What happens when battery runs low?

Hardware MKR Family MKR1000
1

To prevent permanent damage to the battery, it is necessary to reduce (as much as possible) the drain on the battery once it gets below a certain voltage. Is there a latch-off or something similar done in the MKR1000 to do this?

I see a few components which could theoretically do this (the Q3A or the U2 voltage regulator, https://www.arduino.cc/en/uploads/Main/MKR1000-schematic.pdf ), but I am not sure they are there for that purpose. If I run a MKR1000 on battery until it's drained, will I risk destroying the battery in the process?

Cheers,

B.

2

It does have its own LIPO circuit so the theory is that when it gets below a threshold it simply shuts down.

Not seen anyone say it continues to drain yet.

3

@Ballscrewbob

I recently bought a 3.7V 900mAh lipo battery, when i connected it on MKR1000 battery connector, board didn't light up..but when I connected it on pins of the board, it was working.

why the battery is not working with battery connector on board but its working on pins.

Is it possible that new battery I have is charged below threshold level, so its not powering the board but when I connect it on pins it works below threshold level also.

For confirming this point I have connected the battery on board connector and powering the board through USB, red LED on board is on, its not blinking..does it indicate the battery is charging? , if yes then how long will it take for battery to get completely charged through the board?

Thanks

4

@Ballscrewbob

battery is working :-\ , I forget that board LED doesn't glow when powered by battery :stuck_out_tongue: ..

But I have another small silly doubt..
Actually I will power my MKR board using a constant 5V power supply, but that power supply is sometimes off, so I want to connect the battery as a back up option so that when my 5V supply on Vin pin is off for a small duration, the board automatically goes to battery backup...

so my doubt is that when I connect my board on battery power and through a 5V supply using Vin simultaneously, will the board work fine, and will the battery won't get overcharged?

Is there any problem if I connect both battery and Vin supply at the same time..How the board will behave ?

Thanks.

5

Sorry I missed this somehow.

Just connected mine to double check.

A decent test is the "blink without delay" sketch HERE.

Remembered that the two LEDs nearest the charge connector will turn OFF when connected to a battery !

If you load the sketch above and charge the battery then disconnect your USB you should only see the onboard LED blink. Its part of the power saving feature.

6

@Ballscrewbob

Thanks for going through this issue, I got that part and its working as per your description.

But actually where I am placing my node, I am powering it through 5V using Vin and Gnd pins on board..
So my problem is that can I give 5V on Vin and and also connect my board to battery. Will it work the same way as USB and battery ??

7

I dont have time today to go through the specs but they are on the MKR1000 product page.

If anyone else can cover this please feel free...I have a long drive ahead of me today.

8

I tried it..and it worked, both USB and power through the Vin pins work the same way and it didn't damaged the LiPo battery or MKR board. Hence I am sorted on battery issue now :slight_smile: