power loss due to dirty connectors! anyone?

[Vincenzo]

I have 2 xt90 connectors, 4 xt60 connectors and a blade fuse holder (and the fuse) between the battery and the controller, and there are three bullet connectors taken from EC90 male-female wires between the controller and motor. It took me a long time of observation to start thinking that all those connectors need some kind of contact cleaning (or vineger and baking soda, or something to remove the rust) or the bicycle starts loosing power (especially up hills) and sometimes at starting from stand still, there is a kickback for too much current causes lots of voltage drops in those connectors.

Searched in all forums and did not find anything relevant, does my thinking make sense? Did anyone have this issue? and is there a thread somewhere that I missed about regular cleaning?

Below is a primitive hand drawing that explains why I have all those connectors. Basically, ease of disassembly, diagnosis and repair.

 

[99t4]

First impressions: Why so many connectors in the circuit between battery and controller? Seems excessive. Are you sure it's rust? I've never seen it on my XT90 or XT60s and I live in a very wet salty environment.

 

[gromike]

It is called corrosion. Unless your connectors are made of iron, then it's rust. A high resistance connection can cause mayhem with burnt connectors or failed operation. One thing to do is to unplug and replug connectors to wipe the contact area clean. I would use electrical contact cleaner to wash away goo. Maybe distilled water for salt build up. Be careful with that. Maybe an application of a conformal coating could be used. Mechanically cleaning contacts with a fine grade sandpaper can be useful, but you must be careful against removing contact metal. And don't use emery paper. Some use pencil erasures to clean contacts.

 

[Vincenzo]

First impressions: Why so many connectors in the circuit between battery and controller? Seems excessive. Are you sure it's rust? I've never seen it on my XT90 or XT60s and I live in a very wet salty environment.

For the number of connectors, see the attached drawing. I gave a brief answer too, "reliability" and ease of taking apart and speedy repair. May be it's the engineer in me that doesn't want to make it amateurish. It is easy to take it apart. The xt60s can split the battery to 4 parts in series for easy of replacement/repair and to save money. I made all those decisions when I had no other transportation to make it easier to troubleshoot on the road, snow or rain or whatever.

I can probably eliminate one or two connectors and I'll do as soon as I get a chance. The battery is on the front rack to kinda balance the load (weight with the rider)+(hub motor on the rear wheel), so the long wire is in a sleeve that is not as easy to remove and can be disconnected from the battery on one end and the controller on the other to remove/replace either.

The many connectors plus fuse plus 3 feet wires add a little bit of current limiting protection, which is a positive. Or that was the initial thinking.

I'll attach some pictures of some of the suspicious connectors. It's sometimes black/green and sometimes salt-like oxidization. It is very easy to oxidize relatively pure copper and I'm (probably just like you) in central PA...the land of fighting snow and ice with salt.

 

[Vincenzo]

It is called corrosion. Unless your connectors are made of iron, then it's rust. A high resistance connection can cause mayhem with burnt connectors or failed operation. One thing to do is to unplug and replug connectors to wipe the contact area clean. I would use electrical contact cleaner to wash away goo. Maybe distilled water for salt build up. Be careful with that. Maybe an application of a conformal coating could be used. Mechanically cleaning contacts with a fine grade sandpaper can be useful, but you must be careful against removing contact metal. And don't use emery paper. Some use pencil erasures to clean contacts.

Thank you! I used the wrong word above.
So, that's a common issue?
The power changed for different events, e.g. I once was thinking about some cells aging but after I changed the wiring (and connectors), the power noticeably increased.

Thanks for confirming.

So, your treatment is simply by pulling/pushing a few times to file the corrosion?
I saw a video where they use vinegar and salt and then baking soda in water, and finally dielectric grease for longevity of the cleaning. What do you think?

 

[gromike]

That would be to unplug and then replug the connectors to wipe the contact, though that could increase the chance of wire breakage if you ain't careful.
I would not recommend vinegar, salt, then baking soda in water. Just seems too much of the ionic fluids to be a good thing.

 

[Vincenzo]

That would be to unplug and then replug the connectors to wipe the contact, though that could increase the chance of wire breakage if you ain't careful.
I would not recommend vinegar, salt, then baking soda in water. Just seems too much of the ionic fluids to be a good thing.

thanks. I'll do that and use a small screw driver covered with a rough cloth. that cleans the females only. I'll start looking for a long term solution that is less than replacing all the connectors every winter and study dielectric grease

 

[Chalo]

Deoxit. Not cheap, but this job is what it's for.

If you are getting enough voltage drop on the battery or motor phase wires to noticeably lose power, you'll burn them to a crisp almost immediately. So I doubt that's what's happening.

 

[Vincenzo]

Deoxit. Not cheap, but this job is what it's for.

If you are getting enough voltage drop on the battery or motor phase wires to noticeably lose power, you'll burn them to a crisp almost immediately. So I doubt that's what's happening.

Hey, thank you Chalo. Did some cleaning and noticed that some of those connectors got less tight than what I remember the last time.

