13 January 2007
This is my first Lithium based battery pack.
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The pack comes in a nicely sealed box, so you know the battery is new. |
| The humps at the bottom line up almost the same as a six cell IB3800 pack (The IB pack seems just a tiny bit bigger). The manual says it's designed to line up exactly like six GP3700 cells. |
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The humps at the bottom look like this and doesn't interfere with the "stick pack" shape of the battery. |
| Not sure if this is a feature or a defect, but the bottom half of the casing on my pack can be pulled off quite easily. The LiPo cells inside take up most of the space inside the casing. Each 3.7V cell has the full 3200mAH, so only two are necessary (connected in series to make up the 7.4V). In other words, this is a 2S1P pack. |
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The Carbon pack fits very snugly into Tamiya M-chassis cars, and although it is just a bit longer than most stick packs, it'll still fit because the M-chassis battery retainers are flexible and will bend to allow for the extra length. Part of the chassis obstructs the power output tubes very slightly but you can push the battery towards this side a little and plug in the Corally-style connectors. However, to keep the chassis from bending the tubes, it's best to grind away a little of the chassis to create a little space for collisions, etc. |
| So far, it does look like it fits into the TA-05, but I'm only using tape here and not the stock battery holder plate. |
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Also, it doesn't sit very deeply into the cell slots, so the centre of gravity isn't great. If you want the cells to sit well into the slots, some chassis grinding will be necessary. |
| The pack fits into a Tamiya DF-03 but there's a bit of space for it to slide forwards and backwards. To gain access to the Corally tubes, it is necessary to drill holes in the chassis where the front body posts are mounted. Fortunately for me, my bodyshell is mounted with velcro, so that's not a big issue. |
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Am using this charger for now. It charges at "1.3A" but what this actually means for LiPo charging, I'm not sure. LiPo chargers work with a voltage cut-off and the current actually drops to keep the battery from going over the safe voltage (4.2Volts for each cell, if I'm not mistaken). When the current is almost at zero, the charging stops. It took about 3 hours to charge the pack up the first time. Both cells finished charging within a few minutes of each other. |
| The charger is mostly meant for airplane LiPo packs, so it doesn't come with a charging jack. I had to make one up myself out of an old LiPo charging plug, two 3.5mm Corally plugs and a 2mm plug. The battery also comes with 2 free high quality Corally plugs and a Tamiya-style battery connector. I made a Corally-Deans adaptor to make it easier to swap between LiPo and NiMH for now. |
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Runtime:
Even though the battery has only 3200mah capacity, I seem to get plenty of runtime out of it.
Part of this is because of the low internal resistance of LiPo packs.
After a 15-minute run on my Team Losi XXX-T truck with a Novak SS5800 on conservative gearing (15-tooth pinion, 86 tooth spur) on a very hot day,
the battery pack barely got warm, so you know that most of the 3200mah goes into hauling your vehicle rather than heating up the cells.
Another big reason for the long runtime comes from the weight-savings. The battery weighs only 198 grams, so it's about half the weight of an
IB4200 6-cell pack. This doesn't seem to make a big difference to heavy vehicles like monster trucks and stadium trucks, but in lighter vehicles
where battery weight is a large proportion of total vehicle weight (like a Tamiya M-chassis), it really does translate into very long runtimes.
I get about an hour in the M-chassis running a silver can motor with a 20-tooth pinion.
Two packs of these batteries lasted me 45 minutes in one endurance race. Read the race report here.
Performance:
Most people think that 2s LiPo packs have a performance advantage over a 6-cell NiMH pack because it has an average voltage of 7.4V rather
than 7.2V but the truth is that todays top sub-c cells (IB4200 WC) are able to put out 1.3V average, tested at 35 amps (when new). That's 7.8V average!
However, the lower weight of the Orion Carbon helps to give RC vehicles quicker acceleration and higher top speed, and this effect is more apparent
in lighter vehicles. In the M-chassis, the Carbon made the car very zippy. In the XXX-T, I hardly felt any difference. I've also heard that running
a very hot setup (like a Novak 3.5T velociti brushless motor), the battery dips below the safe minimum voltage on hard acceleration, but I have not
tested this myself.
Convenience:
At the moment, LiPo batteries are not allowed in most races where I am, but they are so convenient to use, I can't see myself ever going back to
NiMH. They keep their charge so well, I just charge them back up after each run and the next time I hit the track, I play straight away
without having to spend an hour discharging, cooling and re-charging batteries (all the while hoping it wouldn't rain).
If I stopped playing RC cars for a month or two, I don't have to cycle the batteries. The one thing I find a little inconvenient is that they take
an hour to charge at the recommended 1C charge rate.
Affordability:
I'll give yuo the bad news first - they cost about twice the price of a six-cell IB4200SHV pack. However, I've heard of some Team Orion Platinum
4800mah LiPo packs (also consisting of Kokam cells) that have lasted over two years old and still ran like new, so I'm hoping that the Carbon
will last me as long and save me some money in the long run. Apart from the battery, you would need a LiPo charger. One that has a built-in
balancer is nice but from all accounts I've heard, not necessary for Team Orion LiPo packs. Another thing I would recommend getting is a
low-voltage cutoff unit (like the Novak SmartStop 2S) or an ESC that has a low-voltage cutoff feature (like the new Novak Rooster),
to prevent yourself driving the voltage too low.
The good news is you no longer need: three or more battery packs, battery cooling fans, expensive peak detection chargers, 20 amp dischargers,
electronic discharger trays and new packs every two months.
They are a very affordable alternative to NiMH batteries in the long run, but the transition will cost some money.
Conclusion:
If you don't have one, get two.
