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Author Topic: Twin Brushless Setup – Help Required  (Read 441 times)

Charlie

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Twin Brushless Setup – Help Required
« on: February 05, 2018, 10:35:11 AM »

I'm looking a bit of guidance on how to set up the motors and ESC.
I have fitted twin LC2826-1050kv motors and a pair of Leopard 30A V3 Controllers which have BEC fitted. I'm using a Planet T5, and will use Ch1 for the Port motor, and Ch3 for the Stbd motor. I’m not entirely sure how the BEC works. Do I need to disconnect any of the wires from the ESC’s?
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Tug-Kenny

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Re: Twin Brushless Setup – Help Required
« Reply #1 on: February 05, 2018, 10:39:02 AM »

Yes, because there will be conflicting voltages.

As they both supply a BEC control voltage you will need to disconnect one of the supply wires.  It's normally the centre wire.

Hope this helps

ken


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Charlie

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Re: Twin Brushless Setup – Help Required
« Reply #2 on: February 05, 2018, 10:45:46 AM »

Thanks Ken, will give that a try when it gets warm enough to venture outside to the shed!
I may well be back with more questions later:)


Charlie
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #3 on: February 05, 2018, 11:50:30 AM »

It's the RED wire you need to slip out of the plastic holder on ONE of the ESC's (dont cut it, you need it to set up the ESC by program card )I take it your using left & right prop's ? The difficulty you may have is getting one motor to run at 100% in reverse, I cant remember if the Leopard ESC's are limited on reverse power . . . a card's essential the beeps set up make no sense . .
Bill
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Charlie

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Re: Twin Brushless Setup – Help Required
« Reply #4 on: February 05, 2018, 12:02:30 PM »


Bill - can you recommend a Card? I'm not sure what to look for. Yes i will be using Left and Right props.
Thanks,
Charlie

It's the RED wire you need to slip out of the plastic holder on ONE of the ESC's (dont cut it, you need it to set up the ESC by program card )I take it your using left & right prop's ? The difficulty you may have is getting one motor to run at 100% in reverse, I cant remember if the Leopard ESC's are limited on reverse power . . . a card's essential the beeps set up make no sense . .
Bill
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #5 on: February 05, 2018, 12:27:44 PM »

you'll need to use the ESC manufacturers card, be around £8 ish , if their Leopard you need a Leopard card ,I got mine from Component Shop (on the internet)
 Hobbyking do cards but they only work on their ESC's, Have a word with Component Shop their pretty clued up . . .( ask THEM if you can get 100% reverse power on the 30 amp Leopard ESC , WE KNOW you just swap the wires round twixt motor & ESC for reverse , the stick on the transmitter gives  the reverse command to the ESC )
Bill
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Tug Fanatic

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Re: Twin Brushless Setup – Help Required
« Reply #6 on: February 05, 2018, 12:34:41 PM »


I am not sure why you are so concerned about 100% reverse power. As far as the controller is concerned both are going forward when the boat is going forward. The reverse rotation of one motor for contra rotating props is simply a case of the wiring between the controller & the motor. The controller does not know or care.


Am I missing something?
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #7 on: February 05, 2018, 02:01:29 PM »

I am not sure why you are so concerned about 100% reverse power. As far as the controller is concerned both are going forward when the boat is going forward. The reverse rotation of one motor for contra rotating props is simply a case of the wiring between the controller & the motor. The controller does not know or care.


Am I missing something?
Yes, the ESC 's I've been using are set at 75% at default , if your running opposite rotation , as you say the ESC doesn't care , the commands from the transmitter will give reverse alright , one motor may be running slower IF the ESC isn't set 100% both ways  :embarrassed:  as I found out on a pusher tug I'm working on at the mo' .
Bill
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Re: Twin Brushless Setup – Help Required
« Reply #8 on: February 05, 2018, 04:14:07 PM »



Yes, the ESC 's I've been using are set at 75% at default , if your running opposite rotation , as you say the ESC doesn't care , the commands from the transmitter will give reverse alright , one motor may be running slower IF the ESC isn't set 100% both ways  :embarrassed:  as I found out on a pusher tug I'm working on at the mo' .
Bill


I am not sure if we are agreeing or not.


Assuming that both controllers are set to give 100% forward then both motors will give 100% forward even if the motors are turning in opposite directions.  The reverse setting will make no difference to forward progress at all.


