Battery to order instead of adafruit 354?

[Wyatt Toure]

Hello, 

I'm trying to find an alternative battery to plug into the fed3's extension cord. The adafruit battery that is recommended is sold out (https://www.adafruit.com/product/354) I ordered one from amazon (https://www.amazon.com/4400mAh-Rechargeable-Connector-4-4A-19-28Wh/dp/B09CH9FC35?th=1) but it does not fit the battery extension cable that comes with the FED3 electronics

[Lex]

Hi Wyatt,

There are many places online to buy LiPo batteries - this one looks like a match: 

unfortunately there aren't standards for connectors or polarization (which side has the + voltage pin on the connector) so you have to double check these before plugging a new battery into FED3.  The important things when sourcing a LiPo battery for FED3 is that:

1)  It is 3.7V (some LiPos look the same as the Adafruit battery pack but are wired in series and are 7.2V)

2) The connector is a "JST PH connector" with a 2.0mm pitch, with the red wire on the left side of the alignment ridge when looking at it from above, see photo.  There isn't a set standard for which side is + on this connector so many LiPos online are wired oppositely to this photo - if you plug in one of these into FED3 you can fry the electronics.  If you buy a LiPo that's wired oppositely you can gently remove the pins from white connector and reverse them before plugging it in.

TLDR: I believe this is the same battery that Adafruit sells, but make sure you check the polarity before plugging it into FED3!

Best, -Lex

On Thu, Oct 9, 2025 at 8:43 AM Wyatt Toure <mt3...@columbia.edu> wrote:

Hello, 

I'm trying to find an alternative battery to plug into the fed3's extension cord. The adafruit battery that is recommended is sold out (https://www.adafruit.com/product/354) I ordered one from amazon (https://www.amazon.com/4400mAh-Rechargeable-Connector-4-4A-19-28Wh/dp/B09CH9FC35?th=1) but it does not fit the battery extension cable that comes with the FED3 electronics

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