Electricity bill - Switching on/off

What’s the best way to manage my Farmbot’s electricity consumption?

Letting it switched on 24/7 is wasteful but hitting “Power and Reset -> Shutdown” means having to restart it manually the following day and on top of that, the farmduino stays switched on.

Add a solar panel, solar charge controller, battery and a DC-DC converter (higher efficiency than going from 24 => 230 => 24 but still maintaining constant 24VDC instead of fluctuating battery voltage).

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Thanks for the suggestion but unfortunately it’s not an option as I don’t have the space.

Maybe you overrate the space needed. So just as an example:
When you use a battery you won’t need a solar panel with 150 or 200W. A 100W solar panel should be enough with an according battery and has about 1000 x 700mm. As you are living in Switzerland (afaik Geneva) the mounting angle would be around 45°. So the floor space needed is about 1000 x 500mm. You should also be able to put the batteries and controllers underneath it. So there shouldn’t be more space needed.

Don’t take the above calculations for granted but just as an example.

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Thank you very much for having taken the time to explain. I think that you are right and I shoudl investigate further.

I don’t know much about solar panels and charge controllers. Would you be able to please recommend a good place to start (e.g. which products offer decent value for money)?

Many thanks!

I’m also not a specialist for solar power… But these are my findings and the stuff I bought so far:

There are two possibilities:
12V battery with higher capacity and then DC-DC convert to 24V
2*12V battery in series (=>24V) with lower capacities and DC-DC converter (for constant voltage)

My solar panel is second hand and has 170W but also a size of 1593 x 790 x 50mm. To big but was cheep. I’d suggest a monocrystaline panel due to its higher efficiency.
115W panels are usually sized 1015 x 668 x 30 mm.
175W panels are usually sized 1485 x 668 x 30 mm.
I’m not 100% certain about the minimal Umpp needed because you also have a 24V setup.

For the charger I suggest SmartSolar MPPT ones from Victron Energy. They are capable to work with 12 or 24V (autodetect) and have Bluetooth for statistics.
For the DC-DC converter I suggest the isolated Orion-Tr ones from Victron Energy. In my example I have the Orion-Tr 24/24-5 which brings 120W constant and 150W max). That should be sufficient but does not cover the constant 150W of the power supply which comes with the FarmBot v1.5. To be safe I also have the Orion-Tr 24/24-12 with 280W constant power as backup in the drawer it there are issues.

For the battery(es) I also suggest to go for Victron Energy. I have the AGM Super Cycle ones. For the calculations on capacity needed I’d suggest to have a look here: https://genesis.farm.bot/docs/power-farmbot-with-solar
If you have additional components you will have to take them into the calculation (i.e. rainwater pump). I’m completely overpowered (2 x 12V/125Ah => 3’000Wh => about 6 days at max power (500Wh) without charge :crazy_face:). There is no need to go this high. The batteries do have a high price tag (~600.- per piece in my configuration). So better calculate with less overhead and depending on what you really need. Maybe add a watt meter to your existing configuration and check what your consumption really is within a longer period of time (i.e. a month). This should give you real world data and make it easier to calculate the needed capacity.

I mounted the charge controller and DC-DC converter in a IP55 metal box from Rittal.


For Switzerland there is https://www.swiss-victron.ch/. They have all the Victron parts. Maybe also contact a local solar expert which could help you out. That’s what I did.

Don’t hesitate to ask if you have any more questions. :wink:

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Thank you so much for all the effort you have put into your post. It’s much appreciate and gives me a great starting point to do my research!

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@ClosedCircuit Have you considered using a low-tech option, such as a garden timer that only allows the device to operate for a specified number of hours per day?:

These timers are extremely reliable, inexpensive and easily purchased at any home improvement store.

To avoid data loss, you could create a Farm Event that powers the device down a few minutes prior to the timer.

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Thanks @RickCarlino. I thought about getting one of these but I am also considering inserting a wifi smart plug inside my home, before the electrical cable goes out to the farmbot. This would allow me to control it remotely and/or via IFTTT.

Just stumbled over a Youtube-Channel which talks about solar power and off-grid systems:
Youtube: https://www.youtube.com/c/WillProwse
His website: https://www.mobile-solarpower.com/

Think it may also help to answer some pending questions.

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At the end, I chose to add a smart plug in-between my fuse box (inside the house) and the Farmbot.

Following on from @RickCarlino excellent suggestion, I created a shutdown sequence which is triggered 5min before the smart plug switches everything off.

As an aside, my FB draws 16.1W in standbye mode (i.e. when it’s not doing anything) and 4W after shutdown. Switching it off completely in between planned sequences will therefore save quite a lot of electricity in the long run.

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thanks for sharing this data with us!

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Let’s say that the FarmBot runs about half an hour a day which would result in about 98% standby time. Calculated over a year it is about 138.2kWh for power used for standby. Based on the 100% renewable energy tariff in my region in Switzerland (EBL Grün) that would result in about CHF 49.- a year.

So I need to run my FarmBot on solar in standby for about 40 years to get the break even. :rofl:

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:joy: :joy: :joy:

It’s not just about the money, is it?

Luckily, the myStrom wifi switch was CHF 39.-- and I spent about 10.-- on a plug and socket. Looks like I should break even in about a year.

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:money_mouth_face: :partying_face:

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