Now is the time on Sprokets when we LAUNCH!

I finally got the call yesterday evening.  The fleet manager of my yacht club called to confirm a Friday morning launch.  It comes a week after my intended launch date of May 15th, but that was only partially due to my own unpreparedness.  Fugu is buried 4 boats deep in the storage yard.  And the big powerboat in front of me still has his winter shrink-wrap on.  The yacht club has a "one week rule".  If a boat behind you is ready to launch, the club gives you one week to get ready or goes ahead and moves you, but charges you.  So, after I got Fugu all shined up and her bottom painted, I notified the club and they in turn notified all the boats in front of me.  No idea if the powerboat is ready, but that is not my concern.  I am ready to launch.

I wound up scraping the rudder down to bare gel-coat, sanding, filling and fairing.  After 5 coats of Interprotect and 3 of VC-17, she looks pretty good.  Also, it's been years since Fugu's had a good scrub of her topsides.  So I washed the hull, then did an aggressive compound (Meguiar's Power Cut compound), followed by a polish (Meguiar's Color Max) and finally a wax (Meguiar's Carnauba Wax #56). For those keeping track, that's 3 trips around the boat on a scaffold and countless shoulder presses of an admittedly light polisher.  The hull was painted with Awlgrip in 1993, but several people have told me the paint is "finished", and at 22 years old, that paint job doesn't owe me anything.  So I don't feel bad about using the heavy compound and wax finishes on it.  Next year, I may try a lighter compound/polish to see if I can make a few more of the swirls disappear, but this made a huge difference in her topsides.

I have to say that she really sines now.  Like she's never shone before.  Fugu, you will be the prettiest girl at the ball.  You deserve it.

50 days of gray.

Here we are a month later, sprung forward to DST and officially a week into spring.
My world still looks cold, wet and gray.
The only bright spot in all this is that it is now only 50 days until launch.

ONLY 50 DAYS!

Work that has happened since posting my lists:
none.

That is all.

So very cold, this winter

As everyone in this part of the world has noticed, this winter is so very cold.  And yet, we know that spring is right around the corner, a scant three weeks away.  It still doesn't make the entire week of -20C weather.  With the wind chill, we have had positively Martian temperatures.  What keeps me going?  A number.  A silly little optimistic number I have in my head.  That number is 77.

77 days until Friday, May 15th.

What is important about that day?  It is my target launch day for Fugu.  It is the day that marks the beginning of the sailing season.  It is at the beginning of a long weekend.  It is also the demarcation point for those that launch their boats early versus those that launch late.  I have traditionally been a late launcher, recently as late as September.  So now, I am latching onto this number and decrementing it by one each day upon waking.

May 15th.  77 days away.
Light winds, bright sun, high waters, calm lake.
Can't wait.

Battery storage and self-discharge

My lithium battery bank was removed from the boat in late October, 4 months ago. At that time, the batteries were charged to 100% and then disconnected and brought home. While they should be able to over-winter in the boat, I reasoned that 1) they were expensive to purchase and 2) they are rather light and relatively easy to carry. Spending the winter in a shipping crate in a basement, where the temperature swings are perhaps 5•C would certainly be better for them than in a fiberglass hull where they will be subject to wild swings in temperature, occasionally dipping into the colder side of -40•C. 

Anyway, the batteries were disconnected in to their 4-cell packs and brought home. They have seen no attention since. Last night, I decided to take a few voltage readings. I was pleasantly surprised to see that all 16 cells measured withing 0.001V of each other - 3.328V. Now I don't pretend that my cheap digital multimeter is capable of proving true readings down to mV precision, but since I was after relative voltage, the fact that it gave me the same reading for each cell gives me confidence in the data. They all settled on a reading of 3.328V. There were a couple of cells that hesitated between 3.327 and 3.328, but they did all ultimately settle on 3.328V. According to the storage discharge curve, that puts my cells around the 85% charge point. Right on track for 20% self-discharge over the 6 months of storage. 

More on battery repackaging

I continue to think about battery re-packaging...
I still definitely want to do one large battery box that contains all cells, main fuse, BMS and SoC meter.
I may even add a battery disconnect.  I recovered one when I stripped all the old electrical stuff from Fugu a couple of years ago.  That way, I can completely disconnect the battery pack when I need to service the propulsion electrical.  The only live terminals would be within the closed battery box.

To pack the cells in any kind of battery box will require taking into account one critical thing -- the cell terminals are not equidistant between rows and columns.  Terminal-to-terminal distance is 61mm in columns, and is 41mm between columns.  This means that I will need to do one of two things:

1. Obtain or fabricate some new cell interconnects with a 41mm hole spacing.  This will go with my existing supply of 61mm hole spacing connectors.  The advantage here is that it favours minimal pack width.
2. Add 20mm spacers between columns of  cells.  The advantage here is that I only need one connector size, regardless of how I interconnect the cells within the pack

But now, I am wondering if a 3x6 cell grid is the way to go.  Perhaps a 2x8 cell grid is better.
In a 3x6 cell pack, I would need two spacers which would add 40mm to overall pack width.
In a 2x8 cell pack, I would need only one.
Advantage 2x8 cell pack.

