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rmbler
11-02-2005, 03:15 AM
hi all..... can someone tell me how long i can leave a new & charged li-po battery stored away without recharging it. its 11.1V 860 Mah E-Flight Battery

Regards,
Phil

Unbalanced prop
11-02-2005, 02:48 PM
Depends a lot on the quality and condition of the pack, but I have used packs that sat for a couple months with very little drop in performance. But according to the people who know, if you are going to not use a pack for a while, it should be stored at 40% to 60% capacity. That works out to around 3.8 to 3.9 open volts per cell. That is the way they are stored by vendors and manufacturers.

Doug

Rugar
11-02-2005, 02:58 PM
hi all..... can someone tell me how long i can leave a new & charged li-po battery stored away without recharging it. its 11.1V 860 Mah E-Flight Battery

Regards,
Phil

Some folks have said that they store them fully charged, but store them in the fridge, and have had no ill effects storing them long term this way. I store mine at 3.8v per cell and in a cool spot in the house if they are not going to be used for over a month or so. If less then a month between usage, I just leave them fully charged.

hoppy
11-02-2005, 07:22 PM
From a Manufacturer:







6.8 Lithium Polymer Storage Guidelines








Store the cell in a dry location between –20°C and 30°C. Keep out of direct sunlight.

When storing for an extended period, store between 10°C to 30°C
Store at 40% of capacity.


When charging the first time after long-term storage it may take several cycles to achieve original
performance.


and another:
Storage in a cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, the battery should be partially charged during storage. The manufacturer recommends a 40% charge.


How long will it hold a charge?
Typical self discharge rates:
Ni/MH cell(Toshiba.) : 5 ~ 10%/month
Ni/Cd cell(Toshiba.) : 25 ~ 30%/month
Li-ion battery : 2%/month
Lead-acid Battery :
Pb-Sb alloy group : 25 ~ 30%/month
Pb-Ca alloy group : 2%/month
http://www.powercellkorea.com/eng/knowledge/battery_faq.php

qban_flyer
11-02-2005, 10:06 PM
Thanks for that valuable information Hoppy. I have been storing mine fully charged for a couple of weeks at a time, then go fly them.

Thanks for the FAQ URL also.

rmbler
11-03-2005, 01:48 AM
Thanks for the great info. everyone the 12 v. power supply i am going to use is a vector jump start for autos that has a 12 v. adapter tho it seems to be putting out over 13v under no load so i will assume that i can still use this to charge my feild charger it's the hobbico mkii charger. Any input would be much apprechiated

Regards,
Phil.

EpoweredRc
11-03-2005, 04:05 PM
we keep most of the ones we fly on a regular basics charged,we have went a week or so or longer w/o flying them. I guess if you checked with a meter they might be down a little but you cant tell by just flying them.

roccobro
11-03-2005, 06:57 PM
I pulled a pair of 2s packs down to charge up as it hadn't been used in at least 9 months. It read 8.42V on my meter, which is exactly 8.40 on my AF109. I was was suprised. I'm about to make a fridge box for my lipos now. I coulda swore I discharged all the unused packs a few months back too...

Justin

qban_flyer
11-03-2005, 09:58 PM
I pulled a pair of 2s packs down to charge up as it hadn't been used in at least 9 months. It read 8.42V on my meter, which is exactly 8.40 on my AF109. I was was suprised. I'm about to make a fridge box for my lipos now. I coulda swore I discharged all the unused packs a few months back too...

Justin

Similar results here with my T/Ps 2S1P 1320s.

rmbler
11-04-2005, 03:22 AM
good to know roccobro and Qban what are you gonna use to make the fridge box? sounds like a great idea.

Regards,
Phil

qban_flyer
11-04-2005, 03:35 AM
good to know roccobro and Qban what are you gonna use to make the fridge box? sounds like a great idea.

Regards,
Phil

Hi Phil,

The link below will take you to what I plan on using, not only for this purpose but for also what it was intended for to begin with.

