Lower or Control Amps on USB port charge? Smart charge?

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Bright_Mike
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Lower or Control Amps on USB port charge? Smart charge?

Is there any way to control current from a USB port for charging? I need to charge a small battery, and 500ma (from 1.0 or 2.0) is a bit more than I would like.

Also, is there any way to have the usb port act as a smart charger, so that I can use a plain cord, straight from the computer?

Other tips, ideas, etc welcome. It’s for a drone, and I doubt that the cord is a smart charger.

Rufusbduck
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Check out the USB TP4056 charge boards. You can get them on eBay or MtnE has them. You can order the ones Rich sells with a lower set charge current or DIY(he’ll sell you whatever resistor you need for the current you want. The resistor is small but the board isn’t crowded so it’s a pretty simple level one mod. You can use wires with magnets or kludge up your own set of contacts. I’m a bit leery of magnets for charging though.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

will34
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Is your cable like this?

If so inside the usb housing there is a charging circuit and cuts the charge at 4.2V. I have several of them and the charge current range from 300-800mA. Not a bad charger at all, for such a small battery I don’t think there’s need to change it.

Rufusbduck
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By changing the sense resistor you can dial in the current anywhere from 50mA to 1A. For small cells 1C is a good target.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

MRsDNF
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Rufusbduck wrote:
By changing the sense resistor you can dial in the current anywhere from 50mA to 1A. For small cells 1C is a good target.

1C or 1/2C charge current?

 

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Rufusbduck
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1/2 C would be better but I don’t know if the board will go that low on a 10180. For that I just went 50mA and called it good.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

Bright_Mike
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will34 wrote:
Is your cable like this?

If so inside the usb housing there is a charging circuit and cuts the charge at 4.2V. I have several of them and the charge current range from 300-800mA. Not a bad charger at all, for such a small battery I don’t think there’s need to change it.

!{width:40%}http://ecx.images-amazon.com/images/I/41CbsV7Z1RL.SX342.jpg!

That’s really good to know, will34, it’s one of these:

http://s32.postimg.org/8cx04vf5h/20160515_104259_0_1_20160515_105306.jpg

How were you able to test V and A on battery and charger? Driving me nuts. I got about 3.0-3.1V on the usb with the cord plugged in, even after charging on a USB 1.0 or 2.0 port for 30 minutes or so.

Id like to use the 4056 boards, are there any good ones out there? Mtnelectronics has them?

Was charging an 18650 with one the other day, V went to 4.26V. Is that too high? Pulled battery off, 4.1V, I think. Thanks for all the responses