battery wiring
 

The wiring is rated as 12 awg 200c ,can I go 10 awg 120c

Since #10 wire is heavier, the question must concern insulation temperature.
You did not indicate the actual current or battery size/capacity so I'd have no idea concerning
the actual temperature of the wire or the current it needs to carry.
You also did not indicate any type of cyclical changes that will change the wire temperature. .

My bad ! The plane was given to me by a friend with a Axi Heavy Duty motor and Castle 90+ esc . I will be installing 2,6 cell lipo 4000
45 C mah batteries in series . The original owner of the plane apparently knew what he was doing so I just recorded the info off the components , the original owner passed away and my friend wanted nothing to do with the plane .
I don't believe cyclical change would be involved . I originally was going to install a 23cc gas engine but decided to stay with electric being only having to purchase a parallel charger , series connector and the 2 batteries .
I hope this has given enough info to be helpful . I normally fly glow/gas so this is new to me . I have been going on different sites , reading mags to see what other helpful hints I can gleam .

10 AWG is larger wire than 12 AWG so it will carry a lot more amps before getting hot. I assume the 200C and 120C are temperature ratings? 200C is 392 F. That's hot enough to melt some solders. 120C is 248 F.

I think you'd be plenty safe with 10 gauge wire.

Jack

If you provide the make and model of the motor that would help. If you have the motor's kV raging that would be a huge help. Then we need the size of the prop. With that we can model how many amps you are likely to draw.

Sounds like you are setting up a 12S battery pack so I presume this is a pretty big and heavy airplane.

That is a 44.4V battery pack. Assuming 80 amps that would work out to be 3552 watts. I assume the plane is something north of 25 pounds.


You might find this free on-line book helpful.

EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC POWERED FLIGHT
http://www.rcuniverse.com/forum/m_7100376/tm.htm