PROTEGE DOES 5V, but more on that in a minute...
The recommended Tenergy 14500 unprotected is rated at 900mAh, but my protected AW 14500 batteries, rated at only 750mAh, consistently outperform them by about an hour or so. Nothing technical, I just know I go through more juice and get consistently good 3.6-4.2V vapor production for a longer stretch.
With that said, I've been using two unprotected AW14250 batteries, exactly half the size of the 14500, giving me 7.4V fresh off of the charger. They are rated a measly 300mAh, but last nearly twice as long as my 510 Mega batteries (supposedly 280mAh) and right about the same length of time with my dual unprotected AW10440 batteries in a custom 5v laser pen (rated at 400mAh). The resistor in that mod is likely taking a bit of battery life out of these to cut the voltage down. Again, nothing technical just a guess on my part, but experience wise I've been getting about 4-5 hours of out and about vaping, refilling 510 carts with 15-20 drops about twice, or dripping 5 drops on a penstyle atomizer about 4 or 5 times.
But back to the Protege. The two 14250 batteries give 7.4V off the charger which is ridiculous. But with an HV801 atomizer I have--and both regular HV (around 4.2-4.5 Ohm) and the higher resistance (5.2 Ohm) atomizers have proven to be great vapes--all is well in vapor world. I personally prefer the 5.2 Ohm high voltage atomizer on 7.4V, bringing the vaping experience just about on par with the USB Pass/ Protege Passthrough when the batteries are peak (about 5v). It doesn't last all day. But, it is relatively on par with the 4 hours I currently get from the Tenergy RCR123A batteries in the Prodigy V2 at a fraction of the size (not that that the V2 is big by any means). For comparison again, AW LiFePO4 3Volt batteries (rated at 500mAh) vape about an hour longer and allow me to use more juice than the Tenergy RCR123A batteries in my V2. I also have some batteries from China (though I don't know where I got them from exactly, maybe DX, but they are rated at 1000mAh and are the weakest performers of any batteries I own (aside from a couple especially weak RCR2 batteries). So the mAh ratings are way, way off. I don't know how reliable AW's rating are either, but every battery that I've used from them has held up better than their Tenergy or DX counterpart. All of that is to say that the Protege with two AW unprotected 14250 batteries and a High Voltage 801 atomizer at about 5.2 Ohms is a solid out and about performer for me. When I need to chain vape, I break out the passthrough extension and plug it in. If I need a mellow longer lasting through the day vape, at home or out and about, I have an additional 14500 in my pocket to readjust to the 3.7V experience. That in itself is tough at times, but I'm trying not to stay hooked on exclusively high voltage vaping. It puts any pleasurable experience I've ever had with analogues to shame...no ifs, ands, or cigarette butts about it!
So, this thread was buried somewhere and the last post was back in November 2009. No credit goes to me, others have talked about this on here and within threads on other forums. However, I don't know if anyone actually tried it. I have, along with my HV atomizer, and both of us are still here to talk about it. Bottom line, it's a nice middle ground from Protege to Prodigy, and even you have the Prodigy V2, it's an even more stealth vaping experience. Because the 14250s are 3.6/3.7V batteries, they'll charge in most multifunction chargers, including the ones that come with the Protege full kit using the magnetic spacers included with the batteries.
buGG