Airsoft Battery Power to read the number [526] Published:2016-01-21 11:22:48
Lithium Ion or Lithium Polymer batteries are quite new to the hobby, but they are showing early on that they promise great things
Unlike NiCd and NiMH cells the Li-Po cell has a nominal voltage of 3.6V. Typically these cells would be used in 1, 2, or 3-cell packs giving voltages of 3.6, 7.2, and 10.8 volts respectively. This limits the selection a bit when compared to the other batteries which offer combinations in 1.2V increments for wider voltage possibilities.
The advantage comes in their energy density or energy to weight ratio—as much as four-fold over a typical NiCd battery! Modelers who have adapted these batteries for indoor and park flyers have found they can get long run times compared to using NiCd and NiMH packs.
Self-discharge for the Li-Po is very slight compared to either the NiCd or NiMH. It is generally negligible and one need not be concerned with topping up the cell before use.
Unlike NiCd and NiMH cells,
The internal resistance increases only marginally, the capacity decreases only marginally, and the self-discharge is still negligible. The Li-Po cell exhibits no “memory”. One can charge or discharge the pack partially or fully and still retain the long term capacity of the unit. This means that cycling with a battery exerciser is not required to maintain functionality—Li-Po are considered low maintenance as opposed to the NiCd and NiMH which are high-maintenance batteries.
However, also some cautions to take when using the Li-Po technology. As the technology improves—and it is changing quickly—these will undoubtedly become less of a concern.
The internal resistance for Li-Po is relatively high and thus the discharge rates will be lower than with the NiCd. Most discharge rates are in the range of 5C (five times the capacity) although some have recently been released that can supply 20C
This internal resistance will also limit the charge current. As a matter of fact, to this point, charge rates should be restricted to 1C or equal to the capacity. That same 340mAh pack should only be charged at a maximum of 340ma , taking more than an hour (accounting for inefficiencies) to charge the pack. This may be a little longer than modelers are willing to wait in some circumstances after being used to charging one pack of NiCds while you fly another, then having the first ready to use again by the time you land.
While on the topic of charging, you cannot use the same type of charge circuitry as with the Nickel based cells. Li-Po cells must be charged with chargers designed specifically for them. Do not use chargers that are not designed for the purpose—serious and dangerous consequences could result.
Lithium cells can be very dangerous in a number of circumstances: being discharged too low; being overcharged (maximum voltage on a cell should not exceed 4.2V); being overheated. These batteries should never be charged unattended, nor should they be charged in an environment that is flammable in case the cell “flames-out” or worse . . .
Lithium batteries are still in their infancy and as a result the technology is improving at a rapid rate. Certainly it will advance a great deal throughout the life of this catalog. Keep an eye on its progress and see where Li-Po cells can fit into your modeling future.