Battery Question (Bugs3)

C

Cobra54

New Member
I have a defender 2, toy and just purchased a Bugs3.
I know very little about Quads and batteries in particular.
I've read that the batteries should not be flown below 20% capacity.
I've flown my Bugs3 three times, first on full charge in house (raining and windy the day I received). I ran it until battery low signal then re-charged with supplied charger through balance port. Second time I flew outdoors until battery stopped. Recharged.
Today I flew in house, just practicing hovering at 3 feet and trying to get used to not having auto hover, it's pretty touchy for me still. I flew through the warning lights until the quad's motors would not start. I checked the voltage.. 7.0 total, first cell 3.42 and 2nd @ 3.55.
The battery is a 2c, 7.4v, 1800 mHa.
Is my battery/unit not discharging properly?
Other random facts.. The three flights took place over the course of 8 days, so the battery sat with a full (?) charge (the indicator light was green) for a few days after the initial flight. I just got the voltage reader and dont' know what the full charge was - haven't recharged yet.
I am considering the smaller Venom charger and read a bit on making a special wire to charge one cell at a time to avoid a long recharge cycle, just to get both in sync, but I digress.
My question - what voltage should I expect at full charge? What would a typical reading be at discharge - what should be at 20%, 20% of what the 7.4?
Related Q2 - if I don't fly for a week, should i discharge a battery to 50% before putting away and then recharge the day of use? ...and what is 50%?
Sorry this is so long winded, I don't know what's important to getting an answer... Thank you.
 
Rick M

Rick M

Absent-minded professor
The fully charged cells should be at 4.2 volts. Fully discharged is going to depend on the battery warning on the Bugs 3 and how long you fly it after you start hearing the low voltage warning. I don't remember offhand, but I want to say my Bugs 3 on 2S batteries would be at about 3.5V when I went to re-charge it.

Yes, it's much preferable not to store batteries very long fully charged. Storage charge should be in the neighborhood of 3.75 - 3.8V. Some say not to store them fully charged even for 24 hours. I think that's a bit extreme, but your mileage may vary. ;)

The easiest way to address all your concerns is to buy a decent balance charger. These "balance charge" the battery by feeding current to the cells individually. There are a lot of good options available. The SkyRC iMax B6 series are good and affordable.
 
Jackson

Jackson

USA member at large
Rick M said:
These "balance charge" the battery by feeding current to the cells individually. There are a lot of good options available. The SkyRC iMax B6
Click to expand...
That's not exactly how they work. The typical 4 button chargers push the full voltage to the whole pack then spend a lot of time discharging the individual calls through the balance port to make them even. With a 3S that has one cell quite a bit lower, the 2 that are more fully charged will be spending a lot of time being discharged as the low one catches up.
 
Rick M

Rick M

Absent-minded professor
Jackson said:
That's not exactly how they work. The typical 4 button chargers push the full voltage to the whole pack then spend a lot of time discharging the individual calls through the balance port to make them even. With a 3S that has one cell quite a bit lower, the 2 that are more fully charged will be spending a lot of time being discharged as the low one catches up.
Click to expand...

Yeah, I was trying to do the KISS explanation. I deleted a long paragraph about what a balance charger is doing in the first part of the charging cycle versus the last part, and why they take longer than a standard charge cycle, etc. I shoulda known one of the more technical guys would give me a ration for that. :D
 
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