Voting resources, early voting, and poll worker information - VOTE. ... Adafruit is open and shipping.
0

Which USB Charger for 3v?
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Which USB Charger for 3v?

by SpocksEars on Sat Jul 18, 2020 4:53 pm

Hi all,
I'm trying to convert a flicker candle (2xAA) to be USB rechargeable.
I've looked all around, and there seems to be several products that fit what I need, but I can't choose!

Here's what I'm trying to find.
I need USB charger where I can supply 3v (2xAA equiv) at the same time it's charging (plugged into USB).
https://www.adafruit.com/product/259 *seems* to be what I need since it has a "load" connector.
Is this the way to go, or would something else be better?

Thanks in advance!

SpocksEars
 
Posts: 5
Joined: Fri Sep 25, 2015 12:04 pm

Re: Which USB Charger for 3v?

by adafruit_support_bill on Sun Jul 19, 2020 7:38 am

I assume that you are planning to replace the 2xAA with a LiPo cell - since that charger only works with LiPo cells.

The Load output voltage is wired in parallel with the battery, so the output voltage will vary between about 4.2v and 3v depending on the charge state of the battery. This compares to the output of a 2x alkaline pack which would vary from about 3.2v to 2v over the life of the cells. Depending on the supply voltage tolerance of your candle, you may need to add a regulator to the output of the charger: https://www.adafruit.com/product/2745

adafruit_support_bill
 
Posts: 78721
Joined: Sat Feb 07, 2009 10:11 am

Re: Which USB Charger for 3v?

by SpocksEars on Sun Jul 19, 2020 11:29 am

Great info. Thanks much!

SpocksEars
 
Posts: 5
Joined: Fri Sep 25, 2015 12:04 pm

Please be positive and constructive with your questions and comments.