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ArcticMyst Security by Avery

Open Sauce 10440 Battery Charger Rev. 1.1

Joined
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I was unsatisfied with the current charger offerings. Most are for higher current cells like the
18650. The higher end ones use some kind of sacred source charging algorithm. Frankly I
like to know exactly how my charger is charging my expensive lithium batteries.

The circuit is based around the Microchip MCP73831. It uses the CC/CV charging method,
which is believed to be the safest and most effective. An LED lights red upon battery
insertion and turns green when the charging is complete. It goes out when the battery is
removed to save power.

10440%20Charger.png


MCP73831 datasheet

OSH Park Shared Project

(RENAME TO .zip)
 

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rhd

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Re: Open Sauce 10440 Battery Charger

Good on you for open sourcing this. The forum needs more of that perspective.

It's also cool to note that this IC has 4.35 V versions as well, so it would be an easy task to make a charger for those higher voltage cells.
 

oahu99

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Open sauce? Like ketchup?
(Don't pretend you weren't thinking that when you read the title!)

This is a good idea, and is great that it's open source.
However for all of my lithium batteries I use my rc car charger. I can set the charge current on that, for any lithium battery.
Just some food for thought!

EDIT: What is the charge current set to?
 
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Re: Open Sauce 10440 Battery Charger

ketchup??== A-1 is sauce-- lol

srsly

I any batt charger expert wants to help me with a charger project I will 'fund' it--
this is not your ordinary Li-ion charger and I suspect when we get them done them done we will be able to charge a large number at the same time--

Originally sold to Uncle Sam for a boatload of $$- these chargers where installed in Hummers for the Gulf War- now they are just army surplus at pennies on the dollar.

PM if you REALLY can work with these- I am short on time and lack the knowhow to really take on this task==

I can email you some pics before you commit--hak
 
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Re: Open Sauce 10440 Battery Charger

EDIT: What is the charge current set to?

It's set at 150mA, which is 0.5C for the Sibeile 10440. It can be adjusted by using a different
value for R1, according to the formula R = 1000 / I. Batteryuniversity.com recommends
charging at 0.5C for long life.
 

ped

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Re: Open Sauce 10440 Battery Charger

"Sauce" is a sign that someone is spending too much time reading comments at imgur :)
 
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Re: Open Sauce 10440 Battery Charger

Boards arrived today

Unfortunately they were all loose in the envelope and one of them rubbed some solder mask off one of the
others. A support ticket with Oshpark has been opened.

Oshpark%201.jpg
 
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Messages
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Points
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:bumpit:
I had made a mistake in the original
schematic and connected the green LED in
reverse so it never came on. The OP has
been updated with a new board revision
which should hopefully correct this. The
board size has also been reduced to lower
board cost for anyone :anyone: who decides
to try building these. Otherwise, the boards
work perfectly and I have already charged
several cells with it. Charge time for a
"350mAh" LiMn 10440 is around 4-6 hours.

The picture has also been updated, though
eagle3d was inflating the capacitors to an
enormous size and they were covering the
whole board, so I had to leave all the
components off. It was working just fine
and then all the sudden started acting up for
no apparent reason. All I did was change the
value on the MCP which seems completely
unrelated and changing it back had no effect.
Does anyone know how to fix this?
 




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