What is happening is that I remember when I changed some wiring the last time the maximum power that I could get on uphill max speeds increased from 13XX to 14XX watts (the handlebar display shows the watts), and the last time I had to ride far, yesterday, the max I got was 12XX watts and it was next to impossible to go uphill and it slows down to less than 15 miles/hr.

The previous ride to that one, I discovered that the hub motor rear wheel two nuts where not very tight, so I had to drive a few miles with the tire rubbing a little bit on the metal because I wasn't carrying tools and I started getting the "jerks" uphills but they weren't happening in my 40 mile round trip yesterday!

 

[Vincenzo]

after the cleaning and widening some of the males with a tiny flat screw driver, the power near home in a flat road jumped back to 14XX. That kind of confirm my (and the others participants in this threads) analysis.

From now on, I'll work on finding a better high current connection methods that are based on tightening something and to cancel some of the connectors.

 

[E-HP]

Are they genuine (AMASS) XT90/XT60's or knockoffs from AliExpress/eBay? Brass vs plated steel will result in twice the heat and be susceptible to corrosion.

 

[Vincenzo]

Are they genuine (AMASS) XT90/XT60's or knockoffs from AliExpress/eBay? Brass vs plated steel will result in twice the heat and be susceptible to corrosion.

Gold plated with precious stones and large diamonds all over

 

[E-HP]

Gold plated with precious stones and large diamonds all over

Gold doesn't corrode. If they can't handle 1/3 of their rated power, then they are fake. I agree with Chalo. If your connectors are dissipating 200W of heat going up a hill, that's the same as three of these https://www.amazon.com/Weller-SP175...t=&hvlocphy=9032087&hvtargid=pla-449793898229

 

[99t4]

NO! "vinegar and salt and then baking soda in water..." Who told you that? Deoxit as Chalo mentions above, is good product. Dielectric grease OK once it's all clean and mating well, if what you are experiencing is actually corrosion.

Seems like there's a lot going on here, possible corrosion, possible poor quality (counterfieit?) connectors. Are they crimped in? Soldered? Are they directly exposed to moisture and/or salt washes?

Best if you could post some clear detailed photos so we can zero in and help you correctly repair.

 

[fechter]

If a connector is dissipating 200w, it will be burnt up almost immediately. Are the connections toasty looking? You may have some other issue.

 

[rafalg]

yep, agree with @fetcher - ride for few minutes and then check the connector temperature. If there's an issue they should be pretty hot.

 

[Vincenzo]

Gold doesn't corrode. If they can't handle 1/3 of their rated power, then they are fake. I agree with Chalo. If your connectors are dissipating 200W of heat going up a hill, that's the same as three of these https://www.amazon.com/Weller-SP175...t=&hvlocphy=9032087&hvtargid=pla-449793898229

sorry for the sarcasm.
I hope it was taken as funny and not inappropriate.

I totally agree that even though a sudden or gradual loss of power only at high speeds/power logically leads to concluding having noticeable resistance in the source-to-load path and having had the same connectors for a relatively long time with no real issues (until recently) in that area makes me think that they just can't be of bad quality (like thin copper coating on an electrically bad metal) but think of their deterioration because nothing lasts forever (I could be wrong here!). If they were indeed bad ones, they could've been burned and melted a long time ago. As a matter of fact, I once had a very low end wire ( one of those "silicone" sheathed high gauge ebay ones) go bad at the soldering points to the connectors after a short time of use when its fine strands started turning to white sand-like particles at the soldered ends and was very hard to get solder to stick to them and I had to get a real home depot AWG10 replacement. The connectors were good but I replaced them anyway. We all know that everything is made in communist china since the betrayal actions of enemies of the people like Nixon and Clinton, but there are things that are not economically feasible to fake even in china.

Still, There is a possibility of having connectors going bad sooner than they should.

 

[Vincenzo]

I did the 40 mile round trip again yesterday, and the condition was sadly back. It's a new route to me so part of it is that there's a mile that has the most steep ascending and it occurs in the second half of the ride when the battery voltage is much lower than the initial fully charged voltage and obviously the power that it can give is much lower (P=IV) but I tried to think of the whole ride as a test drive and to pay extra attention to what is going on.

There was a minor grinding feeling/sound coming from the rear (motor wheel) but only when both the power and speed exceeds a certain level. So if I'm going on a flat road, that may happen at speeds over 28/mph, but when all of a sudden I go downhill and release the throttle, it goes away even if the speed increases. Sometimes, uphill, the grinding happens at lower speeds. I was trying over and over to at least prove to myself that it is correlated to a certain throttle angle if not a certain speed, but I couldn't get to that determination with certainty. I stopped several times (even though I was going to a very important job interview) and inspected is the tire or something is touching any metal part but found nothing. I am almost certain that he grinding was restricting the speed/power.

I am still not sure if one of the following or a combination is happening:

1. Something wrong with the wheel construction, build/tightening, or alignment/truing that just started or was a gradual deterioration from use.

