Topic: Problems with brushless set up. (Read 5331 times)

bikerdude666 · « **on:** August 29, 2011, 01:19:50 pm »

Hi all, I've got a boat that's been fitted with a brushless motor and speed controller, I took it down to the lake yesterday to give it a try. Switched it on and out it in the water, but it was sitting too low at the front so wasn't going too well, took it out and removed the ballast, but when I put it back in it started playing up, it still wasn't fast but that's due to the weight but then it stopped responding to the controls and was randomly shootig forward, then it died and I pushed it back to the bank with the flower class.

I took it out the water and had a play around, everytime I switch it on the esc goes through the set up process, the set up only works the wrong way round meaning, the stick has to be fully forward 1st then fully down then back to fully forward then it works so it applies speed as you pull the stick back. But when the stick is pulled back the motor turns a couple of time then does nothing. I then have to return the stick to fully forward, and then it does nothing until you move the stick fully down and then it just goes through the set up process again. I'm using a giant cod 2.4ghz set (of which i have 2 and it does the same with both sets) the motor and esc are also from giant cod, I think the esc is a seaking 25a.

Has anyone got any ideas? I'm new to brushless so have no idea how it works. Oh on the esc it says 'set' on part of it but there's no button or anything?

HS93 (RIP) · « **Reply #1 on:** August 29, 2011, 01:50:00 pm »

the sea King ,was/is it watercooled ? 25 Chinese amps are not the same as UK amps, I half any stated amps. what motor do you have and prop and what type of boat ?

peter

Shipmate60 · « **Reply #2 on:** August 29, 2011, 01:51:25 pm »

The GiantCod set is set up for aircraft so defaults to the throttle stick only operating forward.
Once it has been used once, the stick full travel the ESC can recognise the neutral point.
As to the stopping and starting which batteries are you using as most brushless esc's are set for Lipo batteries and will cut out if the voltage drops below its determined set point.

Bob

HS93 (RIP) · « **Reply #3 on:** August 29, 2011, 02:27:59 pm »

Yes your speed controller is a watercooled one so HAS to be fed with water for you to use it as it will overheat as they use water instead of a big heat sink , have you got your stick switched in reverse a lot of Tx have such an ability.

Peter

bikerdude666 · « **Reply #4 on:** August 29, 2011, 06:42:47 pm »

Right gotta try and remember all the answers now:

It's a baby Severn, fitted with a Graupner minijet, and it was using a 7.2v 1700mah nimh battery pack, the esc is water cooled, a small pickup under the boat and the outlet out the stern. I had the aerial from the receiver poking out a small hole in the deck to make sure it was above the water line.

The battery was fully charged, and when it was going it was only in the water for about 3 minutes.

AT Boatyard · « **Reply #5 on:** August 29, 2011, 06:59:37 pm »

what kv is the motor
regards
alan

bikerdude666 · « **Reply #6 on:** August 30, 2011, 01:03:41 pm »

Unsure what kv the motor is, and I can't see anything written on it, I just tried it only quickly out of the water) with a different fully charged nimh battery pack, and ts working again, so can anyone recommend a lipo set up for me?

HS93 (RIP) · « **Reply #7 on:** August 30, 2011, 04:59:35 pm »

have a look at this section your unit is the same size as the small RTR ones in fact they are coppies, to watercool they normally put a tube in to the jetunit I played about with them last year for a little bit and found the site useful but a lot of reading. they normally use at least a 2400KV and some use a lot higher small heli motors so plenty about cheap

peter

http://www.rcgroups.com/forums/search.php?searchid=30852144&query=jetboat

bikerdude666 · « **Reply #8 on:** August 30, 2011, 06:11:21 pm »

Thanks, though the link leads me to a page that says no results that matched. Will have a look around on there though, had the boat apart today and it should be simple enough to fit better water cooling. Would the intake have to be inside the jet or could I just get 1 of the intakes that bolt through the bottom o the hull?

knoby · « **Reply #9 on:** August 30, 2011, 06:51:08 pm »

I had the same type of problem with my first brushless set up, using a seaking esc on 7.2 volts. My problem was, as soon as the battery dropped to around 6 volts, there wasn't sufficient voltage to work the bec so it cut out. when the motor is running on load it draws plenty of current, this results in the voltage dropping significantly at the battery. I cured this by using a 3s lipo but using a separate receiver battery would also have cured it. don't forget to disconnect the red wire from the esc receiver plug if you use a separate Rx supply.

Glenn

bikerdude666 · « **Reply #10 on:** August 30, 2011, 07:46:32 pm »

Do you have any links for the battery? I've had a look at lipos but I have no idea what I'm looking at, when using a lipo, is there anything else I need to change or is it a case of just plug it in and off you go?

knoby · « **Reply #11 on:** August 30, 2011, 08:05:40 pm »

Firstly, i should say I am no expert on brushless or lipo's, in fact I'm about 3 months ahead of you on the learning curve.
I used these
http://www.giantcod.co.uk/4000mah-lipo-battery-p-405662.html
They seem fine for what i want, I'm not racing anything with them.
You will need a charger that can charge lipo's & you need to set up the esc to cut out before they run flat. If you run them too flat just once. then they are scrap.

