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A very simple Lithium power tank


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Getting more confident with all-night imaging I decided I needed more power for longer. My Baudens power-box is great and will continue to be my main portable source. But with added dew straps at max, 5hrs is about the limit of its capacity. My recent sessions have been pushing 6hrs and I don't see why 8+hrs is out of the question if the conditions are right.


So I needed an extra power box - which I will use for dew straps and mount. I decided to build my own and perhaps save a few £s...

I wanted similar capacity to the Beaudens. My first thought was a lead-acid battery but the weight really put me off. So I decided to design it around a 12v LiFEPo battery and accessorise to meet my needs 🙂 


My wood-working skills are a little lacking (to say the least!) so I repurposed a wooden draw for a box, making a back and base and sealed it with weather proof matt black paint.

The front panel is one of those 12v bike/boat panels via amazon like this https://www.amazon.co.uk/Charger-Cigarette-Waterproof-Voltmeter-Motorcycl/dp/B08PTS3CKV/ref=sr_1_19?crid=3BXLUNUZ0NHS3&dchild=1&keywords=12v+cigarette+lighter+socket&qid=1632138512&sprefix=12v+cig%2Caps%2C164&sr=8-19

I added 3 x 0521 12V ports to the panel and all circuits have 10A fuses.

The 12v battery is the UltraMax LI22-12S.



Here it is under load with my home brew dew controller and dew straps at max.


The powered USB ports are a nice extra. The panel is not of the greatest quality (the power LED worked for a few hours!) but the parts are easy to interchange if needs be.


The box has enough extra space to install 3 or 4 Raspberry-Pis if I should need it.


Ignoring the crimping tool the build cost was <> £140. (£115 just for the battery).


The battery is supplied with a low cost but smart charger, rated at 3A - it does float the voltage to 14.4v when the battery is fully charged and its LED changes from red to green - not perfect or fast but good enough. I replaced the croc clips with a cigarette adapter. Plugging the charger into the battery panel shows me the charging voltage which gives an indication of progress. I may put an ammeter in circuit longer term.



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