Originally Posted by mrforsyth

It shows 4.2 volts at the output when the pack is accepting charge current. 4.15 volts resting voltage as measured by the DMM subsequent completion of charge is perfectly normal and expected. IMO, any charger that charges to 4.2 volts resting is overcharging, albeit slightly. e.g.- wjs is absolutely correct.

Mark

Kind a like trying to go the speed of light. The closer you get, the more you slow down, until you stop. Hence you can never get there.

Haha. Very true.

The asymptotic nature of LiXX charging can be a challenging concept to convey, especially to those who have historical experience with NiXX chemistry.

Now, if we could only have superconductors and lipolys with zero internal resistance...

Mark

I agree it's funny. Still I recommend to calibrate your A6 so that it does what it is supposed to do.

Martin

Hi,

I plugged my power supply into the charger in low light conditions and seen sparks at the port.
Is the thing putting voltage to the outside surface?

Nearly all chargers will do this. It's due to high initial current when the input capacitors are charging. Recommend that you first plug the charger into the power supply and then turn on the power supply to eliminate the spark and any potential damage to the charger input section.

Mark

Originally Posted by Martin.

I agree it's funny. Still I recommend to calibrate your A6 so that it does what it is supposed to do.

Martin

Mine was right on the money. Should probably not change if it is close as the numbers on the MM and charger float so much it is hard to get a consistent reading between the two. If in doubt, leave it.

That may indicate another problem, e.g. dirty contacts or an unstable power supply. Mine shows consistent and stable values when connecting a lipo. The reading was a about 30mV off before calibration.

Martin

Originally Posted by gapi

Hi,

I plugged my power supply into the charger in low light conditions and seen sparks at the port.
Is the thing putting voltage to the outside surface?

Mine did that every single time and it did it for nearly 3000 charges and 7 years later it's still kicking...so I wouldn't worry about too much about it.

Not sure whether it has something to do with the battery.
Currently my Syma107G can only fly less than 2 minutes before it became unresponsive after a full charged cycle. It is funny though, it is responding and can throttle as if it was being fully charged after switch off and on (with no delay) the little switch of the heli, but the flight time will be less and less..

I started to see this problem after I changed the dead motor for upper blade. Then I thought it might be the motor of lower blade that cause the faulty so I replace it as well but it didn't resolved. I should have mention if I give the heli forward or backward pitch or rudder the heli would even go dead faster than just stay hovering.

The problem remain even with new mainboard replaced.
Check the reading of its 1S lipo shows 4.26 after fully charged, and non-responsive state of the heli show 3.75.

SO the lipo was overcharged and possible defective already, but how could the heli is not listening while it still hold 3.75V?
OR what could have causing this headache?

Ps. my DMM read 4.2 on other full charged lipo, so no worry for the accuracy over here.

Originally Posted by guner7

Not sure whether it has something to do with the battery.
Currently my Syma107G can only fly less than 2 minutes before it became unresponsive after a full charged cycle. It is funny though, it is responding and can throttle as if it was being fully charged after switch off and on (with no delay) the little switch of the heli, but the flight time will be less and less..

I started to see this problem after I changed the dead motor for upper blade. Then I thought it might be the motor of lower blade that cause the faulty so I replace it as well but it didn't resolved. I should have mention if I give the heli forward or backward pitch or rudder the heli would even go dead faster than just stay hovering.

The problem remain even with new mainboard replaced.
Check the reading of its 1S lipo shows 4.26 after fully charged, and non-responsive state of the heli show 3.75.

SO the lipo was overcharged and possible defective already, but how could the heli is not listening while it still hold 3.75V?
OR what could have causing this headache?

Ps. my DMM read 4.2 on other full charged lipo, so no worry for the accuracy over here.

How old is your Syma? Usually it becomes unresponsive when the low voltage protection circuit kicks in. If your fully charged battery is going to 3.75V in 2 minutes, you may need to replace the battery. If your heli cuts off due to the low voltage protection circuit, it's a bad idea to turn it back on and run it again. It runs the battery too low and will shorten it's life.

Rob

Originally Posted by mrforsyth

Nearly all chargers will do this. It's due to high initial current when the input capacitors are charging. Recommend that you first plug the charger into the power supply and then turn on the power supply to eliminate the spark and any potential damage to the charger input section.

Mark

Thanks. I am using a Walkera small charger's power supply that came with a Heli. Its 15v ~1000mA. I'll start applying it at the wall instead of the charger.

Originally Posted by Martin.

That may indicate another problem, e.g. dirty contacts or an unstable power supply. Mine shows consistent and stable values when connecting a lipo. The reading was a about 30mV off before calibration.

Martin

Would help if I plugged in a batter first. Dooh. No directions to calibration in my docs. Works good now.

Originally Posted by robgau

How old is your Syma?

It was about 3 months old I guess. I admit the way I treated my Syma in the beginning of time was totally cruel due to lack of knowledge of heli care. I push the battery everytime until it cut off. Then charge immediately, and most of the time it was left unattended for hours, then fly it again once the charge cable is off.

Originally Posted by robgau

If your fully charged battery is going to 3.75V in 2 minutes, you may need to replace the battery.

So the battery is really gone bad thanks to my stupidity.. At least the problem doesn't pull any complexity to be fix.

Thanks Rob.

Originally Posted by guner7

Not sure whether it has something to do with the battery.
Currently my Syma107G can only fly less than 2 minutes before it became unresponsive after a full charged cycle. It is funny though, it is responding and can throttle as if it was being fully charged after switch off and on (with no delay) the little switch of the heli, but the flight time will be less and less..

I started to see this problem after I changed the dead motor for upper blade. Then I thought it might be the motor of lower blade that cause the faulty so I replace it as well but it didn't resolved. I should have mention if I give the heli forward or backward pitch or rudder the heli would even go dead faster than just stay hovering.

The problem remain even with new mainboard replaced.
Check the reading of its 1S lipo shows 4.26 after fully charged, and non-responsive state of the heli show 3.75.

SO the lipo was overcharged and possible defective already, but how could the heli is not listening while it still hold 3.75V?
OR what could have causing this headache?

Ps. my DMM read 4.2 on other full charged lipo, so no worry for the accuracy over here.

Did you replace the motor with a different brand. If the problem started after replacing the motors, your replacement motors may be pulling more current than the original one. This would also give you a much shorter flight time.

Originally Posted by Martin.

I agree it's funny. Still I recommend to calibrate your A6 so that it does what it is supposed to do.

Martin

I calibrated mine in the beginning and it worked great terminating at 4.20v,having learnt now that charging to the last drop may shorten the batt life span of a lipo.I have recalibrated the charger to it's max on the + side this now fools the charger to terminate at 4.18v.I don't use this charger very much as i have better ones but dollar for what it is it's hard to beat.