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Pumpkin drop event

Twin Sparrow - Smoked Power Distribution

#1
This may not be the correct forum for this, but I couldn't decide where else to post it.

I am working on a twin sparrow. I got the SBK and the power pack H twin. I followed along with the video and wired the power distribution (PD) , esc, and motors. I wanted to test the motor(s) direction. This is noticeably missing from the video. I plugged the servo tester into the black/white wire pair, and battery balance lead to the Servo tester. I smoked the PD when i plugged it into the JST battery connection 3S 480mah. ??!!

Is this not a valid setup? I have used the servo tester to test other esc's with built in BECs.

I am a former Navy Electronics Tech. So I'm sure the polarities are correct and no solder bridges.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#2
Whenever I solder, the first time I connect a lipo I do so through a smoke stopper. I know this doesn't answer your question, but it may help prevent future smokings.

 

ElectriSean

Eternal Student
Mentor
#3
The balance lead of the battery is not meant to be plugged into the servo tester, it is just for balance charging. The 5V regulator on the PDB is for powering your receiver/servo tester. If you can post some clear close up pictures of your connections we can figure out where you went wrong.
 

DamoRC

Well-known member
Mentor
#4
The balance lead of the battery is not meant to be plugged into the servo tester, it is just for balance charging. The 5V regulator on the PDB is for powering your receiver/servo tester. If you can post some clear close up pictures of your connections we can figure out where you went wrong.
Agreed - but I was just watching the SE5 build video and Josh shows how you can use the balance lead to power the servo tester (although he cautions to use only one cell from the balance lead). I think we have had this problem posted before and as I recall it was also a problem with powering the servo tester and then powering up the ESCs with a battery.

As @ElectriSean says - pics would help.

DamoRC
 

ElectriSean

Eternal Student
Mentor
#5
Agreed - but I was just watching the SE5 build video and Josh shows how you can use the balance lead to power the servo tester (although he cautions to use only one cell from the balance lead). I think we have had this problem posted before and as I recall it was also a problem with powering the servo tester and then powering up the ESCs with a battery.
I haven't seen either of those videos, but it seems like a pretty terrible way to go about it... It's way too easy to connect wrong, especially considering most new people don't really understand what voltages are present in the balance plug. I'm not a proponent of servo testers in general anyway, in my experience they don't center very well - you're better off just using the receiver. I guess on the bench without an Rx or the airframe around they could be useful.. I digress ;)
 
#6
ElectriSean; Thanks for the info. I made a smoke stopper with JST connectors. This time I will be sure to wire it up with a receiver properly. I may post a photo before power up.
DamoRc; I am certain I plugged in the servo tester correctly (it still works).

thanks to both of you for the info and suggestions.

I already unwired the board. guess I need to rewire the motors and esc so to be certain the motors spin in opposite directions. I have TWO of the Emax power distribution boards on order to be here on Saturday.

If I have problems with the replacement board I will post photos.

I am not familiar with FCs and quads. There is a small switch on the Emax board. What does it do??? I couldn't find any information on it on the emax site or Google.
Have to go outside and trim some pine trees and cut down a birch tree.
 

ElectriSean

Eternal Student
Mentor
#7
I think that switch controls the LED pads output. If you're nervous about powering up with the new board definitely post some pics when you get it put together.
 
#8
OK; I received the new FCs last night and this morning I wired it up. I took close up photos, but didn't apply power yet.
Please take a look and see if I did everything correctly. I will test for shorts after I post this. I may rewire the 5V lead as I don't like the angle it is coming out at. I wired the one throttle to the receiver THR; receiver power to GEAR; and the other throttle to AUX1. Off to test for shorts. I also got ESCs but I didn't replace those. 20180908_124311.jpg 20180908_124305.jpg 20180908_124315.jpg
 

w1lp33

Active member
#10
Pull the red wires out of the esc plugs, the receiver is getting 5v from the pdb. If you leave those red wires in you'll be feeding 5v to the receiver from 3 places... Both escs and the pdb. You can lift the tab on the servo plug, pull the pin out, and just electrical tape it down so its out of the way
 

DamoRC

Well-known member
Mentor
#11
Looks like you are using the 5V line from the PDB to power the receiver through the Gear channel. If so, then you should probably pull the red wires from your ESC connectors to the Receiver. Conventional wisdom is that you should not have multiple power supplies into the receiver because that can cause a conflict with the supplies (I say conventional wisdom because you will hear different view points on this.) however, if you pull the red wires from the ESC connectors to the Rx you will not have any issues.

DamoRC

EDIT - oops, @w1lp33 great minds think alike (and fools....) @
 
#12
OOPS! ElectriSean; I put servo extensions on the wires going from the ESC to the receiver. They have a red wire, but it doesn't go anywhere. The ESC doesn't have a BEC. There is only a white and a black wire going from the ESC to the receiver.

PS Added later: I found this "FT Dart Build | FliteTest Builds" on Youtube. It show Josh testing a Power Pack H but he didn't connect the battery balance connector to the servo tester. He just put the receiver lead and both throttle connectors into the servo tester.
 

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ElectriSean

Eternal Student
Mentor
#13
OOPS! ElectriSean; I put servo extensions on the wires going from the ESC to the receiver. They have a red wire, but it doesn't go anywhere. The ESC doesn't have a BEC. There is only a white and a black wire going from the ESC to the receiver.
I didn't think they had a BEC, hence the confusion. Looks good to power up, let us know how it goes :)
 
#14
OK: I have both working!! YYYAAAHHHH!!!! I had to replace one of the ESCs, I must have damaged it. but at the same time I got the Board, I got two of the ESCs. so good to go. I am making one of the Walmart chuck gliders. But it will be raining here in the northeast US for the next week or two and flooding is an expectation (certainty).

Thank you to everyone who helped and commented.
 
#16
Another twin sparrow issue. I built the twin sparrow using a speed build kit with the power pack from Flitetest. I had two great flights using a 2cell 800 battery. The third flight not so well. The right motor is putting out much more power than the left. I have a differential power setting and it is easy to see when differential is selected that the left motor is just not performing. I'm thinking bad ESC. Any suggestions