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Finding a good battery


#1

Hello, I have read many informative posts on here about batteries, however I could not find one that seemed right for my application. They were all regarding very powerful batteries for driving motors.

I currently have in development a PCB which has all of the components of a domino integrated onto the PCB as well as a USB hub which branches out to two USB ports. Also I am using the standard 128x64 LCD screen. I have measured the required power and it seems to peak at 500 mAmps when running at 6 Volts. I tried powering this with a standard 9V battery just to see how it would behave. It seems to drain the battery very fast, and when transferring files between two USB memory sticks it seems to draw more current than the 9V can supply forcing a system restart.

I am trying to find a good battery for running this that needs to be at least 6 volts but can go up to about 12 since we are using the original voltage regulators that come on the Domino. Ideally the battery would not be to large since the device is going to need to fit in someones pocket once the case is designed.

Also, since I am trying to fit everything on a PCB it would be nice if I could find a battery which I could integrate a charging circuit onto the PCB along with everything else.

Any suggestions? ;D

Regards,
Aaron


#2

Look at Lipo RC TX/RX batteries: http://hobbycity.com/hobbyking/store/uh_listCategoriesAndProducts.asp?catname=Rx%2FTx+Batteries&idCategory=307&ParentCat=85


#3

9v are notoriously small milliamp capacity. You definetely need to look elsewhere for something that has more oompfh. As Chris says, LiPo are a great option, but do require some sensitive recharge handling (best is a dedicated LiPo charger). They certainly fit the bill though, one of the best capacity for size ratios.


#4

Would there be any recharger circuits that could be integrated onto a PCB and then charged through a typically 9V barrel jack like the one already used on the Domino? I have a feeling that if I just try to hook these batteries to a voltage with out some sort of current limiting or special circuitry I could damage the battery or harm people using the device.

I might be stretching trying to find something like that, but always better to ask then not to know =)


#5

Like bstag said, you will need to make a recharge circuit. See: http://www.rcgroups.com/forums/showthread.php?t=409659 <- something like that should work well.


#6

if anyone is interested in this thread i found some great integrated charging packages from maxim, you can locate them at http://para.maxim-ic.com/en/search.mvp?fam=batt_chrg&tree=powersupplies

The above post was helpful but it would be unrealistic to integrate all those bjt’s onto a pcb, much more manageable to use a IC.