Your Thoughts On This Wiring Diagram

AzViper · Nov 6, 2014

I am in the process of getting my parts list together. The wiring diagram below is from a member of these forums. I have removed items and added what I believe will work. The power distribution board is for the ESC’s and the power to the NAZA. The second adjustable voltage PDB will be just above the PDB to step down the 6s battery to 12v and 5v for the TX and 3 axis gimbal.

I had planned to use KDE 4014XF-380 motors and KDE ESC’s but the expense has reversed my thinking. I am now going to use Tiger Navigation Series MN4012 400KV motors with SimonK 30A ESC’s using a 6s 10,000mah battery.

Please give me your thoughts whether positive or negative. I am new to quads and your input will help direct me in the right direction.

SJBrit · Nov 6, 2014

Well you know I approve ;-)

AzViper · Nov 6, 2014

LOL... thanks... Does it looked right and is there anything else I need? Maybe a arm and disarm manual switch, etc.

JoeBob · Nov 6, 2014

AzViper said:
Maybe a arm and disarm manual switch, etc.

I have always wondered why a power on/off switch is not used.

1- You wouldn't have to wrassle with heavy battery connectors in a hurry.
2- Using a switch would eliminate sparking at connections.

Is there a reason besides weight?

AzViper · Nov 6, 2014

JoeBob said:
I have always wondered why a power on/off switch is not used.

1- You wouldn't have to wrassle with heavy battery connectors in a hurry.
2- Using a switch would eliminate sparking at connections.

Is there a reason besides weight?

Makes total sense to me. I have found small 30A 24 volt DC switches.

SJBrit · Nov 6, 2014

You'll get a pretty hefty spark from a switch. I would go for the AS150/XT150 bullet connectors instead - great connection, easy to disconnect and zero spark.

Mojave · Nov 7, 2014

SJBrit said:
You'll get a pretty hefty spark from a switch. I would go for the AS150/XT150 bullet connectors instead - great connection, easy to disconnect and zero spark.

I saw this come out in an email earlier this week. Does anyone use switches for their multirotor? If so I am not aware of it. Does anyone think that these still cause a spark when the electric contacts are thrown? Here is the text from the advertisement (the link is at the bottom):

Jeti Main 5-52V/100A & 200A Electronic Main Power Switches with Telemetry and Wireless R3/RSW or Magnetic Switch!!! (Due Next Week)

Main Switch is an electronic switch designed primarily for switching of main power supply of the RC model. It adds an element of safety when handling the model, without the need to physically disconnect the model's batteries. A big advantage of electronic switches in comparison to mechanical switches is in general their higher reliability as far as vibration resistance is concerned. Another advantage of the electronic switch is its ability to withstand an unlimited number of switching cycles. Electronic switches have no moving parts like contacts which would be worn out during switching processes, their longevity is extremely high.

The Main Switch is primarily designed for switching the main battery power supply of the RC models, but can also be used in applications where switching a DC power supply.

JETIMSW100Ma Jeti Power Main Switch 100A w/Magnetic Switch $190.00
JETIMSW100R3 Jeti Power Main Switch 100A w/R3 Wireless Switch $210.00
JETIMSW200Ma Jeti Power Main Switch 200A w/Magnetic Switch $230.00
JETIMSW200R3 Jeti Power Main Switch 200A w/R3 Wireless Switch $290.00

http://file.espritmodel.com/newslet..._medium=email&utm_campaign=newsletter-2014111 [bottom of page]

SJBrit · Nov 7, 2014

A relay can fail open - a very bad idea when flying! Honestly, I think you are searching for a solution to a problem that just doesn't exist. Get a decent pair of bullet connectors and you are all set. Why add the cost, weight and potential failure point of a relay?

SJBrit · Nov 7, 2014

I am actually very unlikely to die if the ignition relay in my car fails, but 100% of multirotors that lose power in flight die. You seem to have made your mind up, so go for it and let us know how it works out. However, in the spirit of your request for advice and affirmation I will ask again: exactly what problem do you think you are trying to solve by jumping through this hoop? What exactly do you find lacking in a quality bullet connector?

AzViper · Nov 7, 2014

SJBrit said:
I am actually very unlikely to die if the ignition relay in my car fails, but 100% of multirotors that lose power in flight die. You seem to have made your mind up, so go for it and let us know how it works out. However, in the spirit of your request for advice and affirmation I will ask again: exactly what problem do you think you are trying to solve by jumping through this hoop? What exactly do you find lacking in a quality bullet connector?

As a Electrical Engineer I have grown to place trust in relays, contactors, etc. As for not using the bullet connectors I like the simplicity of flipping a switch to power everything up. I use solid state relays in many lighting systems where DC voltage is run long distances to control A/C lighting. In thirty plus years I have seen one relay failure and that was the result of surge of power destroying the control circuit. Sure contacts wear out but so will the plugging and unplugging of bullet connectors. We are surrounded by the use of relays in every aspect of our lives. Intersections of every traffic light is controlled by relays. I could bring on boredom to type where relays are a critical part in our daily lives.

