boris4ka

My Blade CP started acting weird 4 battery packs ago. The battery is charged, but when I try to lift off it starts lifting, then when it gets a foot into the air I can hear the RPM's drop and it slowly falls to the ground. Then I keep trying to take off and in a couple of minutes it gets 6 feet up, then slowly falls again. Is this a problem with the battery?

mrasmm

The first things that come to my mind are...
how many cycles has that pack been through, has it ever been over discharged?
How much flight time is on the motor? Does the motor get too hot to touch after flight?
How is the pitch setting? is it at 0 degrees (assuming you have a cp, and not a pro) when the throttle is all the way down?
Is there any binding in the head, main shaft and bearings, that is causing the motor to work real hard? Or is the motor too tight against the main gear?

Was there anything that lead to this behavior, or did it just start doing it out of the blue?

That's just a couple of ideas I have...

boris4ka

It's a NIMH pack, around 20 cycles, never over-discharged or overcharged
Maybe 3 hours total flight time, it doesn't get above normal temp for a motor
pitch is fine and no binding, in fact I rebuilt the head recently.
It's not the pro version, and it's a year old but I barely used it because I gave up on it for like 8 months, but then learned to fly.

Nothing lead to this, was doing perfect hovers and it just started doing this. Basically it acts exactly as if the battery was discharged (even though it's charged).

mrasmm

If it is NiMH, your pack may need to be cycled, especially with that amount of down time. Do you have a charger cycler? That is by far the best option

If not, you'll probably need a multimeter, and a load of some sort. I use a 24vdc motor. You need to fully charge the pack, and then discharge it around 2 to 3c, so for your pack that should be 1.3 to about 2 amps. Discharge it to 1v per cell (so if it's 8 cell, 8 volts, and 7 cell, 7 volts) under load (0.9v per cell max if you are really watching it). This means while it is hooked to the motor or the light or whatever. You've got to be very careful not to over discharge the batteries, because that will kill them. And also an even load is much better than the pulsed load of say your heli.

If you don't have a cycler or a multimeter, there might be someone else that has some good advice too. I've just never had to improvise that way, so I don't know what to use.

A full cycle is a charge then a discharge. Cycle it probably 3 to 10 times. If you have a nice charger you can see how much is going back into the pack, and see if you are gaining any mAh when you cycle.

If your pack does not read atleast 520mAh when charging (if it's the 650mAh pack), then it's probably time to recycle that pack, and get a new one.

Hope this helps a bit....

you could also tell for sure if it is the battery by just going and buying a new one.

Captain Randy

My Feedback: (1)

I had the same problem. It turned out to be the main motor.

Heli007

It could be your motor or battery I would check them both. Make sure the gears are not pressed to tight on the motor gear. This will make your motor drag and have the syptoms you describe. If your using nicads it would be to your advantage to go with lipos. The heli runs so much better and doesn't feel like its in slow motion. Heli007

boris4ka

Gears are fine, everything is fine, so I'll test out the battery.

choppersrule

Boris4ka,

Dittos with Captain Randy, I had a main motor go out on me last night, not exactly your problem, but the heli was acting weird.

Anyway, these tiny little main motors are not designed to last that long, 20 hours plus or minus is about all you can expect from them for 10 bucks. I've gone brushless and it's a world of difference in performance and power.

Hmmmmm, then again, as Mrasmm mentioned the battery could be a gonner, NiMH batteries, when not being used should be charged ever 30 to 60 days to lengthen there shelf life.

Dave / Choppersrule