I've been experimenting a bit with time-lapse photography lately. Still basic stuff. Right now I have to change batteries every so often which is a pain because it's hard not to move the camera when changing the batteries. I've used the ACK-E6 power adapter to run my camera from mains, but this is only possible in some situations.
So I'm looking to somehow attach some higher capacity batteries to my camera.
The regular batteries for my camera (LP-E6) deliver 7.2V. The specifications of the ACK-E6 mains adaptor list the output to the camera as 7.6V 3A.
I've read some things about buck/boost regulators (but I'm hardly an electrical engineer) that I can use to regulate the voltage to that desired 7.2V for my camera.
The goal is to attach a 12V car battery, but have other (smaller, lower weight) options if needed.
I was thinking of buying this buck/boost regulator (or one like this):
3A Power Adapter DC 3.8-32V to 1.3-35V Automatic Buck/Boost Voltage Regulator 3A Drive Power Supply #090040
http://www.aliexpress.com/item/5-PCS-LOT-3A-Power-Adapter-DC-3-8-32V-to-1-3-35V-Automatic-Buck/1609180228.html
I guess the numbers add up, and this should work. But I'm not really sure about the possible risks, because I don't want to damage my camera.
I've searched a lot but I can't really seem to find an answer, so that's why I'm asking here.
Is there a possibility that the 12V from the input goes straight to the output? Are there other risks I have to take into account before attempting this?
Best Answer
In principle, what you want to do will work. But as you say, it's a matter of risk and peace of mind. It is possible, though unlikely, that the unit you are considering (and widely available for almost nothing on ebay) could fail in such a way as to deliver a damaging voltage to the camera, which would be expensive to fix.
The main situation to avoid is over voltage. To avoid that you could add a crowbar circuit (see google if interested), but that seems like work.
The other issue is whether or not the camera presents a highly variable load, as Dave suggests. In that case the 3A rating on the ACK-E6 may be an average that doesn't represent the peak required, which the capacitors on your regulator board may not be sufficient to supply.
A possible workaround for both these problems is to take your existing ACK-E6 and interpose a connector between the brick and the "battery" block. Connect the brick for mains power, and instead connect your DC-DC converter (set to 8V I think from the spec) for alternate power. The ACK-E6 spec suggests that there's some active regulation in the "battery" block, and that would help moderate any over-voltage accident, and I would expect provide sufficient capacitance to handle transient demand.
But all of this is somewhat speculative without schematics!