I wrote:

And.. it would actually be nice to get a 20-30Ah portable battery pack for the dinghy, but they'd need to be 3C cells (to draw 60-90A continuous). Maybe some day...

Quickly browsed through the AliExpress store where I bought my cells. If this product description is to be believed (looks like the same line that I have) these 20Ah cells can handle up to 10C (200A) continuous discharge, for €245. Slap on a €58 Daly BMS and you have a 24V/20Ah (~500Wh) battery for ~€300. Judging from today's trials 5A should be enough power to drive you along in calm conditions, so the range would be up to 4 hours, although under average conditions it would probably be between 1-2 hours. Unfortunately the cells are only available shipped from China so I wouldn't have time to wait for them to arrive. Another time.

Figured out how to wire the BMS:

It was a bit of a challenge due to there first of all being two B- and P- wires (the blue and black ones from the BMS) instead of one in the instructions (since most other Daly BMS's) but they're just doubled, instead of using a thicker gauge I suppose. And secondly due to the sloppy Chinese instructions in questionable English. But I managed in the end and all voltages were correct!

Next up, as I bought a 150A fuse locally yesterday, I connected the Victron charge controller and the ammeter and gave the electric motor a dry run. Worked just as it should, showed a 3.3A draw on maximum revs.

Unfortunately it's been rainy here today and will continue tomorrow, so splash tests will have to wait. And should probably build a better battery box in the meantime anyways. And I will need to get started on sewing the sail. Rain-free days aren't expected here until Wednesday.

Edit: For the production version I think I will wire the solar charge controller directly to the battery, bypassing the BMS. This in order to protect from the case where the BMS shuts off the batteries for whatever reason (low/high voltage), which would potentially kill the SCC if the panels are connected. Although it might be able to handle it since I have 24V panels, it would be more critical if I had something like 96V of solar feeding into the controller, with nowhere to discharge. From what I've read.

I wrote:

Yay, my 24V 190Ah LiFePO4 bank has finally arrived! Now I just need to wait for the 150A breaker to arrive and I can go and give the electric motor a go.

They arrived well balanced, as advertised, with voltages all between 3.267-3.269V.

Grab your own at AliExpress! Price for the above cells is €1325 right now, I paid €1180 back in April.

Oops, I was checking the price shipped from Poland. If you can wait longer (2 months vs 2 weeks from Poland) and order from China instead like I did, then that package is €574.05 + 574.05 = €1148.10. Add a BMS for €112 and you have a 4.5 kWh battery bank for a total of €1260.

I also got a Victron temperature sensor (~€50) as I won't have other charging methods than solar so I don't need low temp cutoff on BMS level.

Cells are held together in two groups of 4 (for easier handling, 2x14 kg) with double-sided tape (gives a bit of spacing between the cells) and hose clamps. BMS cleared through customs yesterday so should arrive any day now. I'm getting excited here!

Anonymous wrote:

While surfing the web looking for website "looks" that might suit the JRA, I happened upon this:

https://www.temofrance.com/en_GB/

Maybe not applicable to small cruisers, but I've been thinking for some time that this is what electric propulsion for a small dinghy ought to look like - more like the "longtail" motors. Having tried unsuccessfully to get a small inflatable off a beach with a regular electric outboard, I was thinking of converting it to the longtail format.

Bonjour

I've seen the prototype at the Paris Boatshow in December 2019. It looks impressive.

I was thinking about it for Mingming.

Eric

Darren, I am really impressed by that 2kW motor. It just reminds me og that technology has left me behind.  Anyway, I was never a whale on motors.

Cheers,
Arne