If opted for using a different cell connector (41mm instead of 61mm spacing), here is how it pans out:
In a 3x6 cell pack, I would need at least 6 such buss bars.
In a 2x6 cell pack, I would need only one.
Advantage 2x8 cell pack.


The 2x8 cell pack is considerably narrower than the 3x6 cell pack, but is 122m longer.
The dimensions of the available space are irregular to say the least.
So now, I really need to decide on which pack better fits the available space.
Both packs will have to be located behind the stuffing box in order to allow access to it for inspection and service.  I think I will just have to mock up both packs from cardboard and test fit them.


Regardless of pack geometry, I feel it is important to keep the positive and negative terminals of the pack relatively close together (but not so close as to pose a short-circuit risk)

Decisions, decisions...

Spring 2015 Projects

Spring projects, 2015

So, at the risk of eternal optimism, here is a quick list of my projects for the spring of 2015.

Integrate an embedded wifi router into Fugu.

The VoCore is a very small (and very inexpensive), 25mm x 25mm router that runs OpenWRT (an embedded linux, specialized in wifi routers).  It is a standard Linux distribution, however and allows one to build all manner of existing software to it.  I already have a Brookhouse iMux, however it only support one wifi device and only runs in Ad Hoc network mode.  It is intended as a wifi cable replacement  The OpenWRT-based Vocore runs a full wifi router suite, with DHCP addressing, NAT, etc.  The VoCore does use nearly 1W of power compared to 0.2W for the brookhouse, but on a 5000Whr pack, this is negligible.  Especially on a day-sailor / weekender.  Here is what the VoCore will do for me.

Add K-Plex to VoCore

One of the tools I am adding to the VoCore is K-Plex, an NMEA routing package.  In other words, this little router will distribute NMEA data to any device connected to the VoCore wifi network.  In short, my iPhone, iPad, navigation laptop and any other wifi-equipped device my crew brings aboard, simultaneously.

Connect battery SoC data to VoCore

The VoCore also has an available USB port.  To this I am connecting my EV-Display battery state of charge meter from CleanPowerAuto.  The EV-Display outputs a fixed-format character string each second that includes a lot of information about the battery pack, such as voltage, temperature, amps, estimated amp-hours remaining, etc.  I can write a parser for this information on the VoCore that will allow three things:

1. Create NMEA strings using the XDR sentence for things such as voltage and current.  The hope is that these could then be sent through K-Plex to be displayed on a laptop or iPhone and become part of a general boat data distribution system.
2. Create a series of web pages that can be accessed by any client connected to the VoCore network.
3. Push this information to a server I control on the Internet.  This will allow me to check battery status remotely.

 Repackage the lithium battery pack

At the moment,  Fugu's propulsion battery is arranged in two columns of 8 cells, which are actually groups of 4 cells strapped together and strapped to a supporting plank.  This was so that I could easily (relatively easily) place the cells in the boat or remove them for winter storage.  After one season, I have come to the conclusion that I would rather have a single consolidated battery pack.  I am going to build a box out of 3/16" marine plywood and a 1/4" lexan top.  The cells will be in a 3-wide (3x 142mm) by 6-long (6x 61mm) arrangement.  Being a 16-cell pack, that will result in 2 5-cell columns and one 6-cell column.  The extra space of the two non-existent cells will be filled with the following:

• the 225A Class-T fuse, required to be within 7" of any source of power
• The EV-Display battery monitor
• The miniBMS.

Hoisting the pack in and out will require some engineering.  I will build a gantry-jig from some pocket-door track and cars, as well as some small pulleys (4:1 reduction) and line.  With this, I can lift the ~130lb pack in or out of the engine bay by myself.  To get it in or out of the boat, I can use the boom and main sheet block and tackle.  Failing that, two people could handle it easily enough.  Either way, this would be best done at the dock and not with the boat out of the water, in her cradle.

Running and nav lights

In 2013, I completely re-rigged and re-wired my mast.  However, since my electrical system was not yet installed, I never got around to filling the old through-deck holes and drilling the 5 (FIVE!) new through-deck fittings for the re-wired mast.  This must be done this year.  At the same time, the wires for my red/green running lights corroded through at the end of last season.  So these wires must be replaced.  It will be an uncomfortable install since the wires are run through the pulpit tubing, into a junction box in the anchor locker (?!) and then along the underside of the deck of the boat back to the main panel at the nav desk.
A number of years ago, I also acquired a new LED stern light.  this needs to be installed, and why not, rewired as well.

