3.7 V Lithium battery vs 3.5 V max Artimis V_BATT input

SPARK-X
1

Will have a project with several Redboard Artimis boards. Will be using a 3.3V board.

Taking a look at the lising in the advanced_arduino_comparison_guide, the Redboard Artemis isa 3.3 V unit, and is listed as haing a LiPo charger.

But the schematic sayz not to have V_BATT greater than 3.5 V. Yet the batteries are listed as 3.7 V.

Am I missing something? or can the 3.7 V battery be connected to the 3.3 V Redboard Artemis?

Second question

How can a single battery be connected to power several Redboard Artemis units?

Or must each Artemis have its own battery?

George B

2

Hello George,

To ensure I’m answering correctly, is this about [DEV-15444?](SparkFun RedBoard Artemis - DEV-15444 - SparkFun Electronics)

3

Yes - it’s about Redboard Artemis, DEV-15444

4

VBATT is intended for our 3V Coin cell batteries and not typical 3.7 LiPo’s. You can find those [here.](https://www.sparkfun.com/search/results?term=coin+cell)

5

From your comment that the note on the schematic is for coin cell (or at least, not for 3.7 V LiPo battery connected to the Artemis’ LiPo charger), is it then true that

the 3.7 V LiPo connected to the Artemis’ charger will operate the Redboard Artemis without problem?

Then the second question,

How can a single battery be connected to power several Redboard Artemis units?

Or must each Artemis have its own battery?

Thanks

6

Unfortunately, there is not a LiPo charger on this board.

The modules could be connected to the same Coin Cell battery but all the other components may pull too much current to support multiple boards on one Coin Cell. So connecting several boards to the same Coin Cell is not advisable.

7

I goofed…looking carefully on the schematic for the Redboard Artemis, DEV-15444, it shows (alongside the batttery) CR2032.

Now, re LiPo Charger, going to the Arduino Comparison Guide (Advanced), the Redboard Artemis, DEV-15444 is the first board shown. It has “LiPo Charger Yes”

That’s my currrent question - what does “LiPo Charger Yes” mean, in the Arduino Comparison Guide?

Thanks for your help.

8

Thank you for bringing that error to my attention. Only one out of the three Artemis boards has LiPo charging, the [Artemis Nano. I have alerted our teams to fix this error.

RedBoard Artemis - No LiPo charging

RedBoard Artemis ATP - No LiPo charging

RedBoard Artemis Nano - Does have LiPo charging

I sincerely apologize for the error and it will be corrected as soon as possible. Thank you!](https://www.sparkfun.com/products/15443)

9

Many thanks, Brandon.

I had not read the Redboard Artemis schematic carefully…thanks for straightening me out.

Then the remailing question - can the 3.7 V LiPo btteries be used to power the Redboard Artemis without a problem? If so, what pin would the 3.7 V LiPo be connected to?

The general higher voltage input goes through the separate connector, “VIN range 5-15V”. So the LiPo batteries are below the minimum voltage required there.

Thanks for your help.

10

At this point, I would recommend not using a LiPo battery unless you can add supplemental circuitry to meet the current power requirements for this particular board.

11

Brandon is correct on the supplemental circuitry : Looking at the schematic off the board , the VBATT is connected with a diode to 3V3 generated on the board. If you put a diode serial with the PLUS(+) from 3.7V LIPO and connect the other side of the diode to the 3V3 on the connector, you will feed the board with ~3V ( and diode typically takes 0.7V). The diode does not need to be a heavy one, 1N4001 or so will do. The LIPO will not be charged of course (given the diode).

12

Thanks, Paul

That provides a means of powering several Redboard Artemis units from a LiPo.

Takes care of most of my issues!

Regards,

George