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30 Apr 2015

obr1695_uvod

 

And it can be added that also simply and cheaply. MCP73831 from company Microchip is „all-in-one“ solution for charging a single Li-ion/Li-Po cell.

Li-Ion a Li-Polymer cells are becoming a No.1 choice for many applications, where they persuade by high energy density, low weight, low self-discharge and for majority of applications also by their favorable flat shape (Li-Po). Their price is also affordable (in regard to their properties) and so there´s usually only one “difficulty” – to solve charging, or more exactly – overall management of these cells. Basic principles were highlighted to you in our article “Try the most favourite types of batteries”. To reach a maximum cell lifetime, it´s also advisable to use initial (preconditioning) slow charging and also important is a proper charging termination as well as repeated recharging after reaching a certain degree of discharge.It´s obvious, that to construct such a circuit from discrete components would be possible, but impractical, bulky and expensive. That´s why there are various charging controllers on the market and in many cases a single chip solution is an ideal solution. This is also a case of MCP73831 chip – a fully integrated linear charging controller. If you use only a single cell and maximum charging current of 500mA is sufficient for you, then MCP73831 will meet all requirements for a quality and safe recharging solution. MCP73831 has integrated output (FET) transistor, current sensing and reverse discharge protection.

Charging current can be easily adjusted by a single resistor, what´s also associated with other parameters like preconditioning current and charging termination. MCP73831 also contains a thermal regulation, which decreases output current in case of increased chip temperature (for example because of higher ambient temperature).

MCP7383x is available in four versions with factory-set regulation (max. charging) voltage. In our store can be found “the safest” first version with 4.20V regulation voltage – MCP73831T-2ATI/OT. In datasheet (p. 25) we can also read that this is the “AT“ version, which starts repeated charging at 94% Vreg (i.e. at approx. 3.95V), in a SOT23-5 package. Supply voltage can be in a range of 3.75-6V, while in respect to a thermal stress of a chip it´s better to supply it by a voltage close to max. output voltage (4,20V).

The chip can be easily supplied by a standard 5V voltage, but in cases of increased risk of overheating (operation at higher ambient temperatures, densely populated PCB,…), a common Si diode in series can be helpful. This will decrease supply voltage in 0.6-0.7V (and takes a portion of thermal loss on itself).
Charging status can be found at the “Charge status output” pin, which can drive an indication LED or can be connected to a host microcontroller.

With MCP73831 you’ll charge lithium cells easily and safely – [Link]

18 Jan 2015

obr1566_1

Perhaps the most frequently used rechargeable batteries on the market nowadays – Lithium-Polymer (Li-Po) can be found also in our offer.

From the beginning of electronics, the world searches for an “ideal” rechargeable battery. So far such a battery doesn´t exist (maybe supercapacitors in the future), but Li-Po (Li-Pol) cells are quite near to an ideal in some aspects.

Very low self-discharge (approx. 5% / month), high voltage of a cell (3,7-3,8V average), high energy density and a low weight, considerably stable discharge voltage and a possibility to recharge anytime are one of the main advantages of Li-Po cells. Another benefits are advantageous flat shape, high variability in dimensions and a long lifetime. No wonder, that Li-Po cells have become no. 1 in consumer electronics, hand tools and in many industrial devices.

Perhaps the only drawback of these cells is their lower chemical stability at overcharging (in a corner case ending up with a fire). But that´s the case which is practically eliminated at a common operation with a suitable charging circuit (chip or a charger intended for Li-Po).

Basic principle at usage is not to exceed approx. 4.25V charging voltage and the battery is almost discharged at a voltage below approx. 3.0V (2.75V). On the very end of a discharge cycle, the inner resistance slightly increases, what can cause a slight heating of a battery at higher currents – it is a normal behavior. Charging is usually based on a method constant voltage/ limited current. In principle it´s possible to use the same chargers and charging circuits for Li-Ion as well as Li-Po cells.

At a usual usage and discharging to say 20-80%, Li-Po cells will reward you by a reliable operation and a long lifetime. Flat shape is ideal for various handheld equipment, as well for usage in flat enclosures. In respect to a low self-discharge it´s possible to use Li-Po cells even as a backup energy source.

In our offer can be found several several Li-Po types from company EEMB with a capacity of 130 mAh to 2000 mAh. Exact list of available types and datasheets can be found below this article. Upon request, we´re able to provide you also many other types.


