Epic solar boat adventurer - deep cycle battery performance

I put my sweet looking battery to the test today to see what would happen running the motor at half speed.

Fresh looking isn't it.

I decided to run it on speed 3 of 5 to see what kind of range I might get without any sun.

I should get around four hours of full sun in spring on the mighty River Murray on a fine day.

Or so I'm reliably informed.





Much of the country on the lower half of the river is effectively desert so there should be plenty of sunny days.


As I move further upstream (to the right) the weather will get more and more overcast. The beginning of the river is in dairy cow country I think. The middle (shown here) is more like that kind of country that's good for growing a goat... maybe even two goats. A few meters either side of the river is nice (in an Australian kind of way), but this is a very, very old land, and this river has dug out a trench to run through so it could ignore the vast parched land surround it and just on with doing it's own thing.

 I have no idea what that being upstream will mean to my levels of sunshine at this stage.

But I wont be in any hurry, so I don't really care.

Today's test involved running the motor, and writing down some numbers every half hour. I also turned the motor off for a minute, then wrote down some more numbers.

Minutes	1	30	60	90
Amp Hours	less than 1	8.71	16.14	23.29
Volts under load	11.7	11.44	10.94	10.36
Volts after 1 minute rest	12.4	12.22	12.06	11.9

After the test I waited an hour and the voltage had bounced back to 12.31v.

I turned it on for another 10 minutes and the voltage dropped rapidly to where it was before the hour long rest.

Final numbers after the additional 10 minutes were 10.36v under load, 12v after a minute rest, and 26.54 amp hours used.

I think what all this means is perhaps my battery might be good enough. I'm hoping to keep it almost full all the time with only a small amount of use for a little light.

That should put me within range of humans for 80% of my journey, but there will be a few sections where I might not see people for a few days.

To be honest, I have no idea. 

I hope I don't die!


120 Things in 20 years hopes I don't die.

Epic adventurer - Solar boat progress

I made some progress today buy building the frame to hold the solar panel on my little boat.

Not a lot of progress, but a bit.

I was prompted by Dave, a solar panel exporter from China to make some progress, so here is the result.

I made it all out of 25mm aluminium pipe, and plastic plumbing fittings. It should work well enough once I tie or wire it down. I might add some wire tension as well to make sure it all stays where it should.

The best part of my new adult construction kit is that I'm able to adjust any of it on the go with nothing more than my hands and some luck.

At some point I plan on building a solar tracker so my panel always points to the sun regardless of where my little boat is pointing.

As a result, I?'ll need the design to be flexible enough to allow me to add electronics and some kind of actuators to raise and lower different ends, and sides of the panel.

The basic plan will see me sit at the end with the chair on the right, looking under the solar panel when I'm sitting, and looking over the top of the panel when standing. This height gives an unrestricted view when sitting or standing.

When sitting, I wont cast a shadow on the panels even when the sun is setting directly behind me.

The panel will sit on top of the two bars and form the final bit of structure.

That should work.

Epic adventurer - Solar fail-safe kill switch

I've been worried about all my dodgy electronics on my solar boat, so I figured I should have a master kill switch that couldn't fail, and came up with a fuse holder and a 6mm bolt, tied to some artfully arranged paracord in the form of a survival bracelet that my brother made for me.

Cut the threaded bit off the bolt, tie a nice grippy paracord handle to it, then put the bolt in the fuse holder that connects all the electrics to the positive terminal.

One pull and everything stops.

It should work.

If it does, I should also be able to clip onto it with with a 2m bungee cord when I want to move around the boat if I'm under way. That way if I fall off, the motor will stop. I think it's called a dead man's switch. I was originally planning to create one digitally, and I still might if it turns out to be a pain, but if I need it, I'll build it on the boat. If I did it digitally, I'd make a simple sonic tape measure with a PICAXE chip that would notice if I left my chair. Then it would beep in 60 seconds, then kill all power to the motor if I didn't wave my hand in front of it within 15 seconds.

I think I prefer paracord and my bolt fuse.



120 Things in 20 years realises a solar deadman's switch sounds like safety overkill, but I'll have junk everywhere, no side rails, and 2000km is a long way to chase a boat moving slightly faster than I can swim on the Murray River.

Epic Adventurer - The (revised) Murray river trip on a solar powered boat

I like walking pace.

In fact walking pace is my favourite pace.

I've mentioned that before.