If it was me i would try the boat with a separate Rx battery, even if you just boj it in there to see if it solves the problem, if you get it wrong with lipo's it can be expensive.
i was lucky as there are a few guys at the local club who know their stuff when it comes to lipo's & brushless & they held my hand through the early stages.

Glenn

HS93 (RIP) · « **Reply #12 on:** August 30, 2011, 08:57:35 pm »

this was it sorry
http://www.rcgroups.com/forums/showthread.php?t=1403921&highlight=jetboats

peter

MikeA · « **Reply #13 on:** August 30, 2011, 11:44:50 pm »

i had similar problems with my brushless seaking and i just turned the LVC off, fine now.

bikerdude666 · « **Reply #14 on:** August 30, 2011, 11:53:36 pm »

Lvc? What's that and how would I do that? Am I right in thinkin lipos are lighter than nihm pack? The boat needs a serious diet, when it was working it was just burying it's nose in the water.

MikeA · « **Reply #15 on:** August 31, 2011, 01:12:53 am »

nimh are lighter than lipos. the LVC or low voltage cut off on a NIMH battery needs turning off. its only necessary for lipo batteries. when the motor gets going the voltage drops and the lvc kicks in. making the motor run slowly and sputter.

bikerdude666 · « **Reply #16 on:** August 31, 2011, 05:38:21 am »

Hmm ok sorry for all the questions but... How did you turn the vlc off on your esc? As far as I can see there are no buttons on mine? Can try and post pics if it will help?

barriew · « **Reply #17 on:** August 31, 2011, 06:40:48 am »

Quote from: bikerdude666 on August 31, 2011, 05:38:21 am

Hmm ok sorry for all the questions but... How did you turn the vlc off on your esc? As far as I can see there are no buttons on mine? Can try and post pics if it will help?

Mad Mike - "nimh are lighter than lipos." I would disagree with that statement. It does of course depend on what voltage and capacity, but all my LiPo packs are lighter than the equivalent NiMh.

Biker - the ESC must at least allow you to set the battery type. This is normally done by using a programme card, or by listening to a series of 'beeps' and pressing a set-up button or using the Tx. Setting to NiMh would disable the low voltage cut off, or at least set it appropriate for NiMh.

Barrie

This link is for the instruction sheet for the ESC

http://www.hobbywing.com/upload/manual/SeaKing_080628_e.pdf

MikeA · « **Reply #18 on:** August 31, 2011, 01:37:14 pm »

sorry i put a typo. lipo defintely lighter than nimh for sure. and yes you need to go threw the bleeps to swtich off the low voltage cut off. i have found on my seaking that even if you set it to nimh the low voltage cut off still kicks in. just switch it off entirely then when you get the drop in speed you know to bring your boat home.

bikerdude666 · « **Reply #19 on:** September 01, 2011, 07:24:27 am »

Thanks for the link to the instructions, seems I was missing the page that had all the set up instructions on, only had the 1st sheet. Still considerin lipos but I don't understand all the different wires on them or the need for a balancer?

wibplus · « **Reply #20 on:** September 01, 2011, 08:20:22 am »

Quote from: bikerdude666 on September 01, 2011, 07:24:27 am

Thanks for the link to the instructions, seems I was missing the page that had all the set up instructions on, only had the 1st sheet. Still considerin lipos but I don't understand all the different wires on them or the need for a balancer?

Lipo batteries are a whole different thing. They need a special lipo charger and you should not attempt to charge them with any other charger. If they are mistreated they can cause a violent fire which can destroy the model or worse. If used and treated properly, they are no danger at all but you absolutely must learn about them before using them. Google lipo batteries, or talk to people who use them such as model flyers.
Remember............. dedicated charger, minimum voltage in use, no damages etc,etc
Above all, be careful and stay safe.

barriew · « **Reply #21 on:** September 01, 2011, 08:27:21 am »

Quote from: wibplus on September 01, 2011, 08:20:22 am

Remember............. dedicated charger, minimum voltage in use, no damages etc,etc
Above all, be careful and stay safe.

.... and don't be tempted to charge at more than 1 C rate.
There are two sets of leads on a LiPo - the heavy leads are the output to your ESC etc, the thinner wires are the Balance Lead that connects to the Balance port on your charger. If you buy a Specialised LiPo Balance/charger and follow the above advice, then LiPos are in my opinion entirely safe. Following these rules mine don't even get warm when charging.

Barrie

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Author Topic: Problems with brushless set up. (Read 5331 times)

bikerdude666

bikerdude666

AT Boatyard

bikerdude666

bikerdude666

knoby

bikerdude666

knoby

MikeA

bikerdude666

MikeA

bikerdude666

MikeA

bikerdude666

wibplus