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Voltage drop and the dreaded "Brownout" , What's really at fault ?

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Voltage drop and the dreaded "Brownout" , What's really at fault ?

Old 10-03-2015, 08:46 AM
  #151  
dirtybird
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Originally Posted by John_M_
That's just a general disclaimer so no one will blame the author of the video if the individual screws something up... typical disclaimer legalities.


I use silver solder, and use the acid flux on a Q-tip, the silver solder flows better than the rosin core 60/40 solder does... when I say silver solder, I mean the low temp solder... I clean the cell ends well with some mild soap and water afterwards to get any flux residue off.

Now, I have not yet tried soldering the next gen ANR26650M1-B A123 cells... but Harris makes an aluminum solder and flux paste that works on aluminum as well as regular 60/40 solder does on brass... but my understanding is the next gen A123 cell metal casings have a coating on the aluminum, and the special solder and flux is not needed... I've solder several of the ANR26650M1A cells using the 60/40 or the silver solder with no problems... in my opinion the silver solder flows much nicer with the same heat, or less applied.


I will also add this... the solder tabs are induction spot welded to the cell ends after the cells are manufactured... when you solder on your own tabs, and you do it quickly as you see in the videos, I personally don't think any more heat goes into the cells than when you induction spot weld the solder tabs on... and don't forget, the MFG'er (A123) solders the end button caps over the fill / vent after the cell is manufactured.... but having said that, if you don't know how to solder well, then you could put too much heat, but with my experience, they solder extremely well.


John M,
Acid flux is not a good idea for any electrical soldering. The acid will creep up the wire under the insulation and cause corrosion of the wire.
Scoring the end of the cell with any kind of abrasive will remove the coating and make it very hard to solder to. They have always had a coating.
You cannot touch the end of the cell quick enough to transfer heat as small as spot welding.
Old 10-03-2015, 02:45 PM
  #152  
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Originally Posted by dirtybird
Acid flux is not a good idea for any electrical soldering. The acid will creep up the wire under the insulation and cause corrosion of the wire.
Scoring the end of the cell with any kind of abrasive will remove the coating and make it very hard to solder to. They have always had a coating.
You cannot touch the end of the cell quick enough to transfer heat as small as spot welding.
DirtyBird, its just a smear of flux on the end of a Q-tip, not enough to wick under anywhere... besides, the area in which you are applying the flux and solder to, has no insulation to wick under... just a few wipes with a 3M scotch brite pad and a smear of the flux and the solder flows very well... then a couple drops of mild dish soap in some water and scrub the ends with an old tooth brush to get any flux residue off.

My inlaw and I have been doing this for over three years, he longer than I, as he and I were sharing his aircraft for a while, until I got something large enough to fly for myself while I refurbished my Sig 1/4 cub... the amount of heat transferred into the cell casing is very small...the solder will pass more current than 4 small spot welds will... I'm extremely confident that the integrity of the battery is in no way compromised... the battery temperature at the ends after soldering is no where near as hot as if you where to pull 30 amps through the cell for a few minutes... now if you lay the soldering iron on for too long, you going to damage the end cap insulators inside the casing, but once you see how quickly they solder with the right iron, solder and flux, you won't have any concerns


Jon M,

Last edited by John_M_; 10-03-2015 at 02:49 PM.
Old 10-03-2015, 05:14 PM
  #153  
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Well John all I have left to say is it is your airplanes.
Good luck
Old 10-03-2015, 07:23 PM
  #154  
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Soldering directly to cells to make your own packs is not for everyone.It is an advanced technique. I agree with John here. If done correctly it poses little risk of internal damage to a cell. If you need to touch an iron for more than 1 or 2 seconds at the most you have already failed. Correct fluxing and solder selection are also important to make it happen.
Old 10-03-2015, 08:24 PM
  #155  
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Thanks Aerocal for the support... tinning the cells, 2 seconds is usually all it takes, joining the straps 2-3 seconds per cell using a good quality soldering iron with a heavy tip... these a123 cells are pretty robust inside... there are images on the web where someone dissected a cell, and the connections inside at the ends are fairly substantial, its the plastic insulator disc inside at each end you have to be careful not to overheat.

As you say, its for the individual that knows how or has experience with... not everyone has the skill, but once you have done the first one, you get the feel for it... you can always practice on some old cells first.


We'll leave well enough along and move on with the subject at hand... there is a battery forum to discuss this in.



