I was wondering how you get you LiPo packs to the 3.8 to 3.9 volts per cell so you can store them. I'm new to Lipo's so I want my packs to last! Help will be much appreciated!!!

What you will want is a balancer and charger which is capable of cycling, charging and draining your lipos. using these 2 tools you can do anything you can think of

What I do is to hook up my Whattmeter and run the motor until I get down to 3.7 volts PER CELL. Then I wait about 15 minutes and do it again since the battery will pick up some voltage. You may need to do this several times before you get a steady reading of 3.7 volts per cell.

Hope this helps.

Well I don't have the money to go out and buy one of those fancy balancer/charger deals. I have the e-flite celectra charger and I was going to get the great planes equinox balancer and keep all my cells balanced correctly. Since its winter I don't get much flying time, so I just want to properly maintain my packs. Also will it be okay to just fully charge/balance my packs and just store them with a full charge? Or will the full charge cause the cells to drift and discharge at different rates? I just want to keep my packs in good shape. So would it just be a good idea to get the balancer and keep my packs balanced? Rather than shell out the cash which I don't have for a new charger?

I store mine charged, has not been an issue yet.
I had a couple of packs I bought new that were slightly overcharged from the manufacturer. I had to discharge them some before I could balance them.

Why must lipos be stored at 3.7V-3.9V?Never heard of that before ... from the factories its just like 65% charged and they can be stored. I just store mine fully charged.

I was reading that in a few post, and it kept resurfacing so I tried to find an explination as to why but I couldn't. There are so many different things people say you should do with your LiPo's, that it seems to be more of a hassle than good. One thing I have heard is just get a good balancer and keep them well balanced, which makes complete sense to me. I belive I'm just going to order the great planes equinox and use that with my e-flite celectra charger. Will that be sufficient do you think?

FYI

Radical RC has a pretty good FAQ (Frequently Asked Questions) section. The below is specifically written for information on charging and balancing LiPo batteries with the why's and how's. Nothing is mentioned about storage, however, he probably has something in his FAQ's about that. Meanwhile, take a look at this. It is very informative and written in plain english.

http://members.aol.com/davthacker/li...tructions2.htm

"Red" Scholefield from the RC Battery Clinic (http://www.rcbatteryclinic.com/ ) told me, via e-mail, that the recommended way to store lipo's is to charge or discharge them to 3.7 volts per cell. Red said this was the way the manufacturers keep their cells prior to building a pack.

So how does one charge or discharge a battery till its 3.7V per cell using a 'your average standard' charger? This is most interesting ...

I certainly don't want to dispute Mr. Scholefield' recommendations but if storage voltage is so important why have none of the multitude of lipo batteries I have owned mentioned this in any literature from the manufacturer and the only way this recommendation is even mentioned is from a 3rd party through an email or from rumors floating around.
Like I said I store mine fully charged and it works fine for me. I don't have any ancient lipo batteries but do have a couple that are several years old and still going strong.

Now I know why I am more of a glow guy than an electric.

At the "end of the season", just empty the fuel tank, or run it dry on the ground, then add a few drops of after run oil, plug up the muffler hole and the carb intake port, remove the RX battery and store it in a cool and dry spot, and put the aircraft away.

At the beginning of the next season or whenever the weather is OK during the 'winter', a couple days before flying, cycle the RX and TX batteries a couple times with no fanfare (no balance no nothing), then on the flying day, refuel, prime, hook up the glow driver, turn the engine and it starts (typical OS), tune and go fly. (don't get on me about not mentioning pre-flight because that is presumed with EVERY RC first flight of every day whether electric or glow).

Nothing to it.

CGr.

The only minor problem with the 3.7v storage recommendation, is that all batteries experience "self discharge" over time.

If your LiPo's end up getting too low, you've effectively ruined them and the may not be capable of being recharged.

So you have to take into account the amount of time the LiPo will be stored as well.

I've rarely seen more than 50-100mA of self discharge on LiPo 2200mAh+ packs over a 3 month period... which is pretty good.

I don't fly my electrics as often as I probably should. This may lead me to a problem because I don't know the charge status of my LiPo batteries, and I have about a dozen of them in various sizes and shapes.

I guess I ought to take a look and see what's going on with them to make sure they are ok. I do have a balance gizmo for the different types so I can go ahead and hit them with the charger with the balance gizmo attached and see how that works out.

Of course, all this is done out on the outside concrete patio... with a LiPo sack.

CGr.

OKay my question has still not got answered, I have the celectra charger by e-flite, I am going to get the electrifly equinox balancer, will this combination of keeping them charged and balanced, presumably be the ticket for maintaining and keeping my lipo's fresh?

You haven't gotten an answer because there is dissagreement about it.
My opinion? YES use the balancer and keep your batteries charged and you will be golden.

Well that wasn't quite your original question, which was more about voltage levels vis-a-vis storage.

Lipo's have finite lifespans in terms of charge/discharge cycles.

Keeping them balanced and preventing; overdischarge, overchargine, charging at too high a rate; drawing from the battery at too high of a rate, undue temperatures, etc. are the best techniques for longevity.

A good charger merely aids this process.

I appreciate your responses, and if you look at post # 7 I did state my previous question. Also I noted were I had seen my original question. I know there is a dissagreement, yet why can't we all get along? Also CGretired, put a lable on you packs telling you the date of charge and if it was a full charge or not, that will give you an idea on when you should check/ apply any "maintenance" on you packs. Hope this helps!

Controlled debate on subjects we may not agree on is good. We do all get along, we just don't agree on everything. That just proves we are human and not a bunch of mind numb robots

Some of this stuff is not black-and-white. There are quite a few differeing opinions on how to take care of this. But, generally, the same applies, and that's not to overcharge nor to let them get to low. Other than that, well, you can read.. so...

CGr

Ah yes, I just don't understand all the misconceptions on lipo's, they seem to be high maintenance if you ask me.

Oh yeah, and a lot more. I guess the key thing with them is to be safe with how you handle them. They have a potential for some serious problems if not cared for properly.

CGr.

That is a fact. I just came from the doctors office and while I was there I read an article about testing the FAA did with lipo batteries and a ban on loose lipo batteries that can be in checked in luggage as a result. Seems, as I read, that airplane fire suppresion equipment can't handle lithium fires.
For those planning on flying and bringing your electrics check ahead on any restrictions.

Exactly, thats why I just want to be as safe with them as possible, I mean I work extremely hard for my gear and these packs don't come cheap! I just want them to last, and I dont have the funds that allow me to buy all the fancy gadgets and charges, so I have to do the next best thing.

We do agonize over LiPo's quite a bit because of their high costs.

If they were cheap, but otherwise the same, there would be less emphasis put on storage voltages, etc.

There is so much variability that you are best advised to follow the already stated guidelines and use your own techniques.


I keep mine indoors, in a ammunitions metal locker box which keeps them slightly below ambient temp.

I charge them prior to storing them, and I top them off before flying with them again next season, using a balancer connected to the ICE charger.

I have over 36+ LiPo packs of different capacities.

I charge, check and maintain them using an ICE charger which has features missing from many other chargers.
I will sometimes quick charge them at the field using Accucycle chargers mounted on my E-Flight power box, powered by two 21mAh batteries.... however I usually haul enough batteries out to the field to enable me to fly all day long w/o recharging.

If I note any issues with a pack I will use the ICE charger's cycle/historical capability to analyse capacity, voltages, and temperature.

I balance charge the batteries

Those are my guidelines.