Isolating Lipo battery on arduino MKRxx00

Hi all,

I'm using a 3.7v battery on a MKR1400 because I'm told the board needs it to cope with spikes in current to the GSM module.

I will only ever use the project on a 12v supply, so I want to cut off the lipo battery when the supply is disconnected.

I was thinking of using a loop of wire on the power connector... thus connecting the lipo when the 12v supply is connected. However, this brings out the 3.7 lipo battery to the chassis socket, and I don't really like the sound of that.

Plan B is using a single pole relay across the +ve battery output. It will be held open using the 5v for the arduino Vin.

Is there a better way?

If there's anyway to eliminate the battery completely, that would be nice.


Using 4 2.7V 1uF caps?

4 caps gives 2 pair.

Solder each pair in series.

Solder the series pairs in parallel.

Now you have one 1uF 5.4V super cap that could/should supply the necessary surge current when needed.

Thanks for your reply.
Would you put the super cap across Vin and GND?

I had considered using a big (something around 100uF) capacitor near Vin... would that achieve similar results? (that's what I did with the old GSM shields).

I've since really gone off the idea of a relay on all the time.

My supply to Vin will be a 2A switching regulator so it should really be able to cope anyway. I've gone back to the Arduino hardware page to see if I could find out why I specifically needed the battery connected. I can't find anything about it now! Perhaps I was confused, but I'm certain I read it somewhere.

I think exceeding the voltage rating of the capacitor circuit would be the limiting factor on which part of the circuit the capacitor bank would attach.

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