Model Boat Mayhem

Please login or register.

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

Author Topic: Mtronics ViperECO27 how much juice can she take?  (Read 10321 times)

flybobby

  • Guest
Mtronics ViperECO27 how much juice can she take?
« on: July 12, 2006, 03:51:56 pm »

I am looking to use the above mentioned ESC with 12v supply (2x 6v gel cells).
The guy in the shop said that it would be fine, but on reading the spec sheet, it gives 4.8-9.6v input.
This is the first time I have used ESC and am a trifle wet behind the ears on the subject; can this unit be used with a 12v supply? ???
Logged

A Model World

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
  • Model Boat Mayhem does what it says on the tin
    • A Model World
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #1 on: July 12, 2006, 05:23:19 pm »

Hi Fly hobby

the speed controller you have bought is a car one and yes the voltage on the sheet is maximum 9.6V you will fry it at 12 volt? ?there is no reason it wont work in a boat but maximum 9.6 v? the 27 bit stands for the number of turns on a car motor and as such there is no correlating graph with boats as they generally have motors that are anp rated. If you told the shop it was for 12volts then take it back you need an mtroniks Viper 15 at the very least,? this will run 4.8 to 12 volts the 15 in this case stands for amps which I cannot answer with the info given as to whether 15 will be enough amps

The eco 27 is now old stock incidentally as it is all viper nowadays trust this helps it wont be branded viper and eco or it shouldnt be??
Logged
Daily flogging?of the ships crew will continue until morale improves

flybobby

  • Guest
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #2 on: July 12, 2006, 05:49:20 pm »

Thanks for that, the shop has mis-sold me that then, will be taking it back. :o
Logged

barriew

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,111
  • Location: Thaxted, Essex
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #3 on: July 12, 2006, 06:11:56 pm »

Make sure you get a Marine model - car ones don't always have reverse!

Barrie
Logged

Peterm

  • Inactive
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 414
  • Location: Southam,Warwickshire
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #4 on: July 12, 2006, 06:23:41 pm »

Get the Viper 15,  Pete M
Logged
I`m not just old, I`m ancient

flybobby

  • Guest
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #5 on: July 12, 2006, 07:18:40 pm »

Just read the spec on the viper 15, what does it mean by capable of 4500mAh cells?  If  i were planning on 2x 6v 4ah gels in series for 12v, would this exceed the vipers limits?
May seem like a dumb question, but I want to make sure I have everything right to avoid expensive mistakes!!

Thanks all  ;)
Logged

PIT

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 32
  • Model Bioat Mayhem Forum is theBest!
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #6 on: July 12, 2006, 09:46:27 pm »

Make sure you get a viper that is new stock and has a rapid astern ramp up speed. I have a shed load of the early vipers, and the astern apears very slow as the ramp up speed is restricted, or that is what the helpful man at Mtonics told me!? A slow astern respons speed can certainly put a dent in ones pride! :-\? ? ?PIT
Logged

Doc

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 327
  • Location: Oklahoma USA
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #7 on: July 13, 2006, 07:20:28 am »

flybobby,
"Capable of _ _ _ _ mAh"?  No idea why that would be included since a battery's capacity wouldn't mean anything as far as the ESC is conserned.  The amount of current draw, yes.  How much current is in the battery, no.  Sort of like telling you a fuel pump's rating in fuel tank size.  Meaningless.
 - 'Doc
Logged

flybobby

  • Guest
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #8 on: July 13, 2006, 08:59:57 am »

flybobby,
"Capable of _ _ _ _ mAh"?? No idea why that would be included since a battery's capacity wouldn't mean anything as far as the ESC is conserned.? The amount of current draw, yes.? How much current is in the battery, no.? Sort of like telling you a fuel pump's rating in fuel tank size.? Meaningless.
 - 'Doc

Thanks Doc, put my mond at rest  :)
Logged

wombat

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 625
  • The view from the shallow end of the gene pool
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #9 on: July 13, 2006, 09:57:22 am »

Not sure that it is meaningless myself........

Nothing to do with the capacity of the battery driving it. I have thought about this a bit after getting my three brand spanking noo Vipers.

It is, I think, a guide to the average draw that you can pull from the thing without overheating it. Effectively if you are drawing more power from it, you can only run it for a shorter time before letting it cool down, or before it goes into thermal shut down. 4500mAH gives a 100% rating - it will happily pull 4.5A continuously. If you want to pull 9A, you have to do it with a 50% duty cycle (e.g. 5mins on 5mins off). If you want to pull 15A you have to do it with a 30% duty cycle (e.g. 3mins on 7 mins off).  I guess you could up the AH rating by forced cooling the module - say water pipes in the fins at the bottom of the module, or a more efficient heatsink.


