how do you figure out how many amps?

[mk351e]

so people talk all the time about how many amps their system pulls, but how do you figure it out? I'l have:

12lb Muggy, Neu 1515 1Y (2200kv), MMM, Hyperion 6S 4800mah, 18T pinion. As usual, I just don't get it

[BrianG]

Those people do one of two things:

- Calculate average amp draw by the runtime they get with the battery they are using. Or, this page can help...

- Use a logging meter such as the Eagletree or similar device.

[lutach]

I'm going to take a wild guess here and with your motor, battery and gearing you will see the limits of the MMM. I have a DPR-150 and it can read up to 250A and it's a good device to have to figure out how many AMPs your system is pulling.

[Sammus]

I've always wondered about this eagle tree elogger things.. surely theyre only really useful for HV setups, being limited to 100A, or the newer ones 150A. Even then it seems like your really pushing its limits, will that thing blow if you over current it? I nearly bought one not long ago but was concerned that I'd be throwing $150 down the can on my first full throttle start...

[sleebus.jones]

Originally Posted by Sammus

Even then it seems like your really pushing its limits, will that thing blow if you over current it?

No. I've seen the new 150A one record 180A+ spikes with no failures.

[zeropointbug]

I have seen the 100amp version easily handle runs with spikes frequently in the 135amp range. Don't worry about it, I have never heard of one of these things failing as of yet.

[bdebde]

Dude, that set up will pull A LOT of amps; start out with a 12t pinion (50 mph), and go up from there if you need more. Trust me, you won't be driving a Muggy much over 50 mph! Give your electronics a break, so they don't break!

[ReV:-O]

Originally Posted by bdebde

Dude, that set up will pull A LOT of amps; start out with a 12t pinion (50 mph), and go up from there if you need more. Trust me, you won't be driving a Muggy much over 50 mph! Give your electronics a break, so they don't break!

if you got the Neu 1521 over the 1515, would that pull less amps because its more powerful and therefore less battery-demanding? and also could you gear it higher to get 60mph? thanks

Your motor on 6s is like 50,000 rpm isnt that way to hot? Mike tells me to stay around 30-35k at the most.

[Sammus]

Originally Posted by coolrunnings

Your motor on 6s is like 50,000 rpm isnt that way to hot? Mike tells me to stay around 30-35k at the most.

I think that guideline is more for poorer quality motors like feigaos... Neu's I think are their most efficient up around 50k. Someone correct me if I'm wrong...

[MTBikerTim]

Originally Posted by Sammus

I think that guideline is more for poorer quality motors like feigaos... Neu's I think are their most efficient up around 50k. Someone correct me if I'm wrong...

I think part of the reason for staying around the 35k rpm mark is that is makes gearing a lot easier in most cars. My buggy comes with a 13t pinion with the nitro motor and that was plenty fast enough for our track. If I put a 50k max rpm setup in it the smallest pinion would be an 11t and I would still be geared for over 50mph and if the system got hot from being over geared the only thing you could do would be buy another motor.

[ReV:-O]

loads of people run 6s on the 1515/1.5D, which puts them right around 60,000RPM and run with generally no problem. i think its best if you gear for 40,000RPM and then hav no problem whatsoever...

[jayjay283]

Originally Posted by ReV:-O

loads of people run 6s on the 1515/1.5D, which puts them right around 60,000RPM and run with generally no problem. i think its best if you gear for 40,000RPM and then hav no problem whatsoever...

Are these loads of people 2 guys from the traxxas erevo forum who have 3 MMMv1 and 1 MMM v2 blown up between them ? Those are the only 2 ive heard of and they fried all their escs

[Finnster]

Originally Posted by jayjay283

Are these loads of people 2 guys from the traxxas erevo forum who have 3 MMMv1 and 1 MMM v2 blown up between them ? Those are the only 2 ive heard of and they fried all their escs

eh, not too bash, but its a silly setup. One of them has killed a few more electronic bits than that on past setups, and as far as I can tell its just running spd runs up and down the street. Put it on the track or bash it hard offroad (like hill climbs and such) and you are going to see lava. Whatever, to each his own, but I have been seeing alot of "why is my Neu 200F?" or "why are my lipos melting?" threads lately w/ these setups. If you want so much power, go higher voltage.


On topic:

Anymore I have a good idea of the power of the system. If its a ~10 lb MT or 1/8th scale, if you are pulling 45mph, you are prolly around 1600W. 50 mph=2000W, and 40 mph=~12-1400W. Then just divide the watts by # of cells*3.5V (assuming decent batts)

That usually puts you in the ballpark of peak amp draw. More detail than that you need a ET.

[ReV:-O]

yah loads as in 2 lol. what so one of them had a MMM v2 that still blew? thats bad news