Since it doubles as a cooler (down 40 degrees from ambient temp) and warmer (up to 120 degrees) I can use it to warm or cool food or drinks I may take to the field with me as well. All temps given are on the Farenheit scale.

They have different models, but this one is the one I have settled on.

L8R

http://www.walmart.com/catalog/product.do?product_id=3942757

roccobro
11-04-2005, 07:37 AM
I'm not sure yet. I'm thinking some plastic with cardboard dividers. It will need to be a special size/shape to make it invisible and contaminant free from the little gremlins that climb into and out of the fridge daily just to spill stuff (silly kids!). I'm collecting small boxes for trial fitting into recesses or unused door space. Not like I need some high speed contraption to whip out some of my lipos I have not used in almost a year...

QBan, will you just leave the cooler plugged in inside your house when "storing"? Walmart site is down at the moment, but I have the idea of what you are talking about.

Justin

Unbalanced prop
11-04-2005, 12:42 PM
Don't forget guys that to get the best performance out of lipols, they must be warm. The cooler may be a good idea for storage, but when you go flying they are better with some heat in them.

Doug

Matt Kirsch
11-04-2005, 12:54 PM
Hence qban_flyer's cooler/warmer idea :)

I have a similar unit, picked up from one of those discount stores (Grossman's Bargain Outlet/Mr. 2nd's) a couple of years back. It works pretty well, but I just don't get much chance to use it. This year I have an electrified trainer on floats that I plan on flying off the snow. The warmer function of this unit will be PERFECT to keep my batteries toasty out in the cold weather until I'm ready to use them.

qban_flyer
11-04-2005, 04:23 PM
QBan, will you just leave the cooler plugged in inside your house when "storing"? Walmart site is down at the moment, but I have the idea of what you are talking about.

Justin

Nope, I store the stuff in the basement, which quite cooler than the rest of the house, especially in Winter. BRRRRR!!!

The Walmart cooler/warmer is just under $35.

roccobro
11-04-2005, 08:54 PM
Link works now. :) Just what I imagined.

I want ot make the fridge storage box for teh unused/unloved packs. :) Their planes are in need of repairs!

Justin

qban_flyer
11-04-2005, 11:17 PM
Link works now. :) Just what I imagined.

I want ot make the fridge storage box for teh unused/unloved packs. :) Their planes are in need of repairs!

Justin

Our basement's temp remains around 68 in Summer and goes down to 60or so during Winter. I guess it's cool enough for the batteries while in the house.

I'll put them the cooler when I go to the field in Summer. I don't fly in Winter unless the temps go above 55 degrees here in the DC area. Rare occurrence, but it happens once in a while.

roccobro
11-05-2005, 01:23 AM
I wish I had a basement. You don't see them very often in CA. Maybe I need to move just for my lipo storage. :p

Justin

qban_flyer
11-05-2005, 03:26 AM
I wish I had a basement. You don't see them very often in CA. Maybe I need to move just for my lipo storage. :p

Justin

Good idea! They come with most every house here in Maryland, so you won't have to spend extra $$$ for a Li-Po storage cooler. It's already waiting for you when you get a house.

Median price for these Li-Po Kooler equipped houses here in Montgomery County is 'round $900,000 or so for a three beedroom unit. Not bad when you consider the added convenience of a built in Li-Po Kooler. Saves you lots of $$$.
:D
:D
:D

roccobro
11-05-2005, 03:49 AM
DU'OH! And I thought the SoCal housing market was freaking expensive.

Justin

qban_flyer
11-05-2005, 04:11 AM
Hence qban_flyer's cooler/warmer idea :)

I have a similar unit, picked up from one of those discount stores (Grossman's Bargain Outlet/Mr. 2nd's) a couple of years back. It works pretty well, but I just don't get much chance to use it. This year I have an electrified trainer on floats that I plan on flying off the snow. The warmer function of this unit will be PERFECT to keep my batteries toasty out in the cold weather until I'm ready to use them.

HMMM!!!

You just put me on the right track.

Instead of going to Walmart tomorrow I'll ride up to National Wholesale Warehouse to check and see if the have something like this at a reduced price.

THKS!:)