DC-DC regulator needed

[dnix71]

I got a "Magic Tap" to play with from our company's facilities manager. He ordered one from Amazon, it didn't work and they didn't want it back. The flaw was in manufacturing. It has a momentary microswitch mounted vertically with a metal lever that is pushed by a plastic rocker switch when you want liquid pumped. The flaw was the lever was longer than the switch (common among this type of switch). Because of the way the switch was mounted, the lever bottomed out before the body of the switch did and prevented it from working. I cut off 1/8" from the lever and it works fine now.

The DC-DC converter I need is to fix a design flaw noted by many people who have reviewed the item. The pump is direct dc powered from 2 AA cells. When the batteries are fresh liquid is pumped fast, but as the batteries drain the pumping rate becomes so slow they need to be replaced before they are fully used up. There is plenty of room under the hood for electronics. Does the converter listed below look like it would work?

http://www.ebay.com/itm/Step-UP-Power-Converter-Voltage-Module-Input-1-3-3V-Output-3-3V-DC-DC-/281051710512?pt=LH_DefaultDomain_0&hash=item416ffcc430

This is the "Magic Tap" itself.

[Mary B]

What voltage do you want to run off? 12 volt battery? That converter doesn't look right.

[dnix71]

I want to run it off the 2 AA batteries just like it comes, but regulate the voltage at some fixed value until the batteries are exhausted. I put 2 AA sized LiFePO4 cells in it and it spun really fast, but I don't want to burn out the motor.

Rechargeable NiMH cells would be a better choice in the long run, but I don't think Ed (the facilities manager) has the discipline for that.

If my mod works I can swap him for the other and tinker with it.

I would have made the riser smaller, too. All the liquid in it falls back when you stop. That's wasted energy.

[OperaHouse]

With all the Li cells you have, I would be thinking buck converter like 2596 if memory serves me.

[dnix71]

It would make a nice cooler tap if I didn't mind drilling a hole in the lid. My Engel cost too much to do that, maybe. It would save opening the lid.

If I give it back to Ed I don't want to give away my disposible LiFePO4 cells and charger to go with it.

[Simen]

If it runs on 2 standard AA batteries in series, wouldn't one AA sized LiFePo4 battery be a perfect replacement? (or 2 in parallel, for extended runs?)

Edit;
And LiFePo4 cells shouldn't be run lower than 2.5V, which probably are around your 'too slow' rate, by your description...