Yeah, as a matter of fact we had that conversation lastnight at school, I'm going to school to get my A&P license and we were discussing that issue!

WOW opjose! I only have three packs and I'm flipping out about storage!!!

What I heard about storage is simple, makes sense and is easy to do. Store the batteries at 50% +/- period.
After a full charge run about 1/2 the amount of run time off your battery and put it away. Just what I read and makes some sense.

And this is debateable...

What about self discharge?

Let's say you store a small 600mAh LiPo for many months.

With approximately 300mAh remaining, the battery may turn useless in 3 to 6 months of storage.

I've received brand new phone & PDA LiPo's that had been sitting too long, where this had happened. The whole batch was useless.

Better to store them charged up enough to survice the storage interval. Even better to figure out what the self discharge rate is for each of your packs and use this as a guideline for determining how much charge to put back before storage.

It is debatable! small batterys have less discharge? This was what I read from the MFG. of the batteries and seemed an easy process and thats what the poster was looking for. If you don't pay attention to your $40+ batteries in 6 monthes-shame on you!

Yes it also means not enough flying time!



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Re: Small batteries

You should test them.

I have.

This is why I gave the scenario I did, even though LiPo's are very good with self discharge rates.

If the battery will be stored for a good length of time, storing them at half capacity may not be a good idea.

And if they will be stored for close to a year or more, it would pay to recharge them periodically.

Get a Cellpro 4S charger. It has a setting that will charge the pack to 50%. It will also balance the battery as it charges. It has got to be the most user-friendly charger on earth. You just plug in the battery and let it do its thing. On top of that, you can charge your packs at 2C and 3C if you are in a hurry without having to worry about the pack burning up. It is truly a great charger.

I spoke with a leading manufacturer for lipo, they are based here so some of you might be able to guess who. There is no truth in needing to store a lipo at 3.7V. Manufacturers DO NOT store it at full charges because:

i. there is less risk if it shorts
ii. they do not need to charge the battery (extra work, extra cost)

Its safe to store your battery at full charge even. Just do not store it near 3.1V or 3.2V, its obvious why. Hope this clarifies things for all.

JCB - not all packs can handle 2C-3C charging rates, the new FP/PQ/Hyperion/TP ones can BUT it will degrade the life span. Want things to go fast ... well the life span goes fast too. Fact of life I guess ...

If you are going to charge at 2C - 3C, then may I suggest you do so out doors? Or at least make sure your home owners insurance is paid up.

This is a direct quote from Radical RC a known battery expert:

Note that he states 'at the maximum rate of capacity X 1 (which means 1C). He may not have emphasized that, but that's the safety issue here. Why would you want to charge it at 2C or 3C anyway? If it's that important that you get back in the air, then buy a second or third battery pack.

CGr.

Fires are a fact of life too. Why charge any of them at that rate? What's the hurry? If you are in that much of a hurry, buy a second or third pack. Jeech.. this is not rocket science here.

CGr

Cell pro charger-Amen brother, I have one and it is great. Charge to 50%, call it a day.

Just keep your homeowners insurance current and paid up.

This is one reason I always put the thermal sensor on the batteries I'm charging, ( though I only charge at 1C or less ).

If the battery starts getting warm, and rises above a present safe temp, the charger automatically stops the charge.

It's a great fire prevention safety feature...

It makes my ICE chargers worth it.

Charging at 2C-3C is safe for sure in batteries that can handle them if not you can rest assured that certain lipo companies who are minting money will end up bankrupt. The batteries are rated for such charging rates. Still I am not keen to charge at those rates because it not worth killing the batts. Better to buy another pack.

opjose - thermal probe is not the be all and end all ... hehehehe ... probe failure ...

CGr - some people live in bunkers

When I start the charge I always check the probe. The display shows the current probe temp. If it is not working the display reads the wrong temp.

It's far more likely that you'll short a connector than it is for the probe to fail...

It may not be the "end all", but it can and will catch battery puffing, overcharging, charging damaged cells, etc. with just a bit of care.

I'm confident enough in the probe's ability to handle this that I can go into another room while charging my LiPo's and do something else.

I really rather have it around then not.

opjose - my remark was in jest only ... just teasing you ... hehehehe

Good point. And I DO have a temp probe for my ICE. Trouble is, I don't fly the electrics an awful lot so I forget some of the little hints to keep these things save.

All said, though, I still charge them AT 1C outdoors, even though my homeowners insurance is current and paid up.

3C just isn't safe, I don't care what you say. And all the experts seem to feel the same way. Why push it? What's the rush? If you can afford a 4800 mah LiPo, then you can probably afford two or three and keep them charged.

CGr.

Rockenroller6-As you can see by the many differing opinions, nobody really knows, everyone has an opinion based on what works for them-Me included. CGRetired said it best on Black & white-Just don't go to low or to high for storage-thats why most batteries come 50 to 60% charged. I would invest in the cellpro 4s-it is so simple and takes the guess work out of charging and I believe was one of the top rated chargers you can buy for simple plug and play, good price too! Regarding fast charging-let the cell pro charge for you at factory setting and forget it. Everyone agrees charge ANY battery at safe levels and they will last. If your in a hurry buy another battery, you really only need two.
Just think in a very short while you can post the (your) the correct way to store LiPos!

Now you've done it. [:@] Where can I see this charger? [:-] How about a link or something?

I hope I have enough in my checking account..

CGr

See: http://www.fmadirect.com/

I've looked at and played with the earlier version.

It handles 123 batteries too...

However it doesn't have all of the reporting capabilities of the ICE, nor some of the other functions. The display is small and limited.

It is firmware upgradeable though.

Yeah, Opjose.. I found it at FMA Direct. $79.95 I believe is what the price is. Thanks for the input, though. I appreciate it.

I have the Triton and the Ice. I use the Ice much more often than I do the Triton. It will charge NiCd, NiMH and LiPo's and I have the memory set for my 1200mah NiMH's as well as three of my various LiPo's, even though I don't use them that much. Jeech.. I must have about 10 of the darned things (LiPo's) in various sizes sitting there in my field box. I ought to get my electrics back in flying order just to use the batteries!!!

CGr.

OOPS! sorry dude, My intention was not to spend your money, but it is a very nice charger for guys (electrically handicapped) like me.

No sweat, Frenchie. Thanks for the recommendation, though. As I said, I have a Triton and an Ice and use the Ice most of all. The Triton is somewhat complicated to setup.. for a pea-brain like me, which is why I like the Ice.. and probably would like the Cellpro 4S. I noticed they have the 10S too.. pricey little gizmo, but sounds like it's pretty capable.

Ah just what I need.. another charger.. I've got about 6 of the things now!!!

Last night I bought a Goldberg Skylark 70 and an OS 75 AX engine to go with it. Got a pretty good deal at my LHS so I jumped on it. I know, off the subject, but I just wanted to tell ya this because I may not be buying much for the next few weeks... [&o]

CGr.

Tower calls me if I don't order twice a month! I only have two electric planes a Sig ep42 that i put an AXI motor and lipo system in it and a Herr Little Something Extra that is also electric. This plane is super. I built its big brother and put an 46AX on it. Now I have one for the field and one for home (big back yard). I heard great things about the 75AX-A real stump puller. I own two 46's and a 55 that I haven't flown yet. Next will be the 75, which will be the largest 2 stroke I'll own besides gas. LOVE them OS engines. Crap-enough of this, need to keep this post on track-sorry.