pretty much a non-issue. My charger has profiles for
lithium packs from 8 to 18 cells. My pack is 16 cells. So if I lose a
cell or two, I can still charge the pack properly. However, with my
Battery Management System in place, any plain old constant current /
constant voltage power supply would work just fine, so long as the BMS
can control it, which it can via a solid state relay on the charger's AC
supply.
So, my critical components are a 100ah lithium cell and a programmed
motor controller. Everything else is just hardware that can be cobbled
together from any electronic parts store or West Marine. Since spare
cells can be carried on board by way of a small house bank, that leaves
just the controller and its programming as the critical path.
In closing, as a quick plea to all the vendors out there, any chance we
can home on on this remote CANbus management idea? It really would be a
boon to the e-boating industry as a whole if one vendor can provide
hardware for another vendor's system, and then allow the individual
vendors to support their customers remotely. The Raspberry Pi with a
CAN controller would also allow for system telemetry to be sent to the
vendor for ongoing profiling and customer support. This is also
something that is available for larger diesels and is certainly going to
be an option for new installs on smaller ones as well. A massive data
set of engine performance would also do wonders for our field.
Cheers,
/Jason
--
Jason Taylor
--
S/V Fugu
1978 Beneteau First 30
Electroprop PM-20
Posted by: GNHBus@aol.com
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