I want a 3.7volt with charging capability built in. The cheapo DIY box mod at madvapes is an ideal size. They do sell a nice little usb breakout board for a connection. They only real concern I had was for the charging circuit its self. I have an extra usb charger I could use, I'm just not sure it would fit properly. Another though was finding the proper PCB to throw in it that wouldn't cut off when being used. I have seen many like this LINK just not sure which one would work OK. Thanks for any advice you can give.
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Here is the one I would use:
MikroElektronika - USB Charger Board - Li-Ion, Li-Polymer battery charger with MCP73832 circuit
It may be a little more expensive but it already has the USB adapter on it. This also says it will do li-ion and li-poly cells.
Sorry I did not get back to your PM was busy (as usual)
Hope that helps.
Dan
MikroElektronika - USB Charger Board - Li-Ion, Li-Polymer battery charger with MCP73832 circuit
It may be a little more expensive but it already has the USB adapter on it. This also says it will do li-ion and li-poly cells.
Sorry I did not get back to your PM was busy (as usual)
Hope that helps.
Dan
Here, hope this help:
Thought I save you the trouble of asking were all the wires go
Dan
Thought I save you the trouble of asking were all the wires go
Dan
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I've used a few of these and they work pretty good. If there is a shortcoming it's that the ending charge is a bit low now at ~ 4.12V, that's after well over a year's use. But in the long run that's actually good for your cells.
And unlike e-cig chargers when charging is done, the single tiny red LED goes off. No additional, plugged-in LED to try to disable or deal with.
Swapping out the full size USB connector is a drag though.
2Pcs USB 5V Lithium Li-ion Battery 1 Cell Charger Board | eBay
And unlike e-cig chargers when charging is done, the single tiny red LED goes off. No additional, plugged-in LED to try to disable or deal with.
Swapping out the full size USB connector is a drag though.
2Pcs USB 5V Lithium Li-ion Battery 1 Cell Charger Board | eBay
Just checked the data on that bugger and it looks like it is set up to run in line with your end circuitry. There is a positve and negative solder point to attach you circuitry to the board and your batt's to a separate connector. Of course the connection is simply parallel to the batteries.
The charge controller chip data sheet looks impressive...
I like the Microchip charger controllers a lot. They really stand out for simplicity and ease of use. Microchip is also notable for excellent documentation on their products. Though, one thing I don't like about them is they require good heat sinking for higher rates. My latest mod uses a 1A charging rate and I had to use the DFN package to keep the part from going into thermal limiting. The DFN package has a large heatsink contact underneath that really does the trick. Though, it's a 3x3mm no-lead package and it's a RPITA to solder. Would be nice if the MSOP and SOT packages included the heatsink contact underneath, much easier to work with.
Would putting a heat sink on top be efficient enough to make a difference or would you not get enough heat transfer through the plastic body?
Funny you should mention that because I tried that very thing. At that point, I had never attempted a DFN package and didn't know if I could do it. Turns out I can, and reliably, but I didn't know that at the time. Running a heat sink on top helped a little, but didn't solve the problem. Soldering the thermal pad of the DFN package to the PCB ground plane is hugely more effective (you need to use "ground plane vias"). I believe it's because the thermal pad is actually in contact with the silicon die where a heat sink on top has a layer of packaging material in between. Now if they put a thermal pad on top, that would make an over-the-top heat sink much more effective.
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