Please recommend rechargeable Li batteries

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HKPhysicist
 
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Please recommend rechargeable Li batteries

Post by HKPhysicist »

Hello,
I need to find a battery for my board:
https://www.microchip.com/en-us/develop ... l/EV75S95A

From its manual, it requires that:
minimum battery capacity 400 mAh
charging voltage 4.2V
battery output voltage 3.3V DC
My board's battery connector is: S2B-PH-K-S; Pin Header 1x2, 2mm THM, right entry, 100V AC/DC, 2A AC/DC (AWG #24)

Please recommend some of your battery models to fit the above requirements.
I have found this from a provider. Does it fit my requirement?
https://www.adafruit.com/product/2011

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dastels
 
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Re: Please recommend rechargeable Li batteries

Post by dastels »

That battery should work fine. The docs say at least 400mAh. Be VERY careful about the polarity of the JST connection. There's two ways to wire them and that board could be either. The red wire on batteries from Adafruit is positive., black is ground.

Dave

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HKPhysicist
 
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Re: Please recommend rechargeable Li batteries

Post by HKPhysicist »

dastels wrote: Mon Jan 23, 2023 3:18 pm That battery should work fine. The docs say at least 400mAh. Be VERY careful about the polarity of the JST connection. There's two ways to wire them and that board could be either. The red wire on batteries from Adafruit is positive., black is ground.

Dave
I have found design pictures of my board. However, I cannot find a schematic picture of this Adafruit battery connector's orientation.

Can you please give further opinion whether their polarities match or not.
SAM board
SAM board
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SAM board top
SAM board top
sam board top.png (47.39 KiB) Viewed 111 times

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dastels
 
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Re: Please recommend rechargeable Li batteries

Post by dastels »

Yes, I found a bunch of pictures, and the official documentation but nothing that indicated the battery connector polarity. From the pictures on the battery product pages (e.g. https://www.adafruit.com/product/2011) you can see the connector polarity. (red is +, black is ground). Connecting a battery that doesn't match the board connector's polarity will likely break something, so make sure first.

Dave

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dastels
 
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Re: Please recommend rechargeable Li batteries

Post by dastels »

You can use a multimeter to check which side of the JST connector is connected to ground by measuring the resistance between the two pins and ground.

Dave

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adafruit_support_bill
 
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Re: Please recommend rechargeable Li batteries

Post by adafruit_support_bill »

The '+' & '-' markings on the JST connector in the Assembly Drawing above seem to match the polarity of our boards and batteries. But it is still a good idea to verify with a multimeter as Dave suggested.

In any event, it is not difficult to swap the wires to the connector if necessary to correct a polarity mismatch. You can use a toothpick or similar implement to press on the little metal tabs on the underside of the connector to remove the wires. Then just snap them back into the correct location.

Just be careful not to let the bare metal contacts touch each other when they are out of the connector shell.

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HKPhysicist
 
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Re: Please recommend rechargeable Li batteries

Post by HKPhysicist »

Ok.
I followed the battery's reference to a compatible charger. This picture confirms the battery connector's polarity orientation.
Image

It matches with my board's requirement.

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