John M,

Last edited by John_M_; 10-03-2015 at 08:27 PM.
Old 10-05-2015, 04:25 AM
  #156  
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I would like some info on the monitoring of A123 cells How do you know when a A123 pack or a lifepo4 pack (soft pack) is starting to show sine's of weakness and should be replaced?
I have been using NiCad and Nickel Metal for 40 plus years and have grown old with them. I check the batteries constantly and can see the drop in voltage to give me a clue that they need to be charged or are getting weak and should be replaced. I have had times a fairly new NiCad or NiMh pack are weak, The A123 and Lifep04 packs maintain there voltage and current and have a very short time when the battery fails to deliver the required current. I have used Lipo batteries for quite a few years. but it's been in small electrics. And have had a battery go from good to bad. I know about not letting the battery discharge to far and not to exceed the current draw of the battery and to store them properly. But A123's are new to me for using in my flight packs.

I have a Hyperion battery checker. But am new to using it for this style of battery.

When storing A123 packs should they be drawn down for storage? The reason I ask is they were used in power tools and I know they were not always maintained.
Old 10-05-2015, 04:45 AM
  #157  
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A123's are very hardy cells and put up with a fair amount of abuse. They have no memory and you can store them fully charged w/o issue. Indeed I charged up some stuff for an event next weekend when I got home Sunday afternoon and put everything in the trailer. All I have to do Saturday morning is pull in, unpack, and fly.

To answer your question I monitor the amount of charge being put back in after a given flights. If it changes much then I cycle the pack on a discharger to determine capacity.
Old 10-05-2015, 05:26 AM
  #158  
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I am not sure if you posted your source and what mah batteries you use. Can you post this info?

Thanks
Old 10-05-2015, 05:34 AM
  #159  
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Me?

www.wrongwayrc.com 2300 and now 2500 mah packs
www.taildraggerrc.com as well

WrongWay will make any combination of wiring you desire, I charge using a CellPro 4S which gives a pretty accurate remaining capacity when you plug it up and indicates the Mah returned to the pack
Old 10-05-2015, 06:47 AM
  #160  
dirtybird
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Originally Posted by BarracudaHockey
A123's are very hardy cells and put up with a fair amount of abuse. They have no memory and you can store them fully charged w/o issue. Indeed I charged up some stuff for an event next weekend when I got home Sunday afternoon and put everything in the trailer. All I have to do Saturday morning is pull in, unpack, and fly.

To answer your question I monitor the amount of charge being put back in after a given flights. If it changes much then I cycle the pack on a discharger to determine capacity.
When A123's first appeared I obtained a large number harvested from Dewalt packs . Most were used. I just charged them all up with my Celpro 10 charger. Some have sat in my garage that sometimes hits 140 d. in the summer. Thats been seven years. Most when I pull them out are still charged. Some have been bad but then they were used cell to begin with.
I used a pack of nine made up to resemble a radial engine to power a Lazy Ace. I got about 400 6 minute flights before I had to replace them. The current while in flight was about 20-30 amps.
There is no practical way to measure and know the power left. You just have to keep track of your flight time.
If you have a decent transmitter you can program it to do that for you

Last edited by dirtybird; 10-05-2015 at 06:50 AM. Reason: ad info
Old 10-05-2015, 06:53 AM
  #161  
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Just looks like a new learning and trust curve for me Thanks for the information guy's
Old 10-06-2015, 10:06 AM
  #162  
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I read this thread with great interest. I have not read the "other" thread, so I go on the assumption that the other thread was about brown outs too.

The answer is fairly simple. Size the electronics in your plane for the maximum amp draw that the plane is capable of. The main word here is "capable".

You can use the KISS method. Usually this means no redundancy, and not enough amps.

I am all for redundancy in a plane larger than 33%. I use a Power Expander (PE), A123's and pin switches.

The movable switch is usually the most likely failure point in any system, new or old. The pin switch is always open except when your prop isn't turning.

One thing I have not seen talked about, but is extremely important. The servo lead connector. This connector is only good for 2 amps or so. This is the biggest bottle neck in our "electronics package" that we fliers are using to date. Add more connectors between the RX and the servo, (extensions, y's etc) the resistance goes up & the amps (voltage) go down. Always make sure that you only have 1 connector in the line to the servo, and that is at the RX/PE/powersource. Learn to solder.

For the life of me I cannot understand why someone would use a 3 pin connector to power a RX with many amp drawing servos hanging off of it. It is beyond me. I also see some setups where they have used as many as 4 of these connectors to power the RX from the battery. Good grief dudes, talk about potential brown outs! Other posters have seen spikes in the 30 amp range. Do you think 2-4 of these 2 amp connectors are going to pass 30 amps to the RX for a couple seconds?

