new to boats need some help

[00kitty]

i got my first boat the other day. its a spartan with the castle electronics basically stock. i bought two 3s lipos and an octura x640 prop. i was reading the spartan prop thread on here so thats why i picked that one. anyways the first drive was awsome way faster than i ever thought it would be, so much so that i didnt pay attention the the heat of components. about 3/4 of the way throught the run i thought about it. checked and the stuff was hot but i could keep my hand all components besides the motor and the batteries were a little puffy. so on the second run i noticed that when i would hold full throttle it would cut out on me after about a second. i could let off and go back to full throttle and it would do the same thing. this didnt matter if i just started driving it or was at the end of the run. once im pretty sure the thermal shutdown kicked in and so when it started working again i drove the boat over and it was warm but nothing like the first time i ran it with the new prop and batts. not sure if i toasted something that first run but my batteries are charging to full cap and the boat still runs strong, its just at wot it cuts out. any help would be great and suggestions on better ways to cool this thing

[Make-a-Wake]

An x640 is too much prop for that setup on 6s...............x440......possibly x442.............. Apparently Traxxas has gone to an 1800kv motor now...............thats just crazy in my opinion to suggest 6s so you need to back off on the prop.

[dag-nabit]

The stock prop is 42mm diameter x 59mm pitch. The X442 is 42 x 58.8mm, pretty much identical to stock, but a metal prop will give some performance advantage over fibre props because metal props don't flex under load.

I have been suggesting either the Octura X442 or Prather 215 for the stock components because we still don't know what the Castle ESC is rated at, so it is best, IMO, to stay a bit conservative selecting props for the use with the stock electrics.

Kevin

[00kitty]

i was thinking it was a bit much so on the next run i planned on going back to the stock prop just to see if i could hold wot. thanks for the help anyone know if or why it would be cutting out like that, it almost seems like its just drawing to many amps and cutting out i know there is a thermal overload but do they have some kind of overamp protection?

[marksp]

What are your battery specs? MAh, C rating, brand, etc.?

[midnightsabotage]

What are your battery specs? MAh, C rating, brand, etc.?

I was thinking this too, especially if you have your LVC setting of your speed control set high?
WOT drawing on your batteries with an aggressive prop might just pull the voltage down to the cutoff on the ESC?
more likely if you have lower quality batteries or a low c rating... (please correct me if i'm wrong here - i believe that a high amp draw on your cells actually lowers the voltage your getting out of the battery a bit)

...then again, your batteries might puff quite a bit if your amp draw is yanking your battery pack's voltage down far enough for the LVC to kick in. Atleast on a full pack.
If your boat wasn't cutting power at full throttle during the beginning of your run however, then just maybe you have low quality packs and a high low-voltage-cutoff set.

We need a little more info to figure out your riddle. But definitely use a smaller prop as step #1 - and see if that fixes your problem or not.

[00kitty]

i am running dynamite 4000mah speed pack. 3s 20c, 40c max discharge. the batteries worked very good the first run, but did get hot and puffed up a little. i let them cool over night discharged them and then charged them. they charged to aprox 4043mah and 3970mah. (side note i am using a Triton EQ charger). the battery that got the hottest was allso the one with a lower charge cap. i kinda feel like i trashed the batteries that first time running that prop. is it possible for them to charge good but not hold a stable voltage under load. i know lipos are finiky. allso i dont remember seeing anything about the speed controler where you can adjust LVC i know you have to enable the function but is it adjustable?

[midnightsabotage]

Did you say that you discharged the packs after you ran them? How far did you discharge them? If you discharge the packs past a certain point, you can do permanent damage to the cells.

I would try the same packs with a smaller prop - don't change anything in your setup other than the prop to start out, & see what happens.

[dag-nabit]

i am running dynamite 4000mah speed pack. 3s 20c, 40c max discharge. the batteries worked very good the first run, but did get hot and puffed up a little. i let them cool over night discharged them and then charged them. they charged to aprox 4043mah and 3970mah. (side note i am using a Triton EQ charger). the battery that got the hottest was allso the one with a lower charge cap. i kinda feel like i trashed the batteries that first time running that prop. is it possible for them to charge good but not hold a stable voltage under load. i know lipos are finiky. allso i dont remember seeing anything about the speed controler where you can adjust LVC i know you have to enable the function but is it adjustable?

Those packs are a bit under rated for use in the Spartan.

Your continuous max discharge rate is 4000mah (4ah) x 20C = 80 amps, and your max peak discharge rate is 4000mah (4ah)x 40C = 160 amps.

Generally it is recommended minimum 5000mah at 30C discharge and most of us are choosing to run 5000mah 40C or higher.

Your batteries were over discharged (i.e. completely flat) if you put 4000mah of charge back into a 4000mah battery. As a rule of thumb you want to leave approx. 20% residual capacity remaining in the battery after running, so your batteries should take about 3200 mah of charge if not over drawn.

As suggested, you may have damaged the batteries.

I know batteries are expensive, but if possible, try a set of 5000 mah with a minimum of 30C discharge rate (higher if you can afford them) and try running a smaller prop. If the problem continues, there may be a problem with the ESC.

Kevin

[Make-a-Wake]

You are abusing batts than can only put out 80a constant, with that prop you were pulling over that. You need at least 35c constant discharge batts, 40c preferrably.

[GeoVW72]

You can adjust the Castle esc with castle link, the preset lvc is 3.2v.

Agreed, those packs are a little underpowered for the spartan. I've seen the stock prop pull 120A regularly and I have run an x640 and the amp load I saw was around 150A. Well beyond what those packs can do reliably at 80A.
You don't need to discharge li-pos after they have been run.
Yes you can damage the packs running them beyond their specs, the SMC 3s 8000 20C that I've used can't push the boat for more than a couple minutes before hitting lvc now and have puffed. You need at least 5000mah 25C+ to keep up with the demands of a boat.
I did pick up a few Traxxas Li-pos(3s 5000 25C) and they do perform well, but they come back a little warm.

I'm not sure what's up with the Castle escs cutting out at WOT, but I would guess that they may have an amp load cut out.

[Make-a-Wake]

Here ya go.................40c 5000 3s for 39 bucks................and in the US warehouse. They'll get to you in 3 day. Ya cant beat 'em for the price.
http://www.hobbyking.com/hobbyking/s...dProduct=16788

[00kitty]

thanks guys this really helps i have raced on and off road but never got into boats and there were no lipos then so im still trying to figure it out. as we all know money seems to be no object when it comes to rc even if you have none! haha. i discharged the batteries out of habbit form all my years of racing nicd and nimh. but they only discharged for about 5 min and 15-20mah. i prob will not buy new batteries until next year because the season in MN is almost over but from what i have gathered i need to get a diff smaller prop and some new batteries. the speed controler seems to work just fine so im not to worried about that, just upgrade the cooling and i should be good to go. im not at home right now but when i get back on friday i will have a new prop waiting for me and go test with my current batteries. i hope this thread helps some other rookies with their battery, and prop selection. i will say though, that boat hauled ass for that first run and now im addicted even if it trashed the batteries its the most fun ive had with rc in a long time

[midnightsabotage]

Oh dang, didn't even notice you were in MN!

Whereabouts in MN are you?

[00kitty]

i am in stillwater just east of st paul where are you at