Try the most favorite type of batteries – [Link]

24 Dec 2014

2014-12-06-03-05-41-600x627

Jason over at Rip It Apart did a teardown of a Kentli PH5 1.5 V Li-Ion AA battery:

The PCB that holds the 1.5 volt regulator is inside the end cap, with the rest made up of the Li-ion cell itself. Curiously enough, the cell inside is labeled “PE13430 14F16 2.66wh” which is interesting in more than one way. First of all, the rated energy content of the cell is less than what’s on the outside label (2.66 watt-hours versus 2.8), and the cell inside is actually a Li-ion polymer (sometimes called a “Li-Po” cell) type; I was expecting a standard cylindrical cell inside. Unfortunately, my Google-fu was unable to pull up any data on the cell. I might attempt to do a chemistry identification cycle on the cell and see if TI’s battery database can bring something up.

[via]

Teardown of Kentli PH5 1.5 V Li-Ion AA battery – [Link]

11 Aug 2014

obr1566_1

Perhaps the most frequently used rechargeable batteries on the market nowadays – Lithium-Polymer (Li-Po) can be found also in our offer.

From the beginning of electronics, the world searches for an “ideal” rechargeable battery. So far such a battery doesn´t exist (maybe supercapacitors in the future), but Li-Po (Li-Pol) cells are quite near to an ideal in some aspects.

Very low self-discharge (approx. 5% / month), high voltage of a cell (3,7-3,8V average), high energy density and a low weight, considerably stable discharge voltage and a possibility to recharge anytime are one of the main advantages of Li-Po cells. Another benefits are advantageous flat shape, high variability in dimensions and a long lifetime. No wonder, that Li-Po cells have become no. 1 in consumer electronics, hand tools and in many industrial devices.

Perhaps the only drawback of these cells is their lower chemical stability at overcharging (in a corner case ending up with a fire). But that´s the case which is practically eliminated at a common operation with a suitable charging circuit (chip or a charger intended for Li-Po).

  Basic principle at usage is not to exceed approx. 4.25V charging voltage and the battery is almost discharged at a voltage below approx. 3.0V (2.75V). On the very end of a discharge cycle, the inner resistance slightly increases, what can cause a slight heating of a battery at higher currents – it is a normal behavior. Charging is usually based on a method constant voltage/ limited current. In principle it´s possible to use the same chargers and charging circuits for Li-Ion as well as Li-Po cells.

At a usual usage and discharging to say 20-80%, Li-Po cells will reward you by a reliable operation and a long lifetime. Flat shape is ideal for various handheld equipment, as well for usage in flat enclosures. In respect to a low self-discharge it´s possible to use Li-Po cells even as a backup energy source.

In our offer can be found several several Li-Po types from company EEMB with a capacity of 130 mAh to 2000 mAh. Exact list of available types and datasheets can be found below this article. Upon request, we´re able to provide you also many other types.


Try the most favorite type of batteries – [Link]


3 Feb 2012

This is a tiny, easy to make USB Lithium-Polymer battery charger. It’s based on the MAX1555 charger IC.

Tiny USB Li-Po battery charger – [Link]

6 Oct 2011

RGB LCD Arduino Intervalometer @ The Custom Geek. [via]

I am getting ready to sell some kits and wanted a good way to photograph the assembly without fumbling around trying to hold a camera in one hand and a project in the other. The answer? An intervalometer. A device that can send an IR signal to my Nikon, triggering the shutter. The video above explains all of the features including; automatic delay calculation, auto stop, multiple LCD and LED feedback options, Li-Po charging, FTDI headers, and manual control via button or plug-in foot switch.

This project will work with most Nikon DSLR cameras without changing anything, but can easily be adapted to work with Canon, Sony, or any camera that will accept an IR remote.

RGB LCD Arduino Intervalometer – [Link]

18 Oct 2009

l_dsc_0100

Alex at Tinkerlog writes:

For my latest projects I used a lot of single cell LiPo batteries. They are really nice. High power density, low self-discharge, no memory effect and they can deliver quite an amount of current. But LiPo battery handling is a bit more complicated than other rechargeable batteries. You have to take care of under voltage and over charging as that may destroy the battery.

I used the Sparkfun LiPoly charger, based on MAX1555, for some time and it works really well. The only thing I missed was a way to control the current. After some research I decided to try another chip, the Microchip MCP73833. [via]

LiPoly charging with MCP73833 – [Link]

15 Feb 2008

charger_2.jpg

This is a Li-Po charger and balancer project for R/C hobby.The charger circuit is based on the circuit of Electron head and all folks in the DIY electronics topic on the rcgroups.com. [via]

Li-Po charger and balancer – [Link]



 
 
 

 

 

 

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