How to Measure Resistance of a Solder Connection

[Logan's_Rcs]

Hey everyone,

I'm currently wondering how I should go about testing the resistance of my solder joints of my esc connectors. I don't think I did the greatest job of soldering, and I'm looking at upgrading to QS8 plugs anyway. I have a multimeter, but I am unsure of how to test the resistance with it.

Any help would be appreciated!

Thanks!

 

[SrC]

Set the DVM to Ohms, and check for continuity touching probes to both ends of the Joint. There is no polarity needed. either probe at either end is fine. I am sure it will show "Zero" Ohms, if you even did a slightly good joint. The main issue arises when the joint was soldered "cold", looks dull. Bad soldering. Joint should always look Shiny. Otherwise, when running, the joint will get warm, a sign of a bad joint or even under amped or worn out connector. Videos may help better. A temp gun to check the connector when running is one additional way to judge. The more resistance the warmer or hotter it will get. Normal for connectors be "slightly" warm, wires as well. Over 160F may be a sign of a bad joint or connector.
Connectors themselves are consumable items at some point and get replaced. But a good solder joint should always be permanent if done correctly.
Always wipe off any Remaining Flux with alcohol or solvent after finsished and before using Heatshrink wrap over the joint. Remaining flux is corrosive and over time ruins the joint and the wire strands. Hence resistance.
Always tug firmly on your finished joint after it cools. A very cold joint will come apart. One way to check.
Hope this helps.

 

[Logan's_Rcs]

Set the DVM to Ohms, and check for continuity touching probes to both ends of the Joint. There is no polarity needed. either probe at either end is fine. I am sure it will be zero if you even did a slightly good joint. The main issue arises when the joint was soldered "cold", looks dull. Bad soldering. Joint should always look Shiny. Or when running, the joint will get warm, a sign of a bad joint or under amped connector. Videos may help better. A temp gun to check the connector when running is one additional way to judge. The more resistance the warmer or hotter it will get. Normal for connectors be "slightly" warm, wires as well. Over 160F may be a sign of a bad joint or connector. Connectrors are consumable items at some point and get replaced.
Hope this helps.

Yeah it does! I'm asking because I was actually told on a tekno group that bad connectors can cause motor heat... On my MT410, i have a castle 1520 geared to 62mph and it gets to 104 degrees (with fans) after running full throttle in grass for a whole pack in around 65 degree weather, which I wouldn't consider bad. However, other members of this FB group say they have theirs geared to around 75mph and their motors don't get past 120. One guy even says he runs a 1515 on 6s, no fan geared for 75mph and the motor doesn't even get warm in summer months. I'm a little skeptical of that, but he claimed that my soldering was bad and that the motor couldn't get it's power well enough, causing it to heat up...

I have doubts to the validity of these claims, but I thought it would be interesting to at least see if I could improve my soldering.

 

[dure16]

Yeah it does! I'm asking because I was actually told on a tekno group that bad connectors can cause motor heat... On my MT410, i have a castle 1520 geared to 62mph and it gets to 104 degrees (with fans) after running full throttle in grass for a whole pack in around 65 degree weather, which I wouldn't consider bad. However, other members of this FB group say they have theirs geared to around 75mph and their motors don't get past 120. One guy even says he runs a 1515 on 6s, no fan geared for 75mph and the motor doesn't even get warm in summer months. I'm a little skeptical of that, but he claimed that my soldering was bad and that the motor couldn't get it's power well enough, causing it to heat up...

I have doubts to the validity of these claims, but I thought it would be interesting to at least see if I could improve my soldering.

I also have an MT410 with a 1520. Why are you worried about 104F on the motor? It's barely warming up at those temps. You should start getting concerned at 160-170F and set your auto cutoff to 180F.

MT410 gets stupid hard to control when geared much higher than 60mph. Your current gearing is the sweet spot and I bet it's fun as hell.

Post some pictures here if you're curious about your solder joints. We can guide you.

P.S. The dude claiming no heat issues with a 1515 geared for 75mph is full of crap. Been there done that.

 

[SrC]

I wouldn't place much emphasis on what you heard.
There are many other factors that contribute to motor heat temps. And no two identical rigs ever run exactly the same. What works for some, doesn't always for for the next guy.
Soldering is only one factor. And rarely assumed the issue initially. IMHO.
Your temps are good. I surmise your soldering is just fine.
A pix of your soldering may help, if you are unsure.
I also have an MT410. I don't gear it for all that much speed. It's a SWB Freestyle stunt truck that doesn't do great at high speeds anyway. I want torque. And I only run 4s packs. I prefer it better than 6s packs. (HW XR8 Plus/ 2250kv full sensored Combo.)

