Huge difference between esc temps and motor temps

[RuntheraceAMC]

I recently blew up my Raider 150 (my fault. Running way too many amps). I bought the ETTI 220a ProII and love this esc. It lays down the power. But.... My temps have me scratching my head.

My set up: DFE 36, Leo 4092 1730kv, 648 prop, batteries: 5s 1p 70c; 6s2p 45c, 6s1p 70c. COG is 10 inches from the transom. 33" from transom to tip.

On the raider I would see 110-125. Motor up to 110F

On the new esc.... 5s: motor 90F. Esc 140F. 6s: motor 105 esc 155-160

Could it be timing? I thought I had it at 2.5 but this esc is hard to program. Am I missing something?

[JimClark]

How long do you run? Or how much is left in the lips after a run?

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[RuntheraceAMC]

That's a 5 min run. Just sport running with half a dozen full throttle passes

[RuntheraceAMC]

I'm not sure what you mean by how much is left in the lipos after each run? I run them down to 3.2-3.3 per cell each time I use them

[JimClark]

That's a 5 min run. Just sport running with half a dozen full throttle passes

So you are you at low throttle a fair amount of time?

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[RuntheraceAMC]

No. Half to 3/4 throttle for half the passes and full or near full throttle for the other half for a solid 5 mins

[Fluid]

How many mAh do you put back in the packs after a run compared to the total pack capacity? We need to know more than 6S2P etc, we need to know the total mAh for each setup.

Are you timing the runs or just guessing? That alone could be the reason especially if there is a difference in pack capacity.


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[RuntheraceAMC]

My 5s and 6s packs are 5000 mah. I am putting 4600-4900 back in them each time I charge. On one or two occasions I have recharged them and it was over 5000 mah. My last run (when I noticed the abnormally high temps) it charged and it took 4800.

I also have two 6s packs I am running in parallel. 4100 each for 8200 total. I am recharging them 7200-8000 each time.

I don't time my runs. I quit when I notice a drop in performance.

[NativePaul]

Your packs wont last long treating them like that.
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[fweasel]

Your packs wont last long treating them like that

I agree. I set my LVC to 3.2V in my Zelos and my 3S packs usually read 3.55V when I bring the boat in after 3.5min. In my other two boats that don't draw as many amps, my packs come back closer to 3.7V after about 5min runs.

[TRUCKPULL]

My 5s and 6s packs are 5000 mah. I am putting 4600-4900 back in them each time I charge. On one or two occasions I have recharged them and it was over 5000 mah. My last run (when I noticed the abnormally high temps) it charged and it took 4800.

I also have two 6s packs I am running in parallel. 4100 each for 8200 total. I am recharging them 7200-8000 each time.

I don't time my runs. I quit when I notice a drop in performance.

A 5000 pack -- Recharging to 4800
This means that you are running your packs down to 4%

6S 2P 8200 packs --- Recharging to 8000
This means that you are running your packs down to 2 1/2%

These numbers are way too low.
You will start seeing the magic smoke if you keep this up.
You could be causing a lot of extra heat when the voltage drops.

The old rule for LiPo's for them to last for a good number of cycles is ;
Never charge over 98% and Never discharge below 20%

I run 2P setups of 10,000 total for racing.
My run times are about 2 min.
My packs are usually down to about 45%

My suggestion to you would do some testing; run 2 min. recharge to see what you got left.
Try again at 2 1/2 or maybe 3 min.
When you find your right point, then always time your runs.

Larry

[RuntheraceAMC]

As you can tell.... I had no idea

[srislash]

It's a learning curve. After awhile you just kinda get used to a 'time'. But run a timer, it will save you money in the long run. Run two sets of packs to get your fill, it is better than running one set and killing it in months, or less.

[Fluid]

The OP's temperatures are higher with the 6S2P setup because they ran a lot longer before they hit the LVC. As mentioned above, running the packs so low will shorten their lives and performance as well as heating everything up.


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[785boats]

RuntheraceDMC
Keep a copy of this chart handy. Time your runs. Check your cell voltages after each run, & compare them with the chart to see where you're at with run time & discharge.