I have been building battery packs for many moons now. I have built nicad, nickel metal, Li, LiPo & A123 packs. As of this writing I have had one Nickel metal pack fail on me (many years ago). I solder on all with a very big iron. Some of my A123's have been in service for 7 years. Still going strong. For the average / above average flier I see no need to fly with any other chemistry. You can damn near weld with the amp output of these packs. Even the cheaper knock offs (of A123) put out more than our models will ever need.

I have also been using A123's with all my Hitec servos. From the 56XX series to the 79XX series. All have lived up to A123's unregulated. I don't need anything better(?) than a 7955. My fingers can't tell the difference!

In conclusion, get rid of that slide switch, one 3 pin connector per servo and run a PE with A123's through Deans connectors. Your system will NEVER have a problem with not enough amps/voltage at the servo* or at the RX.


Regards,

Stan


* The one condition I can see overloading the connector to the servo is if it stalls, that servo is going to draw more amps than the connector can pass. At this time, with the 3 pin connectors being used, this cannot be helped.
Old 10-06-2015, 11:49 AM
  #163  
boater
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Originally Posted by Whymee


* The one condition I can see overloading the connector to the servo is if it stalls, that servo is going to draw more amps than the connector can pass. At this time, with the 3 pin connectors being used, this cannot be helped.

Have you ever had heat damage to a servo lead connector??
Old 10-06-2015, 12:09 PM
  #164  
dirtybird
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(* The one condition I can see overloading the connector to the servo is if it stalls, that servo is going to draw more amps than the connector can pass. At this time, with the 3 pin connectors being used, this cannot be helped.)

The servo motor will burn out long before the connector.
That amp rating for the connector is for continuous duty.
The short term spikes will not bother it.

Old 10-06-2015, 12:25 PM
  #165  
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Originally Posted by Whymee
I read this thread with great interest. I have not read the "other" thread, so I go on the assumption that the other thread was about brown outs too.

The answer is fairly simple. Size the electronics in your plane for the maximum amp draw that the plane is capable of. The main word here is "capable".

You can use the KISS method. Usually this means no redundancy, and not enough amps.

I am all for redundancy in a plane larger than 33%. I use a Power Expander (PE), A123's and pin switches.

The movable switch is usually the most likely failure point in any system, new or old. The pin switch is always open except when your prop isn't turning.

One thing I have not seen talked about, but is extremely important. The servo lead connector. This connector is only good for 2 amps or so. This is the biggest bottle neck in our "electronics package" that we fliers are using to date. Add more connectors between the RX and the servo, (extensions, y's etc) the resistance goes up & the amps (voltage) go down. Always make sure that you only have 1 connector in the line to the servo, and that is at the RX/PE/powersource. Learn to solder.

For the life of me I cannot understand why someone would use a 3 pin connector to power a RX with many amp drawing servos hanging off of it. It is beyond me. I also see some setups where they have used as many as 4 of these connectors to power the RX from the battery. Good grief dudes, talk about potential brown outs! Other posters have seen spikes in the 30 amp range. Do you think 2-4 of these 2 amp connectors are going to pass 30 amps to the RX for a couple seconds?

I have been building battery packs for many moons now. I have built nicad, nickel metal, Li, LiPo & A123 packs. As of this writing I have had one Nickel metal pack fail on me (many years ago). I solder on all with a very big iron. Some of my A123's have been in service for 7 years. Still going strong. For the average / above average flier I see no need to fly with any other chemistry. You can damn near weld with the amp output of these packs. Even the cheaper knock offs (of A123) put out more than our models will ever need.

I have also been using A123's with all my Hitec servos. From the 56XX series to the 79XX series. All have lived up to A123's unregulated. I don't need anything better(?) than a 7955. My fingers can't tell the difference!

In conclusion, get rid of that slide switch, one 3 pin connector per servo and run a PE with A123's through Deans connectors. Your system will NEVER have a problem with not enough amps/voltage at the servo* or at the RX.


Regards,

Stan


* The one condition I can see overloading the connector to the servo is if it stalls, that servo is going to draw more amps than the connector can pass. At this time, with the 3 pin connectors being used, this cannot be helped.
+1 Stan.

In my situation I don't need the power requirements say for example a 35-40% 3-D plane when your pulling several servo's at one time to their max. Additionally I don't have vibration issues. My main variance from your post is I use heavy duty slide switches. Not saying its the best way , but it works in all my set ups and so far no problems.

