Aquaponics Cherry tomatoes

Those crazy cherry tomato plants I have growing directly in my fish tank water are producing some really nice fruit.

This bunch looked like a likely candidate for some photos so here they are...

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Epic solar boat adventurer Stress testing my old battery

Ive had this big old deep cycle battery for years, and I dont know enough about it so I thought Id learn some stuff.

Its a conventional, unsealed, 100ah lead acid, deep cycle thing.

At least I think its 100ah. Thats the kind of thing youd think someone would emboss onto the side rather than adding it as a stamp. That and the voltage.

At least they went to the trouble of embossing the + and - marks.

So with this kind of battery, it seems they dont mind being run down as much as, say... a car battery might. Car batteries hate it when they are run down, and it shortens their lives in a big way.

A deep cycle battery (also called a flooded battery apparently) is a bit more forgiving, but they still see damage with every bit of use. The lower you allow the voltage to get before recharging, the less charge cycles you get from them before they need replacing. 

As I understand it, 11.8v is considered "empty", but thats at rest 6 hours after you stop using it.

I need to know what "empty" is when Im cruising along drawing 20 amps or 35 amps (that being the amount of juice the motor pulls from the battery at speeds 4 and 5 of 5.

So my education for today turned into more questions than answers. It looks like its business as usual.



120 Things in 20 years thinks the Internet might not know something I need to know.

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Electronics Aquaponics Demand feeder hits

It turns out the fish have been hitting the lever, but the switch hasnt been working.

It should be an easy fix, but for the time being, this will have to do.

[edit from the future - I fixed the switch and got a few proper hits with feed delivered within a few hours]

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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 isnt 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 Im 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 thats 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 its 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 dont really care.

Todays 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. Im 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 dont die!


120 Things in 20 years hopes I dont die.

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Electronics Infinite battery life camera

Ive had to make a few compromises with version 2.0 of the demand feeder.

One is that Ive re-written the code and made it a lot more simple than it was originally. Ive still got the old code, and Ill use it and post it when I make it a little better, but the full version resets each day at dawn as one of the overfeeding protection measures. I only have two silver perch in a 100L fish tank, with 300L of filtration media, so they can have as much feed as they like. To encourage the pressing of the button, Ive made it so that they only get a small amount of feed each time, but they have the opportunity of more feed after only eight minutes since the last feed. The point of making a simpler version of the software was so that it would keep a running total of all events like the number of times the fish have hit the feed lever when the light is lit, and the number of times when the light isnt lit.

The fish pressed the lever only once in the 24 hours since I added it to the system. This may have just been a tail swipe, but it would have delivered feed, so some reinforcement of the behaviour of getting at least near the lever has begun!

It wont take them long to get the hang of it.

I ran the camera until the batteries were dead last night, but the hit must have happened some time since dawn while the camera was on charge. To solve this two hour filming limit, I created this.

Its a camera taped to its battery charger, that is in turn taped to a tripod.

I plugged it into the earth leakage safety switch that the rest of the system is plugged into.



It blends in a bit with the actual feeder, but thats the feeder with the birds nest of wires sticking out of the back of it. The orange looking light under the camera is the LED that tells the fish feed is currently available. The red light at the top is the power on LED, and the yellow one is flashing out the number of feeds allowed in a day (even though the thing no longer resets after a day, so really it shows the number of feeds allowed ever). There are also LEDs that flash out the number of feeds so far, the feeds remaining, the number of attempts made at the lever when food isnt available. That is when the feed LED isnt lit, because they just fed recently. And one more that flashes out the size of each feed thats delivered. The size is measured by how long the motor is on for, and doesnt actually represent the amount of feed, but on average, should spill a predictable amount each time. Currently, they would get around 5-8, 3mm pellets each time they hit the lever.

Hopefully, Ill have some video soon.



120 Things in 20 years - Electronics - Infinite battery life camera - This project is far from finished.

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