Battery and general internal electrics info

ok, ive been asked to post some stuff about batteries...
before i start, feel free to add/contradict/question to anything i say


Some general info
Types of battery used in airsoft-> NiCad NiMh LiPo

NiCad:
simply put, stands for Nickel Cadmium, these arent used much anymore due to poor efficiency, but are still often supplied with clone AEGs
Advantages: High burst discharge rate
Cheap
Reasonably efficient
Disadvantages: Low capacity
Noticeable power drop througout use
Short long term battery life

NiMh:
Nickel-Metal Hydride, these were the replacement for NiCad, they are much more efficient, power drop isnt as apparent throughout use, have a high capacity.

These are your most common cells in airsoft, theres not a whole lot to say about them, other than charging info which i'll go over later..

LiPo:
Lithium Polymer. These batteries are the latest and greatest around, the main advantage of these cells are that they have a voltage of 3.7v per cell, and are capable of huge discharge rates..
These batteries shouldnt be used in standard AEG's due to the fact they run at very high voltages, and are easy to damage.
LiPo cells have a very short lifespan, usually less than 500 cycles, which is nothing compaired to the 5k+ you get from NiMh cells.
discharge rate of this type of cell is supplied by C which means: discharge rate (C) * capacity of pack
i.e
1000mah (1Ah)pack 20c
20*1 = 20 Amp discharge rate.. simple as that

generally used terms:
Discharge Rate : this is the current that the pack can release power at, measured in Amps
Cycle : 1 charge and 1 discharge = 1 cycle
Burst : The current at which a pack can discharge at a higher rate than normal, for a short period of time (under 5 seconds)
Cell: single battery

Taking care of your batteries

1st off, ALWAYS ALWAYS ALWAYS use a peak charger.
this is the 1st step towards keeping your packs performing at their best, and giving them the longest life..

peak chargers detect when a battery is at its optimum capacity. overcharging a battery will cause heat damage, and shorten the lifespan of the pack, undercharging a new battery will cause it to have a lower capacity throughout its life.


New batteries:
this method of charging new batteries isnt always available to everyone, due to some peak chargers not having the ability to change charge rate

1st charge: for small cells charge at 100mA, for large cells charge at 300mA
then once charged, fully discharge the battery (to the point where the gun is struggling to fire)

2nd charge: for small cells charge at 500mA, for large cells charge at 1A
then once charged, leave to completely cool then discharge the the battery again

3rd charge: for small cells charge at 1A, for large cells charge at 2A
once again, leave to cool then discharge

4th and final charge: for small cells charge at 2A, for large cells charge at 3A
again, leave to cool then discharged

if you have the ability (or patience) to do this to your packs you can expect better performance from the packs when youre using them, (higher ROF, longer life)... and about a 30-50% longer total life span..


I will continue to add to this thread when i have time (i.e tomorrow sometime)

hi m8
that is great info and should come in very useful when i purchase my new stuff.
just a couple of things for the last bit. did you use a pro peak varipulse 2500 for that explanation?
and when you bringing a bew battery into life say its a big fucker how long should i charge it until/for? then do the discharge. what discharger do you use cos i dont have one.
then when you say do the 500ma charge that will be a fast charge on my charger. and then discharge. at 1a that is also fast. is this right?

The charger i use is an Imax B6, but if you get a propeak with a variable charge rate it'll do the same job..

as far as discharging goes, for the 1st charge you should be able to discharge it with the aeg, as this draws around 10A
as you go through the cycles you'll find that if you have a large pack that an entire days skirmishing wont discharge it fully, so give it a day's skirmish... then after that if you have a discharger discharge to .08v/cell
luckily NiMh cells dont suffer from the memory problems NiCads do, so general discharging isnt essential, just gives you a little extra...

to work out how long you need to charge your packs for on a slow charge, divide the capacity by the charge rate, making sure that theyre in the same unit
i.e 3700mah pack charging at 300mA
3700/300 = 12 hours 20 mins