Indeed, a new form of power is rising. Fueled by the need for more capacity to combat the popularity of nitro, the electric world shifted its focus from NiCad to NiMH a few years ago. Now it seems that another shakeup is preparing itself in the electric scene, and this shakeup is far from being an aftershock!

Lithium Polymer packs have been prevalent in the flying segment of the hobby for quite some time. However, they are just now becoming a driving force in the land-based segment of the hobby. They offer a pack that weighs considerably less, and yet provides a more constant voltage throughout the run than both NiCad and NiMH packs do. This makes for some very interesting possibilities for those diehard electric fans who are upset with all the attention the nitro guys are getting.

It all sounds good doesn't it? Better power delivery, combined with a low pack weight. However, I'm sure many of you are saying there has to be a catch to all of this. So let's spend a little time exploring what these packs have to offer and see what turns up.

Scorpion packs are manufactured by FMA Direct, which is a company that dates back to as far as 1972. The Scorpion lineup is their land-based Lithium Polymer offering, of which there are currently four type of battery packs to handle the various needs of those in the car segment of the hobby. Two of these packs are for the mini-market, offering a runtime of either 1250mAh or 2000mAh. For the larger scale electric market, they offer 3200mAh and 6400mAh solutions, to provide extra long runtimes with a nominal voltage of 7.4 volts.

The Scorpion Li-Po packs themselves are quite an engineering marvel compared with other Li-Po packs on the market. As Li-Po technology is still in its infancy, new advances in this segment are coming quickly. The Scorpion packs by FMA Direct are a perfect example of this. One of the first things I noticed when holding the pack was it's weight, or really the lack of weight would be more appropriate. A typical nickel-based pack weighs around 14 oz. The 3200mAh Scorpion Li-Po tips the scales at 7.7 oz. This is a substantial difference, giving the vehicle it's installed in a serious weight reduction.

The packs offer a very low internal resistance, which translates to plenty of punch off of the line. On top of that, Lithium Polymer batteries do not suffer from the same rate of gradual voltage drop-off the way NiCad and NiMH do. Just like NiMH tapers off slower than NiCad, Lithium Polymer packs hold their voltage even better than NiMH. This means that closer to the end of a race, when the NiMH and NiCad powered vehicles are starting to taper off in regards to voltage, a Scorpion Li-Po pack will give you an edge with a higher voltage that provides more punch.

Li-Po batteries are very susceptible to becoming damaged if they are pulled down too far once they are depleted. To help prevent this, and extend the lifespan of the battery, the Scorpion packs come with a built-in LVC (Low Voltage Cutoff) system. Once the pack drops to 5.8 volts, the power is interrupted and then pulsed on and off at intervals of several seconds. This notifies you that the pack needs to be recharged, and prevents you from accidentally damaging the pack itself while allowing the vehicle to be driven back to the pits. You'll see this demonstrated in the video that accompanies this review.

The Scorpion charger is made specifically for FMA Direct's Scorpion packs. Due to their special Safe Charging Process, it is the only recommended method of charging their batteries. So even though you may have other chargers capable of charging Li-Po packs, keep in mind that FMA Direct will not warranty the pack if used with any other charger. FMA has designed these packs to be the most reliable and safest packs currently available, but in doing so they have taken steps that have not been used by other manufacturers. The safety, protection, and cell equalization features are only utilized by FMA Direct's specific charger.

If you have been following me so far, you should have noticed I mentioned cell equalization being one of the items that FMA Direct has built into these packs. What this amounts to is that the Scorpion charger actually monitors the voltage and current delivered to the cells that make up the Scorpion pack during the charging process. As the pack is charged, the Scorpion charger matches the cells to ensure they are matched as closely as possible. How close? How does within a few hundredths of a volt sound?

The FMA Direct Scorpion charger is a DC-only charger, and capable of charging the Scorpion packs at rates ranging from 500mA to 10A. This charging range has the capability of charging a 1P2S pack, like the one I used, to 90% capacity in about 20 minutes. Try charging a 3200 NiMH pack at a rate that will provide that capacity in that short amount of time, and you'll find yourself with a dead pack in no time. Even at 90% capacity, the Scorpion pack will easily outperform most NiCad and NiMH packs. However, if you are looking for that last bit of capacity for a racing situation, you can leave the pack on the charger in top-off mode. The manual states that the pack will top off in one to three hours, but my charger never needed more than another 20-30 minutes before it indicated a full charge.

