Torqeedo Cruise 4.0 on a 2.8 Dinghy - my experience and a request for other info

[jshukis]

Here is my Torqeedo experience:

I recently picked up a Torqeedo Cruise 4.0 on eBay for a really great price. It was new/unused and never previously sold, with full warranty, but was an older model left sitting on a shelf for over a year.

It arrived looking good, and worked great in the livingroom, so I mounted it on my Avon 2.8 inflatable and fired it up. Or rather I tried. I got an instant error.

Long story short, this older model had a fiber reinforced plastic motor pod, and a particularly gruff shipper dropping the box just the right way could cause the skeg to push up into the motor housing and crack it. This is what happened to me.

Torqeedo support was EXCELLENT. They acknowledged the issue, and let me know that they had already changed over to CNC aluminum to address this issue - but had raised the price $400 to cover the more expensive material. In spite of the price increase, they offered to replace my older motor pod with the new one at no cost to me, except that I covered sending the motor to the US service center.

I received the updated Cruise motor over the holidays. I launched it, and it is absolutely awesome. It is lightweight and very powerful. It is also very quiet, doesn't smell, doesn't leak fluids and ruin clothing, and can be safely stored below deck. Yes, Torqeedo is rather expensive, but as an occasional dinghy user who hates the noise, smell, and hassle of outboard motors, the Torqeedo is a revelation and worth every penny. My Honda is now officially retired. Were I a full-time cruiser I'd likely feel differently, but as a weekender I'm a huge fan of electric.

Here is my setup:
Avon 2.8 inflatable dinghy with high pressure inflatable floor - 2006 or so model
Torqeedo Cruise 4.0T
8x BMZ 24V 20Ah Lithium batteries, configured 4P2S into a 48V 80Ah pack. These batteries are tiny, and the whole pack fits under the dinghy seat**

Results:
With the standard propeller, I plane easily at 11 knots drawing 3,200 watts. It's a 4,000 watt motor, capable of drawing 5,000 watts for some number of minutes, so with my lightweight dinghy the motor is RPM limited only. I plan to try the "speed" propeller instead, which will provide significantly more speed and possibly better efficiency at lower speeds - we'll see about the latter.

Just for fun, I ran with the throttle set to use 1,000 watts in order to simulate a Torqeedo travel 1003. While certainly just fine for a leisurely non-planing trip from the boat to shore, and a decent simulation of my Honda 2 hp outboard, I have to admit that I liked having the other 3,000 watts to play with.

** Like the Torqeedo deal, the batteries were another eBay find. BMZ is the German battery manufacturer that makes the Torqeedo batteries. But instead of $5,000 for two Torqeedo batts, I paid $1.080 total. Granted my pack has only 80% of the capacity, and lacks the very cool Torqeedo CAN bus communication, but my setup is only 1/5 the cost for goodness sake. BMZs are rated for "10 year" lifespan and are VERY nice batteries. I will end up making a water resistant case for them - I'm thinking of building it into the dinghy bench seat. Total pack weight is around 64lbs.

Question:
Most people are using the Torqeedo travel with the inflatables. Has anyone else used the Cruise 2.0 or 4.0 on a small inflatable? Has anyone tried the "speed" propeller?

[charm quark]

Hello jshukis

I can tell you some of my (similar) experience with a cruise 4.0 on a "Grabner Speed" inflatable.

http://www.grabner.com/boote/motoris...aten-ausstatt/

I am using it for 4 (or5?) years now (only in holydays, in the mediteranean), and I am very pleased with it. and excited! and still impressed...
Only one DIY "conversion" I did for that, and I think it is badly needed or recommended, or a "must" in that configuration, is a very flat and stiff, lightweight (stackable) carbon fiber bottom inlay. Fix-mounted on this, as the center seat, is the box that holds the battery, I am using 16-S Winston 90Ah LiFeYPo - and it was always sufficient.

Boat is somewhat >30kg (sorry, only know SI), + Battery app.50kg.
I am running it with the v30 prop w/o issues, with one person only, speed is above 27km/h (15knots), with two, up to 24km/h (13)

With the std prob, speed is around 20km/h (<11knots) only, but even with two persons it hardly draws more than 3500W on full throttle, and it is still able to plan with even three persons... but this is a little too much payload for this small rig. It's more fun riding it "solo" with the v30 prop - that is almost like a powered surf-board (its' possible to steer it by moving the center of gravity) or like a kind of jet ski.

[myocean]

How do you charge your batteries?

[charm quark]

by just a simple 800W charger, which is specially designed for 16S LiFeYPo4... (sure you could also use a 4S charger and charge each 4 in parrallel... but it would take 4x more time at the sam current) I Don't use any BMS or somthing, just monitor (and document) each single cell voltage bevfore/after each ride/each charge. From time to time I do a little balancing - but it is not really needed within 3 weeks of daily usage (I typically use less than 80% charge), so I actually do it only once, over long time period, before each season (by storing the cells connected in parallel at 3.7V).