Cylindrical Cell Recommendation Needed

Hi, Team Hologram and Everyone,

I’m looking for a recommendation for a cylindrical cell to use as a backup battery. The Hologram-supplied PK Cell pouch cell works great, but I’d ultimately prefer a cylindrical cell due to it’s sturdy package (vs. a pouch cell).

I’ve now tested a few PCB-protected 10440 and 18650 cells, but I’ve come up against an interesting issue: When used as a backup cell, the cells perform fine and shut off at the claimed lower-limit voltage. Unfortunately, they “latch” there, so that returning 5V USB power does not allow charging resumption / Dash function without first disconnecting and then reconnecting the battery to the circuit. That means that auto-reboot when USB power is restored is not possible. Conversely, the PK Cell does not exhibit this behavior: When it shuts off at low voltage, subsequent resumption of USB power brings the board and charging back online.

I recall that back in the “Dazzling Duke” days, there was talk of a Konekt making a protected 18650 cell available.

Possible commercial application being considered here, so I’d like to move to cylindrical from the easily-mishandled pouches. Any recommendations are much appreciated!


The pouch cells provided by Hologram have a cut-off voltage of 3.0v and the 10440’s and 18650’s with protection have a cut-off at 2.5v. Is the charging circuit designed to work with specific battery parameters? If so are they available? Thanks!


Any thoughts?

Bueller? Bueller? :slight_smile:

Still looking for any recommendations for cylindrical cells and/or specific battery parameters for Dash charging circuit. Thanks !

Here’s the datasheet for the battery charger on the Dash. It’s designed for use with single-cell Li-Ion/Poly batteries. You can take a further look for other parameters for operating characteristics to find batteries that would be suitable for use. Hope that helps.

Hi Ryan,

Thanks ! The documentation notes that some of parameters are programmable. Is it possible to reprogram the charger?


Unfortunately the charger is not under software control. The programmable parameters referred to are by hardware only, via capacitor and resistor value selection.

Got it…Thanks Erik!

Very good to know, Erik - thank you!