Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1] 2   Go Down

Author Topic: Problem with TT Neptune sub.  (Read 7843 times)

sealion

  • Guest
Problem with TT Neptune sub.
« on: May 23, 2009, 09:21:32 AM »

I posted this in another Forum but no real luck with replies.

I have recently finished building the kit version of the Neptune and have tried out the sub in our local lake.

My problem is that after only about 5 minutes the sub is very slow going forwards and will not dive even with the hydroplanes fully functioning. I have managed to submerge statically a couple of times 3/4 feet and on returning to the surface it refuses to sink anymore.

I lift the sub out of the water and the pump continues to run and water is expelled from the bag until I switch off.

Returning home on both occassions I have checked the battery voltage (at the charge terminals) and each time the voltage was above 12 volts.

I have spoken to Amerang (the UK importers) but the Service guy can offer very little help. He suggested the (new) battery might be faulty or the control board might not be working correctly. Basically he did not know what to suggest.

Can anybody offer any advice please?
Logged

das boot

  • Guest
Re: Problem with TT Neptune sub.
« Reply #1 on: May 23, 2009, 10:32:16 AM »

Person to ask about this is Andy(subculture)...drop him a pm or an email, he'll sort you out.

Rich
Logged

sealion

  • Guest
Re: Problem with TT Neptune sub.
« Reply #2 on: May 23, 2009, 11:56:59 AM »

Thanks. Tried to send Andy a PM but not sure if it went OK.
Logged

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,721
  • Location: South Cumbria
Re: Problem with TT Neptune sub.
« Reply #3 on: May 23, 2009, 12:24:32 PM »

My son bought one of these second hand.

It sounds like you have something pulling a lot of current causing the battery to drain - I know you said the voltage is ok when you get home, but batteries recover some voltage when rested, this recovered voltage soon vanishes again when under load.

Is the drive free to rotate with fingers - ours has almost no resistance.

The electronics have a low voltage failsafe sensor that puts the pump to empty the bag when the voltage drops, this continues to run until the power is switched off, again suggesting power drain from the battery.

If you have a similar battery it would be worth swapping over and trying again - Not a 5 min job I know, but you need to eliminate things one by one.

Alternatively, return to your supplier and tell him its not working as it should and request a refund or replacement.

Let us know how you get on

Ian
Logged
if at first you dont succeed.....have a beer.....

sealion

  • Guest
Re: Problem with TT Neptune sub.
« Reply #4 on: May 23, 2009, 12:34:58 PM »

Will do, thanks.
Logged

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,721
  • Location: South Cumbria
Re: Problem with TT Neptune sub.
« Reply #5 on: May 23, 2009, 02:58:03 PM »

Thinking about this somemore while making a mess in the workshop - ours doesnt go particularly fast, nor dive fully on the hydroplanes only. I think this may be normal, as to get a dynamic dive would need the sub to move quite quickly.

Regarding the dynamic dive, the battery is only a 3a/hr battery, so wont last too long if you dive lots and run it at full speed. We tend to dive to just below the surface - any deeper and we lose sight the water is so mucky!

Make the checks I suggested, but it may just be behaving as expected, unless someone else has better experience.

One other check I recommend is to put it in the bath without the yellow plsastic outer shell, run the pump to fill the bag and make sure the overpressure switch operates to stop the pump.

When we got ours I tested it in my tank and the bag split, filling the watertight tube. I tracked this down to the pressure switch failing. If this had happened in open water the sub would have been lost.

Ian
Logged
if at first you dont succeed.....have a beer.....

Mankster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 770
  • Wheelerdealer
  • Location: London, UK
    • RC Model Submarines
Re: Problem with TT Neptune sub.
« Reply #6 on: May 23, 2009, 03:24:54 PM »

I think Colin had a similar problem with his, so it does not seem to be a one off. It should be pretty easy to diagnose the fault but will require a bit of investigative work. Can you reproduce the problem on the bench? if so hook up an ammeter and see what sort of current your pulling. If all is ok, it may be the battery, try swaping it on the bench and see if you get the same problem. Still giving you grief? Then it could be a faulty low voltage saftey cutting in- try swapping to a 12v NiMh pack (voltage shouldnt drop below 12v under load) and see if that sort out your problem.

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Problem with TT Neptune sub.
« Reply #7 on: May 23, 2009, 05:17:16 PM »

Mike Stothers gave an excellent response to this over on RC Groups where you also posted, and is much better qualified than I one these matters. His answer makes a lot of sense.

http://www.rcgroups.com/forums/showthread.php?s=a1428f5ad0fbc679b9d2ce51c3cbe499&t=1053453

You might want to consider replacing the lead acid battery with some Ni-Mh batteries, which can deliver more current, and also give you more capacity for their size and weight.

Another alternative would be A123 Lithium LiFE batteries. Four of those would give you 13.2 volts, which the Neptune's kit should easily handle, and will give a little bit of voltage in hand if Mike's prognosis is correct.

The electrics in the Neptune seem to be the only fly in the ointment of an otherwise very well engineered kit.

I didn't receive your PM, BTW.

sealion

  • Guest
Re: Problem with TT Neptune sub.
« Reply #8 on: May 23, 2009, 08:04:57 PM »

Gentlemen, thank you all for your help.
Logged

6705russell

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,233
  • Model Boat Mayhem Forum is the Best!
  • Location: Staffordshire
Re: Problem with TT Neptune sub.
« Reply #9 on: May 23, 2009, 09:15:52 PM »

I had the same problem with mine, did some tests and found it to be a faulty circuit board, sent to Amerang and they replaced within a week.

