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Topic: Cant get the mkr1310 run on batteries  (Read 490 times) previous topic - next topic

Hjojohan

Hi
I have been trying to get my new MKR1310 to run on batteries, I have 3.6VDC 'D' cell and a resistor divider so I feed 3.3 VDC to the board.  The battery is a lithium cell and is NOT suitable for charging.


When I run on USB the 1310 unit works just fine, If i put the 3.3 to VIN pin the LED is on green but the code does not seem to execute.

The product description says the 1310 support Batteries of type  rechargeable Li-Ion, or Li-Po  but I dont have that.. does it matter what kind of batteries I use when I dont plan to use rechargables ?


Please tell me how to use my 'd' lithium 3.6VDC

All the best
Johan

sslupsky

Do not connect your D cell primary lithium battery to the MKRWAN battery connection.  Doing so could cause a fire and/or the battery may explode.

I do not understand what you mean by "resistor divider"?  That doesn't sound like it will work properly.  You need a low dropout voltage regulator or a buck converter to the regulate the 3.6V Primary cell voltage to 3.3V.  You can then connect the output of the regulator to the 3.3V of the MKRWAN.

cthomas57

In regard to "Do not connect your D cell primary lithium battery to the MKRWAN battery connection.  Doing so could cause a fire and/or the battery may explode"...

1. Are you referring to when USB is connected?

2. If a Li batteries should not be connected at any time, then what should be used for battery power on MKR Boards?  Li Batteries are the only ones I found that can handle extended temperature ranges and have enough capacity to last for years (if power is managed properly).

Thanks in advance.

sslupsky

The MKRWAN 1310 now includes a secondary lithium battery charger circuit.  Secondary lithium batteries are "rechargeable".  Secondary batteries are commonly referred to as "Lithium Ion" or "Lithium Polymer".

Lithium primary cells, such as Lithium Thionyl chloride batteries, are not rechargeable.  Primary batteries are sometimes referred to as "Lithium Metal" batteries. 

1.  If you attach a lithium primary cell to the charging port of the MKRWAN 1310 and the MKRWAN is connected to an external power source such as USB or a power adapter, the battery could catch fire or explode.

2.  To use a lithium primary cell with the MKRWAN 1310, you should use a regulator to regulate the battery voltage to the voltage level of the MKRWAN.  Typically, this is 3.3V.  (I have operated the MKRWAN at 2.7V).  The regulated voltage can be applied to the +3.3V input of the MKRWAN.

sslupsky

Regarding point 2 above, remove the solder jumper at the output of the mkr wan power supply when using an external power supply.  This eliminates leakage from the external power supply into the mkr wan's power supply.

ageissler

#5
Jan 10, 2020, 11:53 am Last Edit: Jan 10, 2020, 11:54 am by ageissler
@sslupsky would it be possible that you post a schematic or picture who shows the exact position of the solder jumper? This would be very nice  :D THX!

sandeepmistry

A quick note, in case you haven't done so remove the
Code: [Select]
while(!Serial); line from your sketch if it has one. If it's present, the board will wait for the Serial Monitor to open the IDE.

ageissler

#7
Jan 10, 2020, 06:36 pm Last Edit: Jan 14, 2020, 10:16 am by ageissler
The MKRWAN 1310 now includes a secondary lithium battery charger circuit.  Secondary lithium batteries are "rechargeable".  Secondary batteries are commonly referred to as "Lithium Ion" or "Lithium Polymer".

Lithium primary cells, such as Lithium Thionyl chloride batteries, are not rechargeable.  Primary batteries are sometimes referred to as "Lithium Metal" batteries. 

1.  If you attach a lithium primary cell to the charging port of the MKRWAN 1310 and the MKRWAN is connected to an external power source such as USB or a power adapter, the battery could catch fire or explode.

2.  To use a lithium primary cell with the MKRWAN 1310, you should use a regulator to regulate the battery voltage to the voltage level of the MKRWAN.  Typically, this is 3.3V.  (I have operated the MKRWAN at 2.7V).  The regulated voltage can be applied to the +3.3V input of the MKRWAN.
Just an idea...
When USB is connected to the MKR1310 there are 5V on the 5V-pin present, right? Then should it be possible to switch a normal closed relay with it. And over this relay is the Lithium battery connected. At the moment you connecting USB the relay will open and break the battery connection... Provided the 5Vpin can supply enough current to switch the relay... is there 10mA possibly on this 5V outpin?!?

... or with a diode in front of the + battery ...

sslupsky

The jumper is marked "SJ1" on the bottom side of the board.  You can see it clearly in the 3D render I attached below.  You need to cut the bridge between the two pads to disconnect the onboard power supply.

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