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Lithium Ion Charging
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Lithium Ion Charging

by SpocksEars on Thu Apr 22, 2021 6:42 pm

Hi all,
I'm converting one of my phony flicker candles into something rechargeable.

I'm interested in this battery (x2!):
https://www.adafruit.com/product/1781

and I have this charger:
https://www.adafruit.com/product/259

Can use that charger to charge 2 of those batteries that have been placed in parallel?
I'd like to use 2 to increase the capacity, but they're the perfect size.
If not, what do you suggest?

Thanks in advance!

SpocksEars
 
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Re: Lithium Ion Charging

by adafruit_support_bill on Thu Apr 22, 2021 6:51 pm

I'd use one of these instead: https://www.adafruit.com/product/354

Making your own packs from loose cells is not recommended. Even small differences in cell characteristics can lead to dangerous pack imbalances.

The factory assembled packs are made from cells from the same lot that have been precision matched and balanced for charge & discharge characteristics.

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Re: Lithium Ion Charging

by SpocksEars on Thu Apr 22, 2021 7:50 pm

Thank you so much, that looks absolutely perfect!
Ordering one right now!

SpocksEars
 
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Re: Lithium Ion Charging

by SpocksEars on Sun Apr 25, 2021 12:09 pm

Sorry, one more final question before I order.
What is the smallest Li-Ion charger that I can get away with for these paired batteries?

Would either of these work?

Power Boost 500
https://www.adafruit.com/product/1944

Power Boost 1000
https://www.adafruit.com/product/2465

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Re: Lithium Ion Charging

by adafruit_support_bill on Sun Apr 25, 2021 12:19 pm

Either of those will work. The PowerBoost chargers have a voltage boost section for generating 5v output. If you do not need that, there are several smaller charger-only modules that will work also:
https://www.adafruit.com/product/259
https://www.adafruit.com/product/1905
https://www.adafruit.com/?q=micro+lipo&sort=BestMatch


The trade-off is a slower charge rate. Mini and Micro size chargers have lower charge-rates and will take longer to charge your cell.

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Re: Lithium Ion Charging

by TopHatRaver on Mon Sep 13, 2021 2:15 pm

Hey I just wanted to confirm that I can use your Adafruit LiIon/LiPoly Backpack Add-On for Pro Trinket/ItsyBitsy #2124 with a Trinket M0 to charge the Lithium Ion Cylindrical Battery - 3.7v 2200mAh #1781. This is my first time using that battery. And if so, I assume I can jumper the backpack to charge at 500mH?

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Re: Lithium Ion Charging

by adafruit_support_bill on Mon Sep 13, 2021 2:56 pm

Yes, you can chare the 2200mAh cylindrical cell at 500mA with that. Please note that the backpack was designed to match the pinout of the Pro Trinket - which is a little different than the Trinket M0. So you won't be able to simply stack it using a 3-pin header. But you can connect it with wire jumpers.

To use with the M0 Trinket, connect:
GND->GND
BAT->BAT
5v->USB

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Re: Lithium Ion Charging

by TopHatRaver on Tue Oct 19, 2021 7:03 pm

Thank you! I cut the trace between the battery output holes and added an on/off slider switch. It works great while on battery. But, when I plug in the USB, the lights come back on without turning the switch on. How do I stop that from happening?

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Re: Lithium Ion Charging

by adafruit_support_bill on Tue Oct 19, 2021 7:34 pm

The USB jack is on the Trinket and feeds power to the Trinket directly. The switch on the backpack can only control the power coming from the backpack.

To control power coming in via USB you could use one of these: https://www.adafruit.com/product/3439

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Re: Lithium Ion Charging

by TopHatRaver on Tue Oct 19, 2021 8:57 pm

Bummers, I'm making a small lighted wearable item so I'm trying to keep the profile as small as possible. Do you offer other controllers where I can still pass thru power to the battery from the USB to charge it but without it lighting the LEDS at the same time?

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Re: Lithium Ion Charging

by adafruit_support_bill on Wed Oct 20, 2021 5:19 am

The Feather boards all have built-in chargers and an Enable pin. With a switch between Enable and GND, it will disable the output of the voltage regulator and shutdown the whole processor - regardless of the power source.

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Re: Lithium Ion Charging

by TopHatRaver on Thu Oct 21, 2021 11:11 am

I do love a feather board! It states that the charging on it is 100mAh so if that's connected to one of these lipoly batteries thats 22 hours of charging time for a full charge? Is there any jumper to increase that charging rate or any power booster I can use to shorten that time?

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Re: Lithium Ion Charging

by adafruit_support_bill on Thu Oct 21, 2021 11:55 am

Unfortunately, the charge rate on the Feather charger controllers is fixed.

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Please be positive and constructive with your questions and comments.