Battery Charging Graphs

PdxSteve · Apr 10, 2016

I logged data for 2 different charges, the stock charger and a cc/cv converter set to 6A. I graphed it using google charts and thought it was pretty interesting so thought I'd share. Samples were taken at 30 second increments.

Charging 3DR Solo Batteries - JSFiddle

If anyone is interested in the raw data found in the javascript, the row format is:

[[H,M,S],L,A,V]
H=Hours
M=Minutes
S=Seconds
L=Percentage (full) Level
A=Amps
V=Volts

Like "[[0,30,0],42,3.20,15.46],"
is
0 Hours
30 Minutes
0 Seconds
42% full
3.20 Amps
15.46 Volts

CanadianSolo · Apr 10, 2016

PdxSteve said:
I logged data for 2 different charges, the stock charger and a cc/cv converter set to 6A. I graphed it using google charts and thought it was pretty interesting so thought I'd share. Samples were taken at 30 second increments.

Charging 3DR Solo Batteries - JSFiddle

If anyone is interested in the raw data found in the javascript, the row format is:

[[H,M,S],L,A,V]
H=Hours
M=Minutes
S=Seconds
L=Percentage (full) Level
A=Amps
V=Volts

Like "[[0,30,0],42,3.20,15.46],"
is
0 Hours
30 Minutes
0 Seconds
42% full
3.20 Amps
15.46 Volts

I like it! I just got my hands on an Arduino so I will be dusting off my code skills for battery management! Ugh lol lol. Cheers good info bud!

SPP · Apr 11, 2016

Nice Steve, thank u

Pedals2Paddles · Apr 11, 2016

Have you experienced the battery shutting down before it's fully charged, yet claiming it is 100%? On numerous occasions, my batteries will cut off alleging they're 100% full, but the voltage is only around 16.3 volts. It will be charging away, still pulling 5 amps, and cut off saying it's full. Then of course, it thinks it is full and cannot resume charging again.

pyrate · Apr 11, 2016

interesting, 30 minutes per battery is a great time savings
I suppose we just dont know what the long term impact is?

Pedals2Paddles · Apr 11, 2016

You will never recharge an empty battery in 30 minutes. I don't think he showed anything like that either?? The solo smarty batteries will not allow charging at a rate more than 5.9 to 6.0 amps. The best you're going to do is a little under an hour on a fully depleted battery if use charge at the max rate using a LiPo charger or CC/CV power supply.

RichWest · Apr 11, 2016

Pedals2Paddles said:
You will never recharge an empty battery in 30 minutes. I don't think he showed anything like that either??

The difference in time to charge....dummy....

PdxSteve · Apr 11, 2016

Pedals2Paddles said:
Have you experienced the battery shutting down before it's fully charged, yet claiming it is 100%? On numerous occasions, my batteries will cut off alleging they're 100% full, but the voltage is only around 16.3 volts. It will be charging away, still pulling 5 amps, and cut off saying it's full. Then of course, it thinks it is full and cannot resume charging again.

Only what I mentioned in my notes on the page; both batteries reported about 95% full when they disconnected (stock charger and CC/CV). I mean the actual number it reports, not the number of LED's. However, it appears it was misreporting because after it disconnected itself I turned the battery back on and it reported 100%. The voltage was also 16.8. All cells were 4.2V. So it was indeed charging to 100 even though it said it wasn't. When I reconnected the battery to check it - it didn't take a charge. Not sure why yours would be doing that.

PdxSteve · Apr 11, 2016

pyrate said:
interesting, 30 minutes per battery is a great time savings
I suppose we just dont know what the long term impact is?

I suspect not much, if any. 6A is barely above 1C.

Pedals2Paddles · Apr 11, 2016

3DR specs on the battery state it can safely recharged up to 2C (10.4 amps). I can only assume that's what the cells can handle as far as heat dissipation and such. We can't actually achieve that in reality due to the battery's brain cutting off at 6 amps. So I agree, charging at 6 amps will have no ill-effects on the battery. That 6 amps is still well under the maximum the battery can handle.

PdxSteve said:
Only what I mentioned in my notes on the page; both batteries reported about 95% full when they disconnected (stock charger and CC/CV). I mean the actual number it reports, not the number of LED's. However, it appears it was misreporting because after it disconnected itself I turned the battery back on and it reported 100%. The voltage was also 16.8. All cells were 4.2V. So it was indeed charging to 100 even though it said it wasn't. When I reconnected the battery to check it - it didn't take a charge. Not sure why yours would be doing that.

Frustrating. Hopefully they will reset (for lack of a better term) upon a full discharge and recharge cycle.

Do you know if the % remaining on the app/controller is MAH used vs the 5200mah battery capacity parameter in Arducopter? Or is the % remaining being reported by the Smart Battery only?

PdxSteve · Apr 11, 2016

% remaining is what is reported by the battery. There is a new(er) BATT_MONITOR type parameter in arducopter, type 5, which is SMBus battery. When enabled, it ignores any hardcoded mAh rating and goes by what the battery reports.

See: Complete Parameter List — Copter documentation
and
Smart Battery — Copter documentation

Pedals2Paddles · Apr 11, 2016

I noticed that parameter last time I was perusing Mission Planner's parameter list. I had a feeling that would tell it to use what the battery reports. I think this is a good thing. Otherwise, Arducopter assumes the battery is fully charged when it boots up, and compares MAH used to the battery capacity parameter. If you put a half dead battery on it, it would blindly assume it was 100%. Allowing the battery report it's % allows you to fly knowing what the battery's real condition is. For a consumer packaged product as opposed to DIY use, this is a necessity.