Edited.

 

[Logan's_Rcs]

I also have an MT410 with a 1520. Why are you worried about 104F on the motor? It's barely warming up at those temps. You should start getting concerned at 160-170F and set your auto cutoff to 180F.

MT410 gets stupid hard to control when geared much higher than 60mph. Your current gearing is the sweet spot and I bet it's fun as hell.

Post some pictures here if you're curious about your solder joints. We can guide you.

P.S. The dude claiming no heat issues with a 1515 geared for 75mph is full of crap. Been there done that.

I'm not worried about 104 lol, I thought it was actually pretty good. I was just shocked to hear that people run a 23tooth pinion on 6s with the same system and don't have heat issues... I know if I gear over a 19 tooth in the summer, it will over heat, so a 23 tooth seemed to be crazy to me...

I wouldn't place much emphasis on what you heard.
There are many other factors that contribute to motor heat temps. And no two identical rigs ever run exactly the same. What works for some, doesn't always for for the next guy.
Soldering is only one factor. And rarely assumed the issue initially. IMHO.
Your temps are good. I surmise your soldering is just fine.
A pix of your soldering may help, if you are unsure.
I also have an MT410. I don't gear it for all that much speed. And I only run 4s packs. I prefer it better than 6s packs. (HW XR8 Plus/ 2250kv full sensored Combo.)

Here's the photo. I usually have trouble keeping the wires still while soldering, and sometimes I have to re-do joints like 2-3 times. Is there a jig or something that you would recommend in order to keep the wires still?

Thanks!

 

[dure16]

I'm not worried about 104 lol, I thought it was actually pretty good. I was just shocked to hear that people run a 23tooth pinion on 6s with the same system and don't have heat issues... I know if I gear over a 19 tooth in the summer, it will over heat, so a 23 tooth seemed to be crazy to me...

Here's the photo. I usually have trouble keeping the wires still while soldering, and sometimes I have to re-do joints like 2-3 times. Is there a jig or something that you would recommend in order to keep the wires still?

Thanks!

I’ve seen many people claim no heat issues with high gearing, and then get surprised when their motor or ESC dies. Many people don’t actually monitor their temps at all.

 

[Tex Koder]

...

Here's the photo. I usually have trouble keeping the wires still while soldering, and sometimes I have to re-do joints like 2-3 times. Is there a jig or something that you would recommend in order to keep the wires still?

Thanks!

Yes.

$29

Or

$20

They're called Helping Hands...

 

[Garcbomber]

Grab an

 

[SrC]

Yeah many guys in other threads cry about how hot or brag about how cool their motor runs. Yet they never actually state Temp readings using a temp gun.... Merely Touching wires, connectors and motors, tells nothing.

That aside. I think Your connector is do for a replacement anyway. And not because of the soldering. The connector's bullets themselves look over heated from the soldering process. The whole thing does. Appears to have some Flux remaining as well
A jig makes for a better aligned and quicker soldering job. There are many to choose from. A small securely mounted Vice is even good. The clamping block types are common.. Actual proper soldering is done quick as long as you prepare all else first. A hot Iron and clean Pretinned "large" Blunt tip is what you need for these connectors. Or you send too much time melting the solder. NG. You don't want to melt the Plastic jacket. Mounting the connectors in a jig matters You can improvise as well. But the connectors should be firm and still no matter how you mount it for soldering. Alway place an un-soldered mating connector into the other end. This will keep the bullets aligned during soldering. Heat tends to misalign the Bullets. This will cause bad bullet alignment of Female and Male ends. Hence resistance and a shortlived connector.

Yes.

View attachment 327501
$29

Or

View attachment 327502
$20

They're called Helping Hands...

I have similar. I don't use it for heavy soldering however. "Third Hand" Jigs are useful for smaller work, not really for larger XT90's. IMHO.
I would search for many different connector soldering videos, ideally XT90's, and find one that looks easy to follow. There are many ways to do it properly . But in the end what works for you and gets good results is what matters.

 

[dure16]

Here's the photo.

Negative joint looks fine to me. Just needs to be cleaned up with some rubbing alcohol.

Can you take a picture of the positive joint? Why does it go off at a weird angle?