From: Neil <picdude3@narwani.org>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Tue, 6 Oct 2020 12:56:32 -0700
Subject: Re: [EE] Re: Lithium battery confusion.
Thread-Topic: [EE] Re: Lithium battery confusion.
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A couple years ago, I had issues charging "standard" LiPo batteries to 4.2V=
..
Turns out the batteries (very low-cost ones from China) just would not=20
get to 4.2V, so charge-done was never indicated.  They only charge to 4.1V.
IIRC it was a Microchip 73833 chip, and further investigation revealed=20
that I could get the charger chips (for the same LiPo technology) in=20
different pack voltages -- 4.1V, 4.2V, etc.
So IME there are possible variations even for the same technology.

Cheers,
-Neil.



On 10/6/2020 2:52 PM, Dwayne Reid wrote:
> Topic tag added
>
> Russell M is probably best to answer this but I'll pass on what I've
> learned over the years.
>
> As far as I know, standard Li-Ion and Lipo cells have almost
> identical chemistry.  There used to be a slight difference between
> cells from different manufacturers in the anode material used.  This
> lead to different nominal voltages (3.6V xs 3.7V) where the maximum
> charge voltage was 4.1V for the 3.6V cell and 4.2V for the 3.7V cell.
>
> Also as far as I know, most Li-Ion and Lipo cells are now of the 3.7V
> nominal voltage version.
>
> Do note that I am NOT talking about the LIFEPO4 cells (3.2V nominal).
>
> The charger module that you linked to seems entirely
> appropriate.  Stupid expensive, though.  There are far less expensive
> ready-made chargers available from Oh So Many Asian suppliers.
>
> Or - you could roll your own with free samples from Microchip.  I use
> their MCP73831T-2DCI/OT in two of the products that we have built in
> the past.  Less than Can $0.50 in 25 lot or free if you ask Microchip nic=
ely.
>
> dwayne
>
>
> At 11:01 AM 10/6/2020, David C Brown wrote:
>> I have cell phone  battery from a reputable manufacturer - Motorola - wh=
ich
>> is marked
>> 3.8v Lithium Ion Polymer battery.  And I am seeking a charger module.
>>
>> I was under the impression that Li-ion and Li-poly were different
>> chemistries which require different charging regimes.  Is that not so.
>>
>> And would this simple module https://tinyurl.com/y48gp4hu be suitable.
>> __________________________________________
>> David C Brown
>> 43 Bings Road
>> Whaley Bridge
>> High Peak                           Phone: 01663 733236
>> Derbyshire                eMail: dcb.home@gmail.com
>> SK23 7ND          web: www.bings-knowle.co.uk/dcb
>> <http://www.jb.man.ac.uk/~dcb>
>

--=20
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