USB battery pack keep-alive load

£6.75 - £14.95 (Inc. Tax)
£5.62 - £12.46 (Ex. Tax)

Customers outside the UK pay the lower (Ex. Tax) prices when ordering. However, some countries require you to pay tax on imported parcels. Details here.

(21 reviews) Write a Review
Calculated at Checkout

USB Electronic Load to prevent power-bank low-current shut-down

USB battery packs are a convenient way of powering low power USB devices such as WSPRlite. Unfortunately many USB battery packs switch off (go into a sleep mode) if the current being drawn is too low. This means that your device works for a few minutes and then stops. Often just a few extra milliamps current draw will keep the battery pack alive. There are various circuits on the web that give a pulsed load which works with some battery packs - but unfortunately our tests have shown that such circuits don't work reliably with all battery packs.

Our solution is a variable electronic load. We have designed it to be very simple to use. Just plug it into your battery pack and increase the current until battery pack stays on reliably (6 - 150 mA). Depending on the current that your powered device takes that may be a little as a few milliamps. An on-board LED indicates if the battery pack is live. The load supports a standard USB data connection. USB plug and socket for easy in-line connection. Clear heat-shrink sleeving is provided to protect the unit in the field.

Available as an easy-to-make kit suitable for a beginner or fully built and tested. Note that the built unit is supplied encapsulated in clear heat-shrink sleeving.

Easy to use

To use, just plug the Keep-alive load between your battery and item to be powered and adjust the blue potentiometer on the unit with a fine screwdriver. Set it fully clockwise at first (maximum current) and gradually decrease the current until the battery pack just cuts out. Then increase the current until the battery pack stays on reliably. That way you only draw just enough current for reliable operation - increasing the life of your battery. 


Instructions are available HERE!


Also available from our international agent(s):




21 Reviews Hide Reviews Show Reviews

  • 5
    Easy To Build, Works Brilliantly

    Posted by Clayton Moore on 22nd Jan 2021

    I was going to order the ready built option but they were out of stock so rather than wait I opted for the DIY build. I'm so glad I did and saved the money now. It took me about 10 minutes to solder all of the components in place and another 5 minutes to set the pot to the correct level for my device. The web instructions are simple to follow if needed, the only slight problem I had was which way round to mount the transistors as it's been to long since using them and I couldn't work out which leg was positive, lol, but after checking a photo I was finished. Great device, saves having to use a bulky breadboard and good value, it even comes with a shrink wrap to keep the built unit safe.

  • 5
    Works great

    Posted by Dave on 10th Apr 2020

    Item arrived rapidly and worked just as advertised. Thanks for putting together such a useful little tool.

  • 5
    USB battery pack keep-alive load

    Posted by Lagert on 18th Dec 2019

    Good ! Work well with powerbank and Star Aventurer. Utile pour alimenter la monture Star Aventurer avec une powerbank.

  • 5

    Posted by Rob Evans on 8th Dec 2019

    Easy to build, works perfectly.

  • 4
    Useful tool to have in your box

    Posted by Ian Pryke on 22nd Sep 2019

    Sotabeams has useful equipment some of which are on my to-do list

  • 5
    USB battery pack keep-alive load

    Posted by Joe on 18th Jul 2019

    Easy kit, I have a 4 amp cell phone charge pack that shuts off when powering the WISPRLite. This keeps it running with a minimum current drain.

  • 5
    Worked as promised

    Posted by Roger Baugher on 5th May 2019

    Found it frustrating that battery packs would turn off at the low power draw of an Arduino. I found a circuit online, but I preferred not to build it. I was glad to see this product completely met my needs.

  • 5
    48 hours of music during our event

    Posted by K Verburg on 17th Mar 2019

    We are using this USB powerbank tool to have music and background sound on several locations in the woods combined with large powerbank and microSD speaker/player.

  • 5

    Posted by TERRY SAYNER on 18th Oct 2018

    This is well worth buying if using a power pack.

  • 5
    Usb battery keep alive

    Posted by naaman meir on 12th Sep 2018

    Works great just as expected