If you reverse the motor direction by switching the direction on the transmitter then it might matter - I have not tried it to see.
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #9 on: February 06, 2018, 12:52:57 AM »

I'm new to brushless / Lipo's etc so it's been a learning curve for me , so far I've tried Inrunner's / Outrunner's , prefer Outrunners ( not as revy plenty of torque if you pick the right motor ) . . .
Usually used NihM's , but being persuaded into LIPO's . . .
Tried three types of ESC's so far, 2 marine & 1 truck type , they're all set to  LIPO mode default when new , using NiHm's or SLA's you need to change the setting's on the cut off mode to NO PROTECTION to give clean running , and also reverse is set at 50% by default , need to change this to 100% (but not for LIPO's ! ) one of them I couldn't change the reverse power & each ESC needed the dedicated program card , there are folk who can program using the 'beeps' but I'm not one of them  :embarrassed:  the truck card has 12 stations on it , 5 of them I've no clue what they do . . . . it's a case of suck it & see .
Bill
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red181

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Re: Twin Brushless Setup – Help Required
« Reply #10 on: February 06, 2018, 10:25:44 PM »

just wondering why you want the motors on separate channels? is this not just overcomplicating things? or is this a specific requirement for the boat, to have independent operating motors
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Tug Fanatic

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Re: Twin Brushless Setup – Help Required
« Reply #11 on: February 07, 2018, 07:24:22 AM »


just wondering why you want the motors on separate channels? is this not just overcomplicating things? or is this a specific requirement for the boat, to have independent operating motors


Why not? I cannot think of any disadvantage & for models like tugs they are a very good idea.
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McGherkin

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Re: Twin Brushless Setup – Help Required
« Reply #12 on: February 07, 2018, 08:48:15 AM »

just wondering why you want the motors on separate channels? is this not just overcomplicating things? or is this a specific requirement for the boat, to have independent operating motors


This is the way real boats are driven at low speeds.
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #13 on: February 07, 2018, 09:34:47 AM »

just wondering why you want the motors on separate channels? is this not just overcomplicating things? or is this a specific requirement for the boat, to have independent operating motors
Hey Paul , if it's a tug you need 'Tank' for maneuvering , you've got to be authentic  :P  twin drive / one ESC is OK for the gin sipper's on pleasure cruisers  {-)  brushless tend to hammer ESC's with a twin drive . . .
Bill


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Charlie

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Re: Twin Brushless Setup – Help Required
« Reply #14 on: February 10, 2018, 04:28:18 PM »


Thanks for all the replies and advice, much appreciated. I ordered the Program Card from Component Shop, and it arrived within 36 hours! Great service as always. And blow me down, it's a piece of cake to use, so both my Controllers are working fine. Only took me a few minutes to complete the setup. I must admit I was not sure what to set items 3 & 4 at.
Item 3 is low voltage Cutoff Threshold; 1) No protection 2) 2.8V/Cell 3) 3.0V/Cell 4) 3.2V/Cell and 5) 3.4V/Cell - Is there a recommended setting for this?
Item 4 is Timing - what does this mean? There are 5 options between 0.00 and 22.50


And to answer Red181, I have always set my models up like this as I find it easiest to manoeuvre. And there really isn't any added complication.


Charlie
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imsinking

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Re: Twin Brushless Setup – Help Required
« Reply #15 on: February 10, 2018, 06:03:27 PM »

Item 3 , voltage cut off threshold = the type of battery your using , so a lipo must not drop below 3.0 volt's a cell & you would set this at value 3 or 4 ,  NiHm's batteries / SLA's need no protection value 1 these batteries dont feed the power flow like a LIPO so will cut out or have erratic running  as the ESC get's confused , you really need a cell meter/ alarm if your using LIPO's as some ESC's are not to clever at turning  power levels down when near the cell limit , the boat wont stop dead in the water just feeds enough power to get to safety.
Item 4 , Timing , I haven't a clue , I've been looking on LIPO hardened forums , haven't seen anything as yet , must do something . . .
Bill
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JimG

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Re: Twin Brushless Setup – Help Required
« Reply #16 on: February 10, 2018, 07:11:18 PM »

For safety with LiPos stick to 3.4V per cell minimum, 3.2V per cell is getting too near the absolute minimum and 3V per cell will leave the cell near dead.

Item 4.
The timing is for the motor and can be thought of as being like The advance/retard settings on an ic engine. With brushed motors timing was set by rotating the end cap and changing the position of the brushes on the commutator. It meant that the motor would give more power in one direction. For scale you will be wanting the same power in reverse as in forward so leave the timing at 0.

Jim
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red181

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Re: Twin Brushless Setup – Help Required
« Reply #17 on: February 10, 2018, 11:07:32 PM »


thanks for the info, I was just wondering, I have a couple of brushless twin screw and just have them on one throttle channel, they don't need to manoeuvre that precise.
lipos, minimum voltage as Jim says, 3.4v, 3v is on the threshold of no return, and the timing is for the speed controllers. If operating slow, the motors are "jerky" or not smooth, up the timing in incremental stages.


I found certain speed controllers don't like to operate slow, or might induce a screeching sound from the motor, changing the timing can help, if plug and play default works ok, then just leave it. I think the poles on the motor also comes into play, and the motor spec sheets can sometimes suggest the esc timing.


My 4 foot twinm screw fireboat, I had a terrible time trying to sort this, the hobby king esc's kept cuttting out, turns out the low voltage shutdown was kicking in way too early, as I accelerated, the current and amp draw obviously spikes, and the esc's kept thinking time to shut off, I turned this feature off and all was well. I use cheap lipo low voltage alarms on all my lipo cells, they plug into the balance lead, set at 3.6v per cell, so if they bleep, I have time to get back to shore


Paul
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