Lipoly Voltage vs. State of Charge 2S - 6S Packs.JPG

fweasle.
As you see on the chart, at 3.55v, you are seriously overdischarging your packs.
Resting voltage after a run should be above 3.7v/cell.
I'd raise your cutoff setting a bit to prolong the life of your packs.

[RuntheraceAMC]

Thanks for the chart

[785boats]

You are most welcome.
But even better is one of these cell checkers.
They give you voltages, and capacity remaining as a percentage. For both pack, and individual cells. Very handy little unit.

http://www.offshoreelectrics.com/pro...emp-eossentry3

Also try not to run at part throttle too much. That's is a quick way to burn out an ESC.

[fweasel]

fweasle.
As you see on the chart, at 3.55v, you are seriously overdischarging your packs.
Resting voltage after a run should be above 3.7v/cell.
I'd raise your cutoff setting a bit to prolong the life of your packs.

Thanks for the tip. I had to lower my LVC to 3.2V because it was tripping too early at 3.4V. The boat runs much better now and I'm in the process of fine tuning my run times on a 2 pack configuration. 3.55V was after 3.5min, next time out I'll stop at 3min until I start running with 4 batteries.

[785boats]

Are you sure it was tripping too early? Or was it tripping at the right time to leave the packs at over 3.7v/cell, ie 20% capacity remaining, when at rest?

[boredom.is.me]

Forget the battery stuff for a minute. What about motor timing? If you were running at default on both, that may have something to do with it. Or would that only cause the motor to get hot?

[RuntheraceAMC]

That's what was confusing to me. If it's timing, why isn't the motor hot. Even with the battery talk. Why is my esc 140-150 and the motor is at 90-100. If it was too much prop the motor would be hotter too

[NativePaul]

I don't know either of your ESCs but if the ETTI has default switching frequency that can cause much higher ESC temps and depending on the motor the motor may see no difference.

[RuntheraceAMC]

Are you saying that I constantly have to reprogram the timing. It's switching the timing on its own?

[srislash]

I believe Paul is reffering to the PWM. Do you recall modifying that step? I will have a look at one of my manuals when I am up and moving for the default setting.
Also, Do you have a cap bank on it as recommended by them? Always a good idea

[RuntheraceAMC]

What is the PWM? Yes I have the extra bank of 5 caps. Total of 7 caps. image.jpg

[srislash]

What is the PWM? Yes I have the extra bank of 5 caps. Total of 7 caps. image.jpg

Ok well I see a Y split in the water line, turf that. You may only be effectivivly cooling half the ESC. This is foremost! And while we are on that, water in to ESC then to motor. Is this how it is routed?
What size connectors and how much wire between batteries and ESC? Shorter is better. What I am looking at is the yellow connection block as a possible problem.

We will get to PWM

[RuntheraceAMC]

I have separate water lines to motor. As for the Y's. I heard this many times but I can't just remove the cooling set up I have without tearing out everything. Next time I need to pull out everything I will be eliminating the Y's. But why we are on this subject: there are four cooling tubes on the esc, two on each side stacked vertically on top of each other. Each side has water from a separate pick up. I ran hose with 4mm inside diameter to the Y and then after the Y about 2" of hose (3mm inside diamete) to each cooling tube. This means minimal line after the Y with no kinks or severe bends. But even if flow is restricted to one they are stacked on top of each other so cooling is getting to at least one of them on each side. Plus the cooling plates on top are getting cooling to at least one.

I realize there is a better way to do this but it can't be horrible the way it is. It has to be getting some cooling.

I am using XT90 connectors for the batteries and 8mm bullets from the esc to the motor. I'll send some pics of the battery wires and my parrellel connector wires. All wires are 10 gauge

[RuntheraceAMC]

image.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpg

[Mxkid261]

I would ditch those XT90 connectors those have like 4.5mm bullets. 6.5 castle connectors would be a much better option

[srislash]

I am suspect of the XT90 plug as well as the cooling lines. I looked the XT's up and cant find the size of bullit. But the dimensions of the housing that I found would not allow big enough connectors for this. How can one expect to give enough power to warrent 8mm connectors at the motor when the battery connector is only 5mm? If it is even that. Neat connector though with the anti spark but you should have 8mm there too. Anti spark is not really necessary for 6s.