Russ
Logged

microgyros

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 208
  • Location: Glasgow
    • microgyros website
Re: Problem with TT Neptune sub.
« Reply #10 on: May 23, 2009, 09:47:33 PM »

  Reading some internet searches on "TT Neptune" battery and charger would suggest it is worth getting the charger function checked out and using a decent charger meantime.You can't go wrong with a proper lead-acid charger with a two step action with a bulk charge rate of 0.5 amp.
 
 
Logged

getemuphigh

  • Guest
Re: Problem with TT Neptune sub.
« Reply #11 on: August 01, 2009, 01:02:08 PM »

If the battery has low voltage the internal RD LED should be flashing, see page 24 in the manual.
Logged

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: Problem with TT Neptune sub.
« Reply #12 on: August 15, 2009, 09:39:08 AM »

just came across this thread. Mankster is right, got the same problem. have the control board changed by Amerang. no difference. using a decent charger, no improvement. the batteries do seem to be ok, ran it forever on the bench, ok i know that is minimum load, but still ran for several hours, with the occasional pumping carried out.
can i ask, have you ever used the tranny with the arial down?
colin
Logged
grumpy old XXX

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Problem with TT Neptune sub.
« Reply #13 on: August 15, 2009, 11:40:40 AM »

It's been a year nearly since the first shenanigans with your Neptune, so you'll have to forgive me if I'm repeating myself. Did you try swapping out the ESC with a known good one?

The control board is only a straightforward microcontroller based relay switcher. I suspect the voltage checker is based on a potential divider routed through the microcontrollers A/D converter, although this is guesstimation as I haven't seen the control board up close.

As this now your second board, and it's unlikely (but not impossible) for lightning to strike twice I'm starting to lean towards the ESC.

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: Problem with TT Neptune sub.
« Reply #14 on: August 15, 2009, 11:52:15 AM »

i am starting to suspect the the tranny, took her out the other day, ok close in, but the minute it was down a bit, wollpop. all went wrong. put her in the car and ran me e boat. that was fine close in, but the minute it went out about 20 ft, wollop, lost it. common denomitator, the tranny.
hoping to try her later with a different tranny
colin
Logged
grumpy old XXX

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Problem with TT Neptune sub.
« Reply #15 on: August 15, 2009, 12:40:11 PM »

Do a range test in air. Put it down in a field or something and walk away and see when you lose the signal (easier if you have an assistant).

sheerline

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,201
  • Location: Norfolk
Re: Problem with TT Neptune sub.
« Reply #16 on: August 16, 2009, 09:36:28 AM »

Try putting the tx down and walking off with the boat.... don't need an assistant! :-))
Logged

das boot

  • Guest
Re: Problem with TT Neptune sub.
« Reply #17 on: August 16, 2009, 09:47:43 AM »

Try putting the boat down and walking off with the tx...it's lighter!!   %)


Rich


Yea, I know....I'll get me coat.
Logged

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Problem with TT Neptune sub.
« Reply #18 on: August 16, 2009, 10:08:29 AM »

I'd still rather have an assistant, as they can operate the controls as you take the boat or TX away. If you're on your own, all you can do is latch on a function, like the ESC and move away, and hope that the reason the motor keeps spinning is because it's still receiving and not for some other reason.

tigertiger

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,019
  • Location: Kunming, city of eternal springtime, SW China.
Re: Problem with TT Neptune sub.
« Reply #19 on: August 16, 2009, 11:27:58 AM »

Do a range test in air. Put it down in a field or something and walk away and see when you lose the signal (easier if you have an assistant).



Or where I live, put it down in a field or something and walk away and see when you loose your kit. I imagine that most of them (thieves) would think 50m would give them enougbh of a head start. If they left it much longer someone else would beat them to it.

I jest not.
Logged
The only stupid question is the one I didn't ask

sheerline

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,201
  • Location: Norfolk
Re: Problem with TT Neptune sub.
« Reply #20 on: August 16, 2009, 05:41:35 PM »

It's only a Neptune, hardy a back breaker chaps! If the sub is working, all the controls will be static as the sticks aren't being waggled around. Walk away with the sub, as it goes out of range, the rx will struggle to decode the weak signal and the servos will begin to glitch,  the motor may also intermittently cut in and out. This is an indication that you have reached the limit of your useable range. There is no need to waggle the sticks when range testing.
Logged

sheerline

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,201
  • Location: Norfolk
Re: Problem with TT Neptune sub.
« Reply #21 on: August 16, 2009, 05:46:12 PM »

Forgot something, if the thing is fitted with a failsafe, it should set to failsafe when the signal is lost so, plenty going on there as the signal goes out.
Logged

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: Problem with TT Neptune sub.
« Reply #22 on: August 23, 2009, 08:10:41 PM »

really hacked off. chandged the tranny for the one i use in the Layfette. annoyingly there is an improvement. it now dives and runs, for a bit, then packs up. better than before, where a foot or two down she packed up. did a range test. was ok for a bit then i got a bit of twitching, and the motor bliipping.
guess that is implying that the second tranny is also low on range. apperently the "trannsmitting" part can go wrong in degrees, so maybe my second one is not as knackered as the first. guess i will have to bite the bullet and bye a new tranny and receiver.
colin
Logged
grumpy old XXX

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Problem with TT Neptune sub.
« Reply #23 on: August 23, 2009, 09:12:55 PM »

I might have missed this, but you have tried swapping out the receiver with a known goody too, haven't you?

colin-stevens

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 694
  • Location: Southwater
Re: Problem with TT Neptune sub.
« Reply #24 on: August 24, 2009, 02:52:10 PM »

no, i didnt do that. didnt occur to me. but will try it next. getting very aggravating. trying to avoid changing the thunder tiger ESC, ect, as i am not sure what alll the extra pcb boards do.
Logged
grumpy old XXX
Pages: [1] 2   Go Up