Stock castle motor repalcement??

[suzukipro]

I'm looking to prevent my boat (spartan) from starting on fire or destroying any more batteries (puffed) due to the heavy draw on the batteries. Does anyone one have any suggestions for a lower Kv repalcement motor that would mount up to the stock tray and run off the stock castle ESC? Thanks,

Suzukipro

[dag-nabit]

Leopard 4082 1500 or 1600kv has been used successfully by many, Also Tacon 4074 1700 is an option.

Not sure how many have tried these motors with stock ESC, most have also upgraded to a T180 ESC when changing up the motor.

Kevin

[JT13031]

Ok, I'll give you that I'm new to RC boats...but I'm far from new to high powered brushless setups. The amp draw on your batteries has to do with the work being done (the speed you want to be going) and the efficiency of the motor. Changing the motor to a less efficient motor and maintaining the same speed should theoretically draw more amps from your batteries. I'm not sure of the exact efficiency of the Castle motor in the Spartan but the rest of the Castle/Neu motors have a pretty good efficiency rating. My buest guess is that the Leopard motors are at least 5% less efficient. If you change to a lower kv motor and keep the same prop you will draw less amps because there is less work being done, the boat won't be going as fast. If you want the same speed your amp draw will be greater with the less efficient motor. If your puffing batteries I would suggest buying better batteries. I have only had my Spartan about a month but I have logged well over 10 hours of actual run time and haven't puffed any batteries and everything has been pretty cool after running. I primarily run on 4s, I have one 5s pack to run, and I tried 6s once to see what it was like. I didn't see a huge performance gain going from 5s to 6s. I'm not sure if any of this helps you but it is my experience.

[suzukipro]

I think the batteries are of good enough quality as they had worked flawlessly in my E-revo and Emaxx with no issues at all. 5 minutes in the Spartan and they puffed and broke their hardcases. I think the problem lies else where as I have heard of others having issues with batteries including the ESC wires becoming unsoldered due to the high current demands. I would like to stick with a castle motor, but 'I"m not sure what direction to go at the moment and I hate to spend a ton of money on an ESC & motor for less performance?

Suzukipro

[Stinger9D9]

If you want to draw less current while running the same voltage, you'll have to sacrifice speed, plain and simple.

If you don't mind going a little slower, try some smaller props. All else being equal, you will draw less current that way and it is by FAR the cheapest thing you can do at this point.

As far as prop suggestions, no idea, I don't know what that boat comes with but a few members here surely must have some ideas in that direction.

[Fluid]

I think the batteries are of good enough quality as they had worked flawlessly in my E-revo and Emaxx with no issues at all....

Boats are not cars. This is a common misconception among new boaters. The fact is that the demand placed on packs by boats is WAY greater than in cars or trucks. The amp draw is higher and lasts far longer, putting a huge stress on packs. Cheap packs will fail sooner or later if the amp draw is too high, as it is in the Spartan. Tell us what packs you have and that will help us to help you.

A lower Kv motor can increase boat speed, but it can definately decrease the amp draw. You can go faster with a lower rpm if you can spin a larger, more efficient prop and load the motor at its peak efficiency load/rpm. But even if the boat's speed remains the same or drops a little, the risk of damaging the electronics is reduced. Lower Kv motors are also less sensitive to small load changes which can cook a high Kv motor. Traxxas has made the mistake of using a motor with a Kv too high to be safe for most of its customers - too bad.



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[dag-nabit]

I think the batteries are of good enough quality as they had worked flawlessly in my E-revo and Emaxx with no issues at all. 5 minutes in the Spartan and they puffed and broke their hardcases. I think the problem lies else where as I have heard of others having issues with batteries including the ESC wires becoming unsoldered due to the high current demands. I would like to stick with a castle motor, but 'I"m not sure what direction to go at the moment and I hate to spend a ton of money on an ESC & motor for less performance?

Suzukipro

JT13031 identified a good point about your batteries possibly being the source of the problem (I overlooked that you had mentioned puffed batteries in your op). The quality isn't the issue, it is the discharge C rating, you can have very high quality batteries, but if they are not rated properly, you can have problems.

Others have already provided good info on the kv ratings, the difference between boats and cars, and possibly propping down a bit to lower amp draw. (stock prop is 42mm diameter x 59mm pitch)

But let's start with your batteries. You want a minimum of 5000mah 30C batteries for the Spartan, and most here would agree with the recommendation to go with 40 or 45C to give a good buffer on AMP spikes.

JT13031 posted some Eagle Tree data on the stock setup running 5S, and was pulling 105-107 amp spikes on that setup. On a 6S setup you will likely pull 120 plus amp spikes.

