Battery Question - Parallel vs large battery

[rwilabee]

Looking for some input re batteries. I have built an Octo Copter. I have 2 5000 65-130 C Batteries I put in parallel. After 5 minutes of flying as a test one battery took 3273mah and the other took 735mah. Is it normal for them to not go down evenly. I'm trying to figure out if I'm better off to run 2 in parallel or get one large battery. I have found a 10,000 mah battery at 25C continuous. I'm running 8 Avroto motors and they say the max power at 14.8 volts is 390 watts. So I figure that is about 9.3 amps per motor or almost 75 amps.

Thanks
Rich

 

[Efliernz]

They should be almost even - you have a problem somewhere because what you have is definitely not normal.
I suspect one of your batteries is not as healthy as the other. Every model with parallel batteries I've used/seen the difference between the two were less than 5%

Pete

 

[rwilabee]

One of the batteries is actually swollen a bit and the other is not. You may have hit on my problem.

They should be almost even - you have a problem somewhere because what you have is definitely not normal.
I suspect one of your batteries is not as healthy as the other. Every model with parallel batteries I've used/seen the difference between the two were less than 5%

Pete

 

[RyanMcCrae]

You need to check the batteries internal resistance; which is done on the charger. It sounds like its probably stuffed.