I am stumbled with an odd situation.
I am using Zippy 25C 4S batteries for smaller craft that drains 13-14A at loiter and decided to use them in parallel for a Tarot 690S that uses 4006 680kv motors.
this is a 3kg platform now and it draws around of 23-24A at loiter with peaks up to 50A at rapid movement.
what I have observed today - on a fully charged parallel pack that should be 10000mah after it used up 5400mah voltage under load has dropped down to 13.6-13.5V level. upon disarm it goes back to 15V.
what is a rule of thumb - what battery I need to get for Tarot hex to be able to use as close to max battery capacity as possible without those odd sideeffects?
those zippies were not stressed up at all, batteries were barely warm when drone landed, but it is odd to see them go to 13.6 while they still have half of capacity unused.
Would it be safe to continue to drain from this pack as voltage under load keeps falling that low? Or does it mean a different battery with 35C or 40C or higher is needed here?
What is the rule of thumb for a battery decision should be?
I attach a picture from the MP showing voltage drop - red one is volt, left scale, green it current.