2 Amp's

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2 Amp's

Post by Paul.Allen » Thu Sep 12, 2013 7:32 am

I did a test tonight with the black board with the 100uH inductor powered from a power supply (it drew 1Amp so you could use a wall USB that can supply that) and charged a single cell at 2 Amp's. I would say it is the upper limit you should attempt but that being said the inductor got up to a reasonable 46C. That's not cool, but it's not too hot either. The test made me feel we could do 1.5Amp pulsed between the two slots and have the high charge rate be 750mA instead of 500mA.

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Re: 2 Amp's

Post by Mark » Thu Sep 12, 2013 2:20 pm

I measured 49 degrees on the inductor on the latest revision 6 board that I've got - whilst charging at 1 amp only, so I'd say that's a huge improvement! :-)

I think that the only problem with charging at 1.5 amps is that it'll be drawing more than the normal 500 mA available from most USB ports.

What I'd suggest is that the default code in the firmware on the charger should charge at only 1 amp max, and for those wanting to charge at 1.5 or 2 amps, they can download a file from the forum or web site that they can put onto their SD card which will modify the charger behavior and allow them to have it charging at their desired rate.

BTW, I've got the latest code able to detect a reset after a brown out condition (i.e. if the charger tried to draw too much current) so it could in theory restart the charge at a conservative rate, but I don't think this is the best way to go - it would add complications on what to do if the board was doing an analyze and one cell was charging, but the other was discharging when a reset occured. Without constantly writing to the EEPROM the charger wouldn't know where it was actually up to and where to resume!

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