The Treo 680 cries for batteries. Frequently! The trimmed down Treo comes with a slim, 1200 mAh marvel that has, since the beginning, created a tempest among owners. Seidio offers an extra-beefy 2400 mAH extended battery – at the cost of a bulge on the back of the Treo - they supply a replacement cover. That bulge causes a problem with any formfitting case, so the Treo ends up in your pocket or stashed in your purse, instead of safe in a case.

Seidio also offers a 680 battery of normal size that’s a little bit higher capacity, at 1300 mAh, but no distended battery door needed. It’s much higher cost, however - $34.95, versus Palm’s original at $24.95 replacement cost and Mobi Products’ entry, the subject of this review, at $19.95.

If you need all the mAh’s you can get, and can’t stand the extra bulge of a mega-battery, plan on getting one or more spares. Drop one in and do the little pink bunny thing: keep on going.

Hours of amps

The mAh moniker stands for milliamp hour. That means a one-thousandth of an amp sustained for one hour. Not a lot of power, but the Treo, being a computer, doesn’t need much. Naturally, your mileage will vary, but you can reasonably expect a battery’s life to be approximately proportional to its mAh rating. By most accounts, 1200 mAh’s don’t keep longwinded talkers talking all day long on their Treo 680’s. Even if you spring for one of the extended batteries, you might still want to horde a spare battery for just those occasions when you need some more power and there’s no place to charge.

A spare battery has to be recharged, even if it’s not used. Over time, lithium-ion batteries, which are what keeps Treos going, lose their charge, even if connected to nothing. The easy way is to give each of your batteries a turn in the device, so they all stay fully charged. I do this with my digital SLR’s batteries – rotate them systematically to the charger and into the camera, so I can take the whole kit out for a location shoot on a moment’s notice, confident.

Even a longer-life Treo battery will deplete eventually, especially if you talk or roam a lot. Indeed, roaming where signals are poor eats up a good bit of power because the phone keeps transmitting, looking for a cell tower to honor its signal. The Gremlins in Charge of Misfortune dictate that those desperate times when the battery level goes cuckoo coincide with there being no power to hook up to for a recharge.

First the math

Mobi Products’ replacement battery for the Treo 680 comes in at 1050 mAh. That’s a bit less than Palm’s original (and replacement) 1200 mAh battery, but it’s a little less expensive. That’s about 12.5 percent. If only it were also lighter, too.

The batteries weigh almost exactly the same – about 0.9 oz (25 grams) each, and they’re within a fraction of a hairsbreadth the same dimensions. Why there’s any difference in capacity at all is anyone’s guess. My electronic scale totes up even grams only, so there could be a weight advantage, although if there is one it’s less than a gram, so I wouldn’t even mention it, even if I could.

Usability

Mobi Products’ spare pops into the Treo just like the Palm battery, and it runs out of “juice” just like the original, only a little bit quicker. For me, however, the difference in run time isn’t all that noticeable. I keep my 680 charging, on my desk, unplugging it to use the calculator or make calls – then return it to the charge cable. I take it out for several hours at a time, but rarely all day, and usually don’t do more than an hour’s worth of talking on it at a time. In two months, I didn’t even know I’d left the Mobi Products battery in it, instead of the Palm original, and I never had a problem. But of course I’m not a power user.

The facts of life are out there for your consternation anyway you look at it: Lower capacity means less talk time, less standby time, and even worse, less Bejeweled time. However, as a spare to tide over that extra couple of hours after the main battery’s given up, the lower capacity isn’t much of a problem. Charge them both up again, and have at it the next day.

Other than capacity and selling price, I can find no difference between the batteries. Apparently, my Treo 680 can’t, either.