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Old Jan 10, 2006, 08:26 AM
Vampowered!
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Crestview Florida
Joined Dec 2003
1,816 Posts
Careful!
Another REAL close call....take a look

This is what happens when you get complacent and careless. This guy was lucky.... lucky.
1) No charging container
2) Charging ON vehicle
3) Admittedly charged a 3 cell on 4 cell setting.

DOUBLE CHECK EVERYTHING.
All lipo's are volatile and please try to never forget that. This guy is my nephew and very lucky he is not walking everywhere he goes.

Peace
Vammy
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Old Jan 10, 2006, 08:58 AM
My Bulldog is my copilot ..
TheLost's Avatar
Joined Feb 2004
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Today might be a good day for everybody to remember lipos must be treated with respect.

Fred Bonk just had his garage burn down charging a 3s pack at 4s.

~Brian
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Old Jan 10, 2006, 12:12 PM
Who put that TREE there!!
Columbia, MO
Joined Dec 2005
622 Posts
wow, I'm brain storming on a safer way to store my lipos for the winter that I'm not using... guess I'll go get one of those sentry fire safes to keep them in. what charge state should lipo's be left at for safe storage?
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Old Jan 10, 2006, 12:38 PM
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Joined Sep 2005
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I am thinking about following the directions and not charging them on the wrong settings myself
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Old Jan 10, 2006, 01:26 PM
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United States, VA, Chesterfield
Joined Mar 2001
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We need a charger with a default of off or won't work until you adjust a dial or series of lights for cell number and amps. I have had two fires (thankfully contained to the bench) because of forgetting to switch the cell number from 3 to 2. These autodetects scare me and the same goes for the ones like Apache and Kokam that have little jumper clips--tired and old eyes don't see these too well. Need a dial or led or screen--sort of like the Astro 110D was. I don't want a charger that is on until I turn it on after selecting the cell number and amps.

Pat
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Old Jan 10, 2006, 01:31 PM
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USA, TX, Trophy Club
Joined May 2002
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Quote:
We need a charger with a default of off or won't work until you adjust a dial or series of lights for cell number and amps
I agree Pat. One charger I have never been able to fool - the Triton. I set it wrong once, it started beeping within a couple of minutes. Wrong voltage set.

We just can't get lazy about it but I fear nothing will ever be foolproof.

Mike
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Old Jan 10, 2006, 01:42 PM
On loan to Texas
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United States, TX, Benbrook
Joined Oct 2005
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Iím feeling pretty good now with my auto detect charger.
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Old Jan 10, 2006, 01:43 PM
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Joined Dec 2004
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I guess the purpose of the charger on a car battery to kick up the voltage if you are charging a 4 cell Lipo, or to more quickly charge a 3 cell even though the sourse voltage is 12.5. but if you are charging a 3 cell, since most all car batteries at 1-3 amp drain are still in the 12.5 range, cant you just put a lipo directly on the car battery and leave it for an hour for a 3-4 amphour charge? sure seems logical for a field charger if you have an hour to loose.

as Ive mentioned, im new to the lipo game, but did some research after i almost toasted a Lipo (thanks to this forum for the info to learn about the tech.), i was able to revive a slightly overcharged battery and use it successfully for sometime now.
I still havent broken down to buy a "correct" charger, but at home, i charge my lipos with my varible voltage powersupply that i set at 12.6volts applied to the battery (usually 13.5 volt on the charger) , then after 15min of about 3amp charge, i drop it down to 12.7 volts on the charger and it applies 11.8 to 12 volts for an hour or so at 1-2amps, after 1 hour, that drops to sub 1amp and finishes the 2 hour charge at 50ma, 12.5-6 volts on the battery (all on a 4200 3s2p Lipo). Is there a problem with charging this way, other than the hassle factor?
thanks!
mark
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Old Jan 10, 2006, 01:51 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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Quote:
since most all car batteries at 1-3 amp drain are still in the 12.5 range, cant you just put a lipo directly on the car battery and leave it for an hour for a 3-4 amphour charge? sure seems logical for a field charger if you have an hour to loose.
LiPoly are charged with a CC/CV charger. The CC must be limited to a max. of 1C. There is no real current regulation if a discharge 3S LiPoly is connected across a 12.5 V source of allmost unlimited amps briefly. A 11 volt 1000 mAh (iAh) . Lipoly receivng the inrush from a 12.5 V 400 A burst power source could be most interesting.