A 5000mah 30C battery is good for about 150 amp max discharge without damaging the battery, but you will be running without much fudge factor on a 6S setup, which is why 40-45C batteries are what most would suggest.

Given your comment about your trucks, you obviously have experience with lipos batteries, so I'm assuming you are confident the lvc activated properly and you didn't over discharge the batteries?

So... Let us know what you are running for batteries, that will give us a starting point for some suggestions on how to get the most out of your Spartan.

Kevin

[JackBlack26]

Leopard 4082 1500 or 1600kv has been used successfully by many, Also Tacon 4074 1700 is an option.

Not sure how many have tried these motors with stock ESC, most have also upgraded to a T180 ESC when changing up the motor.

Kevin

Agreed. Here is some video of my freshly built Spartan running on 2, $16 5000mah 20C Zippy packs, for 4S with an HK "Birdie" 200A ESC and Turnigy 4082-1600kv motor. She ran like a dream. ESC and motor came back like never been run. Batteries ware warmest at around 80-90*, or so. I forgot my parallel adapter so I could not run 4S, 2P. And then the servo went out so I couldn't run 6S. But all in all for what it cost me, I love this boat!!!! Not blistering fast and I could probably get more speed out of it with a 50mm prop or larger.

http://www.youtube.com/watch?v=p_RAOI7pVRs

[suzukipro]

The batteries in question were Venom 2s - 60C 5600 Mah and 2s 40C 5000 Mah batteries. I'm currnetly running some Gens ace 3s 40C 5000 Mah batteries and I can tell they swell slightly even after 1 minute of high speed passes, the battery connectors (traxxas) get in the 140+ range though. I usually stop and change batteries before continuing with the ESC and motor temps are in the 90- 115 range which seems OK from everything I've read. I'm running a stock plastic or Octura X442 balanced and sharpened prop, although it is also worth noting that I destroyed one set of batteries while testing out a Prather 220 prop which I have stopped using since.

[Stinger9D9]

The batteries in question were Venom

'nuff said...those...aren't good.

You may be over discharging the cells too. Don't wait for the voltage cutoff to kick in, they generally will over discharge before you get any indication. Over discharging is a sure recipe for puffing your packs. Once you've done it the first time, the pack's days are numbered.

Not sure of the Gens Ace pack quality.

[dag-nabit]

The batteries in question were Venom 2s - 60C 5600 Mah and 2s 40C 5000 Mah batteries. I'm currnetly running some Gens ace 3s 40C 5000 Mah batteries and I can tell they swell slightly even after 1 minute of high speed passes, the battery connectors (traxxas) get in the 140+ range though. I usually stop and change batteries before continuing with the ESC and motor temps are in the 90- 115 range which seems OK from everything I've read. I'm running a stock plastic or Octura X442 balanced and sharpened prop, although it is also worth noting that I destroyed one set of batteries while testing out a Prather 220 prop which I have stopped using since.

I know Venom lipos get a fair bit of bad press on the forums, but I've never run their lipos so I can't comment.

The mah and C ratings on your batteries are suitable for the Spartan.

The props you are running should also be fine (with the exception of the P220, which is a pretty big prop for the stock setup, IMO)

The temps on the connectors seem a bit high, and heat increases resistance, but I don't know that it is enough to be causing your problem.

Does your battery charger give you information on residual voltage and battery capacity before charging, or tell you how many milliamps of charge was required to charge the battery after it completes the charge cycle??

Kevin

[Fluid]

The mah and C ratings on your batteries are suitable for the Spartan...

Poor assumption. The issue is battery quality, meaning in part how much you can believe the "C rating" printed on the wrapper. Some cheap cells are obviously over-rated and simply do not perform like higher quality cells with the same rating. I've seen cheap cells which club members have purchased swell at well below what should be safe discharge rates for their numbers.

This is exactly the same thing we saw six to ten years ago with nickel cells - cheap ones were purposely over-rated since the end user usually couldn't test them to verify their exact performance. We had cells costing half what known quality cells did with better performance numbers. Bottom line, you can't trust low quality cells to be what the label says they are.

Cheap cells work fine in low discharge applications like most RTRs, and some will work okay at somewhat higher discharge levels. But the Spartan has too much for most cheap cells to handle without changing the prop, etc. One reason some folks get by with the Spartan in stock condition is the use of better quality cells (by accident or by design). Good batteries stress the ESC a lot less too - another reason some buyers who seem to do okay with the stock Spartan setup, or at least less trouble.



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[JT13031]

I also have discharge graphs for a stock Castle Spartan on 4s. I didn't see the huge spikes on 4s that I seen on 5s. I have a graph from the first run on my Traxxas 10000mah packs where I simply put the boat in the water and held full throttle until the lvc kicked in, 60-62amp draw the entire run.