Author Topic: battery capacity (Read 1767 times)

bill rutherford · « **on:** June 23, 2016, 09:00:56 PM »

I have been running my E flight e32 and Berger esc on thunder power 2700 5 cells. I have been happy with the set up. At the end of the flight I show 14 percent left in the battery. This has been very consistent. I just got some iperium 2800 five cells and at the end of the flight I show 4 to 6 percent left. Sometimes it runs out of juice before the end of the flight. My timer is set for 5 min 10 sec. The only thing that I can think of is the Thunder power is a better battery. I have been told that you should have 20 percent left for battery life. What gives. Bill

Fred Underwood · « **Reply #1 on:** June 23, 2016, 09:19:34 PM »

Stated battery capacity isn't always real capacity. You might get some idea here

http://stunthanger.com/smf/gettin-all-amp'ed-up!/calculated-or-stated-battery-capacity/

You haven't noted your put back milliamps for recharge. Recharge milliamps is a more accurate way than % left or used, in my opinion, to look at use.

What you are finding could be a reason to switch to 6 cells, or look at line length or prop. Assuming that you are happy with line length and prop, that makes the 6 cells with the extra watts reasonable, and may be the most weight conscious way, vs larger capacity cells.

In addition, Thunder Power has new 2800 mah cells, capacity not yet verified by use, but they seem to be accurate on the 2700s.

John Cralley · « **Reply #2 on:** June 23, 2016, 09:25:59 PM »

Got to agree with what Fred says! I have seen references on other forums that imply that some companies misrepresent the capacity and C ratings of their batteries.

Crist Rigotti · « **Reply #3 on:** June 23, 2016, 09:32:15 PM »

Bill,
What does the charger say that went back in during charge? Where did you get your 14% and 6% figures from?

William DeMauro · « **Reply #4 on:** June 25, 2016, 11:53:49 AM »

Bill,
Are those 2800HV battery? If so are you charging them to 4.35v per cell? If not you are under charging them(4.20v per cell) and you only have the equivalent of a 5s 2500 standard pack(That's only an approximation for those of you that like to do exact math). If I remember right you have a PL8 and the firmware has to be updated to charge HV type batteries to full capacity. I also recommend that you figure your percentages only using the real numbers and not by what some meter or charger says. My meters constantly say 15%,16%, 17% but in real numbers I have 25-30% left in my pack after flying.
William

Kim Doherty · « **Reply #5 on:** June 26, 2016, 10:02:55 AM »

First as has been stated you need to know (and keep constant track of) how much you put back in the pack. Also keep track of the individual cell voltage.
To make sense of what is happening you also need to consider:
Prop pitch, prop diameter, number of blades, under camber, thickness, line length, line diameter, lap speed, weight of model, KV of motor.
We did not have to be so exact with IC because fuel has a much higher energy density than a battery. Since electricity is less efficient we need to optimize all of the parameters to achieve true Zen happiness.
The battery "could" be at fault but probably not.

Kim

Target · « **Reply #6 on:** June 26, 2016, 07:08:59 PM »

Quote from: William DeMauro on June 25, 2016, 11:53:49 AM

Bill,
Are those 2800HV battery? If so are you charging them to 4.35v per cell? If not you are under charging them(4.20v per cell) and you only have the equivalent of a 5s 2500 standard pack(That's only an approximation for those of you that like to do exact math). If I remember right you have a PL8 and the firmware has to be updated to charge HV type batteries to full capacity. I also recommend that you figure your percentages only using the real numbers and not by what some meter or charger says. My meters constantly say 15%,16%, 17% but in real numbers I have 25-30% left in my pack after flying.
William

What he above said... The Hyperion 2800's are only 2800 if you charge to the higher voltage. They are 2500's at 4.2V, so I think they are in line with the TP 2700's...

bill rutherford · « **Reply #7 on:** June 26, 2016, 09:44:44 PM »

I have been using a thunder power charger so will have to check out the charge voltage. Will you might be getting a call from a confused guy from Texas, Ordered some new 5 cells 2800 from thunder power. thanks for all the advice. This learning curve keeps changing .Thanks for the help guys

David Hoover · « **Reply #8 on:** July 01, 2016, 03:03:10 PM »

Quote from: William DeMauro on June 25, 2016, 11:53:49 AM

Bill,
Are those 2800HV battery? If so are you charging them to 4.35v per cell? If not you are under charging them(4.20v per cell) and you only have the equivalent of a 5s 2500 standard pack(That's only an approximation for those of you that like to do exact math).

What is the exact math? Just curious.

Author Topic: battery capacity (Read 1767 times)

bill rutherford

battery capacity

Fred Underwood

Re: battery capacity

John Cralley

Re: battery capacity

Crist Rigotti

Re: battery capacity

William DeMauro

Re: battery capacity

Kim Doherty

Re: battery capacity

Target

Re: battery capacity

bill rutherford

Re: battery capacity

David Hoover

Re: battery capacity