Install the pressure water pump

I divesting myself of all things diesel, I traded a Racor fuel filter for a pressure water pump.  I really ought to install this for this season.  That will also require that I reinstall my 90L flexible water tank and new hose to my galley and head sinks.  I will also have to install a pressure faucet in the boat. I will keep the foot pump, but I may switch it to raw-water.  Who knows.

Electric update

My 2014 launch was delayed until late August for several reasons, not all in my control.
The batteries didn't arrive until early July, then came  the cell-balancing process which took close to a week.
Then there was the hemming and hawing about battery pack geometry and how to secure the pack in the boat.
Then of course, once that was decided (but still isn't settled...) I had to fabricate the supports and install everything.
All of this had to happen without taking much time off work and without ignoring my family.
Ultimately, I did my first electric propulsion tests in mid-Septemer and moved from the service dock a couple of weeks before my birthday.  Fugu's first electro-sail was the weekend of my birthday, with my very patient family, who were rewarded with a glorious day-sail and lunch at anchor, out at the sandbar.

Real performance vs projected.

It turns out that my real performance is just on the better side of what I projected from Eric's numbers from Serenity.  So my range at 4kts is just about 15nm, 25nm at 3kts.  This is more than satisfactory.  For getting out to the club races, I can go nearly up to full throttle and make 5.5kts, do the race and have ample power for calmly coming back to the club -- we usually sail back anyway.

Varia

Since I switched from a left-hand to a right-handed prop, the prop-walk pulls the boat the other way, and unfortunately, this is away from the slip.  Still getting used to that one.  Maybe I'll practice backing the boat into the slip.  Other factors affecting prop walk are the pitch of the prop.  Since my prop went form a 12x8 to a 12x14, the amount of prop walk is significantly more.  On the plus side, the low-speed control of the shaft RPMs is amazing.  I can throttle right down to about 100 motor RPM which gives about 40 shaft RPM.  Ultimately, docking will become easier, once I acclimate to the new methods.

Another neat thing is the awareness of your speed you have with electric propulsion.  Since I can theoretically empty my battery bank on a single outing, I do pay more attention to my throttle settings.  With my old 1-cylinder diesel and even only a 3-gallon tank, I could go all day at full throttle and not worry about running dry.  My electric setup includes a battery state-of-charge meter that counts amp-hours consumed and is aware of the size of my pack and the usable amp-hours.  So I can show remaining usable amp-hours and match that with the day's sailing programme to ensure that I don't get stuck out there.  Slowing down a single knot is enough to nearly double my effective range.  It's pretty neat.

I am still nervous with leaving my battery pack charging unattended.  So when I get back to the dock, the first thing to do is plug in.  We can then take our time putting away the boat, perhaps have dinner at the club and then check in on things before disconnecting the charger and heading home.  A full charge takes about 5 hours from completely empty (20% state of charge).  Most days, I would come back with about 60-70% SoC so charging up takes significantly less time.  A benefit of LiFePO4 batteries is that cells are just fine with being left in a partial charge state.  As a matter of fact, they actually don't like to be kept at 100% charge all the time, so float-charging is a no-no.  The lithium batteries stay in "bulk charge" mode for much longer than lead acids -- up to about 90-95% charge.  As a matter of fact, when equipped with a well-balanced pack and a battery management system (BMS) that monitors each cell, the consensus is moving towards "dumb" constant-current/constant-voltage chargers that are controlled by the BMS.  This amounts to an output voltage configurable power supply where the constant-voltage is set to (cell-count * cell-charge-voltage) volts, in my case, 16 x 3.5V = 56.0V.  The BMS or some other monitor on the power supply would then wait for the current to drop below a threshold like (cell-capacity / 80), in my case this would be a CC of 100Ah / 80 = 1.25A.  Once the current going into the pack drops below the 1.25A level, the power supply could be cut and the pack would be considered essentially fully charged.  If along the way, any individual cell gets above the CV setting, the BMS cuts out the AC current to the power supply and throws an error.

Winterization

Since I have a lot of money invested in my battery pack, I am not keeping on the boat over the winter.  Each 4-cell group weighs only about 30lbs and can be lifted out easily enough, even at arms length.  The procedure for storing lithium batteries is to charge them up, then disconnect them and ignore them for 6 months.  So they are currently sitting in a crate in my basement, waiting for launch-day.  They are in their 4-cell groups and the BMS modules are still attached.  Current draw from these modules is very low, on the order of about 5ma.  So total draw from my 100000mah cells will be: 5ma x 24 hours x 183 days = 21960mah or about 22ah from my 100ah cells.  Regular self-discharge is also about 3%/month so I expect to lose another 20% in 6 months.  My pack should come out of winter at about 60% SoC -- just fine for lithium storage.

2014 was a short season.  Here's to hoping for a long and adventurous 2015 sailing season!

93 days to launch!