How to figuer out mAh and a few questions to ask the PROS

4th_Dimension · Oct 11, 2020

Good morning everyone,
So I am finishing up " 5" BEAST build" "Freestyle" flying I will be doing. I am trying to figure out a few things here before I Fire her up...... so if anyone can help out it would be AWESOME.

1>) I can run (3S-6S) for my build but how do I figure out how many "mAh" for the batteries? 1100mAh,1550mAh,2000mAh..etc
2>) ESC SPEC's...32 bit,Voltage/Current limiting,Constant: 51 Amps,Burst: 80 Amps AND No BEC, OPTO only. Should I really be concerned about "NO BEC". I believe I can set this in BLHeli32 or do some kind of "Throttle Cut" on my RC so I don't hit full draw of current
3>) Even though my FC doesn't have any (Current Sensor or 5V BEC) My PDB and FC are compatible via the "FFC connection) Matek told me. Actually everything between the PDB/FC will now be done with this cable. But I just want to ask the PROS if anything else I may miss here.
and Last question
4>) Motors are GR2207.5 2400kv 4S. Could I possibly run 5S and be safe?

Thank you all for your time and help (can't wait to fly me BEAST!!!)

HighTechPauper · Oct 15, 2020

It all has to do with size and weight, we would all run a 30,000 mah battery and fly all day if we could lift it off the ground. The number of cells will have a bearing on the mah too, 4s 1300-1550 is usually the sweet spot, but for a 6s it is usually a 1050-1300 area.

A BEC isn't needed at all, don't worry about it or a throttle limit, you won't blow it up from that, no battery can create that much real current so the ESC's will never see anywhere near 50 amps.

Don't know anything about Matek "FFC" connection, and the current sensor would only be on the FC if it was an AIO where the battery pigtail is connected to the FC. Normally, wherever the current is read (if it is capable) is fed to the FC through a wire, nothing new there.

People run those motors on 5s all the time, and you likely won't need a throttle limit for it if the whole build can take full throttle punches without de-syncing an ESC or anything, you just never know till you build it up (add a big cap to it if one doesn't come with), it is all about the ESC rating and durability for this concern, but many people run 4s motors on 6s and usually they handle it fine.