If you can not afford the correct LiPoly chargers then do not purchase the LiPoly batteries.

Charles
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Old Jan 10, 2006, 01:54 PM
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Quote:
Originally Posted by pda4you
I agree Pat. One charger I have never been able to fool - the Triton. I set it wrong once, it started beeping within a couple of minutes. Wrong voltage set.

We just can't get lazy about it but I fear nothing will ever be foolproof.

Mike
Not to single out the Triton......

But with chargers that handle multiple chemistries like the Triton you CAN get into big trouble by charging a Lipo on Nicad or Nimh........ That is why many prefer a Lithium charger that ONLY does Lithium.

Auto detect has problems at high series packs where there is voltage overlap and even though a "user confirmation" is a good feature it wont stop some complacency.

"User Select" is subject to "User Error"......

The only solution is education and not getting lazy..... but as you point out nothing will ever be foolproof.

Brad
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Old Jan 10, 2006, 03:33 PM
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Very true - thankfully all my errors have been on the LiPoly settings. No question a time with NiMh would have been devistating, as can the higher charge currents.

No charger made smarter that us?!

Mike
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Old Jan 10, 2006, 05:30 PM
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I understand, but isnt there an easy fix to that? just have a 2-3 ohm resistor on initial hook up that is turned off after some charge time (ie 1min or something). then, the current wouldnt "spike". I would think there is some internal restance in the battery to keep spikes from being in the 400amp range, but thats a guess on my part. either way, ive been using a fluke meter to monitor current in the battery on initial hook up an usually, i take my powersupply and start at near 11volts applied and move up from that for the next minutes until i get to an applied voltage that gives .75C (usually 12volts or so)

I could be missing something here, but it seems pretty simple, but unusually unforgiving for any mistakes. is this kind of the situation?

I just dont fly that much any more and becuase the charging operation is pretty easy if you do it right manually, i take 2-3 hours one day approaching fly day and charge the lipo, and then i go to the field and and use my 2 2400ma nicad packs for the first flights and then my Lipo for the long and much more fun flight (huge difference in power and weight!)

MK




Quote:
Originally Posted by everydayflyer
LiPoly are charged with a CC/CV charger. The CC must be limited to a max. of 1C. There is no real current regulation if a discharge 3S LiPoly is connected across a 12.5 V source of allmost unlimited amps briefly. A 11 volt 1000 mAh (iAh) . Lipoly receivng the inrush from a 12.5 V 400 A burst power source could be most interesting.

If you can not afford the correct LiPoly chargers then do not purchase the LiPoly batteries.

Charles
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Old Jan 10, 2006, 05:51 PM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
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But most days I fly many times. My average is approximately 10 hr. per week.
I flew one LiPoly 385 times in one year. I have flown many single LiPolys 75-80 flights in a month for testing. My charging system needs to be efficeient, I do not want to spend all of my time charging. Having seven LiPoly chargers and approximately 80 LIPolys means that I can go to the field and fly for awhile without running out of juce.

Charles
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Old Jan 10, 2006, 10:20 PM
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United States, VA, Chesterfield
Joined Mar 2001
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Charles

I must have at leat 50 lipo packs--all 2 and 3 cell-- nothing else. When I fly with my buddies, I drive 200mile roundtrip and I fly for 6 hours or so. When I get home, I am tired. I usually start charging that evening. Sometimes --actually twice in 5 years of lipos, I have made the mistake of pluggin a 2 cell pack into a simple kokam charge on set for 3 cells. This is 2 mistakes out of problably 300-400 charging sessions (I fly about 100 times a year)--so my error rate is pretty low.

What I want is a charger that makes me make the same mistake at least twice in a row -- ie. charger won't work till you set it. If it sets wrong it tells you and you have to fix it. Maybe that will cut down the problem.

Pat
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Old Jan 10, 2006, 11:11 PM
Tied to the whipping post
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Warm-Sunny-no-Wind, Az.
Joined Dec 2003
2,479 Posts
I use my tritons (2) all the time but it is used to only charge lipos 2 and 3 cell. If it is set incorrectly (2-3 cell) it complains loudly. Just ask my wife!

A good lawyer might be able to have Chevy pay for damages (sic)
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