Very high capacitry to weight and pretty hiogh power to weight ratio is
Disadvantages are teh need for a different charge regime, and the
ability of te cells to catch fire and pop - sometimes even explosively -
if overcharged or damaged in a crash. The cases are deliberately less
tough than Nicads to stop them being shrapnel grenades if they over
heat, and that makes them less crashproof.
Lots of info on the E-zoen -
Suggest you look there
and abosrb all the data before dedciding.
For us leccy flyers the pleasure is well worth the pain. I am not sure
the advnantages for glo flyers are sufficient to make it worth while tho.
Nowhere. Not $40 for a 40 sized plane. More like $400.
Hmm. TYhats an ambigous statement..did you mean 'current capacity in
mA/h or CURRENT capacity, in amps?'
Actually, capacity martches nicads, but peak currents don't. You can
dischareg a sub C at 100A plus and get 4 15 minuite burns out of it, but
a Lpio will explode ...so you nbeed them in paralellel.
The real reaosn for low capacity is that sub C Nicads were developed for
power tools, LIPOs were developed for mobile phones and laptpos - which
donb';t take that sort of power.
Yes. If someone can post the all up weight of a typical wet powerplant
including fuel, tank, muffler and servo, and engine mount, it would be
interesting to compare the two. The lower vibration of elecetrics means
that lighter structires are possible as well.
As someone else has pointed out, another great gain from LIPO
technology, is that even fairly inefficient brushed motors can gain huge
increases in power to weight and duration. This makes multi-engined
electric scale models a LOT easier - and cheaper - to design, and fly.
Actually LI batteries are a cinch to charge right. Dump a voltage and
current limited supply on them. Limit the current to the one hour charge
rate and the voltage to (IIRC) 4.2v per cell, and when the current drops
to bugger all, they are charged. Or near enough for most puroposes. You
CAN get a bit smarter than that - using pulses to shorten charge time a
bit, but that will get you 90% there very easily.
The big danger is overheating by applying too much of volts or current.
They burn nicely, and may semi-explode (pop?) or turn into miniature
rockets. They will also do this if shorted. Protection circuits introdce
too much power loss for electric flyers, so we run em 'dangerous'
Precautions of a more strict nature than with Nicads are indicated,
however for every LIPO fire there have been dozens of Nicad fires.
Again, there are more Nicads out there...
One pother hint from the E-zone. Dump suspect and rapidly heating packs
in SALT water. Its sup[posed to cool, discharge safely, and generally
ruin the ability of the pack to be dangerous fairly quickly.
I wopuld disagree on the 'don't charge them in teh model' thoo.
That's tantamount to saying 'never put methanol fuel in a model as the
model may catch fire'
Its true, but an acceptable risk IMHO.
Red Scholefield wrote: