Power Raspberry PI using Solar Panel

So, here's where I'm at so far.

Even changing to a RPi B+ and using an SDCard, it kept only lasting about 6h.

Last night, I made a change.

I know for a fact that, that a 10.000 mAh power bank lasts all night and still has power left - Using a RPI 4 and an SSD .

But this would imply that I had to disconnect it to recharge. So, I've connected the solar charger to the power bank (to charge it) and the power bank connects to the RPi, like in the picture:

As of this morning, it was still connected.I just tried to open the webpage of the AllSky software and it was loading and I could see the time lapse from last night. I haven't check the charge of the power bank - but I will assume that the solar charger was depleted - last night, around 11pm I went to check and the last led (it has 4 to indicate the charge) was blinking.. I would assume it was odd, but I know that the power bank wasn't fully charge, so it could have been to charge the power bank to the max.

I haven't been home since this morning, but the solar panel should be charging the solar charger and thus charging the power bank and RPi should still be on - When I arrive home will see if this is the case.

I've already ordered some 12.000mAh 18650 batteries to use in the solar charger so I can ditch the power bank (I'm hoping) .

Best regards

Thank you all for the replies.

Powering a RPi with solar is really really hard.   But lets not discourage.

What about a 12v battery with a solar controller ?

Like something like this:

with something like this ?

I still have to try the Raspberry PI Zero W 2 .

12V battery is probably more scalable but the initial cost might end up being quite high. Depends if you are planning on adding additional load in the future. There should be lots of off-the-shelf kits available due to off-grid camping.

Wesley did an off-grid solar project over on element14 presents which may be of interest:

/challenges-projects/element14-presents/project-videos/w/documents/28102/episode-598-how-to-build-a-portable-solar-charged-off-grid-power-station

However, you have previously stated that the 10000mAh power bank provided sufficient capacity to power the R-Pi 4 setup, and that it works being charged off the solar power bank. You could perhaps just use that as a solution and increase the size of the powerbank if needed. 

However, it should be possible to get around 10500mAh out of the Waveshare solar powerbank using 3x 3500mAh 18650 cells. So perhaps worth taking a closer look at your existing '3350mAh' cells and replace them with known high quality ones that will give the full stated capacity. It's the neatest solution but those higher capacity cells can be quite expensive.

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Alternatively you could perhaps look at using an external 3.6V power pack with the solar charger, using 4x 2500mAh cells which probably works out cheaper to give similar capacity of around 10000mAh.

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The 3-cell battery holder looks like it plugs into the circuit board so would just need unplugging and a slot cutting in the cover to pass a power cable through and allow it to be plugged in. 

There is potential to expand this to 13400mAh if required, either using an off-the shelf pack containing 4x 3350mAh cells

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or building a custom pack (with appropriate protection). I think the Waveshare battery holder is just three cells in parallel, I didn't notice  any fuses to protect against shorted cells. 

If using external batteries, there are also the larger higher capacity 26650 sized cells. 

However by this stage, replacing the Waveshare solar powerbank with the likes of a Voltaic laptop one might end up being better value 

https://voltaicsystems.com/v88/ 

as although is is at around $149 you are getting around 24000mAh capacity which sounds like it would be enough to power your setup for 2-3days.

Another thing to consider is your solar charging capacity over the typical year. As nights grow longer and there are less sunny days, then you may need additional solar collection and storage to keep things running through the night. You may want to power down the R-Pi during daylight hours to conserve power rather than adding batteries and panels.

Thank you beacon_dave for the information.

I would love to keep using the Waveshare Solar Charger - I've bought it for this purpose . I will take a look at those batteries.

beacon_dave said:

The 3-cell battery holder looks like it plugs into the circuit board so would just need unplugging and a slot cutting in the cover to pass a power cable through and allow it to be plugged in. 

There is potential to expand this to 13400mAh if required, either using an off-the shelf pack containing 4x 3350mAh cells

I'm not against this - heck, I would prefer this. Need to dig a bit further on the solar charger to see if I can replace that.

I have 3 cell packs at home for a LED cube project - that sits there - and I don't mind to use them..

Again, thank you.

Thank you beacon_dave for the information.

I would love to keep using the Waveshare Solar Charger - I've bought it for this purpose . I will take a look at those batteries.

beacon_dave said:

The 3-cell battery holder looks like it plugs into the circuit board so would just need unplugging and a slot cutting in the cover to pass a power cable through and allow it to be plugged in. 

There is potential to expand this to 13400mAh if required, either using an off-the shelf pack containing 4x 3350mAh cells

I'm not against this - heck, I would prefer this. Need to dig a bit further on the solar charger to see if I can replace that.

I have 3 cell packs at home for a LED cube project - that sits there - and I don't mind to use them..

Again, thank you.