easymoney

Can this desease cause the death of your plane...

strato911

"Black Wire Disease" makes the wires brittle, and reduces it's current carrying capacity. They can break during flight, resulting in a total loss of control, leading to an abrupt meeting with the ground.

There's a comprehensive explanation on the website http://www.rcbatteryclinic.com/ hosted by the moderator of the Batteries forum.

r1morris

My Feedback: (1)

Been there had that and lost a plane to it years back. Now I check my battery packs and cycle them and keep all my nicads and NMH's in good shape. I'll admitt neglect was the cause of the crash.

Geistware

My Feedback: (16)

Technically no.
BWD will cause the power stored in your pack to not be available to the receiver. No receiver power "WILL" cause the death of your plane.

strato911

If you REALLY want to get technical, it's the sudden stop as the plane encounters another object (typically Mother Earth) which causes the death of the aircraft.

Failure to inspect your wires for BWD can be the first step in the chain of events leading to the aircraft's demise. Kind of like saying that the person who pulled the trigger of a gun didn't kill the person who was hit by the bullet. The end result has to be traced back to the original cause.

davo74

My Feedback: (1)

Im kinda new to this, how do i check for this on my battery packs???? Do i have to cut into the wires to check?
Never heard of it before.

mikenlapaz

i'm new to RC as well. Just how far does this BWD travel just to first connector from battery or further?
Sounds like salt air corrisonof wiring that boaters deal with when they do not use marine grade (continuous pre-tinned strands) in the wire their installations.
I bet that true aircraft grade wire it tinned as well.

strato911

The R/C Battery Clinic (by Red Scholefield of the Batteries forum) explains BWD pretty well.

http://www.rcbatteryclinic.com/blkwire.html

How far can it travel? Given enough time, it will work it's way around the entire circuit... But usually doesn't make it that far without the vibration of flight causing it to break. Typically, it won't make it past the power switch. The BWD will cause the switch to make bad contact, which could result in the receiver losing power during flight = loss of control = CRASH!!!

How to identify it? Check the connectors, and cells for any evidence of white powder or corrosion. I give my entire radio system a thorough inspection at the start of each flying season. In humid conditions, it may be wise to check more frequently. That goes for the transmitter batteries as well...

Gary Retterbush

One excellent way to start BWD is to leave your gear turned on and run the batteries extremely low.

Pull a servo connector out of the receiver and inspect the pins with a good 10X glass. If it isn't nice and shiny, watch out! If you then cut this servo wire you will most likely see that the wires (especially the minus) will be black and crystallized.

This then leads to a broken wire which in turn leads to a broken airplane! But then everything will be so screwed up that you probably won't note the real problem.

davo74

My Feedback: (1)

How long does it take for this to happen? Over a season or a couple of months? Thats kinda scary.....

Gary Retterbush

As always, there is no clear cut answer (time frame). It depends on a lot of things; just don't leave your gear on after you come home! Better yet, unplug the battery from the switch.

strato911

I believe two of the most common causes of BWD are:

1) draining the pack to far, allowing one of the cells to reach zero and effectively "suck" the electrolyte from a neighboring cell.

2) charging the packs to fast, to hot. The venting gasses contain the vaporized electrolyte which mixed with carbon-dioxide in the air to make potassium carbonate. With humidity, this returns to electrolyte, and attacks the wire.

http://www.rcbatteryclinic.com/blkwire.html

davo74

My Feedback: (1)

so, "dump charging" all summer can be the deathknell of your batteries then.......and your planes

Red Scholefield

My Feedback: (9)

What do you mean by "dump charging". If you mean taking the pack all the way to zero by leaving a load on a pack for quite a while - yes, this can bring on the black wire problem.

Maybe its a good time to post the black wire story again as suggested by Dennis Balla Strato911

