I've used an Aerolatte frother for years and love it except that I have to change batteries every two weeks (or less). I also don't like always worrying whether I'm going to get one more use out of the batteries or if it will start slowing down as the batteries drain.
To solve all these problems I devised a simple modification for use with a 120 volts, AC wall adapter. It actually works much better now that I can plug it into a mains outlet. Also, this mod doesn't damage the Aerolatte so you can always go back to battery use in the future. Here's how to do it:
I used an AC/DC wall adapter to supply 3.3 volts DC, almost exactly what you would get out of two fresh AA batteries (They are usually rated at 1.5 volts each). The trick with the wall adapter is that it must be heavy duty enough to supply the amperage (power) needed to drive the small motor in the Aerolatte (motors draw more current than other small, purely electronic devices). The correct amperage rating for the adapter turned out to be 3.0 amps (sometimes stated: 3000ma.). So your adapter info should read something like this:
INPUT: 120V 60Hz 0.3A
OR, if it is what they call a 'Universal Adapter':
INPUT: 100-240V 50/60HZ 0.3A (a universal adapter is good in most foreign countries).
Output should always read:
OUTPUT: DC 3.3V 3A (or 3000ma) (the little broken-line symbol means Direct Current (DC), the correct type for the Aerolatte.
I had to order this lightweight adapter online since it wasn't available in town. I bought it from PowerStream, Lund Instruments Engineering who were very cooperative. You can find the adapter here - it cost a little over $20 with shipping:
When your adapter arrives, cut the plug off at the end and discard it. You won't be using it for this project. Split the adapter wires at the end enough to fit into the dowel adapters you will make (see the photo below). Strip a little of the insulation from the end of each one. If you cut the negative wire a little shorter than the positive one, it will allow them to lie flat as they exit the machine (see polarity and how to tell which wire is which below).
To make the dowel battery blanks to insert into the Aerolatte, I used two lengths of Douglas fir dowel with a diameter of ½ inch, each piece cut to 1 7/8" length.
I drilled a hole down through the middle of the each dowel piece large enough to allow one wire of the split adapter zip cord to run through the center of each dowel. Once threaded through the dowels, at the contact end (the end which will contact with the springs inside the Aerolatte battery compartment), I soldered small circles of tin cut with scissors from a tin can as contacts and filed off any excess solder so they were more or less flat. On the other end of the dowels, I cut grooves for the wires to lie in as I wanted to allow for the original battery compartment door to slip back on. I also filed an exit groove in the plastic rim that runs around the battery compartment opening, on the side opposite where the door will slide on, to allow the wire to exit neatly. Make the edges of this groove smooth so as not to abrade the wires.
Polarity: One thing to keep in mind is the polarity of the power supply. As it turns out, if you reverse the polarity by accident (how do I know this?), it just makes the motor run in reverse but I don't know how good that is for it so I adhered to the original polarity in my design. On your adapter, there will be one side of the zip cord that will have grooves in the outer insulation and the other side won't though it might perhaps have some printing. The grooved side wire is the positive, the other, negative.
You want to mimic the same polarity as the batteries would deliver so you want the positive adapter wire to feed into the contact where the Aerolatte expects the positive battery charge. This is a little counter-intuitive as the Aerolatte has a + sign on the battery slot where you will insert your negative wire. This is because they are instructing you to insert that battery with the + (plus) side up, meaning that the - (negative) side of the battery is down and in contact with the spring contact beneath. This is actually the side in which you will insert your negative adapter terminal. Insert the other (your positive adapter terminal) into the side marked - (minus). When you plug the Aerolatte in and hit the switch, this should make the motor rotate in a clockwise direction, viewed from the handle. If not, reverse the adapter battery blanks.
Fold the wires neatly and slide the battery compartment top in place.
That's really all there is to it. You will see that the modded Aerolatte is more robust and works better with this adapter than it ever did with batteries. It runs evenly and strongly and you will never have to buy another battery for it.
Needless to say, this is not a factory sanctioned mod. I have found no overheating or any other signs of problems with mine but I'm sure modding it in this way will void any factory warrantees. However, at $20 for a new Aerolatte, it's not too much to worry about. Also, use of this now mains-powered appliance means you must adhere to all safety precautions for any electric kitchen appliance. Never submerge the motor handle in water and always unplug it whenever not in use for frothing.
So, now your Aerolatte works even better then when it was born. The foam it makes in a few seconds is thick enough to stand a spoon in and I also mix the sugar (and sometimes cocoa) in my coffee cup with it to make an incredibly smooth, homogenized drink. But just remember, it's still not a blender. It was meant to whip low-viscosity liquids like hot milk so don't be tempted to make smoothies with it or it won't last. It's also meant to be used for brief periods not 20 minute mixology sessions.
If you ever want to revert to battery use for traveling or any other reason, just remove the adapter and re-insert batteries.