I think it is done this way rather than a power rating because the power rating in any specific configuration is indeterminate once you start to factor in varying battery voltages and motor back-EMFs. The power dissipated in the controller depends on the FET on resistance and the current  (I^2*R), so to specify the power as an AH rating gives a more meaningful and usable measure.

Tim (the Wombat)
Logged
The prat in the hat - www.floatingwombat.me.uk - Have look & say Hi

A Model World

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
  • Model Boat Mayhem does what it says on the tin
    • A Model World
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #10 on: July 14, 2006, 06:56:54 am »

The amperage of the unit is 15 amps for the viper 15? ?they do have a slight overrun on that but that?s not to say you can run 17amps through it, 15 is the lot they do produce a 20 and a 25 for that purpose

The batteries and speed controllers referral to 4500 mah is really nothing to do with the rating of the speed controller on the amps side as above 15 20 25 and so on.

This relates mainly to the battery capacity mah stands for milli amps per hour so if you had a stick pack rated at 3300 and 12 volts its absolutely fine likewise you can have a lead acid (or better still 2 X 6v gives better boat balance) rated at 4.5 this = 4500 mah, its usually quoted on lead acids as the shorter figure as they go so high?we are only moving the decimal point ?but using two 4.5 (4500) mah at 6 volt run together to make 12 volts will still only have a 4500 mah and again this is fine but to be honest with that weight of about 2Kg in the boat it is likely to be a larger boat and I would advocate going for an electronize then.? ?

Without making this post extremely complicated the potential chance of blowing the esc at say 7.2 mah does exist but first of all you would be better with an electronize here as its going to be a bigger boat but if you used a viper you would still be OK if you were just light running, it is whem you are flat out and/or full duration of the run of the battery when you would cause harm to the ESC

Trust this helps also we have had a couple of PM?s on this but for others wiring 2 X 6 v to 12 easiest way to remember is join one batteries + terminal to the other batteries ? terminal, this leave a negative terminal on one battery and a positive on the other battery which is now the 12volt + and -
Logged
Daily flogging?of the ships crew will continue until morale improves

flybobby

  • Guest
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #11 on: July 14, 2006, 09:16:44 am »



The batteries and speed controllers referral to 4500 mah is really nothing to do with the rating of the speed controller on the amps side as above 15 20 25 and so on.
This relates mainly to the battery capacity mah stands for milli amps per hour so if you had a stick pack rated at 3300 and 12 volts its absolutely fine likewise you can have a lead acid (or better still 2 X 6v gives better boat balance) rated at 4.5 this = 4500 mah, its usually quoted on lead acids as the shorter figure as they go so high? ?but using two 4.5 (4500) mah at 6 volt run together to make 12 volts will still only have a 4500 mah and again this is fine but to be honest with that weight of about 2Kg in the boat it is likely to be a larger boat
Thanks for that useful info, you answered another question I were pondering, that is if I were using 2x 6v in series, would the capacity be doubled too.

Thanks again ;)
Logged

dougal99

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,326
  • Huntingdon, Cambs, England
  • Location: Huntingdon, England
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #12 on: July 14, 2006, 12:17:14 pm »

Running batteries in Series increases the voltage but not the capacity (amps). Running in parallel increases the capacity but not the voltage.

HTH

Doug
Logged
Don't Assume Check

rats

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 179
  • Location: Cornwall
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #13 on: July 14, 2006, 01:05:49 pm »

 I need a couple of speed controllers for tug I am building - I always intended to get Vipers ( mainly because they are guarranteed waterproof) but could anyone tell me what the advantages of Electronize controllers are?
Logged

flybobby

  • Guest
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #14 on: July 14, 2006, 02:39:28 pm »

Running batteries in Series increases the voltage but not the capacity (amps). Running in parallel increases the capacity but not the voltage.

