Have I missed where it states the maximum current which the Batteriser can supply?
To the best of my knowledge no claims have been made about how much current the Batteriser can supply.
The Garmin GPS that has been mentioned in the testing needs around 150-200mA based on the run time that forum member 5ky measured.
A digital camera running from 2x AA cells would need a peak current of around 1A. The 1A current has been measured in some of the Batteriser videos, but there has never been a demonstration of a digital camera running from AA with the Batteriser. Since the majority of Digital cameras use rechargeable Li-ion this is a mute point.
A survey of available ICs for this job suggests that 500mA may be possible. The switches in the IC would be handling twice about twice the output current. The space limitations also limit the inductor to about 2A. The inductor needs to be around 2uH.
Other people have suggested that the IC is the Analog Devices ADP1607.
Here is the published efficiency curve from the ADI datasheet:
It would have difficulty doing 500mA even from a 1.2V source.
There are two reasons that this is likely to be the chip that was used on the prototype:
1) This part has a minimum output voltage of 1.8V The chip needs the output voltage to operate itself after start up. The 1.8V has been mention in the Batteriser videos.
2) The part will fit a picture of a board layout shown in the Batteriser campaign.
The inductor that was used by ADI to get the datasheet graphs is too large for the space at the end of an AA cell.
Sooner or later you run into the maximum power theorem. Given the ESR of an AA battery is around 0.2 Ohms, maximum power would be delivered into a 0.2 Ohm load.
The maximum power would be:
(V
oc/2)
2 / 0.2 = 2.5W which is about 2W into the load given the estimated boost converter efficiency around 80%.
There will be proportional problems for different size cells.
Regards,
Jay_Diddy_B