I like it so much, that what I really, really want to do is travel 2000km at it, on an epic adventure on a river. 2000km at 3kph should take roughly a very long time.

Roughly.

It was originally going to take two and a half times that when I was thinking about going there and back, and when I thought I could travel the entire length of the river Murray.

That would have been 5000km.

That's why I now have a revised Murray river epic solar powered boat adventure plan.

Both 2000km and 5000km are probably a bit long to be travelling at walking pace unless I can figure out some way to make walking pace a little faster, or perhaps break up the trip into lot's of more manageable chunks.

Making walking pace faster would be pretty easy to accomplish by only going downstream when the river is in flood. As far as I can tell, it flows at around 1-5kph, so starting at the top might be a good idea if I'm only going to travel at walking pace. My little boat runs at around 3kph, and if the river is flowing at 3-5kph, 5000 km backwards might get dull after a while. And 5000km backwards from the Murray mouth is... well... the south pole, and those last few hundred kilometres would be difficult on a boat, what with all those rocks and ice. On the other hand, I don't want to tear along at the un-tranquil pace of as high as 8kph by going downstream.

Perhaps I'll just drift.

That would give me loads of spare amp hours to get up to water skiing pace and blare out music into the tranquillity.

The Murray river has thirteen weirs along the 1986km long stretch from the Yarrawonga Weir, to the Coorong where it meanders into the ocean. As far as I can tell the weir at Yarrawonga is the highest point up the river I can travel by boat. All the weirs along that stretch incorporate locks to allow boats to navigate it's length.

So, my revised plan would probably be to start at the closest boat ramp to the Yarrawonga Weir, then follow the river west, or as I like to call it, left. Then turn left again a thousand kilometres later or so, and continue south until I hit the beach.

Sounds like a plan.  


View Murray River National Park in a larger map

Epic adventurer - Solar boat trolling motor

I got one step closer to setting out on my zillion mile epic adventure on the mighty Murray river, on my little solar powered boat.

That step included testing just how much juice I was going to need to run the trolling motor, and seeing if the solar panel I have will provide enough.

My boat is a displacement hulled catamaran. That means it doesn't do the skimming across the top of the water thing that most other racing cats do, so it's very outdated for racing, but it floats well, and the hulls are very low drag.  At their widest, they measure only 20cm or so. They are 4.2m in length, so they slide through the water without a lot of effort. Probably even slicker than a kayak.

The result of all this is that I can tick along at walking pace with an electric trolling motor on it's slowest setting.

I like walking pace.

In fact, aside from jet aircraft pace, and insane motor bike pace, walking pace is my favourite pace.

So I think, the result of all that is that I should be able to power my little boat with my single solar panel. That question has been nagging at me for ages. My solar panel says it delivers a maximum of 230w at 37v and also mentions 7.5 amps or so.  I think that means that at 12 volts after an MMPT solar charge controller, it will offer the battery a maximum of 19 amps. Probably much less.

But...

I just put my trolling motor in a bucket of water (large bucket) and ran it through my multimeter. As far as I can tell, it draws around 12 amps on the lowest speed setting. I'll be taking a 120 amp hour deep cycle lead acid battery. From memory, before I had the solar panel, that battery gave around 5 hours cruising when I ran it down to 11v. But my memory is terrible for stuff like that.

Also as far as I can tell, I think that means I should be able to cruise for a reasonable amount of time each day. There's also the option of running a bit faster during the middle of the day, when my solar panel is generating the most power. It would be nice to leave the battery with a healthy amount of charge at the end of each day so that I could use some for light, charge my phone and UHF radio, and to power a laptop so I can get some blog posts out.





I'll probably want to set up camp each afternoon when there is still plenty of light, and get up early each morning to pack up camp and get under way when the river is at it's best. If I leave a full battery at the end of each day, I should be able to set off at first light, and then make up the charge by the end of the afternoon.

Or something.

But I have no idea how this will all pan out in the real world.

What I need is a 36v to 12v MMPT solar charge controller that actually works, and wasn't sold to me fraudulently by that trader on E-Bay.

Now I don't trust the world any more.

But I'll probably get over it.

But on the up side I now know how much current my little trolling motor draws, and I've also found a brand new way to inject a lot of oxygen into my fish tank very quickly, and perhaps mince fish.

Which is nice.

This is the trolling motor on it's highest speed setting.

Excited water.







120 Things in 20 years thinks it's found the worlds fastest way to empty a large bucket of water all over itself and it's shed, without actually picking it up and tipping it over itself.