That they are!! I had measured a 4.5v drop under load!! Logged in at 16v, max drop was 11.5v!! I spoke to FP about it and they told me the packs were wrong for the application. However, they told me that if I doubled the packs, it should have helped to further confirm that, but it is still doing the same!! This project has been very frustrating!!!!

How are pack temps? If they are dropping that much with ~120A current, they should be quite hot. A 4.5v drop at 120A is 540 watts! That kind of power should easily be able to be felt as heat somewhere. Granted, that's burst power, but still a heck of a lot!

If pack temps are within acceptable limits, I would start looking at contact/wire resistances. A voltage drop ANYWHERE from the battery, wires, or connectors will cause issues. An easy way to find problem areas is to feel for higher temps manually. Where it's hot means there is resistance (=v drop). So, after a run, feel various places and note higher temps.

The packs are warm after the run. The hottest location in the whole setup is where the wires come out of the ESC, and those temps are really not out of the ordinary, about 140-150.

Then, that v drop must be very momentary or you would DEFINITELY feel the heat. Ever feel even a 60w light bulb?

Have you tried decreasing the "torque selection"? It's not supposed to be used for amperage management, but if the motor isn't trying to ramp up so fast from a stop, it will by nature pull less current.

Also, what battery setting are you using? Lipo normal, lipo high, or manual?

man i wished i would have read this thread sooner so i could tell you about my setup. in my yusa w/2speed running a mega 22/45/2 i would only see 115 on my esc running 8s1p a123's. with everything the same but on 12s1p a123's, the hottest i've metered was 135 i think. may have been 133. this is using the turnigy 100amp hv controller and geared for 109mph. i'm not sure what its going because i just haven't had the opertunity to test everything out, but there looks to be room to gear up a bit more. the power i'm putting down is just simply too much with the 12cells. on my street infront of my house i have to ease into it very slowly to keep traction and simply run out of room by the time i'm at 1/4. i'm thinking you really need a larger motor to continue with this project. if my thinking is right you'll pull less amps from the larger motor simply because it doesn't have to work as hard. what are your motor's temps and after how long of running?

I am using Manual, 3v per cell.

Motor temps are about 100 until the ESC stops

i don't know what to say then because thats pretty low. must just be over working the esc with amp draw or too many poles then like whats been suggested. look into a plane esc and add mechanical breaks.