User's Manual

23
INSTRUCTION MANUAL
Warning: Before charging your battery packs test the charger to see if the voltage begins at 0 V and then rises to the
correct voltage or if it give a short ‘burst’ of high voltage to test the battery first. If your charger gives a high voltage burst
to begin, you must disconnect your packs from the Weatronic receiver first as the high voltage ‘burst’ will damage the re-
ceiver.
10.5 Lithium Polymer (LiPo) Batteries
LiPo battery packs have no memory effect and do not suffer from self-discharge (less that 5% per year) and due to this you should store your packs
with a 50% charge and they do not need to be discharged before you re-charge them. The perfect method of storing LiPo packs is to have each cell
at a voltage of 3.7 – 3.9 V which should equate to 50 – 70% charge and that is the condition in which the manufacturers distribute them. The only
time when it is advantageous to discharge your packs is after storing them over winter, during which time the packs should be kept cool (cellar) if
possible. You can expect the capacity of your packs to drop by around 20% over a period of 3 years. As individual cell voltages tend to drift, you
should always use a Balancer connected between the packs and the charger when charging. The following points should be followed when charging
LiPo battery packs to prevent the risk of a fire.
Avoid short-circuits at all costs! Never let the poles of a LiPo cell or pack come into contact with a metal object as the high
discharge current will cause the cells to ignite within milliseconds.
Never subject them to a mechanical load and protect them from damage.
Do not damage the soldering tags or attempt to re-solder them.
To ensure 100% safety when charging LiPo packs, they should be removed from the model and placed into a ceramic con-
tainer or a specially designed LiPo bag or a metal container.
LiPo packs can only be charged using a charger which is designed for that use. LiPos require a different method of
charging than other types of cells and the use of an incorrect charger will destroy the cell and could lead to a fire.
Double check that your charger is set to the correct number of cells and that the current and discharge voltage settings
correspond to the capacity of the cells which you are using. Refer to the battery manufacturers recommendations as well
as your chargers instructions.
After a crash LiPo cells should always be replaced as they may be damaged internally even if they appear to be OK from
the outside.
To prevent one of the cells within a pack being over-charged or too deeply discharged it is vital that a balancer is used.
10.6 Lithium Iron Phosphate (LiFe) Batteries
Lithium Iron Phosphate packs have an extremely low internal resistance which mean that they can be subjected to high loads without the voltage
dropping. They can also be fast charged and have a long life expectancy. The nominal voltage per cell is 3.3 Volt and due to their chemical composition
they can be charged at up to 4 C which means that the pack can be fully charged in 15 – 30 minutes.
10.7 Nickel Metal Hydride (NiMH) Batteries
Nickel Metal Hydride packs do not suffer from memory effect but do have a noticeable self-discharge rate and for this reason packs should be
discharged after use to 90% of their nominal voltage and then re-charged shortly before you intend to use them. If the packs have been stored over
a longer period of time, it is advantageous to cycle the packs a couple of times using a computer controlled charger to ensure that they are producing
their full capacity. Long-term storage (for example, over winter) should be at between +10 and +30°C.
Weatronic recommend replacing NiMH packs every 2 years as after 2 years their reliability may reduce and a new pack will cost a fraction of what
a crash would.