Blew my Raider 150 and SK180. What now?

[RuntheraceAMC]

unfortunatley after a couple weeks of the boat running well I've run into a few problems. Before I give details let me share my set up. DFE 36 cat with Leo 4092 1730kv, running 648 and Prather 235 (50mm) props with OSE Raider 150. Batteries I've been using are 5s 70c 5000mah and 6s2p pulse 6s 45c 4100mah. Temps even on my most stressful set up never topped 115F

Last week I started experiencing trouble with the boat stalling on 6s. It would in for 30 seconds and then stall. After another 20-40 seconds it would start again full power. It did not matter if I was crushing or doing top speed runs, it would regularly cut out. When it stalled I could hear it Rebinding or I could hear the 6 beeps usually heard after initially connecting power. Then the rudder would work till the power came on within 20 seconds or so. I tried running 5s and even 3s. No change. I also lost reverse. It would never work. This made me think I should reprogram the esc. After reprogramming I had reverse but no change in the stalling.

Next I changed the radio receiver. No change. Then I threw my old SK120 esc in and it ran fine on 5s. No stalling. So I know it was the raider esc causing the issue. Unfortunately right after my 5s run, I blew up my SK120 when I ran 6s2p.

What now. I was thinking the SF200 because I want to run 8s next year (on a lower kv 4092). Thoughts?

[Fluid]

That's a pretty high-draw setup on 6S, enough to pull well over 150 amps. It is never a good idea to run any ESC at maximum voltage and amperage. I assume that you used the SK-120, not the SK-180 in the thread title. No surprise you blew it up.

Measuring temps after a run can be misleading. While the motor and packs are large enough to hold their temps for awhile, the ESC may not. If you don't take the temp reading within a minute or two of the last WOT run the ESC can cool off. But it isn't the external temperature which matters, but the internal temperature. Years of data logging had demonstrated that the logged internal temperature can be 50* to 75* or higher than what a temp gun reads on the exterior.

Two things which kill ESCs are high temp (not amps although they are closely related) and ripple current. The latter should be kept under 2volts. A third is a faulty ESC, or one on the low end of the QA/QC limits. The Swordfish have been very spotty in quality, club members have run about a dozen and all but one failed in a few months or never even fired up. Decent ESCs are a current shortcoming in the hobby.



.

[RuntheraceAMC]

That's a pretty high-draw setup on 6S, enough to pull well over 150 amps. It is never a good idea to run any ESC at maximum voltage and amperage. I assume that you used the SK-120, not the SK-180 in the thread title. No surprise you blew it up.

Measuring temps after a run can be misleading. While the motor and packs are large enough to hold their temps for awhile, the ESC may not. If you don't take the temp reading within a minute or two of the last WOT run the ESC can cool off. But it isn't the external temperature which matters, but the internal temperature. Years of data logging had demonstrated that the logged internal temperature can be 50* to 75* or higher than what a temp gun reads on the exterior.

Two things which kill ESCs are high temp (not amps although they are closely related) and ripple current. The latter should be kept under 2volts. A third is a faulty ESC, or one on the low end of the QA/QC limits. The Swordfish have been very spotty in quality, club members have run about a dozen and all but one failed in a few months or never even fired up. Decent ESCs are a current shortcoming in the hobby.

.

I knew I was pushing it on the SK 120. It was just my backup esc. The raider was prob not enough as well. When I propped up I think I was asking for trouble.

What is Ripple current?

So if SF esc's are questionable what do you suggest as an alternative?

[Fluid]

Ripple currents are indicative of the packs not able to supply enough power for the demands of the motor. Things like long power wires, poor connectors, and low C-rated cells are the usual causes. The ripple overworks the ESC and according to Castle was the most common reason for the failure of their ESCs in boats.

http://forums.offshoreelectrics.com/...ghlight=Ripple

I use converted Castle aircraft controllers for most of my boats. They last a long time for me until I put a bad motor in the boat.


.

[RuntheraceAMC]

Ripple currents are indicative of the packs not able to supply enough power for the demands of the motor. Things like long power wires, poor connectors, and low C-rated cells are the usual causes. The ripple overworks the ESC and according to Castle was the most common reason for the failure of their ESCs in boats.

http://forums.offshoreelectrics.com/...ghlight=Ripple

I use converted Castle aircraft controllers for most of my boats. They last a long time for me until I put a bad motor in the boat.


.

How can I find what you are using? Do you have a link. What do you think of the ETTI 220a proII?

[dmitry100]

Fluid, do you think it is mostly just a matter of cooling an ESC fast enough to be able to pull double the amps its rated for? I'm assuming it's not exactly as simple as adding a bunch of watercooled aluminum/copper plates on top of FETs since most FETs don't cool so well from outside unless you have water tubing on the PCB too?

In your case, since you're using the castle air esc's... I'm assuming you're adding your own (additional) cooling to them.

[Fluid]

If we could circulate liquid CO2 then we could run a lot more amps through the ESC. But we have to use pond water running between 35*F to 90*F. Better cooling could extend the amp limit somewhat but that often requires rebuilding the ESC.

More water flow is not the problem, it is getting the heat to the water. I install cooling tubes on Castle 200 Lite ESCs board increasing cooling. Based on all the ESC failures I've seen in many brands, the modded Castles are about all I use.

http://forums.offshoreelectrics.com/...ht=ICE+cooling


.

