Rigger puffing 3s battery

[Mxkid261]

Looking for suggestions. Ran this over the weekend for the first time in 2 months since ambient/water temps have risen 30-40*F. Run's great on 2s after about 8 minutes motor was 100*F, ESC 120*F, 2s SMC 6500 110*F. Let it cool off for a while as we had some beers. Threw in a SMC 7200 3s pack and ran about 5 minutes all 3/4 - full throttle. Motor was 110*F, ESC 170*F, battery puffed and split the case, it was like 150*F. Running a 42mm CNC prop, might be to much? I have a x637 on the way to try out. When it was colder outside a 3s pack puffed slightly so I knew I was pushing it, but never puffed like this Lol. I'll prop down and see how that helps. But I'm wondering if the Dynamite 120 isn't enough speedo, maybe I should cram a 180 in there? Thoughts? Trying to determine if I'm swinging to much prop on 3s, if the ESC can't keep up, or if its a combination of both. Thanks.

Poseidon 28", TP3630 3480KV, Dynamite 120, 42mm/2 CNC prop, strut level with tub, smooth driveline, 3mm gap between strut/drive dog.

18813414_10158754455330716_8973642016191056_n.jpg

Video of last time I ran it about 2 months ago

[RaceMechaniX]

How much are you pulling out of the batteries? I suspect you are running too long and pulling them down too low.

[Mxkid261]

How much are you pulling out of the batteries? I suspect you are running too long and pulling them down too low.

The 3s 7200mah was at 3.7v each cell after the 5 minute run. The 2s pack was about the same but it wasn't full throttle running the whole time, probably why it went like 7-8 min. I was letting my buddy drive it on 2s and checked my temps/voltage as soon as he brought it in. Am I running this setup to long?

[Fluid]

The 2S pack lasted longer because it pulled fewer amps. Increasing the voltage with no other changes always increases the amp draw.

The ESC did not cause the pack to fail, excess heat did. As Tyler stated, you probably ran it too long at too high of an amp draw.

One wonders, if you knew you were pushing things with 2S and cooler temps, why did you increase the voltage by 50% and expect it to work?

You will have to reduce prop size, and probably time your runs instead of relying on the LVC. These are often notorious for malfunction. Good luck.


.

[Mxkid261]

One wonders, if you knew you were pushing things with 2S and cooler temps, why did you increase the voltage by 50% and expect it to work?

.

Sorry if I didnt specify I figured I was only pushing it on 3s. 2s it runs great Ive probably put 20 packs through it on 2s, temps are always 100-120 depending on ambient temp and how hard I drive it. But only ran it a couple times on 3s. I guess 3s may only be for a few SAW passes and not running hard laps Lol. Lvc sucks on this esc I have it turned off otherwise it kicks in instantly on 2 or 3s. I run a volt alarm instead

[rol243]

Yes some Transmitters are fitted with a Beeper that you can set for the desired time you want to run the model so theres no worries about over working the battery pack, keep you runs short or have a run and stop the boat for a minute so all can cool down before the next hit.

[RaceMechaniX]

Hopefully you have answered your own question. It sounds like 2S is the right power for this combo. With 3S regardless of run time or voltage it is pulling too many amps and causing the pack to overheat. I suspect the cells are not terribly stout either. If you want to run 3S, make short passes and only a few passes or change to a smaller prop.

[Mxkid261]

Thanks I'll report back when I try the 637.

[Thunder29]

Increase in voltage decreases amp draw. Basic electronics math. Watts / volts = amps. The higher the voltage the less amps.

[NativePaul]

For a given power yes, but if you just increase the voltage from 2s to 3s without either dropping kv or propping down, you are trying to spin the same prop 50% faster which takes a LOT more power than the extra voltage provides and the current will go up to supply the power. I would expect to have doubled the amp draw in this circumstance.

[kfxguy]

For a given power yes, but if you just increase the voltage from 2s to 3s without either dropping kv or propping down, you are trying to spin the same prop 50% faster which takes a LOT more power than the extra voltage provides and the current will go up to supply the power. I would expect to have doubled the amp draw in this circumstance.

This.