SJBrit · Nov 7, 2014

Very true, but a multirotor is a high vibration environment. I'm sure a relay would be fine, but you must remember that you will still have a mechanical connection for your battery so you can take it off to recharge it. So, you are adding a redundant connection for the sake of a switch which may or may not be mildly easier to actuate than pushing a bullet connector together. Your call.

AzViper · Nov 7, 2014

SJBrit said:
Very true, but a multirotor is a high vibration environment. I'm sure a relay would be fine, but you must remember that you will still have a mechanical connection for your battery so you can take it off to recharge it. So, you are adding a redundant connection for the sake of a switch which may or may not be mildly easier to actuate than pushing a bullet connector together. Your call.

Very true in regards to vibration, but ever solder joint in every connection within every component is subject to the vibration. Solder will break loose from traces as I have seen that a number of times.

SJBrit · Nov 7, 2014

AzViper said:
Very true in regards to vibration, but ever solder joint in every connection within every component is subject to the vibration. Solder will break loose from traces as I have seen that a number of times.

Perhaps a good reason to minimize the number of solder joints? One way to do that is to omit redundant components - like relays. I'm actually really interested to see how that works out for you, but I'm afraid I've spent too much time trying to make missiles fly to ignore the KISS principle lightly.

AzViper · Nov 7, 2014

SJBrit said:
Perhaps a good reason to minimize the number of solder joints? One way to do that is to omit redundant components - like relays. I'm actually really interested to see how that works out for you, but I'm afraid I've spent too much time trying to make missiles fly to ignore the KISS principle lightly.

Engineers have a tendency to over engineer. Now in regards to the KISS principle there are a number of them, "Keep It Simple, Stupid", "Keep Short and Simple", "Keep It Simple and Straighforward", "Keep It Stupid Simple". I like to throw it out there to see how others react. Whether I do or do not use a very simple circuit is my call. Until I have components in hand and the build process begins I may adhere to the KISS.

SJBrit · Nov 8, 2014

Seriously - go for it: I'm very interested to know how it works. I went through the same thought process on my build before finally abandoning the idea.

Gary Seven · Nov 8, 2014

AzViper said:
 I am in the process of getting my parts list together. The wiring diagram below is from a member of these forums. I have removed items and added what I believe will work. The power distribution board is for the ESC’s and the power to the NAZA. The second adjustable voltage PDB will be just above the PDB to step down the 6s battery to 12v and 5v for the TX and 3 axis gimbal.

Hello AzViper. I was just wondering about the second PDB you plan to use. Is this it?
http://www.hobbyking.com/hobbyking/...d_And_Dual_UBEC_ALL_In_One_120A_and_10s_.html

How do you plan on mounting the two PDB's on your vehicle? One on top of the other with standoffs?

By the way gents, this is an excellent thread. Thank you all so much for this.

AzViper · Nov 8, 2014

Gary Seven said:
Hello AzViper. I was just wondering about the second PDB you plan to use. Is this it?
http://www.hobbyking.com/hobbyking/...d_And_Dual_UBEC_ALL_In_One_120A_and_10s_.html

How do you plan on mounting the two PDB's on your vehicle? One on top of the other with standoffs?

By the way gents, this is an excellent thread. Thank you all so much for this.

Hi Gary,

Yes that is the second PDB. Yes the second PDB will be mounted with standoffs on top of the first PDB.

Gary Seven · Nov 8, 2014

AzViper, shoot a note off to [MENTION=1]Bartman[/MENTION]; as this forum is his baby. Maybe his site developer can fix this.

RotorJockey · Nov 8, 2014

The subject of Sparking is addressed in:

http://www.multirotorforums.com/sho...void-Sparking-During-Battery-Connection/page7

Have a look

RotorJockey · Nov 11, 2014

Negative! ('scuse the pun).

A circuit consists of two wires. Switching either would produce a spark. The switch rating is (say) 200-Amps - that means, once closed, the metal parts in the switch can 'handle' that current. The same as when touching two connectors together, the switch metal will spark as the two parts touch, eventually burning away the contact(s). Even then, the switch introduces a small value of resistance in circuit, causing heat losses.

The current (at time of contact) will be in the order of thousands of amps. The capacitor 'sucks' the current according to 'little-r' (or Equivalent Series Resistance) in the order of 25 milli-Ohms. Applying Ohms' Law - Amps = Volts ÷ Resistance. Substituting: 40V (6S) ÷ 0.025 Ohms (say) = 1600 Amps (for about 20 milli-Seconds, until the capacitor(s) charge up)!

Even a large arc-welder would do well to reach this level. The figures above are representative, but give the idea.

You have to introduce a current limiting fixed resistor temporarily in series with the (+ve or -ve) lead to lower the charging current, and allow the time for the capacitor(s) to fully charge; then 'short-out' this resistor to allow the circuit to draw the required current to operate efficiently. Remember that a circuit (device) draws current relative to the applied voltage and the resistance (impedance) of the device.

Capacitors are a virtual short-circuit over the battery until charged.

This Is The (Physical) Law ...

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