Soldering Wires to Motors

Does anyone have any good advise on the best way to solder wires to the FP, Banebots (775, 550,…), etc. motor terminals. I am looking for best electrical practices. They can be a little difficult to solder 12GA or 14GA wire to. We have used 3/16" female spade connectors and soldered those onto the wire and terminals in the past but I am looking for better ideas. Anyone have any?

I amj interested in what the more experienced guys have to say about this.
We currently just solder the wire [12awg] right one and put heat shrink on it.

Make sure you have a good quality soldering iron, not one of those 20W soldering pens because the key do doing this successfully (and without ruining your motor) is to do it fast and getting the solder to tin (cover with solder and allow it to wick into) the wire properly. Tin your wire with plenty of solder and make sure it has wicked into the strands nicely- not a cold blob on top of the wire strands. If you have trouble doing this you need a more powerful soldering iron before attempting the next step. Then tin the terminal on the motor and let it cool. You must be very careful how much heat and for how long you apply it to the motor contacts as they can melt the plastic insulation/brush assembly. Place your tinned wire next to the tinned contact and press the soldering iron on top of the wire. The idea here is that the wire has a higher heat capacity than the motor so you want to melt the solder on the wire before the contact. Then once the solder in the wire and on the contact are molten, wiggle the wire a bit for the two masses of molten solder to join nicely and then let it cool while holding the wire in place.

Don’t forget to carefully curl the wire back toward the front of the motor and secure it to the motor case with a tie wrap to prevent it from wiggling around and snapping a contact off the motor.

My favorite way to do it is clean the wires with flux then solder quickly and carefully it leaves a good conductive medium for the motor to run also what fox 46 said

hey so for banebots 775, are you supposed to just solder the 12 guage wire on or are we supposed to use female connectors? and do ring terminals work alright?

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I would like to add to this that soldering these motors, for the very reasons that fox mentions, can seriously damage them. For this reason, I would suggest that you only resort to soldering in a last-ditch attempt to get a connection. In the past, when we soldered these motors, we found that the only effective soldering tool to use was a 200W soldering gun, as anything else would simply drip solder onto the terminal without solidifying the connection.

Properly stress relief-ed 3/16" QDC terminals (available at your local RadioShack or electronics supplier) held in place with hot glue (be careful not to block the armature vents!) will hold up perfectly fine. You may want to look into getting flag terminals to facilitate stress relief.

@jessica, ring terminals work fine in the right application; I assume you will be using them on the speed controller end to tie them into the M+ and M- terminals, and they work just fine for that purpose (provided your terminals are designed for #6, or at worst, #8 studs). Just keep in mind that ring terminals limit serviceability (if you ever have to replace the connector, you’ll have to take out the entire screw to do so).

This is what I use and it works quite well with a maximum output of 60W. You can also get small butane powered soldering pens that will work well. I personally can’t stand those soldering guns and have never had good luck with them.

The $20.00 Radio Shack butane powered soldering gun is the bomb. Best thing since bubble gum.

Here’s a good video:

Ring terminals work alright for connecting to the right speed controller. If you’re using the older tan jaguars, DO NOT REMOVE THE SCREWS COMPLETELY. The way they are designed, removing the screws completely will destroy the mounting and send metal shavings directly into your jag.

I recommend that teams use uninsulated push on terminals. Most of the motors have a protective coating that prevents solder from bonding with the motor terminal. I scrape the motor contacts first with a sharp blade to remove the coating. (This coating is broken through by the contacts when used in production) We solder all terminals on the wires first. Then push the terminal on the motor terminal. Large irons are not needed for this operation but your iron should have a large tip. We are using 30 watt irons with a 1/4" flat chisel point for this operation. Melt a fair amount of solder on the tip of the iron to give good heat transfer, then touch the iron to the back side of the wire terminal. Apply solder to the split side of the wire terminal until it starts to flow and then remove the iron from the terminal. You don’t need a lot of solder, just enough to hold the terminal in place. We then add heatshrink tubing to insulate the joint, run the motor wires down along the motor and secure them to the motor with wire ties. We use PowerLoc connectors on the other ends to allow quick removal and replacement.
FP motor in particular have internal thermal cutouts. If you apply heat for too long or at too high a temp, the thermal mechanism or brush assembly will actually move out of alignment. When this occurs, the motor will trip out early or fail to produce the expected power. Essentially this kills the motor.

If you do solder, make it quick. Our irons put out 800 degrees, doesn’t take long. If you use female quick connects, pinch them just a little smaller so the terminal on the motor is snug, sometimes the motor terminals are thinner than the male quick connects. Whichever method you choose, I suggest leaving another 6’’ of wire available to cable tie to the side of the motor itself, or to something close to the motor to relieve any strain on the motor terminals. If you break the terminal, it’s garabage.