BeltCPuser

With the charger included with the RTF kit, how long should it take to charge? The first time I charged the battery when brand new it took over 4 hours and the battery never even got slightly warm.
On the second charge it has been on the charger for 3 hours now, battery still cold to the touch.

With a fully charged battery should the power gradually taper off or should the motor run at a desired rpm and then suddenly slow down and go dead within 5-10 seconds of the rpms slowing down?

shizack

LiPo or NiMH battery? If you have a LiPo and the orange "CHARGER EK2-0851" it should take about 2½ - 3 hours to charge. The battery should never get warm while charging. If it does, throw it outside and cover it with dirt. I'm not kidding. LiPos burn FURIOUSLY and water only spreads the flames.

If it's a NiMH, it'll take forever. Leave it on the charger 'til it goes from warm to a little warmer, then take it off and fly. Being 1800mah, I suspect it's a LiPo.

LiPos will run strong and suddenly lose a bit of power. TIME TO LAND! Do not ever over-discharge a LiPo.
NiMHs will taper off and you can run them 'til the rotor won't turn.

I suggest you do a search for "Lipo care" or "LiPo safety" as you sound like a relative newbie. These things have revolutionized RC flight, but if handled incorrectly they are literally deadly bombs.

RussianFlyer

The stock charger charges at 800 mah. Your 1800 mAh battery will charge in 2 hours 15 minutes...but that's a utopian calculation really. In reality, it can take significantly longer depending on how unbalanced the cells are and how much current the charger actually puts out. As far as discharging, the performance of the heli will begin degrading. You'll notice lower headspeed and as a result a less responsive and unstable tail. This is usually my sign to bring the bird home.

mrasmm

yeah (like everyone else has said), I would say 3 hours is a reasonable estimate, and your lipo packs should be cool (about 80F) to the touch, any hotter than about 90F while charging and you could have some real problems. If it's NiCD or NiMH you want them to be closer to 100F when you take them off the charger.

If the RPM's go dead, you've drained your pack too far. As a general rule a no load voltage test should be at nominal after flight. So 11.1 or so for lipo's, andything much lower than that and you've probably damaged your battery by over discharging it.

civichb98

So if I buy a lipo battery that is 850mah then I can't use the stock Esky charger???

RussianFlyer

An 850 mah battery can be charged using the esky charger. Most of the lipo batteries on the market are to be charged at a 1C rate. Since 850mah is the capacity of the battery, charging it at 800mah is almost exactly a 1C charger rate (1 x Capacity).

USHobbySupply

Yup, i charge all the time at less than 1c. When they say you can charge at up to 1c, it don't mean that you should. Most people advocate a slow break in process for lipo's and most of those call for a reduced 'c' initial charge rate.

FMB42

It's a good idea to check the cell voltages both before and after charging. I run my 1500mAh Esky battery down to ~ 3.70 (no load) volts per cell and charge it until it reaches ~ 4.05 to 4.10 volts per cell. IIRC, this batt needed just over 2.5 hours of charging (w/ the EK2-0851 charger) during the first couple of charges or so. However charging times are now 1 - 1.5 hours now that the battery had been "cycled" or used several times.

After awhile you'll get an idea on how long you can fly according to what voltage figures you start with which will allow you to end your flights before the "low voltage" protection kicks in. You will also get an idea of about how long to charge your battery according to how low the cell voltage figures are.

Consider the following Lipo battery tips;

Maximum voltage should never exceed 4.2 volts per cell.

Minimum voltage should never drop below 3.2 volts per cell (this works out to be ~3.70 no-load volts).

Cell voltages should always be within 0.10 of a volt of each other (if not, the cells should be balanced).

Good luck and good flying!