[RuntheraceAMC]

Well.... By the time you posted this I already purchased the ETI 220a HV ProII. Although I think I am going to add some things you did like extra cooling tubes and a fan. Good ideas that make sense. Hopefully this is my last esc purchase for a while. And I think I am done running esc's at their voltage limit. This one maxes out at 14s. I doubt I will ever put more than 10s through it to be safe. Also going to invest in a voltmeter so I can understand the amps I am pulling.

[Mxkid261]

Well.... By the time you posted this I already purchased the ETI 220a HV ProII. Although I think I am going to add some things you did like extra cooling tubes and a fan. Good ideas that make sense. Hopefully this is my last esc purchase for a while. And I think I am done running esc's at their voltage limit. This one maxes out at 14s. I doubt I will ever put more than 10s through it to be safe. Also going to invest in a voltmeter so I can understand the amps I am pulling.

Not sure if your aware but that esc does not have an integrated BEC so you will need one, or a battery pack to power your receiver.

[RuntheraceAMC]

I have one already. Plus I want to run a cooling fan per fluid's recommendation

[RuntheraceAMC]

Ripple currents are indicative of the packs not able to supply enough power for the demands of the motor. Things like long power wires, poor connectors, and low C-rated cells are the usual causes. The ripple overworks the ESC and according to Castle was the most common reason for the failure of their ESCs in boats.

http://forums.offshoreelectrics.com/...ghlight=Ripple

I use converted Castle aircraft controllers for most of my boats. They last a long time for me until I put a bad motor in the boat.


.

Fluid,
Help me understand this if you can, because my thinking about c ratings seems off now. I had been trying to find batteries that were only capable of delivering enough amps to reach my esc's max rated amps. But your saying a battery that fails to deliver the amp demands of the motor and esc could damage them. Aren't both bad?

Or am I free to buy the highest c rated and capacity batteries I can find?

I would image the only way to control amp draw would be to monitor it during runs and prop down to stay below 80% of you esc's limits....

[Fluid]

All the power in an FE boat is in the cells, not the motor or ESC. The higher the cell "C" rating the better, period. A big problem is that there are no standards for establishing a cell's "C" rating so the pack builder can put whatever he wants on the label. This means that not all 40C packs have the same real "C" performance. So one guy may be safe with 25C packs from Onehunglow batteries, while another may destroy his ESC with 25C packs from Sunnoshine batteries.

The best way to tell which packs are more accurately rated is to find plenty of good recommendations on OSE. But this is problematic because many boaters have no experience with more than one or two brands, so most wouldn't know a good pack from a mediocre pack. You usually get what you pay for, but not always. There is one large pack supplier in the US who gets top dollar for his mediocre packs due to slick advertising. Conversely, occasionally a bargain supplier will have a run of very good cells.

I have had good luck with mid-to-top level packs with a minimum of 40C, even for limited boats. But I am a racer and have higher expectations than many non-racers. Bottom line - get the best packs you can afford if you are pushing your equipment or if racing.


.

Fluid,
Help me understand this if you can, because my thinking about c ratings seems off now. I had been trying to find batteries that were only capable of delivering enough amps to reach my esc's max rated amps. But your saying a battery that fails to deliver the amp demands of the motor and esc could damage them. Aren't both bad?

Or am I free to buy the highest c rated and capacity batteries I can find?

I would image the only way to control amp draw would be to monitor it during runs and prop down to stay below 80% of you esc's limits....

[RuntheraceAMC]

All the power in an FE boat is in the cells, not the motor or ESC. The higher the cell "C" rating the better, period. A big problem is that there are no standards for establishing a cell's "C" rating so the pack builder can put whatever he wants on the label. This means that not all 40C packs have the same real "C" performance. So one guy may be safe with 25C packs from Onehunglow batteries, while another may destroy his ESC with 25C packs from Sunnoshine batteries.

The best way to tell which packs are more accurately rated is to find plenty of good recommendations on OSE. But this is problematic because many boaters have no experience with more than one or two brands, so most wouldn't know a good pack from a mediocre pack. You usually get what you pay for, but not always. There is one large pack supplier in the US who gets top dollar for his mediocre packs due to slick advertising. Conversely, occasionally a bargain supplier will have a run of very good cells.

I have had good luck with mid-to-top level packs with a minimum of 40C, even for limited boats. But I am a racer and have higher expectations than many non-racers. Bottom line - get the best packs you can afford if you are pushing your equipment or if racing.


.

I am partial to Pulse, reaction and (From OSE) Revolextrix. Are these good choices? If not what can you recommend??

[Fluid]

I have zero experience with Pulse or Reaction. Several club members run Revolectrix and seem to have good luck. It is all further complicated by changes in the cells by the actual cell manufacturer (different from the pack seller). Chinese business practices being what they are, different lots of the same cells will perform differently even though they are sold as the same. In most cases the pack sellers seem to be victims too.

An example is ThunderPower. Several years ago their packs were among the best, proven by top racers in oval and SAW events. Then something happened and their packs began puffing under normal use and pack life plummetted. Now it sounds as if they are back with good product. A number of pack sellers have had the same thing happen. So, a brand which was great last year may be poop today, and a brand which was terrible last year could be stellar today.

Right now the Revos seem good. Next year who knows.



.

[RuntheraceAMC]

Yikes. Sounds like the best thing to do is to by as high of a c rating as possible and hope it's actually high enough. Otherwise it could get expensive.