HTH

Doug
Top info, thankyou ;)
Logged

A Model World

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
  • Model Boat Mayhem does what it says on the tin
    • A Model World
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #15 on: July 14, 2006, 03:46:02 pm »

Hi Rats

The Mt'S are good and yes they are fully waterproof but generally in the larger tugs you will be on 12 volts and drawing a decent amperage at times now whilst the MT's are OK for this the electronize have a couple of benefits here (yes they are not waterproof but your hull should reasonable be) they will run at higher voltage up to 24, some 12volts batts with an ammeters will register 12.7  12.8 volts MTs will be Ok with this but its safer with an electronize added to which many of them now have variable speed so you can turn them down somewhat, yes the same can be achieved with the throttle, they are also now coming in with auto set neutral so if you are on a ratchet control you can set neutral at ? eg  ? forward ? reverse and the last benefit they are repairable bust an MT and that?s your lot but they are both good escs it generally depends on size of tug the bigger lean more towards Electronie
Logged
Daily flogging?of the ships crew will continue until morale improves

rats

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 179
  • Location: Cornwall
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #16 on: July 14, 2006, 04:09:42 pm »

 Thanks Model World will check out Electronize !
Logged

Doc

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 327
  • Location: Oklahoma USA
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #17 on: July 15, 2006, 12:03:38 am »

If the longer run times of larger capacity batteries is a problem the first step is in providing a little cooling.  If the ESC isn't too small, and you really aren't pushing it too hard, air cooling would probably do fine (vents front and rear mean air flow.  Enough?  Beats me, but shouldn't hurt anyway.).  Next step is forced air cooling, fan.  Then water cooling.  Then a refrigerated system (that I wanna see!).  I know it isn't the 'correct' way of thinking about it but, I figure if an ESC is getting too hot it just isn't big enough (large enough current capacity) or the heat sink is too small.  And I have a phobia about circulating water inside a boat (knowing how I do things, that ain't a phobia, it's smart!).  Oh well, 'nuff of all that...
 - 'Doc
Logged

Mankster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 768
  • Wheelerdealer
  • Location: London, UK
    • RC Model Submarines
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #18 on: July 15, 2006, 12:30:47 am »

Ok I am really confused. I was planning on getting a Mtroniks Viper 25 working off a 6v 12AH gell cell (lots of run time and I will have other working features running off the same battery). The boat manufacture says I need a 15amp ESc  so I thought I'd play safe with the 25 Amp version. Does this mean that the Mtroniks is not going to be suitable??? Still not sure how a high capacity battery will damage a ESC when its drawing the same number of amps as when its connected to a lower capacity battery.

Ghost in the shell

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,704
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #19 on: July 15, 2006, 01:07:22 am »

Thanks for that, the shop has mis-sold me that then, will be taking it back. :o

for 12v, you may be best with electronize, or if they are too heavy, the MPI Tornado 50esc.  I have one for a robbe najade :)
Logged
Go Nuclear!  you'll love it

A Model World

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
  • Model Boat Mayhem does what it says on the tin
    • A Model World
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #20 on: July 15, 2006, 07:53:50 am »

Hi Mankster
12ah is to much for an MT esc to handle I will try and explain but its not the easiest Think of electricity like water. Volts = pressure
Amps = flow
Volts is like pounds per square inch, psi. Says nothing about how much water is flowing, just how hard it is being pushed. You can have 100 psi with zero water flow. Say the tap is switched of.
Amps is flow, like gallons per hour. You can have flow at low pressure and you can have flow at high pressure.  Now there is one last bit
Amp hours are how much flow can be sustained for how long. It is used as a way of measuring how much electricity is in the battery. Like how many gallons of water in a tank. It is a capacity number. Says nothing about flow or pressure, it is about capacity. Imagine if you were to release all the water from a tank down a light plastic hose that would handle a reasonable flow but you then turn the tap on higher it may split the hose just like it will blow the esc as there is too much capacity flowing over it
The amps is the need to buy a hose that will handle the water the amp hors means it will handle it at a constant
As regards the 7.2ah above we have used as an experiment for something else but we knew we were likely to blow it as the battery was delivering more amp hours than the esc could handle and I would not advise it, hence the suggestion to go for an Electronize which can handle 12ah (of Flow rate) and upwards easily. Hope this explanation helps and doesn?t confuse anymore I suppose another thing to say is there are 3 variables amps, volts and amp hours

If anyone is still confused I will get M V to come on and explain he is off today but may have a better way of explaining
 
 
Logged
Daily flogging?of the ships crew will continue until morale improves

Doc

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 327
  • Location: Oklahoma USA
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #21 on: July 15, 2006, 03:47:57 pm »

