Setting TVC

[twjsb]

I had read that setting the voltage cut off to less that 4.2 would increase life a lot.

"Maximum Charge Voltage and Current

A 3.7 volt RC LiPo battery cell is 100% charged when it reaches 4.2 volts. Charging it past that will shorten life substantially. In fact, the cell phone industry did a study looking at the effect of LiPo fully charged voltages in relation to cycle life. These tests were done under ideal laboratory conditions and of course the 80% depth of discharge rule was obeyed! Here are the results:

Charge to 4.1V gave over 2000 cycles.
Charge to 4.2V gave about 500 cycles.
Charge to 4.3V gave under 100 cycles.
Charge to 4.4V gave less than 5 cycles."

So I set mine to 4.18 which is as low as my charger will go. The charger was not storing that setting so I contacted support to see if they knew why it was not saving the settings.

The response was why are you not charging to 4.2 per cell and he had never heard of less giving more life.

Was the teck correct or was it just a way of no dealing with the changer not saving the setting.

[ManInAGarden]

Originally Posted by twjsb

Charge to 4.1V gave over 2000 cycles.
Charge to 4.2V gave about 500 cycles.
Charge to 4.3V gave under 100 cycles.
Charge to 4.4V gave less than 5 cycles."

I think your data may have been taken from here:

http://batteryuniversity.com/learn/a...ased_batteries

Very interesting read which lead me to the conclusion that loading up to 4.2V and discharging just down to 3.8V is a good compromise to get a reasonable good number of cycles on my batteries and also having a sensible capacity/weight ratio for good flight performance.

[twjsb]

Originally Posted by ManInAGarden

I think your data may have been taken from here:

http://batteryuniversity.com/learn/a...ased_batteries

Very interesting read which lead me to the conclusion that loading up to 4.2V and discharging just down to 3.8V is a good compromise to get a reasonable good number of cycles on my batteries and also having a sensible capacity/weight ratio for good flight performance.

My thought was that I could get 3000ma packs vs the stock 2200ma but only charge them to to a lower voltage. According to the data going from 4.2 to 4.1 will double life and only cut capacity by 14%. For only a few more dollars between the 2200 and 3000 I would get a 2500 pack(3000 x 86%) that will last twice as long as the 2200 pack charged to 4.2.

[ManInAGarden]

Yes that could work but the batteries will be more bulky an heavier. The added weight will cost more battery capacity because the motor needs more energy. Also your heli will not perform as good as it does with the smaller and lighter battery.

Maybe you should try that with just one battery or even better simply add the weight difference (from the specs) to you heli with some kind of dummy weight and see where that gets you.

Also the size of the battery can get you into problems. Make sure you'll still get the canopy on and that the center of gravity roughly stays where it should be (just a tad in front of the main rotor shaft).

[Mateyhv]

Originally Posted by twjsb

... According to the data going from 4.2 to 4.1 will double life and only cut capacity by 14%...

There is a reason after all for the Powerlab 8 charger mode called "Long life" that has a max charge per cell set at 4.1v.

[frankiexp2]

Originally Posted by twjsb

My thought was that I could get 3000ma packs vs the stock 2200ma but only charge them to to a lower voltage. According to the data going from 4.2 to 4.1 will double life and only cut capacity by 14%. For only a few more dollars between the 2200 and 3000 I would get a 2500 pack(3000 x 86%) that will last twice as long as the 2200 pack charged to 4.2.

I think, instead of getting a larger battery, you should be okay charing to 4.1 and draining to 3.7 instead of 4.2 to 3.8. Seems like a good compromise.