K.O.
Old 10-06-2015, 02:26 PM
  #166  
Whymee
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Originally Posted by boater
Have you ever had heat damage to a servo lead connector??
Yes sir I have.

In a World Models p-51 that I had bought. I flew it for 3-5 flights or so after the purchase. Was at a fly-in & decided to trade it sans electrics. When I pulled the wing servos (it had extensions) the extension connector in the wing was severely melted. Very close to fail in my opinion.

Granted I did not know its previous history. I flew it with "kid gloves". Never the less it happened and it taught me a lesson. A cheap lesson. For someone else it might not turn out so inexpensive.


Originally Posted by dirtybird
(* The one condition I can see overloading the connector to the servo is if it stalls, that servo is going to draw more amps than the connector can pass. At this time, with the 3 pin connectors being used, this cannot be helped.)

The servo motor will burn out long before the connector.
That amp rating for the connector is for continuous duty.
The short term spikes will not bother it.
This is good to know dirtybird. I just hope I never have to find out if it is true! A 7955 @6V stalled is 4.2 amps, x2, add in a "Y" connector (going through 3 ,3 pin connectors), I personally do not want to take that chance.

Blue Skies,

Stan
Old 10-07-2015, 09:06 AM
  #167  
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Here's an interesting read about DSM2 dated 2010... it just proves there are other causes of loss of link, or lockouts... more the reason I would not fly DMS2 with an expensive model.


http://www.rcmodelreviews.com/dsm2flaw.shtml



John M,
Old 10-07-2015, 09:38 AM
  #168  
Whymee
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Nice read John.

How about this tidbit...

Brownout resistance

Firstly, the clear loser here, and by quite a large margin, was the JR/Spektrum.


http://www.rcmodelreviews.com/2.4ghzshootout.shtml

If I flew JR/Spektrum I would be concerned. Now that I think of it, that's prolly what started this discussion.

In this instance, knowledge truly means power.

Fly safe gentleman!

Stan
Old 10-07-2015, 02:44 PM
  #169  
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Originally Posted by Whymee
Nice read John.

How about this tidbit...

Brownout resistance

Firstly, the clear loser here, and by quite a large margin, was the JR/Spektrum.


http://www.rcmodelreviews.com/2.4ghzshootout.shtml

If I flew JR/Spektrum I would be concerned. Now that I think of it, that's prolly what started this discussion.

In this instance, knowledge truly means power.

Fly safe gentleman!

Stan
That guy that wrote that review used to post using xjet as his handle. I think he got booted off most forums for being a pest.He ranted a long time about loose doors on microwave ovens was going to shoot everyone down. He has a lot of crap on YouTube.
He also had a lot of personal problems with Spektrum.
He once claimed he could make a pulsejet missile cheaper and better than any government. I think he was exposed as a fraud.
I would take his reviews with a grain of salt.
Old 10-07-2015, 02:54 PM
  #170  
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Yeah, but that review was dated back in 2010. Things might be better by now.

Bob
Old 10-08-2015, 04:39 AM
  #171  
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Originally Posted by AirmanBob
Yeah, but that review was dated back in 2010. Things might be better by now.

Bob
Lets hope that things are better now!

I didn't realize the date. My apologies for dredging up old news.
Old 10-08-2015, 07:06 AM
  #172  
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Well how about this folks. There is a lot of DSM2 stuff out there myself included. From what I have researched the DSM2 seems to only have issues when there are a lot of transmitters on at the same time..
I have yet to have any issues with these receivers. But are these receivers out dated and should not be used. I don't have the finances to replace all my receivers. Years back when DSM2 came to market. Horizon had a 2 for 1 promotion. I took full advantage of it. I think I got 4 free receivers. And they are still in use.

Thanks
Old 10-08-2015, 07:21 AM
  #173  
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If you're not having any issue, flying at large events (think LARGE like Nall or IRCHA not a 25 person club fun fly) and are using adequate power to your receiver you won't have any problem.

I would suggest you check that you have the latest firmware on them by linking up the system and turning off and on the receiver. One of three things will happen.
1. Oldest - the system will link in about 3 seconds and the lights will come on steady (I personally wouldn't fly these)
2. Better - the system will link instantly and the lights will come on steady.
3. Latest - the system will link instantly and the receiver lights will flash indicating a brown out.
Old 10-08-2015, 12:54 PM
  #174  
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Thanks I will do that

Can the receivers be updated if necessary?
Old 10-08-2015, 02:35 PM
  #175  
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The "other Andy" would be the one best to answer that, or a call to Horizon support

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