You may be wondering how you know what charging mode the charger is in, since you're only given a few indicator lights. The answer for that is provided in the simple notification scheme that the Scorpion charger provides you feedback with. When charging starts, the yellow "Fast Charge" light is illuminated, and it goes out once the pack has hit the 90% capacity mark. Also, once the 90% capacity mark has been reached, the green "Top Off" light starts to flash. This indicates the charger is now in Top Off mode. Once the green light changes to solid green, the pack is fully charged.

In first looking at a Scorpion pack, you may be a little daunted by the array of wires that makes it way out from under the plastic wrapping that holds the Li-Po cells together. After all, those NiCad and NiMH packs were far from being complicated. That one single plug left little to the imagination. It was easy to determine where it went.

The Scorpion packs require you to use a separate plug for the charging process. At first glance it may seem it's a standard Tamiya connector, but it's not. It uses three prongs, which enable the charger to monitor the individual cells and make sure each one receives an optimum charge. It also provides charging protection, to prevent the pack from becoming damaged. This unique setup provides a more reliable charging process than any other Li-Po setup currently available. It also pushes the Lithium Polymer segment into a new generation of existence and acceptance.

While the white three-prong plug is used for charging, the Scorpion pack offers a low resistance Deans Ultra Plug when it comes time to use the pack. With the higher current draws low-turn and brushless motors need, a low resistance plug such as the Deans is the only option. So you'll need to equip your electric vehicle with a matching Deans plug if it isn't already using them, however I'd imagine that most people considering Lithium Polymer batteries have already made the switch to Deans plugs.

That brings us to the to smaller receiver plugs on the pack. One of these plugs into the receiver, and the other goes to the ESC. This puts the packs low-voltage cutoff circuitry between the receiver and the ESC. Once the pack is discharged, it will begin pulsing on and off. This signals that the pack is depleted, and the circuitry prevents the pack from being pulled below tolerable conditions that will damage it.

Charging the battery is very simple, although you'll want to keep in mind that the charger is DC only. So you'll need to use a power source such as a 25-amp power supply from Radio Shack. Alternatively you can also use an automotive car battery as well, but you'll be forced to recharge the battery from time to time.

In the early stages of owning a Scorpion Li-Po pack, you'll want to decide whether or not you want to "form" the pack. Forming a pack, involves charging and discharging the pack a total of five cycles at a low voltage. The benefit is an extra 1-2% capacity, but the drawback is that the forming process can last several days. Forming the pack is not necessary for normal operation, and since most people will probably not opt to spend time doing so, I felt this review should be performed without forming the pack. After the pack has been rapid charged several times, forming it will have no positive benefit.

After I connected the Scorpion 2s to my power source, I simply plugged the battery into the charger and set it to what appeared to be 9.6 amps. After around 20 minutes the charger switched to top-off mode. Around 30 minutes after that, the battery indicated a full charge. The pack itself was warm, but not hot, when I pulled it off of the charger.

Once the battery is charged, it's time to drop it into the vehicle you plan on using it with. In my case, this was a Duratrax Evader Pro. Once the battery is set in place make sure that it will be securely held in place once the vehicle is being driven, as you don't want to damage the Li-Po battery. In the case of my Evader, there will be a battery bar that fits lengthwise across the pack to secure it.

Once the battery is set in place, plug the ESC into the three-wire female plug. Then take the three-wire male plug into the throttle channel on the receiver. At this point, all you need to connect is the pack's Deans plug to the one on your speed control. The white three-prong Tamiya-style connector is not used when the pack powers the vehicle.

The first thing I wanted to do was to simply use the Scorpion pack a few times. So I started off in the backyard, and used it along with a Duratrax Evader Pro. The first thing I noticed was the intense punch provided with the pack. The Scorpion pack made my good NiMH and NiCad packs feel as if they were budget packs, as I ran them immediately after running the Scorpion pack. That punchy feel remained for a much longer duration of time than it did with the other nickel-based packs as well.

I used the Scorpion pack to power a Trinity P-94 13x2 in the Evader, and even with this motor it was providing solidly long runtimes in the 13-15 minute range. The overall power of the pack though was the big attraction, and I couldn't help but wonder what this would do when someone would combine it with a brushless setup.

There was certainly plenty of torque and power on tap, and after awhile I got used to having it there when I needed it and would hate having to switch back to a nickel pack. However I was dealt one big surprise that I most certainly did not see coming. That was the fact that the pack runs very cool, much cooler than I normally see with standard NiCad and NiMH packs. After running the Scorpion pack from full charge, to discharged, when I pulled it out it tripped my IR handheld at around 112°. That was certainly a pleasant surprise. Given my other battery experiences, the 13x2 motor geared at 18/88 would have been expected to work the pack fairly hard and making it much warmer.