2. The wheel motor needs some kind of maintenance after a number of miles that I'm not familiar with and that I've ignored so far. The motor in those hub-motor kits is not only an electrical part but also the wheel axle. Even the electrical part (the winding wire) is not going to last forever and may start having wire insulation aging and/or contact corrosion. It was my first build and I'm not familiar with how those things age and die.

3. The driver board may need some soldering re-flow love or some caps and other components started getting old. I have another identical controller that I kept as a spare for emergencies that I may put and see what happens.

4. The cells in my battery started aging and I'll need to build a new one.

 

[Vincenzo]

NO! "vinegar and salt and then baking soda in water..." Who told you that? Deoxit as Chalo mentions above, is good product. Dielectric grease OK once it's all clean and mating well, if what you are experiencing is actually corrosion.

Seems like there's a lot going on here, possible corrosion, possible poor quality (counterfieit?) connectors. Are they crimped in? Soldered? Are they directly exposed to moisture and/or salt washes?

Best if you could post some clear detailed photos so we can zero in and help you correctly repair.

This is the guy who recommended the "insane recipe" and I hear everyone I respect talks about Deoxit. I used to think that they were too pricey for me but I just checked their prices now and they are not bad for what they do especially since I'm starting a very fancy job next month. What package/size do you recommend?

The counterfeit connectors conclusion is not solid because they were there for a while and the condition just started. They are soldered in a good way with "Kester" solder (best brand I believe) and lots of flux. They ARE exposed if I understand you right, i.e. there is no water-proof sleeve over the connectors, but I tried to keep them out of direct rain/elements exposure. For example, the connector pair near the controller and the three connectors to the motor are inside the closed plastic box that houses the controller and all the other connectors, and all the battery connectors are inside the plastic battery box.

Here is an example on one that I cleaned before cleaning:

 

[Vincenzo]

If a connector is dissipating 200w, it will be burnt up almost immediately. Are the connections toasty looking? You may have some other issue.

Exactly!
The old corroded/dirty connectors may play a relatively small part of the whole problem. I'm trying to think about other problems.

 

[Vincenzo]

yep, agree with @fetcher - ride for few minutes and then check the connector temperature. If there's an issue they should be pretty hot.

I agree with both of you and I did the test. They are warm, but not the whole 200 watts. Thank you for making me more sensible.

 

[Chalo]

I agree with both of you and I did the test. They are warm, but not the whole 200 watts. Thank you for making me more sensible.

I did wonder whether the throttle plug might be grimy enough that you don't get the whole 4.2V the controller wants when you give it the beans.

 

[Vincenzo]

I did wonder whether the throttle plug might be grimy enough that you don't get the whole 4.2V the controller wants when you give it the beans.

Smart thinking Chalo, as always. It is a very valid probability that didn't cross my mind, even though I find it hard to link it to the grinding that I felt. I'll go check it out and take pictures right away. For a serious test, I'd have to hookup two little digital voltmeter (the ones they use for AA battery testing, dollar a piece on ebay) to the IN and OUT of the Hall sensor transistor looking thing while riding and pay attention to the numbers. I wish I had made the simple two input arduino data logger that I was thinking about to save voltage readings for the whole ride and curve them when I'm home to be safer.

The throttle connector once had a mishap that totally killed the circuit miles from home when I didn't have a soldering iron (off course) and had to walk home. One of the three wires was cut from one of the sides of the connector inside the handle. That was the reason that made me, after fixing the throttle, install the pedal assist ring as a plan B if any wiring issue happens with the throttle in the future. Now I'm thinking about adding an assist disabling switch to disable it on steep uphills to use both motor maximum power from throttle and pedaling. The sum of the two is better than the logic that it was designed to work with, i.e. as soon as you hit the pedal, the throttle get ignored.

Thanks much!

 

[99t4]

Sure looks like the connector in your photo is a counterfeit. The real ones are not hollow like that in the middle. See here:

 

[E-HP]

Sure looks like the connector in your photo is a counterfeit. The real ones are not hollow like that in the middle. See here:

View attachment 339664

They are too good at making counterfeits, so it's difficult to tell visually. Looking at their website, it looks like AMASS makes several versions of XT90 and XT60 connectors, and it looks like the "H" version, as well as a couple others, have the hollow center. The "S" version (anti-spark) and a couple others have the solid center.

产品系列-产品

常州市艾迈斯电子有限公司——专注于大电流锂电过载连接技术，研发生产大电流连接器插头，拥有锂电池插头专利60余项。十几年来研发设计了上百种大电流连接器，广泛应用于各大锂电设备行业：电动工具，代步工具，储能，电动车，航模无人机等。服务于全球近360家品牌企业，产品远销63个国家与地区。

www.china-amass.com

产品系列-产品

常州市艾迈斯电子有限公司——专注于大电流锂电过载连接技术，研发生产大电流连接器插头，拥有锂电池插头专利60余项。十几年来研发设计了上百种大电流连接器，广泛应用于各大锂电设备行业：电动工具，代步工具，储能，电动车，航模无人机等。服务于全球近360家品牌企业，产品远销63个国家与地区。

www.china-amass.com

I don't see any major problems with the "before cleaning" contacts, so I doubt any of the issues are connector related.