Posts: 170
Joined: 4/13/2003 From: Oklahoma City,
OK, USA Status: offline
Anybody, Pro and cons of using a regulator w/ 6V system. Plan to use 2 packs and 2 switches into different RX ports. HiTech Supreme RX w/ JR coreless servos.
Q: Constant voltage vs. one more fail point (regulator) in system?
Posts: 12946
Joined: 4/9/2002 From: Locust Grove,
GA, USA Status: offline
I would not use a regulator with a 5 cell pack. How you are going to wire in the two packs is correct
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Posts: 3479
Joined: 12/3/2001 From: Vineland,
NJ, USA Status: offline
I can offer some experience over opinion. I bought a 40% plane all set up last season and didn't change anything as far as batteries etc. I've been running 6 volts through (2) seperate JR receivers with a total of 11 8411 servos without regulators for about a year now without a problem. You will get a million answers and reasons to a question like this. Talk to some people that use both and then do what you are comfortable with_bob
Posts: 39
Joined: 10/12/2002 From: Fairbanks,
AK, USA Status: offline
Only thing I dont care for is jittery servos when using 5 cells without regulator. This goes away after first flight as battery peak voltage settles down. No other problems noted for me. Not all servos are sensitive to the jitters issue. I like the 5 cell backup theory and use it instead of a backup pack. One cell can fail and you still have a 4.8 volt pack. If this happens you should catch it between flights when you preflight. I have used regulators without problems and like them. Haven't seen failure problems with them, however not many used in this area. Takes care of the jitter issue if you have it and keeps servo speed more consistant through several flights. I also wire my 5 cell pack with two switches for switch backup. I'm still a nicad fan so this probably wont apply to other battery types. Gives me the peace of mind I need.
Posts: 864
Joined: 5/25/2002 From: Catoosa,
OK, USA Status: online
Tack, I disagree with your 5-cell pack backup theory. If you lose a cell in your pack, the others will immediately start to drain and you will lose the whole pack before you know what hit you. This happened to me last month in a Duraplane. One cell shorted in a 5 cell pack and it drained the rest and a crash happened. I had just checked the pack on the ground before the flight. I took the pack apart and the non-shorted cells were still good but drained. I'm guessing I lost the use of the pack around 3 minutes after it shorted out, with no indication in flight except when control was lost. I now use two packs into the receiver through seperate switches.
Posts: 6220
Joined: 6/18/2002 From: Missouri City, TX, USA Status: offline
Jesse, just out of curiosity, was that a NiCd or Nimh pack ? How old was it ? When was the last time you cycled the pack to check if the capacity went below 80% ? Thx.............
Posts: 864
Joined: 5/25/2002 From: Catoosa,
OK, USA Status: online
It was a NiCd 1100 mah battery I got from ebay as new. It was about 1 year old. Unfortunately, my version of "cycling" was to put the battery across a 12 volt bulb to discharge it, then run it through the wall wart to charge. And I didn't even do it that often. My lack of battery maintenance contributed to the event, but it was interesting to see what does occur when a cell shorts out in what I thought was a "good" battery pack. Immediately after the crash, I found the pack close to the wreck and was almost burned when I picked it up. One of the cells was just scalding hot. The connector ripped off so that's when I decided to take it apart. Now that I've learned my lesson, I got a new Supernova to start maintaining these often neglected batteries. Lucky it only cost me a Duraplane and not something more pricey.
Posts: 39
Joined: 10/12/2002 From: Fairbanks,
AK, USA Status: offline
HI Jesse, Actually my theory is correct for nicad technolodgy. When a nicad cell loses its voltage, we say it shorts which does not cause drain on the other cells because they are wired in series, but rather the short lets current from the other batteries flow through the shorted cell. So if you lose one cell you have in effect a 4.8 volt pack. As you can see, this would not work very well with cell types that fail in the open mode as current wont flow across a open cell. Sorry to hear you lost a plane. I hope using your cycler and checking batts. with a ESV between flights will help prevent this in the future. This technique has given me years of safe flying with nicads. It is quite an eye opener to do a ESV check and find low voltage before you fly. Good luck to you.
I'm a little reluctant to use a regulator now, and I'll explain you why.
