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Project Notes

#311 Juice

Building the Boldport Juice battery replacement kit (Project #12).



Juice is a battery replacement kit that uses a pretty nifty set of AA, AAA, A23 and CR2032 inserts to inject the required regulated power where a battery or two would normally be required.

Power can be supplied via the micro USB connector, or any other power supply that can be clipped or screwed on to the body of the Juice.

All the structural parts punch out from the classy PCB like a model plane kit;-) The box folds up and doubles as a “Juice box”.





Regulating the Supply

The core of the kit is the ST LDF regulator, which has a very low-dropout voltage (500 mV max. at 1 A load).

Resistor networks and the “chooser” plug allow switching between 1.5, 3V, 4.5V or an adjustable output.


Ref Description Qty
IC1 Adjustable LDO regulator, ST LDFPT-TR 1x
VR1 20KΩ trimmer, Bourns TC33X-2-203E 1x
R1,3 1KΩ resistor, Multicomp MF25 1K 2x
R2 3.3KΩ resistor, Multicomp MF25 3K3 1x
R4 5.6KΩ resistor, Multicomp MF25 5K6 1x
R5,6 1.2KΩ resistor, Multicomp MF25 1K2 2x
C1,2 2.2µF ceramic capacitor, Multicomp MCMLR50V225MY5V 2x
C3 10µF electrolytic capacitor, Multicomp MCMR35V106M4X7 1x
LED1 Orange LED, Kingbright L-9294SECK 1x
  Micro USB connector, Multicomp MC001009 1x
  6 contacts long pin header, Samtec TSW-106-22-T-S 1x
  3 contacts 2.54 mm SMD header, Samtec TSM-103-01-T-SH 1x





Juice_build_front Juice_build_rear

The SS Juice with CR2032 adapter:


The SS Juice with A-series battery adapters.


Note the jumper to allow multiple batteries to be replaced in series. Here’s the Juice replacing a 2xAA battery holder:


Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.