Q Why are the leads so short on the Xtrema? A The Xtrema's leads are short for very good engineering reasons. The ends are where the connectors have to be for use as a wattmeter. Bear in mind that the Xtrema is not just a charger. It is also a wattmeter capable of up to 100 Amps at 60 Volts. That's 6000 WATTS!
Old fashioned single function chargers don't have to deal with those currents. You don't want long leads that will affect the performance of the motor under test or induce error in the measurements by adding lead resistance. If you put a connector on the existing ends, then you are already adding 2 FEET of lead length to your test connection. (4 wires at 6 " each!)
TME suggests you put the connector there and make yourself a longer charge adapters. But don't get carried away. If you get too far away then you can't use the temp probe without extensions.
Q Why don't you provide a printed manual with the Xtrema? A The Xtrema is designed to change with the times. Free updates are available online or your unit may be returned to us for updates. This means that as we add new features our instruction manual becomes a living document that constantly changes. We ship each Xtrema with a printed QUICK START manual and provide a CD with the latest manual that matches your Xtrema's revision.
In this way we can provide you with the most up to date and complete manual without having to worry about delaying updates because of a surplus of printed manuals. If you do not have a computer to print out your manual you can take it to a friend or nearby library to print it out.
Q Does the Xtrema discharge batteries? A It doesn't actually discharge batteries on its own, per se, but with the load of one of your motors or a big bank of resistors external to the Xtrema you have the ability to discharge and monitor your packs at high enough current to yield useful information. If you have the optional data cable you can discharge your pack at any rate up to full load and have a complete record on your computer including the calculated battery capacity at high loads. This feature is unique to the Xtrema and is much more meaniful than discharging at very low discharge currents as ordinary chargers do.
Discharging was much more important for NiCd's than they are for Lithium batteries. NiCd's were prone to voltage depression (sometimes referred to as "memory") and discharging the packs would bring them back up to spec. Many chargers that offer a discharge feature, do so as a carry over from being a NiCd charger.
Actually, every time you discharge a Li battery you take away one of its life cycles with no benefit to the pack. If you simply want to know the capacity of a lithium battery. the amount of charge you put back in to the cell (assuming you fly until the ESC cuts off) is a GREAT indicator of the health of the battery. Therefore, discharging doesn't really buy you much for a Lithium battery. Monitoring the charge you put back into a fully discharged pack allows you to accomplish the same thing without wasting a discharge cycle on a test. Besides, we think it's best to use up a discharge cycle while flying or running your model instead, it's just more fun!.
Q Does the Xtrema charge NiCd's and NiMh batteries? A No, the Xtrema does not directly support other battery chemistries, just Lithium cells only. We did this on purpose after talking to several experts in the industry.
When we tell our dealers that it is LiPo ONLY, they all prefer our unit over other multi chargers. The reason is that a unit with this much power and capability could do serious harm to a LiPo if inadvertently programmed for NiCad or NiMh or Lead Acid.
While it is still possible to set the current rate wrong and harm a LiPo with our unit, all the other checks and expectations will lead to safer operation and correct shutdown. Especially when used with our temperature probe.
Q The Xtrema is currently sold without an integrated balancer, will the Xtrema have a balancer? Our balance has been announced. More information can be found here...
http://www.tmenet.com/Xtrema_balancer.htmAn integrated balancer is a nice convenience however, there seems to be a big misconception about integrated balancers. They do not permanently repair batteries that repeatedly go out of balance as some people think. Having an integrated balancer in the charger is a convenience and not a cure for a bad pack. A bad pack will have to be rebalanced every charge. The only cure is to replace the pack or just the bad cell if the pack is fairly new.
Balancers are best used to correct minor imbalances and as a testing device to see if you have stressed a cell. Good packs should not need balancing but instead hold their balance and need infrequent testing for balance. Out of balance conditions occur when packs are defective from the factory or have been over stressed by heat, current or physical damage. We believe that most batteries that continually go out of balance are already defective or damaged and cannot be saved. Using a separate balancer is just as good as one built in to correct minor variations. Important to note is that Lithium batteries remain in balance better than any other chemistry on the market. Just take care and use them within their limits.
Some people believe that an integrated balancer makes a charger safer. If dne right that is very true and when combined with the integrated temperature probe and all the other safety features the Xtrema has, we believe the Xtrema charges safer than any other charger on the market. The Xtrema comes standard with a temperature probe that can stop charging very early if the charge is going wrong. This safety feature works with Li batteries that have or do not have balancing connectors.
The Xtrema also has a user programmable safety timer that aborts the charge if it takes to long. It also has an easy to use menu that memorizes common pack parameters. To avoid confusion, the Xtrema allows you to select by cell count (not voltage) and it has an "are you sure" windows to give you a last chance to change settings. With the integrate balancer a final confimation of the cell count and health of the cells takes place before continuing the charge. All these things are unique to the Xtrema making it a very safe charger.
