Model Boat Mayhem - Forum

Please login or register.

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

Author Topic: Which ESC if any.  (Read 1978 times)

Bluechrisp

  • Guest
Which ESC if any.
« on: November 22, 2009, 12:40:08 PM »

Afternoon all,

Just back from the pond, I have a 30" x 8" grp hull, fitted with a 1200KV brushless, with a Mtronics 40A esc, powering it is a 7.5V 9000 battery, it goes fast for abit then slows right down, then stays at that speed, I have a 35mm x prop fitted. the 32m X prop makes the engine scream. is this the ESC not letting the power through?   {:-{

Should I be looking at anything a lot bigger ie 80amps ESC or any ideas such like 80a plus and go for a Lipo 7.5V!

many thanks

ChrisP
Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Which ESC if any.
« Reply #1 on: November 22, 2009, 01:05:42 PM »

Afternoon all,

Just back from the pond, I have a 30" x 8" grp hull, fitted with a 1200KV brushless, with a Mtronics 40A esc, powering it is a 7.5V 9000 battery
many thanks

ChrisP

9000 battery???   what are you using ? if it is gell thats the problem if it is D type the same goes they cannot discharge fast enough.

peter
Logged

Bluechrisp

  • Guest
Re: Which ESC if any.
« Reply #2 on: November 22, 2009, 01:29:08 PM »

Hi,
It's a 6 D cells 7.5v 9000mah, so should look to a Lipo 7.5?

ChrisP
Logged

john54

  • Guest
Re: Which ESC if any.
« Reply #3 on: November 22, 2009, 01:59:10 PM »

Can you program the E.S.C ? It might be set for Lipo,s if it is running on nicad , d cells ect it will react that way.
Logged

Bluechrisp

  • Guest
Re: Which ESC if any.
« Reply #4 on: November 22, 2009, 02:03:25 PM »

Can you program the E.S.C ? It might be set for Lipo,s if it is running on nicad , d cells ect it will react that way.
It doesn't look like it on the device or paperwork, what would you recommend in the way of a charging system and lipo batts for this 1200KV motor?

Cheers

ChrisP
Logged

john54

  • Guest
Re: Which ESC if any.
« Reply #5 on: November 22, 2009, 02:19:12 PM »

A bit funny that   {:-{ No default setting on spec sheet ! As for chargers ect you get what you pay for  ok2 From 20 - 200 Take a look on E*ay loads on there. Try to get a balance charger a MUST when running Lipos.
Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Which ESC if any.
« Reply #6 on: November 22, 2009, 03:07:42 PM »

D cells will not give up there Charge fast enough and are heavy you need to try some nimh batteries borrow a set first to try to see if it sorts the problem  lipo are ok but unless you need them and feel Happy using them stick to nimh's

Peter
Logged

Bluechrisp

  • Guest
Re: Which ESC if any.
« Reply #7 on: November 22, 2009, 03:49:48 PM »

I've used 7.5v 2700mah and the same appears to have happened as well as a 6v SLA, so it looks to be Lipo, unless I stick the old 600 back in?
The esc is an Mtroniks 40A. the small spines on it I have been told are for the factory to reset them if they go back.

cheers

ChrisP



Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Which ESC if any.
« Reply #8 on: November 22, 2009, 03:55:02 PM »

I've used 7.5v 2700mah and the same appears to have happened as well as a 6v SLA, so it looks to be Lipo, unless I stick the old 600 back in?
The esc is an Mtroniks 40A. the small spines on it I have been told are for the factory to reset them if they go back.

cheers

ChrisP






did you mean 7.2v nimhs ?/ just ring  Mtroniks or email them they are very helpfull and will tell you what is wrong.

Peter
Logged

Bluechrisp

  • Guest
Re: Which ESC if any.
« Reply #9 on: November 23, 2009, 09:50:33 AM »

Hello Peter,

I emailed Mtroniks, they told me that the Hydra 30 will take upto 12v either in SLA or 3S Lipo, I did mention the D cells but they didn't remark on that, so made in the market for a set of lipo's and other bits and bobs.

I'm very new to brushless, so what does 3S in lipo speak mean.

cheers

ChrisP
Logged

john54

  • Guest
Re: Which ESC if any.
« Reply #10 on: November 23, 2009, 12:50:56 PM »

3s = 3cell 11.2 (ish) volts But its the C rateing that matters 20c = x 20 of the amp rateing so a 3000 mah 3s 20c can give out 60amp at a push ok2 Lot of info on the web
about lipos have a look :-))
Logged

andrewh

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,064
  • Location: Melbourne, Australia
Re: Which ESC if any.
« Reply #11 on: November 23, 2009, 01:06:34 PM »

Hi, Chris,

I think your speed profile has been explained - that was the D cells doing all they were capable of with the ESC full out all the time.

We don't know much about yourt brushless (apart from its kv) ; not the prop you are driving: but Lipos are not the ONLY choice.  Is the motor from Mtronics as well?

All Brushless motors and most of their controllers like Volts - usually lots of them.  

Many people have had brushless success with 12V gel cells (but it would be easy to pull more current than they are happy about)
NiMh cells would be ideal.  10 of them is 12V and 2 packs of 6 (in series)  would make  anything sit up and take notice (14.4V)

3S Lipo means 3 in series, so the voltages add up.  Lipos are generally described as being nominally 3.7V per cell, so three in series (3S) would be nominally 11.1V.

Nominally cos the fully charged voltage should  around 12.6V and the pack cut off at 9V (or what the cell vendors suggest)
andrew
Logged
Pages: [1]   Go Up