The water comparison example above works fine until you get to the part about opening the tap further and bursting the pipe.  The water pressure is already applied to the pipe whether the tap is open or not.  (So voltage is already applied to the escape no matter what hte current draw is.)  The limiting factor in the water example is the capacity of the pipe to flow water (friction, or resistance for votage).  Measure water pressure against the top edge of a swimming pool, it'll be the same as against the bottom of the pool. (Equal pressure in all directions in a body of fluids, if the fluids are not in motion.)  So, the capacity of a battery shouldn't make any difference to the ESC as long as the current drawn, and the applied voltage are within it's ratings.  Cooling an ESC shouldn't be a 'biggy' as long as you don't try to 'push' the thing further than it can be.  How far is that?  Depends on what the designer used as a margin of error ("fudge factor" = technical term).  The published rating is/should always be lower than the absolute maximum, just good sense, which assumes the manufacturor has good sense...
 - 'Doc

PS - Oops!  After reading the above, the 'pressure already applied to the pipe' does depend on where the tap is, the top or the bottom of the pipe.  I assumed the tap was at the bottom end.  The electrical part still holds true though.

Logged

Mankster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 768
  • Wheelerdealer
  • Location: London, UK
    • RC Model Submarines
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #22 on: July 15, 2006, 06:20:01 pm »

Hi Mankster
12ah is to much for an MT esc to handle I will try and explain but its not the easiest Think of electricity like water. Volts = pressure
Amps = flow
Volts is like pounds per square inch, psi. Says nothing about how much water is flowing, just how hard it is being pushed. You can have 100 psi with zero water flow. Say the tap is switched of.
Amps is flow, like gallons per hour. You can have flow at low pressure and you can have flow at high pressure.? Now there is one last bit
Amp hours are how much flow can be sustained for how long. It is used as a way of measuring how much electricity is in the battery. Like how many gallons of water in a tank. It is a capacity number. Says nothing about flow or pressure, it is about capacity. Imagine if you were to release all the water from a tank down a light plastic hose that would handle a reasonable flow but you then turn the tap on higher it may split the hose just like it will blow the esc as there is too much capacity flowing over it
The amps is the need to buy a hose that will handle the water the amp hors means it will handle it at a constant
As regards the 7.2ah above we have used as an experiment for something else but we knew we were likely to blow it as the battery was delivering more amp hours than the esc could handle and I would not advise it, hence the suggestion to go for an Electronize which can handle 12ah (of Flow rate) and upwards easily. Hope this explanation helps and doesn?t confuse anymore I suppose another thing to say is there are 3 variables amps, volts and amp hours

If anyone is still confused I will get M V to come on and explain he is off today but may have a better way of explaining
?
 


May be I not reading this right but now I am even more confused!
The way I understand it,? AH is a measure of the capacity of the battery (I know that larger capacity batteries have the ability to supply larger maximum currents) So a 6v 12AH battery can theoreticaly supply a constant 12 Amps for 1 hour before discharging completely. If the Current draw is 24 amps, the battery will discahrge in 30min. Similarly if the current draw is only 6amps then the battery will supply that current for 2 hours. I think this bit is well understood by every one.
So say I have a 6v motor that I connect directly to this battery and I measure the current with an ammeter and find it draws a constant 12 Amp, so theoretically anyway it should run for 1 hour. No lets say I connect the a Mtroniks Marine viper 25 between the the battery and motor. and run the mator at full pelt. It is still drawing 12 amps and should still run for 1 hour on a fresh battery. So are you saying this speed controller will blow (dispite being rated at 25amps) if I do this? All the other speed controler I come acreoss make no mention of the maximum battery capacity anywhere in the specifications. Is this a particular to the Viper range? I dont remember the the old Mtroniks ESC's making any such claim.
Surley the current draw on a battery for any one given motor will be the same regardless of the capicty of the battery. And the only 2 variables in an electical circuit is Voltage and current (amps) so why do Mtronik mention battery capacity when no other ESC manufacturer I can find does the same?? ???

Tug

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 163
  • Location: France [86]
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #23 on: July 15, 2006, 06:40:26 pm »

Easy,
go for the electronize 30 Amp job, if it blows electronize will repair it for a tenner return post paid (UK) did mine.

Biggist tug of mine 44" ish is running a big 30 volt motor [bought surplus one day] at 24 volts and it goes a damn sight faster than it oughter. 

cheaper than binning one and buying a bigger one next time. Tug 
Logged
Junk is something you've kept for years and throw away three
 weeks before you need it.

Fast Electricals

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 95
  • Location: Orpington, Kent
Re: Mtronics ViperECO27 how much juice can she take?
« Reply #24 on: July 17, 2006, 11:46:36 am »

The only reason an ESC may blow due to a battery being of too high capacity would be due to it heating up during extended use.  I think that if you are geneous with your current rating, you should not have any problems.

Neil
Pages: [1] 2   Go Up
 

Page created in 0.09 seconds with 21 queries.