connectors

[LROBBINS]

Battery connections on Rachi's chairs are Anderson SB50, but for motor and brake connections I have been using (Anderson lookalike) PowerPole connectors - PP75 for the motors, and small ones for the brakes. An advantage of this is that the pin orientations can be re-arranged so that there is no chance of confusing left for right etc. However, at least for ham-handed Lenny, they have one serious failing - the shells are much more fragile than the ones on the SB connectors and once they crack, or a piece falls off as is often the case for the small ones, we have intermittent or totally failed connections.

I am therefore thinking about changing these when I next have a chance to do so. For the brakes, XT30 seem like a good choice: easy to solder, and not at all fragile. For the motors, however, I'm not sure. XT90 should be able to handle the short high-current peaks and the larges wire they use, AWG10, should not overheat particularly if I use silicone insulated wires. With the fairly short cables resistance shouldn't be a problem. However, the motor wires from the Roboteq HDC controllers are AWG8 and I don't think they can really be stuffed into an XT90. Any recommendations on how to handle this mismatch or of a connector alternative? One possibility is to crimp and solder butt connector ferrules to go from AWG8 to AWG10. Would that be OK?

[shirley_hkg]

[shirley_hkg]

[LROBBINS]

Thanks Shirley for the links. Given the wiring layout, having signal pins in the same connector is not a good idea, but I'm glad to see that higher capacity connectors are readily available, and, in general with or without the extra pins. The AS120 info confused me. The Amass catalog says 7AWG, but the data sheet shows 10 AWG. The QS10 series, up to 4 AWG, would be gross overkill for us, BUT that lead me to the QS8 series which seems a perfect fit for our use: AWG 8 to 12, 130/180 Amp current & reasonably compact.

[slomobile]

I've used about 20 PP75 housings which I think use the same terminals as SB50 and several hundred PP45 with very few failures after switching to a genuine Anderson crimper. Cracked housings only happened for me with a generic crimper and tough terminal insertions into housings. Generic crimpers can leave the terminal too wide (but still able to fit) and cause a weak line in the housing as the terminal is inserted. On the really bad crimps you can actually see a white stress line form as they are being inserted. If they are properly crimped, they take nearly zero effort to insert. 2 fingers, no tools. Just a gentle click. And the terminal should be free to wiggle inside the housing. Easy to remove with a pick to hold down the stainless tongue.
I only mention it because I thought my generic crimpers were doing the job just fine until I had a chance to use the genuine article and see what a difference it made. They have a little plastic box on the long handle orange ratcheting crimper to set each terminal to exactly the perfect depth.

[Burgerman]

Well I am not sure what crimp tool you use. But I have tested the officially made cables on an anderson 50 and one good yank and I pulled the wire out of the crimp.
I also have a draw full of old crimped cables inc some anderson, from 50 years of fixing cars/boats/chairs etc that either only make contact when you bend or twist them, that look great but read about 2 ohms... (oxidation/corrosion) or that dont work at all. And a few that melted due to high resistance. Fixing crimped cables - electrical issues on cars keeps auto-electricians in a job.

With crimped cables what really matters is the thickness of the materials. There are a few heavy walled anderson terminals that you can properly crimp. But most are weak. Thin. No mater what crimps them they dont have the strength to retain that tight crimp. Especially when you yank on them. And because of that they let air in. So water too. And they oxydise and turn into batteies.

So I solder them. Now they cant oxidise or go high resistance and I can literally lift my bodyweight on the cables. Next someone will come along and say it makes the wires fail where the solder ends. Well if a crimp is tight enough to do the job right then its the exact same thing.

So since I solder almost al the other cables, like XLR, 4mm, bananna, XT60 XT90 etc then I do the same with andersons.

[Burgerman]

A picture is worth a 1000 words.

Almost every anderson gets sent out with soft cheap thin walled pins. These take bigger cables like 16sqmm. Or 6AWG or whaever. And no matter what you crimp them with they are weak. And I will pull them off.

And after a bit of salty winter road water or a few humid days they will oxydise and get problematic in some cases in the future.

If you can bend it by tapping with a hammer they are way too weak to crimp properly.

If your look like these, thin walls, solder them!
Then they are then fine permanantly.

If you really want to crimp in a way that is actually secure and will exclude oxygen, water and so corrosion from where it matters then you need some that look like this. Cast, heavy wall. I have a tray of them from ebay.
These are for 6 sqmm cable. You can almost fit 10 sqmm
Even after drilling a fraction bigger for 10 sqmm for a good accurate wire fit, as big as we will ever need on a chair, theres a still lot of meat still in them. You need a good hydraulic crimper as these are hard and once crimped these are never coming off! On that pull test, the cable snaps first.

[slomobile]

The red and black connectors are PP75 connectors loaded with 6AWG terminals from SB50. They are the same general shape as PP45, and can be reconfigured in the same modular ways, but much larger. XT60 connectors included for scale.

only make contact when you bend or twist them, that look great but read about 2 ohms... (oxidation/corrosion) or that dont work at all. And a few that melted due to high resistance.
So since I solder almost al the other cables, like XLR, 4mm, bananna, XT60 XT90 etc then I do the same with andersons.

High resistance or unstable connections are quite often the result of malformed terminal following the crimp, and/or carbon scoring from connect/disconnect under load. If made with correct alignment, there is a wiping action that happens during connect/disconnect. If the terminal barrel has protrusions after the crimp, or if the tongue bends during the crimp, the terminal tries to twist to fit inside the square opening of a PowerPole housing. That causes the electrical mating plane to tilt and become a mating point instead. Which is bad, and the thing that the official tool addresses. Oops. I looked and the "official" tool I have isnt actually from Anderson. Its Powerwerx https://powerwerx.com/tricrimp-powerpol ... mping-tool
On PP45 housings I prefer the 45A 10GA (strong open wing power) or 15A 18GA (small closed barrel signal). I tend to avoid the 30A 12-14GA (medium closed barrel) because they are thin and too easily deformed. Even with the good crimper, the tongue sometimes bends. They can be bent back straight with a thumb.

