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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Dennis Toth on April 20, 2019, 01:54:45 PM

Title: How to check pack load voltage?
Post by: Dennis Toth on April 20, 2019, 01:54:45 PM

Guys,
Ok I fully charged a 4s 2450mah Zippy Compact pack and flew today. This pack is not puffed and took a full charge. However, once in the air I checked the lap time and it was 5.0 sec (59' C to C). This is slow for this ship, it is normally 4.88 sec. I suspect the pack under load is not at full voltage, nothing else has changed with the ESC or timer.

Question is how do I check the pack under load?

Best,   DennisT

Title: Re: How to check pack load voltage?
Post by: Fred Underwood on April 20, 2019, 04:02:16 PM

I don't know your Timer and ESC, but some ESC's such as Castle can datalog and give inflight or loaded voltage.

Governor function of the timer or ESC should in general not give your finding.  I can start off at partial charge, so lower that normal voltage, and have normal lap time/rpm.  I might get three 1.5 minutes runs from a battery as initial trim flights, all at the same lap time and can get the same tach reading at a run starting from storage or from full.

Title: Re: How to check pack load voltage?
Post by: pmackenzie on April 20, 2019, 04:20:01 PM

Get a wattmeter and a tach, will tell you just about everything you need to know.

https://www.amazon.com/Analyzer-Digital-Balance-Battery-Voltage/dp/B0753DPC2D

Title: Re: How to check pack load voltage?
Post by: Dennis Toth on May 05, 2019, 05:46:22 AM

OK, WATT meter arrived yesterday. What things can I check with it? How do I use it to check battery condition?

Best,   DennisT

Title: Re: How to check pack load voltage?
Post by: Crist Rigotti on May 05, 2019, 07:05:13 AM

Quote from: Dennis Toth on April 20, 2019, 01:54:45 PM

Guys,
Ok I fully charged a 4s 2450mah Zippy Compact pack and flew today. This pack is not puffed and took a full charge. However, once in the air I checked the lap time and it was 5.0 sec (59' C to C). This is slow for this ship, it is normally 4.88 sec. I suspect the pack under load is not at full voltage, nothing else has changed with the ESC or timer.

Question is how do I check the pack under load?

Best,   DennisT

Are you flying on a governor?  If so, then pack voltage won't change lap times, especially if taken early in the flight.  Did you time 10 laps and then divide by 10 to get your lap time, or did you time just 1 lap?  I always use the 10 lap method to get an accurate lap time.