Lithium Ion Cylindrical battery for stand alone outdoors pro

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krlos
 
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Lithium Ion Cylindrical battery for stand alone outdoors pro

Post by krlos »

Hello!

I need a high capacity battery for a stand alone outdoors project. I came across these batteries:

LITHIUM ION CYLINDRICAL BATTERY - 3.7V 2200MAH: https://www.adafruit.com/products/1781
LITHIUM ION BATTERY PACK - 3.7V 6600MAH: https://www.adafruit.com/products/353

I plan to charge and manage their usage with the following charger:

USB / DC / SOLAR LITHIUM ION/POLYMER CHARGER: https://www.adafruit.com/products/390

However in the description of those types of batteries (cylindrical ones) states that they should no be charged unattended. Questions:

1. Does this apply even if I use a specially designed charger for that type of batteries? Like the one available on your store.

2. If I can not use the cylindrical batteries, can I use a battery like this one: https://www.adafruit.com/products/328?

Regards!

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adafruit_support_bill
 
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Re: Lithium Ion Cylindrical battery for stand alone outdoors

Post by adafruit_support_bill »

Lithium cells in general are less stable than other battery chemistries. Since they pack so much energy in a small package, if it is released in an uncontrolled fashion it can be quite dangerous. If you search the net you will find plenty of examples of cells bursting into flame.

That said if charged and discharged at conservative rates and not subjected to physical abuse they are safe enough to be the power source for the cell phone in almost everyone's pocket.

But cell phones are products developed by professional electrical engineers designing with safety in mind. The battery in question is sold as a component for DIY projects and will be utilized in less controlled circumstances. That is why we urge extra caution.

You project, being an outside project is less likely to burn a house down or injure someone if the battery is subjected to extreme conditions. Still, it would be a shame to see a project destroyed, so please handle with care and stick with the charge/discharge rate recommendations. The chargers we sell (including the solar charger) use a very conservative charge rate by default. The discharge rate is a function of the load, so do pay attention to that.

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krlos
 
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Re: Lithium Ion Cylindrical battery for stand alone outdoors

Post by krlos »

Hello!

Thanks for the reply!

Is the on-cell protection circuit enough to handle safely the battery?

Should I include myself extra circuitry to ensure the proper use of the battery?

Do you sell or recommend any switch the disconnects the battery if any electrical characteristic is out of the safe boundaries while the battery is being used?

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adafruit_support_bill
 
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Re: Lithium Ion Cylindrical battery for stand alone outdoors

Post by adafruit_support_bill »

The on-board protection circuit will protect against over-discharge. It also has some protection against high discharge currents. If you design your load to stay within the 0.5C (1.1A for the 2200mAh cell) standard discharge rate, you should have no problems.

Safe charge levels can be affected by other factors such as ambient temperatures. If you do expect this to be subject to temperature extremes, there is an optional thermistor input on the solar charger that can be used to monitor battery temperature and stop or decrease the charge rate if the battery is over-temperature.

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andrewg12
 
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Re: Lithium Ion Cylindrical battery for stand alone outdoors

Post by andrewg12 »

I am also looking at doing an outdoor project using an adafuit 3.7v 4400mh lion battery. I have seen fire proof battery pouches elsewhere online for lion batteries in case they do catch on fire, but I am confined by space with my project and can only find battery pouches that are much larger than my battery. I don't see that adafruit sells any kind of battery pouch and I was wondering if I could get some advice on where I could find a pouch that would more closely fit the size of my 3.7v 4400mah lion battery. My batteries dimensions are 3.75in x 1.75in x 1in. Thank you!

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adafruit_support_bill
 
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Re: Lithium Ion Cylindrical battery for stand alone outdoors

Post by adafruit_support_bill »

I don't have any experience with these. But the smallest ones I have seen are still quite a bit larger than a 4400mAh cell.

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