Amperage Calculator? - RC-Monster Forums

Rivermaxx · **Amperage Calculator? -** 09.23.2009, 12:05 PM

I know I have seen one I just cant remember where. Can somebody lead me to a link. I am trying to figure out how many amps I need for a battery for this high speed event I plan on attending. It a one shot high speed run so I dont think I need that much capacity unless I need more availiable amps. I was thinking of running at least 2 3s 5000mah 30c in series for 6s that would be 150 amps continues and 200 amp burst. Should I run 2 6s 5000mah 30c in parallel for 300 amps continues or 400 amp burst. Or is that overkill? I know it is heavy @ over 2 pounds just for batteries. I was also looking at 2 6s 3300 30c in parrallel for 198 amps continues and 264 amps burst also. Which would you guys run.

BrianG · 09.23.2009, 12:48 PM

The only calc I have in my site (link in sig) uses runtime and battery capacity to estimate average and burst amperage figures. Or, use an Eagletree device to get real figures. Other than that, there really is no way to accurately determine amp draw based just on the motor and setup, there are just too many variables to consider.

For speed runs, you're gonna have a pretty big initial burst and then a higher than average continuous current because you are constantly accelerating. Most setups are used for racing or bashing where you have a lot of bursts with lower overall average since there is a lot of stop and go.

_paralyzed_ · 09.23.2009, 12:48 PM

the speed calculator has an amperage box IIRC.

Your motor is good for 2500w burst. I'd go for the 2x3s 30c 5000mah setup.

At 22.2volts 150amps is 3330watts. Already more than you need. And the burst is 22.2v x 200a = 4440 watts. So the two 3s are plenty.

Rivermaxx · 09.23.2009, 01:32 PM

I was thinking if I do a higher than 150 amp continues amp draw batt it would be better. I am not sure if a 10 sec 40 c burst will be enough to get to my top speed. I have seen a calculator that takes all the variables like weight, tire size, gearing, motor size. I think it fugures how many amps you need. If I find it I will post it up so you can critique it.

05:31 PM

Click here if it doesn't show up below.

Rivermaxx · 06:16 PM

I think thats it! cool Edit it keeps giving me weird numbers I dont think it works with my setup. Unless I am doing somthing wrong.

09.23.2009, 07:22 PM

Quote:

Originally Posted by Rivermaxx

I think thats it! cool Edit it keeps giving me weird numbers I dont think it works with my setup. Unless I am doing somthing wrong.

What are you putting in?

Rivermaxx · 09.23.2009, 07:58 PM

Its the most recent 30 pinion 40 spur for my g-maxx speed build. You can see the details I believe in the table.

09.23.2009, 08:01 PM

Quote:

Originally Posted by Rivermaxx

Its the most recent 30 pinion 40 spur for my g-maxx speed build. You can see the details I believe in the table.

They look about right.

Rivermaxx · 09.23.2009, 08:12 PM

681 kv motor and 14022 rpm dont look right to me. Maybe I am not understanding how this works.

09.23.2009, 08:21 PM

Whats the motor youre using? gearing is 30p/40s? what is the transmission ratio?

09.23.2009, 08:28 PM

Ive done the calculation with all the same input as you did but I used 8 seconds to get to top speed. I got 139 amps on 6s. That seems about right.

Rivermaxx · 11:28 PM

I am using a 1515 neu 1.5 d 2700 kv on 6s. Trans ratio is 1.72 : 1. I dont understand why it says I need a 631 kv motor and on spin it ~14800 rpm . It doesnt make sense to me Obviously I am not going to run that motor and that rpm.

09.24.2009, 10:43 AM

Quote:

Originally Posted by Rivermaxx

I am using a 1515 neu 1.5 d 2700 kv on 6s. Trans ratio is 1.72 : 1. I dont understand why it says I need a 631 kv motor and on spin it ~14800 rpm . It doesnt make sense to me Obviously I am not going to run that motor and that rpm.

The problem with this calculator is that its hard to estimate what KV the motor will get under those kinds of loads. have you run the car with this setup yet?

09.24.2009, 10:52 AM

Quote:

Originally Posted by Rivermaxx

I am using a 1515 neu 1.5 d 2700 kv on 6s. Trans ratio is 1.72 : 1. I dont understand why it says I need a 631 kv motor and on spin it ~14800 rpm . It doesnt make sense to me Obviously I am not going to run that motor and that rpm.

If you use that setup on a monster truck with that gearing it seems like it will be way overkill. If you use brians speed calculator using the setup you mentioned, you get 500mph. Youre gonna have to use a much taller gear ratio.

What kind of car is this?