Solar / Battery Power for SBC

Littlenose

Littlenose

Littlenose

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Joined
27 May 2008
Posts
1,115
Location
Petersfield, Hampshire
I'm looking to run a SBC from battery, but solar top up to the battery when the sun's out.
I'm a mechanical engineer and have to admit, the electronics for this confound me, and wondered if someone clever with this stuff can point me in the right direction.

I've tried using a couple of small circuits like the 4096 that is often used for charging batteries, but my complication seems to come from wanting to continue drawing power at the same time as benefitting from the solar.

The project is for logging data from my greenhouse, such as temp, humidity etc.
 
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What voltage you looking to run at?
If 12v then plenty of easy options for you.
5v also easy to do, lithium battery is good for rapid recharge, lead acid can be cheaper, maybe used car battery or something.
Also for charge controller I use a pwm85 for 2 of my cars it's a project by some YouTubers and works very well for my use case
 
Littlenose said:
I'm looking to run a SBC from battery, but solar top up to the battery when the sun's out.
I'm a mechanical engineer and have to admit, the electronics for this confound me, and wondered if someone clever with this stuff can point me in the right direction.

I've tried using a couple of small circuits like the 4096 that is often used for charging batteries, but my complication seems to come from wanting to continue drawing power at the same time as benefitting from the solar.

The project is for logging data from my greenhouse, such as temp, humidity etc.
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Before diving in, by any chance do you have anything running Home Assistant? I've got some Sonoff Zigbee thermometers & hygrometers. They're paired up to HA, so I get full logging of temperature and humidity. Wireless, and powered by a button cell battery.
That might be a more elegant solution: https://sonoff.tech/product/gateway-and-sensors/snzb-2d/

However, if you're already sure of running the SBC, You'll need the solar panels to produce around triple the power of the SBC; to run the computer in the day, and to put surplus into the batteries to run it when the sun's gone in.
The simplest and most 'reusable' method I can think of would be to look at kits for caravans and motorhomes. Those'll be designed to maintain a 12v leisure battery; you can then use that battery to power the SBC.
 
Cheers for the input.
I think I’m really going to have to get my h in some books and learn some basic electronics. Mechanical Engineer here that doesn’t understand stuff he can’t see :D
 
Littlenose said:
Cheers for the input.
I think I’m really going to have to get my h in some books and learn some basic electronics. Mechanical Engineer here that doesn’t understand stuff he can’t see :D
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Start off by looking at the average power consumption of the SBC. If it's a Raspberry pi (or a comparable USB-powered clone) then there's a wealth of knowledge on the raspberry pi forums. It's a fun little project you've got - feel free to come back here and ask for advice before you spend money on anything.

Of course, if you've got bits lying around the house to make use of (spare car cigarette lighter to USB adaptor for instance, and an old 12v battery) then of course you can get to experimenting!
 
cheers @blueacid, it's been something I've wanted to get going in different guises for a long time.

It's on the slow burn, and first I think I'll try to generate a simple garden light to give me some confidence - the simple ones that charge during the day, then decharge in the dark. I'm pretty sure that's just a solar panel, a 4096 board, a 18650 battery and maybe a buck converter. I've got all those lying about.

I'll definitely be asking a few questions and proposing a few things for you guys to ridicule :D
 
No ridicule at all for trying to learn something and to better yourself - respect!
If you want some moochin' and some ideas, definitely take a look at bigclivedotcom on Youtube. He pulls apart all sorts of electrical tat to work out how it works. It might help you out (or just be fascinating).

Depending on how scuzzy you feel like being (wear gloves), discarded e-cigarettes on the street can be a very useful source for li-ion cells. The kind which might just be ideal for some of these projects. Plus you're doing your bit for recycling.
 
cheers, I will check out that YT channel.
Not sure I'm going to be picking up e-ciggies off the street jsut yet though
 
It's probably overkill for what you want but take a look at the Anker Solix C300 DC and running it off the cigarrette lighter port on that. Then add a small portable solar panel to keep it topped up. BUt as I said it's probably overkill.
 
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You can get pre-made TP4056 boards for charging Li-ion batteries some of which come setup to supply power at the same time as charging the battery. Though you can parallel say 18650s with one that generally isn't a good idea and you'd need a boost converter for higher voltages. There are BMS boards which will charge multiple li-ion batteries in a mixture of series and parallel for easier higher voltage applications.

There are loads of YouTubers who cover this stuff but one that is maybe a bit more specific to your application is JulianIlett especially some of his older stuff.
 
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Hades said:
but take a look at the Anker Solix C300 DC
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I've got the AC version - one possible complication here is if the SBC has low idle power the power station may automatically shut off, you can mess with some of those settings in the BT connected app but I've not played around with that to see if you can change that.
 
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Rroff said:
I've got the AC version - one possible complication here is it if the SBC has low idle power the power station may automatically shut off, you can mess with some of those settings in the BT connected app but I've not played around with that to see if you can change that.
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Good point.

Unrelated, but how are you finding the C300 and are you powering anything from the AC ports?
 
Hades said:
Good point.

Unrelated, but how are you finding the C300 and are you powering anything from the AC ports?
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Only recently bought it with the sales around Black Friday, haven't put it to much use yet, planning to put some backup networking equipment on it.
 
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