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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Doug Moon on June 07, 2013, 09:47:28 AM
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LiPos are not to be stored at full charge.
So, if you charge them up with the antcipation of going flying then you can't go for some reason how long can they sit charged before you need to discharge to the storage amount?
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Uh-oh.
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As near as I can tell from flying RC planes, leaving your LiPo's all charged up isn't going to kill them off immediately. It may shorten the life a bit, but if it was an "instant kill" I'd go through batteries a whole lot faster.
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Mike H. usually brings 4-5 fully charged batteries, and sometimes has to go home with a battery or two that are still fully charged. He says something about having to discharge them to "storage level", which I gather is a function that his fancy charger will do, but maybe he has some other piece of equipment that will do that? Probably not a big deal, if you know you can't go flying for a week, but a bit annoying if you figure you might possibly get out tomorrow. H^^ Steve
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My charger is pretty cool, nothing real fancy but it does have a storage setting. It will charge or discharge batteries to the desired long term storage levels.
I was just wondering as I have heard when left fully charged for extened times they can "puff" and then that battery is ruined. Or it can shorten the life cycle and the reduce the capacity.
Just currious about it as I dont want to ruin my LiPos.
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Doug,
Here is a practical answer. It’s practical because I have logged over 800 flights on a variety of battery capacities. All are Zippy or Turnigy Nano tech. I have batteries from 4 years ago that are still hold a charge and can fly the full pattern and not back off. Putting your batteries in storage charge is a very good thing. As a rule I never leave them fully charged for more than three days. My experience is that it does shorten the useful life of the battery and if left fully charged for a long time will cause them to puff. When flown they usually discharge pretty close to storage charge so I don’t worry too much about them for a week or two but will put thee in storage rather then leaving them slightly low.
Hope this helps,
Good luck at the Show!
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...but will put thee in storage rather then leaving them slightly low.
We only need to keep him in storage until after the Nats.
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So, are there chargers out there on the market that will allow one to discharge batteries for storage, and, don't cost an arm and a leg???
;D
Brew
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So, are there chargers out there on the market that will allow one to discharge batteries for storage, and, don't cost an arm and a leg??? ;D Brew
Here is one I have and it works fine - Thunder T610. Has a bit of learning curve on setting it up for your particular battery. The price is hard to beat.
http://www.hobbypartz.com/75p-t610-charger.html
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Both the Thunder Power 610 and the genuine Imax B6AC have a Discharge function that is simple to use. They both also have a "Storage Charge" function.
I have attached a doc file that was created by a major battery manufacturer. It should answer a lot of your questions regarding battery storage.
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I posted a similar question in a thread some time ago because my charger does not have the option to discharge to 3.8v per cell so I was having to discharge to 3.6v (The highest cell voltage on offer) and then re charge to 50% capacity. In the replies it was suggested using an ESC to achieve what I wanted. The CC Phoenix range for example allows you to configure the cut off voltage, so I mounted an old motor with a 5x3 prop and a Phoenix 25 which was not doing anything. I configured the phoenix to cut off at 3.8v per cell and I just connect my packs up to it and leave them running. (Timer set to an hour). It seems to work quite well. Obviously it's using total pack voltage rather than individual cell voltage so I then stick the pack on my LBA10 balancer to finish before finally using one of the battery checkers (Like the EOS century) just to verify the cells are indeed at or very close to the 3.8v. This will probably have people crawling over themselves to tell me it's a bad idea but I'm using packs approaching their 4th season of flying so I must be doing something right.
The only issue is you can't use CL (Or Helicopter) mode (Or at least not on my old Phoenix) because the Hard Cut Off is ineffective so it simply slows the motor to recover the voltage.
I'm prepared to be shot down in flames for suggesting this but it seems like a cost effective solution to someone with an cheap of older model charger.
TTFN
John.
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Improvise ... adapt ... overcome!
Sounds good to me, John!
Dean P.
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Thanks Dean,
I would love to take credit for this but it's Dennis Adamisin who pointed me in this direction. Necessity proved to be the mother of invention I guess but Dennis should take all the credit. If anyone does follow this approach remember that if you have several different cell counts you need to configure the ESC accordingly.
TTFN
John.
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John,
There is nothing wrong with the way you are discharging your packs. To save yourself some time don't bother balancing the cells in storage mode as it really doesn't matter as long as all of the cells are close. They will be balanced when you charge them back up again anyway. Many RC Pilots feel that as long as the packs are discharged to 50-60% of full power they will be fine.
William
PS. If you upgrade the firmware on your old phoenix the hard cutoff may then be effective.
PPS. I rarely notice users post counts but I happened to notice that as of right now we have the exact same post count. just a little bit of absolutely meaningless info thrown in.