Anderson powerpoles are one of the connectors I will not solder any longer because it makes them not fit the housing right if you get the tiniest blob of solder outside the barrel. Anderson SB50 and the larger sizes of housings in that same shape are much more tolerant and easy to solder.

[Burgerman]

How are you getting solder on the outside?

Tin the inside. Tin the wire. Assemble and heat with a turbo lighter for a few secs. Crimping on those is crap.

The real anderson tool costs 3k...
And I can just pull the wires out afterwards! I bought some pre made cables done with the real deal. And... crap like all the rest.

[slomobile]

How do you tin the inside while leaving space for the conductor? Or insert an already tinned wire into a hole that is just barely large enough for the untinned conductor? If there is a large gap, you have the wrong size terminal.

I insert wire. Apply iron so that it touches both the rim of connector and wire at the same time. Apply solder to the same point. Solder melts and wicks into connector and between strands at the same time. As you withdraw the iron, it can drag a little glob over the edge. Thats all it takes to mess it up. My anderson crimper from powerwerx cost $50. The only time it ever made a bad crimp was after I removed the little plastic positioning gauge while trying to crimp a non-Anderson terminal. When used with that part installed, using Anderson terminals, 100% success with 100% pull tests.

[Burgerman]

How to tin it? Very easily. Flux, correct amount of solder. Heat with tiny turbo torch and bang on the bench. And not a chance of a proper joint with an iron unless its enormous. And then you get it on the outside!

Send me one of your crimps and I will video myself pulling it out.

Also will dip it in a little salt water and keep it a few months first so you can see it all corroded. I also have a 4 wire resistance/impedance meter that will show you how bad they are after a few months of corrosion.

Seen it all before. Not a fan.

[ex-Gooserider]

I have one of the PowerWorx crimpers, and it is perfect for the Anderson PP-15/30/45 connectors. I got a die set for it that is supposed to be for the larger sizes (the SB-50 / PP-75's and the next couple sizes larger) but don't really trust it, as it only puts a single dent in the pin, the 'official' crimper puts 4 dents in the pin.... For the SB-50 size pins I use a hydraulic crimper that squeezes to a hex. I use it twice, rotating the connector one flat in order to get rid of the "ears" that are formed the first time you squeeze it. I usually shove a few strands of solder in next to the wire, and then hit it with a torch which gives just enough soldering to keep the wire from pulling out...

ex-Gooserider

[Burgerman]

Same here but with flux. SB50s

[LROBBINS]

The failures I've had with the power pole connectors are not crimp or solder failures. It is fracture of the plastic shell, particularly the thin outer U shaped part. This happens when the wires are stuffed into the rather crowded electronics compartment on Rachi's chair, but I've had it happen on the bench as well when they are hardly ever physically stressed. The SB50 type have much more robust shells. I've now switched all of those over to XT type connectors - XT30 for light currents (e.g. brakes, lift and tilt motors etc.) and XT120 for the drive motors.

[Burgerman]

XT 30,60, 90 etc are great, compact, and low resistance etc. Lots of hobby use. But they are not great when used in a situation where there is repeated reconnection like charging. They soon get worn. I crashed a RC heli because of that. Failed to make good contact, all black and burned inside.

Andersons are king in repeated use applications. But bulky in comparison. They actually spring together, and "wipe" the contact surfaces as they are inserted and removed. Keeping them clean. I doubt they would ever wear out. But I agree the SB50 ones are much more robust and pretty much indestructable.

Old page - how to do it easy! You only need one of those turbo cigarette lighters. The wind proof ones.
https://www.wheelchairdriver.com/crimp-solder.htm
.
.

[Brad_C]

Hey, I'm new here but I've been doing SB50s for years.

There are 4 sized terminals (well, 3 but then there's a sleeve for the really small stuff). If the cable will fit in a terminal properly, there's no room for a bit of solder. If that is the case, even with a third party crimper, the crimp will be strong enough to swing on (for a fat bastard like me). If the wire is too small for the terminal (ie big enough to put some solder in there with it), but to big for the next size down, then solder is what I do. I'd never thought to crimp it first.

A properly crimped joint > solder any day of the week. Having said that, a good soldered joint is easy and a properly crimped joint isn't. To do a proper crimp you need the right wire, the right terminal and the right tool. If you don't have one of those three then solder is a winner.

I've always used a old plumbers iron (bloody big chunk of copper heated up with a blowtorch). Having just read the "https://www.wheelchairdriver.com/crimp-solder.htm" page, I'll be using that technique from now on because it applies as much to the SB50 as it does to crimp terminals for boat/car cables. My previous technique leaves solder dags on the outside of the terminal.

Much appreciated!

[Burgerman]

With the bigger cables the body of the terminal is too thin/soft and so weak no matter what you crimp with. Or how well its done.
Even if it feels and looks great the metal isnt strong enough to compress the cable hard enough to exclude all air. And so water too. So after you wiggle the cable some some strands move. And humidity and water get in...

On the terminals with thicker walls then yes. Maybe...

I think crimp and solder is by far the best and easiest permanant solution.
And essential if using typical cheap ring terminals...

[LROBBINS]

The "standard" XT series will get burnt contacts with "hot" plug and unplug. They are now available, however, in "no spark" versions where one pin first makes contact through a resistor to dissipate stored charge, then when pushed home makes solid contact.

[Burgerman]

Thats not it. They get loose, and when drswing high currents they get very hot and arc.