Best charger for Lithium Ion 6.6A battery pack

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ferite
 
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Best charger for Lithium Ion 6.6A battery pack

Post by ferite »

Hi.

I want to purchase the Lithium Ion 6.6A battery pack, and the charger best suited to charge it the fastest possible, from an AC adapter. So for the charger there are 3 options:

USB/DC Lithium Polymer battery charger 5-12V based on MCP73861
USB LiIon/LiPoly charger based on MCP73833
USB / DC / Solar Lithium Ion/Polymer charger based on MCP73871

I have some questions.

1. Regarding charging speed, the MCP73861 based charger should be better because it can be set up to 1.2A. But the chip is marked as "End of life". For future designs what would be the replacement?. Replacing a chip for other less current capable, doesn't have much sense.
2. In MCP73833 and MCP73861 the battery pin is shared with the load. Should be MCP73871 "More accurate" for having independent load pin. (I am not an specialist but I suppose that a high load can distort the voltage measures that the chip performs in order to control the 3 charging phases).
3. Is there a reason to not use the MCP73871 based charger as "non solar" charger? (by just plugging a 5V adapter instead the solar panel).

Thanks and best regards.

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adafruit_support_mike
 
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Re: Best charger for Lithium Ion 6.6A battery pack

Post by adafruit_support_mike »

ferite wrote:1. Regarding charging speed, the MCP73861 based charger should be better because it can be set up to 1.2A. But the chip is marked as "End of life".
EOL status usually doesn't mean much to the end-user. The existing chips don't stop working, and their projected lifespan will probably be longer than the batteries they charge. It would be something to think about if you planned to buy them in quantity for the next few years and had a needed all your chargers to be identical.

We tend to buy in large quantities, so without checking inventory I'd guess we have several thousand on hand.. enough to cover production while we look at alternatives and select a replacement. The MCP73113 looks like a likely candidate, for instance.
ferite wrote:2. In MCP73833 and MCP73861 the battery pin is shared with the load. Should be MCP73871 "More accurate" for having independent load pin. (I am not an specialist but I suppose that a high load can distort the voltage measures that the chip performs in order to control the 3 charging phases).
The MCP73871 is a bit smarter about load sharing than the MCP73833.

The MCP73833 simply shares its output between the load and the battery. Lipos charge in constant-current mode, so the chip doesn't hold the output at a specific voltage. The output will be the same as the battery voltage at any point in the charging cycle. If you try to run a device with a deeply depleted battery while charging it, the low battery voltage might cause a brownout in the load. The MCP73833 has a built-in charge timer, and if the output voltage hasn't risen to the 'charged' level when the timer runs out, the chip will shut down.

The MCP73871 gives the load priority, even if that means not charging the battery or pulling current from the battery. That allows a device with a deeply depleted battery to start running as soon as it's plugged in. The charging cycle only uses whatever current the load doesn't.
ferite wrote:3. Is there a reason to not use the MCP73871 based charger as "non solar" charger? (by just plugging a 5V adapter instead the solar panel).
You'll get a bit of power-regulation hardware that you don't use, but the load sharing feature makes the MCP73871 an attractive option.

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stork
 
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Re: Best charger for Lithium Ion 6.6A battery pack

Post by stork »

I'm trying to use a Lipoly battery to power a high altitude balloon Arduino payload. I'm planning to use your flexible 6V solar panels, and I've purchased your 3.7V 2500mA battery(s) along with your USB / DC / Solar Lithium Ion/Polymer charger package. I'm wondering if I can use your solar LiPoly charger to charge a 7.4V LiPoly battery, since the charging package is rated at 3.7 volts. If I can't use the solar charging package because of its 3.7V rating and the LiPoly battery's 7.4V rating, then I'd have to use your 3.7V LiPoly battery(s), which I don't think will work with the Arduino.......What do you recommend? Is there another solar charging package available?

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Franklin97355
 
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Re: Best charger for Lithium Ion 6.6A battery pack

Post by Franklin97355 »

This should get you started. Powerboost 1000 Just remember the charge from the solar cells will vary as the sunlight on them changes. You will need to keep the current draw as low as possible. Will the flight be long enough that the 6.6AH battery won't be enough on it's own?

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stork
 
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Re: Best charger for Lithium Ion 6.6A battery pack

Post by stork »

Right now, it's predicted to take an hour & 51 minutes, so if I insulate the battery compartment well enough so they don't coldsoak, the battery power should last.. I don't really think it's a problem anymore......I went ahead and ordered two of the PowerBoost 1000 units, so we should be good to go. Thanks for the reply.

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Franklin97355
 
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Re: Best charger for Lithium Ion 6.6A battery pack

Post by Franklin97355 »

Depending on your current needs perhaps this might get you through if you have enough battery headroom. https://www.sparkfun.com/products/11288

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