Air Craft Data Page

 
Lithium Polymer Charging, Handling, Safety Information
 

Connection:
You must be sure that the correct polarity is observed when connecting battery packs to charger or speed controller:

PINK / RED = POSITIVE (+)
BLUE / BLACK = NEGATIVE (-)

Charging:  Lithium Polymer batteries have specific charging requirements and ONLY chargers rated for Lithium Polymer cells may be used.  The best chargers are those which require the user to manually select cell count and charge rate for each pack of cells, then automatically check to see that the settings are correct.  The Hyperion EOS Charger line belongs to this category.  Chargers which use only automatic detection of cell count (and on that basis set charge voltage) are prone to error, and can damage cells or cause a fire due to over-voltage charging of cells.  We recommend that these chargers be set manually, if used. Other chargers are set manually, but do not include a safety circuit to oversee that setting.  These are prone to user error, and should also be checked very carefully to insure proper use. 

Lithium CC/CV chargers, like those in the Hyperion EOS Charger line, must be used. These charge initially at a constant 4.2V and constant 1C rate, then taper the charge rate as the battery nears full capacity.  Cells are about 90% charged in one hour, and can be left connected for another 20-30 minutes to complete the charge. The maximum permissible charge voltage per cell is 4.2V. The maximum recommended charge rate for Lithium Polymer cells is 1C (ex: 1.5A for a 1500mAh packl). Please do not charge your lithium polymer at any rate higher than 1C.  Doing so may reduce the capacity and life cycle of the cells, with very little savings in charge time. 

Discharging Rules:  Any battery, including lithium polymer, must be discharged within rated current and voltage limits.  Failure to do so will result in damage to the battery, at least, and could even cause an accident.

  • Use a motor speed controller which has auto-cut feature for lithium polymer.  Auto-cut should be set at 3.0V per cell.  A three-cell pack, therefore, should be set for 9.0V auto-cut, for example.

  • Do not exceed the manufacturer's rated maximum continuous discharge rating!
       * Example:  700mAh pack (0.7Ah) rated at 12C continuous > 0.7A*12 = 8.4A
       * Example:  1100mAh pack (1.1Ah) rated at 10C continuous > 1.1A*10 = 11.0A

  • USE AN AMMETER, like Hyperion Emeter, to confirm the maximum amperage drawn by your motor-batter-propeller combination

  • Do NOT count on "unloading" during flight to greatly reduce the current drawn.  In most cases this effect is MINIMAL.  In the case of High pitch props at high RPM, the in-flight amperage may actually RISE substantially.  Factor this into your calculations.

Charging Safety Tips:  Lithium Polymer cells are a tremendous advance in battery technology for RC flight. However, due to the chemistry of lithium cells, there is a possibility of fire if charging is not properly done. It is unavoidable due to the nature of lithium itself. This is no different from many things we use in daily life – knives, kitchen cleaners, automobiles, for a few examples – which are inherently dangerous, but which can be used safely by adhering to simple rules and precautions.

  • Be absolutely sure that the Lithium Polymer charger settings are correct for the battery pack being charged – both voltage and current settings
  • Lithium Polymer must be CHARGED and STORED in a fire-safe container
  • Do not charge batteries near flammable items or liquids
  • Keep a dry fire extinguisher nearby - or a large bucket of dry sand, which is a cheap and effective extinguisher
  • Never charge inside an automobile; not while driving nor even when parked
  • Batteries should NEVER be left unattended while charging
  • KEEP BATTERIES AWAY from Children and Pets at ALL times

Handling Cautions:  New cells may have a high initial charge, and care must always be taken to insure that loose cells are not short circuited. Please: 

  • Never leave batteries inside a car on a hot day, nor any other place where ambient temperature may exceed 140F / 60C.
  • Although environmentally friendly, lithium polymer cells must be FULLY discharged before disposal.  Use a resistor setup (light bulbs, for example) to accomplish this, to avoid the possibility of a short-induced fire after disposal
  • Immediately discharge damaged batteries at 1/2 C rate and dispose
  • Do not put the loose cells in a pocket, bag, or drawer where they could short-circuit against other items, or the battery tabs could be pressed against each other.
  • Do not place the loose cells on any conductive surface, such as a metal-topped table.
  • Keep loose cells and battery packs WELL out of reach of children and pets!
  • Buy pre-assembled packs from an authorized dealer, rather than assembling packs from loose cells
  • Take care that the cells are not punctured, especially by metallic objects like hobby knives.
  • If the electrolyte in the cells should get on your skin, thoroughly wash with soap and water. If in the eyes, rinse thoroughly with cool water. Immediately seek medical attention for this, or for burns.


HYPERION CHARGER PRODUCTS

We have all seen how dangerous lithium polymer packs can be if charged incorrectly, and you probably know that a "balanced" pack will provide better performance, runtime, and service life.  As such, we strongly recommend that Hyperion LVX packs be charged with a combination of Hyperion EOS charger and Hyperion LBA6 Lithium Balance Adapter.

The EOS 5i and 7i Chargers both require manual setting of cell count "S", and they also include Smart circuitry to check your settings.  In this way the human and the machine always "double-check" charge voltage for the other.  In our opinion, chargers that rely on either 100% manual or 100% automatic voltage settings are an accident waiting to happen...

The EOS LBA 6 works with almost any charger on the market, and provides two important functions:
1) It adds an extra layer of charge safety, and it also checks charger voltage against the pack to be sure they are matched, and will turn off the charger if a mistake has been made.
2) It insures that at the end of each charge all cells in the pack are voltage matched and fully charged

   

All Lithium Polymer Batteries we carry are only approved for RC use, and may not be used in any other application.  Battery discharging, charging, electric motors, spinning propellers, and flying models all have the potential for serious injury to persons and damage to property.  In purchasing these products, the user agrees to accept responsibility for all such risks, and not to hold the battery manufacturer, distributors, or retailers - (all including owners and employees) - responsible for any accident, injury to persons, or damage to property. 

As used in radio-controlled model aircraft, discharge rates exceed the manufacturer’s specified maximum rates.  Therefore, the use of Lithium Polymer batteries in radio-controlled models is to be considered experimental, and there is no warranty, expressed or implied, by the manufacturer, distributors, or retailers with respect to the capacity, life in cycles, storage, or discharge characteristics of lithium cells in RC use, nor any other use nor aspect.