The Black Wire Syndrome

The black wire syndrome is an occurrence in battery packs (Ni-Cds) where the negative wire becomes corroded (turns from shinny copper to blue-black). This is the result of either a shorted cell in the pack, the normal wear out failure mode of Ni-Cds, or cell reversal when a pack is left under load for an extended period. The sealing mechanism of a Ni-Cd cell depends to some degree on maintaining a potential across the seal interface. Once this potential goes to zero the cell undergoes what is called creep leakage. With other cells in a pack at some potential above zero the leakage (electrolyte) is "driven" along the negative lead. It can travel for some distance making the wire impossible to solder and at the same time greatly reducing its ability to carry current and even worse, makes the wire somewhat brittle. A switch left on in a plane or transmitter for several months can cause this creepage to go all the way to the switch itself, destroying the battery lead as well as the switch harness. There is no cure. The effected lead, connector, switch harness must be replaced. This leakage creep takes time so periodic inspection of the packs, making sure that there are no shorted cells insures against the problem. The cells should also be inspected for any evidence of white powder (electrolyte mixed with carbon dioxide in the air to form potassium carbonate). In humid conditions this can revert back to mobile electrolyte free to creep along the negative lead. Some "salting" as this white powder is referred to, does not necessarily mean that the cell has leaked. There may have been some slight amount of residual electrolyte left on the cell during the manufacturing process. This can be removed with simple household vinegar and then washed with water after which it is dried by applying a little warmth from your heat gun..

C. Scholefield
8/29/96

Gary Shaw - Model Aviation - Safety Comes First
April 1, 2000
Black wire again. Re: your MA May column.

I have no idea of what Mr. McQueen's long quest is to disprove that Ni-Cds are the primary cause of the black wire problem we see in our R/C equipment. Perhaps he sees some chance of immortality in proving that gravity does not cause things to fall toward the center of the earth.

I have no issue that perhaps some contamination in the insulation might contribute at times to what appears to be corrosion. I do have an issue with the "randomness" of the occurrence or the inability of anyone to site a meaningful experiment to demonstrate the phenomena. And I have a real problem with people denying the obvious. I have had 7 or 8 year old transmitters in the shop with no wire corrosion, simply because the packs were still intact, no leakage. (revealed by the time tested spay of phenol solution turning pink in the presence of caustic). I have had others, same vendor, same age, same black wire with one or more cells bad (shorted and/or leaking) and in 90% of these cases black wire corrosion (and in one case where the user had used white wire for the negative lead) was in evidence. I have yet to see black wire corrosion associated with batteries that show no evidence of leakage. I suppose next you will get a letter from someone putting forth the argument that black wire connected to Ni-Cds promotes leakage.

Joe Balmer's logic...."We never used Ni-Cd batteries which proves that they didn't cause the problem" (corrosion noted in wire with black insulation) makes about as much sense as, "My friend died of lung cancer and he never smoked, therefore cigarettes do not contribute to lung cancer".

I hope your look see via SEM will include both samples of non-battery related corrosion as well as samples from a battery leads.

One more point, in wrapping up the corrosion discussion, you state that the corrosion is uniform along the whole length of the wire. This is true only if the wire has been given sufficient time and humidity under the conditions contributing to the problem (shorted and/or leaking cells). I frequently find cases where one end of the wire is still bright and shinny while the end connected to the battery is corroded....and stripping the insulation along the wire reveals that the corrosion has progressed only an inch or so.

******

davo74

My Feedback: (1)

Meant using a field charger and a 12 volt battery..

Red Scholefield

My Feedback: (9)

If your field charger is properly terminating the charge you should have no problems with black wire syndrome. If it is simply a timer, sooner or later it will mess up the battery an cause venting.

IronZ

My Feedback: (3)

I had a problem with my Ultra Stick one day while range checking. Upon inspection, I discovered that wiggling the wire up by the switch would intermittently make and break the connection. After getting home and checking things out I discovered this "black wire disease" right where the wire enters the switch. After closer inspection I discovered that this was the ONLY place that had the problem. I'm assuming this isn't the typical BWD, so what could have caused this. Luckily it all happened on the ground and the plane lived a little longer anyway.


IronZ

Rodney

Over at least a 30 year period, I have had quite a bit of experience with black wire disease. In every case it was associated with the negative lead on a NiCad battery with the corrosion starting right at the battery and slowly progressing away from the battery. It always stopped at the first junction that wire made with something else. The disease was much more prevalent back in the days when we were using wet cell NiCads. Also, it only occurred in the sealed cells when a cell was overcharged and broke the seal or the battery was ruptured due to mechanical stress. I have been told that there was one type of insulation that would also cause black wire disease but I have never seen or examined such an occurrence and am still skeptical that that was the cause although I could be wrong on that. Now days I rarely ever see this happen but I probably watch my batteries much closer now and the manufacturing techniques have improved. If you don't break the seal by overheating or overcharging your batteries, you will probably never see this happen.