2 years ago, I was testing a setup in my sport plane, before I put it in my $$$patern plane. Simple setup.... A 5 cell 1100 NiCd pack and a voltage regulator, connected to a standard radio setup.
The instructions for the regulator stated that we should connect it between the switch and the receiver, because if we connected it between the switch and battery, we might be unable to charge the battery pack using the charge jack that is part of the switch harness... Just like if the regulator was "one-way" only.
Since I needed an extension from the battery to the switch, and that I remove the batteries from the plane to charge them anyway (storage contraint), I thought there would be nothing wrong with connecting the regulator between the battery and the switch... so I did it.
I fully charged the 5-cell pack, put it back in the plane, and went flying 5 days later. I couldn't test the pack with my ESV, because the one I had then was only able to test 4 cell Rx batteries. So I assumed that my pack was still fully charged. I did one full flight, and shortly after take-off on the second flight, I lost control at 200 feet, full power, doing a split-s. Plane hit the ground 90 deg at an estimated 130 mph. Nothing left as you can see on the pic.
Well... to make a long story short.... I discovered after the crash that the regulator was putting an approximate 8mAh load on the battery... just by having it connected to the battery, even with the switch off. If we make a bit of maths.... 5 days time 24 hours... 120 hours. 120 hours at 8 mAh, that's 960 mAh that was drained from my battery pack before the flight (and I thought the pack was full). So I had just enough juice left for 1 1/2 flight.
I'm not saying that I will never use a regulator again, but I will certainly be more careful. I now have a volmeter that can check 5 cells Rx batteries....
Posts: 145
Joined: 2/24/2002 From: Arlington,
TX, USA Status: offline
It 's not the fault of the regulator. It's an installation or instruction problem. The regulators I've used are explicit that the regulator, if connected directly to the battery, will put a load on the battery all the time. Therefore you must put the regulator between the switch and the receiver.
You have another option as far as regulators are concerned. You could buy a fail safe type unit. Or a regulator and switch built together as one. The problem of power usage in the off position will not go away, however these units only use about 5 micro amps or .005mah in the off position. By using one of these units, you can get rid of the extra connection points. There are a few manufactures of these switch regulator combos, Central hobbies carries the Jaccio switch, Smart fly has one, Maxx products has one, and we specialize in them.
My 1/2 cents
Kurt Co owner chief test pilot Fromeco Scale Avionics LLC [url]www.fromeco.org[/url] [email]wingnut@sandynet.org[/email]
[QUOTE]Originally posted by whstlngdeath Tack, I disagree with your 5-cell pack backup theory. If you lose a cell in your pack, the others will immediately start to drain and you will lose the whole pack before you know what hit you. This happened to me last month in a Duraplane. One cell shorted in a 5 cell pack and it drained the rest and a crash happened. I had just checked the pack on the ground before the flight. I took the pack apart and the non-shorted cells were still good but drained. I'm guessing I lost the use of the pack around 3 minutes after it shorted out, with no indication in flight except when control was lost. I now use two packs into the receiver through seperate switches.
Jesse [/QUOTE]
Failing shorted is the "normal" mode for NiCad failure. It does NOT drain the pack. It simply gives you about 1.2V less for every cell that failed.
Failing open is very rare, especially in flight. It that case you lose the pack as there is no longer a complete circuit.
Posts: 39
Joined: 10/12/2002 From: Fairbanks,
AK, USA Status: offline
Yes, You have to know and understand the regulator you are using. I use the Jaccio units w/failsafe. I disconnect the battery after the flying session because it will discharge the battery in the off position. Checking your batteries before each flight is most neccessary even if they just came off the charger. For me, no ESV check, no fly, Period! It must become habit. The most important preflight check!!!!
Posts: 1495
Joined: 3/22/2002 From: Lincoln, NE, USA Status: offline
My main concern about adding any single point of failure device is just that... i.e., it offers a single point of failure. Regulators would fall into this category, i.e. if the regulator fails, everything connected to that regulator shuts off. I'm sure regulator failures are rare as the device is pretty simple, but it is still a single point of failure.
You could get around this by having two regulators, but this just increases complexity. The more stuff that is added to your system, the greater the chance you will see a failure, but at least with a properly configured dual regulator setup, a signal regulator failure shouldn't bring the entire plane down.
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Red..6V...Regulator or Not - 
Red..6V...Regulator or Not - 