Once the pack reached the point of discharge it would shut itself off for several seconds. Then, it was turned back on supplying current once again. The pack would do this several times, until it reached a point where it would no longer be allowed to supply current at all. This is the safety feature that FMA Direct has built into the packs to prevent cell damage. The "pulsing" provides two important functions. One is that it lets you know the pack is depleted. Secondly, it also provides you with the ability to limp back to your pit area if you happened to be on the track when this happened.

After spending a little time with the pack, and the Duratrax Evader Pro, in the backyard I headed to the track. Once doing this, I can say without a doubt that the Scorpion packs are a perfect match for a track environment. With the additional punch they provide, over nickel-based cells, you'll certainly have the advantage over your competitors. In fact I found that, when swapping back and forth between a NiMH pack and the Scorpion pack, I needed to concentrate a little more heavily on not using too much throttle once the Scorpion pack was installed. The Evader Pro itself felt even more nimble with the Scorpion pack installed, as it's weight was around half of what the truck carried when I had a NiMH pack installed.

The Li-Po pack easily supplied plenty of current to keep the P-94 motor churning along nicely, helping the Evader up over the tabletops and doubles on the track. The tires were getting quite a workout as I came through the corners, exited, and rolled back on the throttle. I found myself using the full throw of the throttle much less than I normally would with a nickel-based pack. This meant that if the traction was available, I still had a little in reserve if I would have been running against someone. However with the dry and dusty conditions and the fact the next race was still a few weeks off so the track hadn't been prepped, a little too much throttle could easily induce a spin and have me pointing the wrong way.

As the afternoon wore on, it became very obvious that the advantages of the Scorpion Li-Po pack were not to be ignored. The truck felt much stronger throughout the run that it did with the NiMH pack I kept switching it with. While that has its advantages in all forms of racing, it's especially important when running off-road. Plenty of torque and power is needed to get the truck up and over the obstacles in its path. Between the two packs, the Scorpion pack simply had that characteristic nailed better, without a doubt.

As a final test of the Scorpion pack, I decided to check some statistics while discharging the pack. After all I had seen that the pack seemed have much more punch overall than standard battery packs, but exactly what was that difference I was seeing? So using a bulb discharger rated at 30amps, I started to drain down a fully charged pack. I stopped the discharging process at the 5 minute mark, as that represents a common race length for electrics and checked the voltage supplied by the Li-Po pack. My trusty meter gave me a reading back of 6.64 volts. This is around a volt more than you would expect out of a matched NiMH pack with a similar mAh rating. This test confirmed what I was feeling in the field. The Scorpion pack was definitely doing a much better job of keeping a consistent amount of power flowing to the motor. If you're a racer, and serious about having the edge, that extra power is certainly worth it's weight in gold!

If you're looking for a racing edge, then the Scorpion packs offered by FMA Direct are likely to be one of the best advantages you can get at the present time. The combination of higher voltage throughout the run, coupled with the low weight of the pack itself, is a huge advantage to those who enjoy spending their time at the track.

Even those who aren't racing may find some advantages to the Scorpion Li-Po packs. With the 2P2S option, rock crawlers and bashers can have tremendous amounts of runtime. They get 6400mAh with about the same weight as a standard 6-cell pack. This is definitely a leap forward in the electric scene and, due to FMA Direct's safety features, Scorpion Li-Po's provide a bigger level of safety and longevity than Li-Po has offered before.

The only real caveat that makes stepping over to the Scorpion Li-Po's hard to swallow, is the entry price. The cost of a 1P2S pack and the Scorpion charger can cost more than many electric kits, and seems rather steep at first. However, when compared against matched NiMH cells and a competition charger the price difference does start to narrow some. There is also the benefit that the Scorpion packs can be run through several hundred cycles with only a minimal drop in capacity. So while there's always a price to be paid for having the ultimate in equipment, no one can argue that there aren't some very advantageous benefits to powering your car or truck with a Scorpion Li-Po setup.

FMA Direct
5716A Industry Lane
Frederick, MD 21704 USA
Phone: (800) 343-2934
Fax: (301) 668-7619
Website: www.fmadirect.com

Spektrum
Distributed Exclusively By
Horizon Hobby, Inc.
4105 Fieldstone Road
Champaign, IL 61822 USA
Phone: (877) 504-0233
Fax: (217) 352-6799
Website: www.horizonhobby.com
Products used: DX3 Radio/Receiver, Z590MG Servo