Got a question for y'all...

[pinkpanda3310]

Have you tried this calculator? This one is more specific to a given set up but will still only average out the power per run.

By the time your finger gets to full throttle, the motor is already building up revs. So my guess is the peak draw on the system is in the first 0.2-0.5 seconds. Data loggers sample every 0.2 sec don't they?

Just realized the data logger thing I said ><

[snellemin]

950A. I don't think so. You maybe could with a bigger motor and dual 5A 50c batts in parallel, but a single pack with a 1/10 motor+MMM, no.

[SunnyHouTX]

That calculator is also very general. And the sample rates of the data loggers available for our little RC budgets are not enough to get any sort of usable data in 1.4 seconds. Very soon, that number will go below 1.3 seconds for me.

@snellemin: but that is also speculative isn't it? So what do you think the peak is if the average over 1.4 seconds is 475A?

[snellemin]

475A sounds about right, as posted before. Why don't you do a 30 second burnout and datalog the ampdraw. You could then see the corresponding voltage under load. You can get a pretty good idea what your battery is capable off with your particular setup.
Do you still warm up your batteries before a run to reduce the IR of your batts? Do you cool down(spray it with something) the ESC at the Tree, so you get the most out of your ESC in that 1.4 second run? Do you have caps added to the MMM?

[pinkpanda3310]

Originally Posted by snellemin

Why don't you do a 30 second burnout and datalog the ampdraw. You could then see the corresponding voltage under load. You can get a pretty good idea what your battery is capable off with your particular setup.

That's a good idea. How about a home made dyno? Get a trolley wheel or something the same weight as your car and rig it to the back wheels. Add a brake to it to simulate wind drag. Might not be worth the head ache to make but just a thought. I'm not an electrical buff (I know, surprising isn't it ) but there must be a more accurate power analyzer you could use then. The weight of it is no longer an issue.

[SunnyHouTX]

Originally Posted by snellemin

475A sounds about right, as posted before. Why don't you do a 30 second burnout and datalog the ampdraw. You could then see the corresponding voltage under load. You can get a pretty good idea what your battery is capable off with your particular setup.
Do you still warm up your batteries before a run to reduce the IR of your batts? Do you cool down(spray it with something) the ESC at the Tree, so you get the most out of your ESC in that 1.4 second run? Do you have caps added to the MMM?

A burnout won't put the same load as a fully hooked launch. As for battery warming, I only do it on days that ambient temps are in the 70s or lower. I like my packs to be around 95 - 100 degrees where I seem to get the best results. And no special cool down of the ESC and no extra caps either, even in the 1.3 second passes I've done.

[snellemin]

They could've been 1.2 passes Sunny. Fets are rated at 25C and not the Texas 37C heat.
A burnout will tell you voltage drop under a certain load. Keep adding pressure to the rear pod for an increase in resistance/ampdraw. See if you can reach 170A with your eagletree in live mode.
Then use your eagletree in a live run and record the voltage drop at startup. There is no point in recording ampdraw at that point as the 10hz recording speed isn't fast enough. The voltage however doesn't rise as fast and the eagletree will catch it. That Voltage at near 0 rpm will tell you what your battery is made out off.

I might not have the fastest reaction time or be as good of a driver, but I can setup your electronics for max performance. That is why there are drivers and engineers in F1.