LIPOLY MAINTENANCE
The first thing that anyone needs to know about Lipolies (lithium polymer) batts is that a special charger is required to charge it. The usual NiMh and NiCd chargers won't work for it, and will damage it. This is characterized by the visual "puffing" of the battery - at the very least. Another description is that the battery "balloons".
These special chargers usually have indicators either on the box, manual or casing of the charger saying that it is lipoly-specific. Some brands like SWALLOW, manufactures chargers which can charge different kinds of batteries - including Lithium Polymer, Lithium Ion, NiCd and NiMh. Of course, its also expensive. If there is no label indicating that the charger is lipoly-specific, then it is safe to assume that it cannot charge lipolies safely.
The next most important thing that needs to be known about lipolies is that they're very sensitive to charging imbalances. In the case of 2S or more (7.4 volts going up), a balancer is needed to ensure that each cell is charged at a normal & safe value... equally for each cell. If one cell is charged more than the other, the overcharged cell will puff up & maybe fireball. So a balancer equalizes the charge of each cell & makes things safe.
Some chargers have a built-in balancer. An example of this is NOVATECH. There are many more brands to choose from (just can't remember others at this time). The advantage of this is that you just plug your battery & wait for it to finish charging without the hassle of having to purchase a separate balancer. The disadvantage is that these chargers are usually lithium-polymer specific, and cannot be used to charge other kinds of batteries. Do not use these special chargers on any other kind of battery.
Of special note: is that you must never leave a charging lipoly unattended. Grab a book and sit beside it while you're charging. Look at it every 5 minutes or so. You can also clean your weapon or effect repairs while charging. Do not leave it alone. Do not charge near a flammable substance such as curtains, table cloths, etc. Some go to the extent of charging the lipoly only inside heat-proof containers (like Pyrex).
Lipoly batteries are sensitive to heat. Do not leave them inside your car during a hot day. Bring them along in a bag, with your 134 or green/red gas tanks.
Lipolies are sensitive to water. If they get shorted, they become very dangerous. If it rains, ensure that the housing is water-proof or simply - stop playing and go for dry cover. Simple moisture will not cause a short, but submersion will give you more than just a jolt.
Puffing of the battery is a bad sign that you've over-used your battery. While in some cases, simple charging of the lipoly restores the battery to normal use & size... this rarely happens. The safest assumption is that a puffed-up lipoly is now unsafe & should be disposed of properly. More on that later.
Do not charge a hot or warm lipoly. Wait for its temperature to normalize to room temperature, then charge.
Do not charge the battery using the Dean's plug/Tamiya plug. Use the small white plug on the side of the battery with many little colored wires sticking out. That is what its for. Charging direct, more often than not - causes damage to your lipoly.
LIPOLY USE
A lipoly cell holds up to 4.1 to 4.3 volts when newly charged. It then levels off at 3.7 volts. Use will of course, bring this voltage down. If you go below 3.3 volts per cell (9.9 volts for a 3S set-up), the battery begins to degenerate. This is dangerous.
Normally, a 11.1 volts 1600mAh 12C battery can be charged up to 500 times. Misuse will radically decrease the life of the battery.
Normal use of a lipoly heats it up a bit. So it being warm after use is normal. It being too hot to hold is a different matter altogether. It means that your set-up is overdrawing more amps than what the battery is capable of giving. Even if your set-up is not overdrawing, but you've gone beyond the 3.3 volts per cell safety requirement... your battery will heat up excessively. Bats used this way tend to puff-up and stay that way even after cooling down. In this case, upgrade to a higher mAh rating or higher C rating or even both (assuming it fits your weapon).
Most sensible radio control modellers carry a battery checker with them whenever they fly. This so that they can monitor the lipoly's charge during the day. Some, make a check to see when the ESC or electronic speed control cuts off - then subtracts 2 minutes from this to determine a safe flying time. Since ESCs don't exist on AEGs and there is no cut-off device to help preserve your lipoly... I suggest one of 2 things: either buy a WHATT meter (from Tower Hobbies), or listen to the recommendations of a guy who has one & who has used it to measure his own guns' amp draw.
I've checked my guns using my Whatt meter: a CQB AEG (370fps), one mid-range (450fps) and one for field (550fps). For everyone's benefit, here are my findings:
The CQB (370fps) uses a 7.4volt 1600mAh 12C batt. The only upgrades I have on this is the spring & bushings. It draws 12 amps on single fire, 18 amps on rapid. Its safe to use for up to 4 high cap magazines (370bbs per mag) after which the voltage is 3.4 volts per cell or 6.8V total. Recharge after 4 mags.
The midrange (450fps) uses a 11.1 volt 2200mAh 12C batt. This one draws 18 amps on single fire, 25 amps on rapid fire. After 5 high cap magazines (again 370bbs per mag), voltage is at 3.4 volts per cell or 10.2 volts total. Recharge after 5 mags.
I've also tried it using a 11.1 volt 2200mAh 15C batt. Amp draw is 20 amps on single fire, 30 amps on rapid fire. Voltage is 3.4 volts per cell or 10.2 volts total after 6 high cap magazines (again 370 bbs per mag). Again, recharge after 6 mags.
The Field gun (550fps) draws 20 amps at single fire, and 35 amps on rapid fire. I use a 3200mAh 15C batt for this. Voltage is 3.4 volts per cell or 10.2 volts after 7 high cap mags (again 370 bbs per mag). Recharge after 7 high cap mags.
Someone is bound to ask so: YES, I shot a lot of BBs to get this info right. BBs are far cheaper than lipolies.
LIPOLY DISPOSAL
If damaged, puffed-up or otherwise deemed dangerous - a lipoly battery is submerged in a highly saline solution to neutralize it. Grab a big bucket of water. Throw in several cups of salt. A good ratio is 5:1. Mix it thoroughly. Dump the battery into the solution. Leave for 24 hours. Get the battery out of the solution with prongs, bury it at least 3 to 6 feet underground.
STORING LIPOLIES
Do not store fully charged lipolies. Do not store uncharged or discharged lipolies. There is an optimum which is 80% of total voltage for storage. In short, partially charge your batteries - then store them. Leaving a battery fully charged or discharged will cause the battery to degenerate. You'll know it when you see them puffed-up when you recover them from their storage area.
Store your batts in a cool & dry location at your home. Do not leave them in places near sources of heat or water. Likewise, avoid exposure to direct sunlight.
What I do is to charge the lipolies to full when I get home, and I fire off a little under 1 magazine worth of BB's. Then I store them for the week. I recharge to full the night before playing.
