It was quite some time since I added anything to this blog. Many reasons, including a broken arm... But the project goes forward successfully (but maybe a bit slow...) So what has happened since last summer? Well, I have doubled the battery bank, so I now have 200A 48V now (8 x 100A 12V AGM) (We tested this pack last week with a 4-5h use during 24h, and then the batteries got quite low...)
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Went out on the water today in the nice weather. Tried to capture some data on how many watts per knot is needed. These are my results: (2.3 knots 410W, 3 knots 750W, 3.7 knots 1200W, 4.5 knots 1700W, 5 knots 2900W) Diagram is made with the fantastic site Wolfram-Alpha. If these figures are correct (there was some wind...), my current set of batteries would only give 4.5 to 14 Nautical miles in 1 to 6 hours depending on my speed. I reckon I should double up my battery-pack to be able do any distances with engine only. Continued installation with fitting of motor controller to the motor jig and testing of water cooling system. Here is a picture of my current throttle control. It is attached with velcro so that it can be kept inside when not used. It is made with a rotary encoder (similar to what you find on a modern car radio?) and an Arduino microcontroller. If you rotate the knob clockwise, the motor will start going forward (indicated with a green led light), counter-clockwise and the motor goes in reverse (indicated with a red led light). Continue turning in the same direction will increase speed, turning opposite direction decreases speed. If you push the knob the motor stops. No manual required ? More on how this was built later. Long time since last post, managed to get the flu real bad so I was down for two weeks. Missed the opportunity to work with the boat during easter break, so suddenly I was in a hurry to just get the motor working in the boat before todays launching. Washing and painting was kept at a minimum, no polishing at all... And the electric installation got quick and dirty just to make sure it worked. Looks like a mess: Here you see (from right to left) the motor, the controller, a watt meter for the motor, a 150 A circuit breaker, a 48 V to 12 V switching DC converter, a watt meter for the 12 V system. Yes messy, but, it works!
(I will improve this) The motor runs fine, no vibrations in the coupling. So boat goes in the water, will the power be enough? Well, first experience is that I got forward and reverse mixed up. OK, just to try to turn the throttle backwards to go forward, no problem. Motor is quiet and smooth to drive. When I reach free water, I try some more throttle and easily goes up to 5 knots. I slow down and go down to make sure nothing is getting overheated (the water cooling is not installed yet), but all is cold. So up again and see how fast we can go. 6 knots without sweat, nice! I let it run at 2 knots and check the watt meter, 500 W. So 10% throttle give 2 knots, promising. I drive around for 10-15 minutes before I lay to in our harbor. Watt meter reports a 3 Ah consumption. Is there a Noble Prize for environmental technology? :) It was time to see if the motor and coupling would fit the saildrive. First I added some more heat-shrink tube on the motor wires - the three phase cables and the sensor connector. Then it was time to go down to the boat. To get the diesel out I had rented a lorry with crane. This time I could take the motor in one hand up the ladder to get it into the boat. Nice improvement. The time of truth, had I managed to measure, calculate, design and install the jig correctly? Looking at the axles was promising, but was it straight and inline enough? So, in goes the coupling as well. What! It seems to fit on first try?!
I checked the gaps in the coupling and turned the axle, it seems to be good enough. To know for sure, I need to test it with some speed also, but it looks promising. A happy Staffan :) went home for some lunch. The motor fitting jig needed some trimming to fit. See the "Beach 2015" version below: So after a vacation paragliding trip to Austria (StubaiCup.at) it was time to see if it would fit better now? Yes ! And the newly added slots for the motor supports were in the right places as well :)
Cut up the 8mm threaded rod in 8 pieces, half of them 157mm and the others 165mm long. These rods will keep the distance of 92 mm between my motor jig and the saildrive, enough to fit the motor coupling in between. Tried them on the motor jig, and it looked Ok. Then I took the jig down to the boat to see if it would fit on my saildrive?
Well, it did not quite fit. I had to put it much closer to the saildrive to get it into place. At 55mm it worked. But as I will need 92mm I will need to get rid of some aluminium material in the bottom corners... And they fit on my saildrive :) This week I got my coupling back from the Stockholm splines experts Ingenjörsfima Helfer AB.
Splines specification is: (Kanzaki, SD20 Sail Drive) 20T 30PA 24/48 DP 22.6mm 0.89inch The coupling is bought from Lexar industrial. I choose a 7/8'' L100 3-piece set with the option for one of the hubs to be "blank" (to get splined). This week I got this solar charge controller in the mail - Genasun GV-Boost
This tiny little device promises to charge my 48V battery bank with any input between 5 and 63 volts. I can now be flexible with connecting solar panels depending on needs. I have recently purchased two 100W thin flexible panels (link) that I can connect in series for maximum charge while out and about, or just use one to charge in the harbour during the week. And for topping up the bank during winter I can use my old 30W marine panel. Today I connected one 100W panel through a watt meter and this controller to my battery bank (four 100A AGM) and it seems to work. Watt meter read only 2.5 watts though, guess that snowstorm is not optimal weather... 1. Re-mounted the motor "jig" (6 parts) using sikaflex on surfaces where stainless bolt and spanners touch the aluminium material. This to avoid any galvanic(?) corrosion of the aluminium. (Never use zinc near aluminium...)
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Staffan RolfssonMy hobby project, converting our sailing yacht Pilsner (IMS-33 one-off) from diesel to electric drive. Archives
August 2016
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