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Old Feb 16, 2005, 03:55 PM
LJH
Moths do not fly inverted
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Greenwich CT.
Joined Sep 2000
4,191 Posts
Whats the big deal about haveing Lipo cut off on your ESC?

I see this time and again about people saying that they have to have Lipo LVC on there ESC's. I have been flying E power for 6 years now and still fly lots of planes that were put together way before we had even heard of Lipo batteries for E flight and I have no issues. Just fly the plane for set amount of time that you will know is safe, then just charge the pack and see how many Mah goes back in and you can get a pretty good idea how long you can fly. I have gotten to the point that I can guesstamate within a min. of how long I can fly for.

Getting off my soap box now.

Cheers,
Jim
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Old Feb 16, 2005, 03:59 PM
Registered User
Strathmore, Alberta Canada
Joined Jan 2004
848 Posts
I have a apache 2020 charger and do not know how to calculate how much I put back into a partially charged pack.. is there some way to calculate this.

I.E charging back at 750mah for 45mins or something
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Old Feb 16, 2005, 04:08 PM
crashin with a smile
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Los Angeles Industry, California, United States
Joined Jul 2004
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Well after a few $50 mistakes in your timing you will see the importance of lvc for lipos. Its not that there is timing issues it is simply that if a lipo charge reaches below 3.6 per cell the batt can go flat and render it useless. I have jump started a few that I have accidentally forgot to change lvc for but they were pretty much useless when it came to having the same punch or longevity
Just my 2 cents but don't be surprised to see many more agree with me.
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Old Feb 16, 2005, 04:08 PM
LJH
Moths do not fly inverted
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Greenwich CT.
Joined Sep 2000
4,191 Posts
Hmmm....Nick you bring up a good point. I guess for someone who does not have a charger with a Mah readout you could use you DVM to check voltage after a flight and figure out how long you can fly by your voltage.

Cheers,
Jim
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Old Feb 16, 2005, 04:17 PM
LJH
Moths do not fly inverted
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Greenwich CT.
Joined Sep 2000
4,191 Posts
SD7,
I am going to have to disagree, I have been flying Lipo since the first Kokam 1020's came out and now own close to 20 Lipo packs and I have never distroyed a pack flying it. You can safely bring a lipo cell down to 3V if not a skoch lower with out distroying it. My 4 E-Tech 1200HP 3S packs normally show 9.3-9.5V resting after a flight and two of them are closeing in on 100 cycles (still taking over 1100mah) and the other two are around 50 cycles (taking around 1225mah).

Cheers,
Jim
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Old Feb 16, 2005, 04:27 PM
A Clinger
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Butte, MT
Joined Sep 2001
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Jim, I am another one that times the flights. I too watch what I put back in and get a 'good' estimate of flying time. I set my LVC at 7.2 (for a 3S pack) and go fly (timed of course) . I have accidently flown 'longer' than I should have a couple of times, but it is very apparent when it's about time to land and of course I do so immediately with minimum throttle to get the plane down.... Never saw a problem with the pack(s) ....

I can see with cheap chargers you probably would have to rely on the LVC .... Of course once you 'hit' the LVC you should have a good idea of the time and time your flights from then on anyway....
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Old Feb 16, 2005, 04:50 PM
crashin with a smile
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Los Angeles Industry, California, United States
Joined Jul 2004
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Jim Remember that running voltage and standing voltage are two different things. I also set my cutoff at 7.2 for 3S but when it is cutoff the standing voltage on ground is still around 9.8 to 10v. I am simply trying to help you understand why we use this system. If you can time flight and judge power of the cell great for you. I know on my gas slimers I have to as well time all flights. Especially with my tequila sunrize. That baby flies awesome but deadstick it drops like a rock
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Old Feb 16, 2005, 05:00 PM
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Australia
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I am the same with my Etec packs..about 8 packs...close to 50 cycles without a Lipo Esc..all is well if u stop flying when the 1st cutoff drops in. My biggest is 3S. I will not do that with packs greater than 3S.
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