RunRyder RC
 1  Topic Subscribe
WATCH
 1 page 494 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Battery Pack Question
09-04-2003 04:31 PM  14 years agoPost 1
jsmx9014

rrNovice

Prince George, VA

My Posts: All  Forum  Topic

I know from building and flying giant scale planks for years that multiple servos, working under heavy flight loads can place momentary amperage loads on the battery of as much as 1.5 to 2 AMPS. That's why we often use huge battery packs, dual receivers and power busses.

I had a friend crash his newly rebuilt, (1st flight), JR Ergo .60 for no apparent reason. There was no glitch, just sudden and total loss of the radio link. It happened as he came out of a high banked, moderate G-force turn. When we picked up the remains, we could find nothing that would indicate what caused the crash. And, battery voltage read 5.2V.

My theory is that he had a bad battery pack, (bad cell or cells), and all those digitals and gyro working under load, caused a spike in the current draw that dropped the voltage so low, the system failed. He was flying with an 1800mAh pack. During testing, when he loaded it with 1.2 AMPs or better, the voltage immediately dropped from 5.4V to almost zero.

So, my question is, how much of a "spike" load should any given freshly charged 4.8V battery pack be able to pull before the current draw pulls the voltage under what you might call "critical voltage", 4.4V? I would think that a pack should stand up under a short term load equal to it's capacity without dropping the voltage below 4.4V.

Whatcha Think?

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
09-05-2003 06:17 AM  14 years agoPost 2
mvhf

rrApprentice

Antwerp, Belgium

My Posts: All  Forum  Topic

If you take some avereage battery usage for a flight, let's take 350mah for a flight. Let's say a flight takes 15 minutes, This means you already have an average load of 1.4 A continuously on the battery. As we al do movements, I think your battry should be able to give at leas 4 to 6 A.
I hope I did my math allright.

regards

Marc

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
WATCH
 1 page 494 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Battery Pack Question
 Print TOPIC  Make Suggestion 

 1  Topic Subscribe

Friday, December 15 - 6:27 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online