Specifications

The stock radio system does a reasonable job with the stock setup, but BL systems tend to
create a lot of RF (radio frequency) electrical noise, and Am radios do not react well, with
glitching and loss of range & control a common problem. Best solution is to upgrade to an FM
radio at the least, or a digital radio is even better, budget permitting.
16. Lipo and A123 batteries
Lipo = lithium polymer. They have a nominal (resting) voltage of 3.7v per cell, and a fully
charged voltage of 4.2, but unlike Nimh cells, you can actually select the fully charged voltage
provided you have a suitable charger; this is handy for escs that don’t like peaked voltages
sometimes (MambaMaxx and Quark 125b for example). When charging, and discharging (running
them in a vehicle), the individual cells in a pack can become out of balance. This means in a 2s
pack for example (s = cells in series), one cell can read slightly higher or lower than the other,
and over time this difference can become large enough to mean that one cell becomes over-
discharged during use; it is important not to discharge them below 2.8v per cell, but 3.2v is a
safer level. This is where the LVC device comes into play, as it cuts the throttle, or reduces power
when the cells have drained down to whatever the cut-off voltage is set to. Some LVCs have
adjustable voltage settings, and cutoff type (reduced power, warning light, warning buzzer, total
shut-off etc), depending on the application; you wouldn’t want to loose all power with a plane or
heli for example... When charging lipos, the balancer device is used to keep the voltage equal in
all the cells of a pack- it can be a balancer that works along with the charger, separate from the
charger, or you charge through the balancer. The end result is the same though- cells with a
lower voltage get extra charge, whilst cells with a higher voltage get drained a little to keep them
in line with the others. This is what the little white plug is for that you see sticking out of lipo cell
packs, it is the balancing plug/tap. The lipo’s battery chemistry requires a special technique,
called the CC/CV method (constant current/constant voltage). Basically, the charger will pump in
a high current (amps) until the cells reach ~4.2v, then they will drop the current but maintain the
voltage level until the cells reach and stay at 4.2v, at which point they are fully charged. Over
charging is very dangerous, as lipo cells contain alot of energy, and overheating them can be a
serious firehazard, hence the items called 'lipo sacks' that should be used to contain any possible
damage caused by a burning lipo. The chances of that are rare these days though, and only idiots
on youtube tend to burn up lipos for fun. Lastly, the C rating thing. This refers to a lipos
maximum discharge rating, and is a multiple of its capacity. For example:
A 20c 5000mah pack can put out 100amps.
A 10c 8000mah pack can put out 80amps.
Choosing the right capacity and C rating is important for any given application, and should be
based on how many amps your chosen motor can draw at maximum load. For example, the
feigao XL motors tend to draw about 80-100amps at peak current levels, so you should select a
battery that can supply at least 80amps continuous. Generally though, the motors pull a
continuous current of about 10-20amps or thereabouts, so the battery wont see very high drain
rates for the whole run, otherwise it would soon over-heat and 'puff'. Once a battery puffs, its
pretty much toast, though individual cells that are still okay can be salvaged- a 5s lipo can be
reconfigured into a smaller pack of 4s etc. It is worth noting though that high mah capacity lipos
with a low C rating at not as capable at discharging large amounts of current compared to a
smaller capacity lipo with a higher C rating, this is because the voltage level droops heavily under
a high load, due to the lipos low tolerance to high current draw; a higher C rating is always
preferable regardless of the packs actual capacity. With the E-Revo, you are limited to a
8000mah 2s lipo, or 5000mah 3s lipo in each battery compartment, though specific sizes of