Wizzard033

I have a Multiplex Twin Star II that I have modified with 2 35mm x 30mm x 1250kv Rimfire motors and I want a 4000mah to 5000mah 3s battery thats capable of handleing a total of around 600 watts. What battery would you sugest and what price range would it be in?

Thanks for the help

JAM MaxAmps

look at our 3S 5250 here: http://www.maxamps.com/Lipo-5250-111-Pack.htm

Wizzard033

very nice!!!

Wizzard033

Also I've noticed that when it's colder the battery I am using is even less responsive. At take-off my current battery was 52deg today and I wasnt able to get many RPM without the voltage of the battery dumping.

JAM MaxAmps

Li-po's drop capacity and at the same time C rate drops as well. You'll see this change start at 65 degrees and colder.

Reduce run times and how hard you run the packs.

Jason

Wizzard033

Thanx so much for all your help. I also noted that i was only able to draw about 30A at this temp. Is it best to keep my batterys at 'room temp' say 75 F until flight time. I fly at a freinds house so this wouldnt be a problem. Also I was considering covering the NACA scoop for the fuse ubntil the temps came back up. Also is the C rate a batteries ability to pass current or only as rating at which it can safely pass a given current?

JAM MaxAmps

Yes you can start with a warm pack but more often the pack will cool to much during use. The C rate is just a rating and it's not a very well proven rating system at that. A 5000 20C pack if rated correctly should be able to support 100 amps constant with out pack damage but running a pack at that rate all the time will shorten it's life span. It's like running a NASCAR engine at high RPM's all day during a race. That engine is only good for that day then it's rebuild time. Always try to have more battery than what is needed. A little cushion is always best.


Jason

Wizzard033

Thanx for the help I think i'm on the right track and getting a good handle on elctric aircraft.