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Jan 16, 2020, 02:40 AM
Slideways at warp speed.......
kiwi_craig's Avatar
BB did find some 2s 6mm motors
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Jan 16, 2020, 02:42 AM
Slideways at warp speed.......
kiwi_craig's Avatar
And yeah 120/130 tail motor for the main
Jan 16, 2020, 02:58 AM
Registered User
main and tail motors could be different in kv. This is important because torque vs kv relationship.
Lower kv means higher torque and vice versa.
Jan 16, 2020, 03:31 AM
Slideways at warp speed.......
kiwi_craig's Avatar
Yes I be been doing those sort of calcs for a long time now with all my various conversions. It was just supposed to be a bit of fun on the side using bits lying around. K110 brushless is around 11,500kv so 46,000 rpm at 4v. K100 doesn't pull the same headspeed as the 110 that's for sure.............. typical 8.5-20 2s brushed motors are also around 46,000 rpm no load so they are in the right ball park for rpm speed with 8 or 9t pinion for sure. that was the rough start point, this should work idea . simply a nice light K100 with extra pop
Last edited by kiwi_craig; Jan 16, 2020 at 04:16 AM.
Jan 16, 2020, 02:44 PM
Hummingbird Assassin
BirdBarber's Avatar
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The plan was a 6mm 2S tail motor (which I finally found) with 0R resistor removed from the main board. Probably use a 2S K130 tail motor for the K100 main motor. I was planing on using that $1 BEC we used on the 2S K110 for the 5V for the receiver but I'm not sure ptern thinks that's necessary anymore if you are running a 2S brushed tail.

So I guess if ptern thinks I can run the main board on 2S then I wouldn't need to remove the 0R resistor. Just hook up the 2S to the B+ and B- pads and leave the throttle/ESC socket empty. If I do use the BEC then I would remove the 0R resistor, wire 2S to the B+ B- and route the 5V to the throttle socket.
Last edited by BirdBarber; Jan 16, 2020 at 03:15 PM.
Jan 16, 2020, 03:23 PM
Slideways at warp speed.......
kiwi_craig's Avatar
we have to keep the brushed motor circuits / mosfets which have a common power supply ?? or can we do the main on 2s and the tail on 1 s ??

so we do need to figure a 5V feed to the board so I think we still need the $1 bec, or just pull 1s from the battery but that unbalances the cells ?

this circuit stuff is not my happy tinkering space..................
Jan 16, 2020, 03:47 PM
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BirdBarber's Avatar
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My assumption (right or wrong) is that the 1S tail motor wouldn't hold with a 2S main motor, and a 2S tail motor would be necessary. So it's just a matter if the main board has to run at 5V thru a BEC or if it can run on 2S without smoking. I think pterm may have a direct drive 2S K130 with K110 main board also running on 2S, but I'm not positive.

As far as if we could feed the two mosfets different voltages, my guess is maybe if we cut a trace and added a jumper, but I'm not sure and I'm out of town so I can't look at the board.
Last edited by BirdBarber; Jan 16, 2020 at 04:07 PM.
Jan 16, 2020, 08:20 PM
Registered User
I used to run my stock k130 on 2s without 5V BEC but very important point is: I use the HV (8.4v) version of the servos so no 5V BEC is ok.

The K110 receiver board was working OK, no drama. But on the K100 without a BEC, it will burn the k100 servos.

On another though, since the servo + gyro board consuming tiny amount of current, you can run them straight off the 1S volt. It would be a little complicated (if you run the tail on 2s).
Jan 16, 2020, 10:22 PM
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BirdBarber's Avatar
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@ptern

Good point on needing hv servos, we don't want to have to use them.

If I remove the 0R resistor then I thought that only the mosfets were hooked up to the B+ and B- pads, and the receiver and servos run off the throttle port power lines. Then if I run 2S to B+ B- and run either a BEC or only the first cell of the 2S battery to the throttle port then the receiver and servos would be at 1S/5V and isolated from the mosfets. Am I wrong? With the 0R removed are the servos powered by the B+ B- pads or the throttle port power?
Jan 17, 2020, 01:07 AM
Registered User
Quote:
Originally Posted by BirdBarber
@ptern Am I wrong? With the 0R removed are the servos powered by the B+ B- pads or the throttle port power?
If we are talking about the K110 gyro (not sure about the K100 gyro cause I have none) then for 1s system:

1. The B- is connected to 0V so this is normal.

2. The B+ would be directly connected to the following :

- to the gyro power section via the 5V boost (in this case up to 4.2v) and in turn, powering the 3.3 linear reg
- via the 0R resistor to power the servos.
- to both of the main and tail the motors FETs

So to use it as 2s system (assuming both tail & and main run on 2s) then
- remove the 0R resistor ( this removes the B+ off the servos)
- the B+ & B- are connected to the red and black wires of the 2s batt.
- run the 1s V+ to the red wire of the servo plugs (middle pin) to provide the V+ (aka VBEC) supply.

this should be working , however, for the 2s battery, the lower cell will be a bit stressed out more than the top cell.
Jan 17, 2020, 01:16 AM
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BirdBarber's Avatar
Thread OP
Thanks for the info.

The K100 board is identical to the K110 board except it has a battery connector on the B+ B- pads, the PIDs are tuned slightly differently and of course the brushed main motor is hooked up to the mosfet / connector right beside the tail motor mosfet / connector instead of using the throttle connector & ESC.
Jan 17, 2020, 01:40 AM
Registered User
Here is a revised info I've posted previously.
Jan 17, 2020, 07:35 PM
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BirdBarber's Avatar
Thread OP
On another topic... what to do with your old V977s you don't fly anymore.

I'm thinking about taking the main board off one of my K100s and putting it on a lonely V977 along with a K110 tail motor to make it a K110. The PID tuning is a little different but I think but I think it should fly fine. Then put the V977 board on the K100 because you really don't need throttle curves on idle up on a K100, you need 100% throttle all the time, which is what the V977 board does. The only down side is the old V977 motors aren't the strongest, especially if they are the chrome ones, but one of mine is a black one and one is an eXtreme Spin motor.

Anybody see any problems with doing this?
Jan 17, 2020, 08:14 PM
Slideways at warp speed.......
kiwi_craig's Avatar
remember Ivan - he was convinced the PIDs where more aggressive on the K100 vs the K110, so they where still agie with the lower powered main and even changed his boards as he was of the firm opinion they where better indoor fliers with the K100 boards................ so adding the K100 board to the K110 made for a more aggressive flier !!

was an easy choice for me, my V977 board expired so a K series board went on in it's place................. I used a K123 board as I got some dirt cheap, they have slower AIi and ele settings but a better tail IMO vs the K110.
Jan 18, 2020, 01:50 AM
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BirdBarber's Avatar
Thread OP
So I guess we should call them the K110, the K110 3D (K100 controlled) and the K110 Sport (K123 controlled) .


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