ESC amperage ?

[tiqueman]

If an ESC is rated at 120A.. and there are tenth of a second spikes here and there at 180 and the ESC has a burst current rating of 240A.. is it able to handle things?

I have 2 in a twin boat and they come in at less then 115F. Usually 100-105F

Heres a Data log of the last run.

Thanks

[Steven Vaccaro]

If an ESC is rated at 120A.. and there are tenth of a second spikes here and there at 180 and the ESC has a burst current rating of 240A.. is it able to handle things?

I have 2 in a twin boat and they come in at less then 115F. Usually 100-105F

Heres a Data log of the last run.

Thanks

I personally would like to see the graph stretched out, to see how long its running over 120amps. It also depends on how good the stated ratings are.

[tiqueman]

I personally would like to see the graph stretched out, to see how long its running over 120amps. It also depends on how good the stated ratings are.

Thanks Steven. I will stretch it out.... Todays the first day using the logger.. but I will figure it out. Lemme go see what I can do.

[tiqueman]

I dunno if Im doing this right.. heres a blow up of one of the 180A spikes. Is that what you were looking for?

[Steven Vaccaro]

That's better. Now that its spread out a bit you can see you where over the rated 120 for a bit. I would say you are flirting with disaster.

[Darin Jordan]

I would say you are flirting with disaster.

Isn't that a song???

[Doug Smock]

Isn't that a song???

Yes, yes it is. http://www.youtube.com/watch?v=rhhtRxqSrys&feature=fvw

[tiqueman]

So what does "240 burst current" mean then? I guess thats what Im trying to underatand. I thought that meant it could handle a "burst" up to 240A.. just not anything continuous over 120A. And also if the ESCs are coming in at +/- 105F doesnt that mean they arent really straining at all???? I would think that 180A for 1/10 of a sec., was what the "burst amperage" would fall under....???

[m4a1usr]

Burst rating a speedo is going to be pretty ambiguous or subjective might be a better term. Duty cycle is essentialy what that rating equates to to. You will see certain manufacturers giving a time duration at the burst limit. A 200 amp speedo with a 240 amp burst rating for 10 seconds. Thats all well an good but if you spike the speedo with less then 240 amps, and yet if those spikes are the less then 240 burst, say 220 amps. And the duty cycle of the spikes is say 10%.i.e. 10% of the run time you are above the 200 amp continous rating it would most likely be more then the 10 seconds at full burst.

All I am saying is that while you could be running below the continous amperage rating, over the given run time, those spikes might be enough to exceed that limit. And whats probably the real killer is heat buildup of the FET's. So exceeding the continous wattage capability would be a better measure IMO. That way you could do a calculation using your end of run data and see if you are on the edge even if it doesnt appear so at first glance or initialy. Just my 2 cents.

John

[tiqueman]

So what method do I use to figure out my wattage? Do I use the "total amount" used per the Logger?

Also, I just thought of something else.. and this could be throwing things way off. I keep reading and I understand what everyone is saying. And John, Im going to pick part of your reply out specifically. You say "And whats probably the real killer is heat buildup of the FET's" If Im coming in after a full run w/ motors under 130F, batts under 100F and ESCs under 105F... Im not seeing anything straining.

The wrench in the equation I thought of... if Im paralleling my power out to both ESC's... the Data logger is logging both ESCs and motors simultaneously isnt it? So my numbers from the recorded data dont mean squat, or do they?

Im so lost... life was so uch easier when you said "yup, shes warm, but no where near hot"... or " uh oh, shes HOT!"

Thanks for the help of understanding ESC ratings Gents.

[domwilson]

So you using a single datalogger to log currents for both ESC's and motors simultaneously?

[tiqueman]

HAHA.. I was just gettin ready to PM you Mr Wilson!

Well, yeah... I didnt think about it... two 3S packs, seriesed to 6S, then parallelled out to both ESC's, so yeah, the logger would have seen both ESC's and motors. So is it 90A?... I vote yes.

[domwilson]

What packs are you running?

[ozzie-crawl]

if running a data logger between parallel batts a 2 escs it wil read they combined amp draw

[tiqueman]

What packs are you running?

Turnigy 3S 5000mah 30C and they are handling it w/ no problems at all. They havent broke 105F.

if running a data logger between parallel batts a 2 escs it wil read they combined amp draw

Thats what I wanted to hear Oz. So I am pulling about 90A per ESC.