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Old May 22, 2012, 02:59 PM
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Accucell-6 LiPo Storage Charge Mode Rate

(Hopefully) quick question with regards to the LiPo Storage Charge mode on the Accucell-6. I understand that in Storage mode, the charger will either charge or discharge based on the current voltage of the battery relative to the final voltage that it should be stored at. That is, if it's less than ~3.8V/cell, it will charge, and if it's more than ~3.8V/cell, it will discharge.

Now, I know that when charging the battery, it's best to charge at a rate of around 1C. But when discharging, the charger is only able to discharge at around 5W. So, with my 3S, 11.1V battery, I can only discharge at 5W, or about .45A. However, the charger, when switching to Storage mode, shows an adjustable rate of .1A.

My question is, if I know that the battery is less than the Storage voltage (~3.8V/cell), can I bump up the charging rate of the Storage mode to the normal 1C rate? And then if I know that the voltage is higher than Storage, I can set the rate to .1A to safely discharge it to Storage mode? Or should I always leave it when in Storage mode at .1A, even though it needs to actually charge to get to the proper storage voltage?

The reason I ask is that yesterday was my first time getting a good workout with my first LiPo battery. It was charged to about 4.2V when I went out, and I came home at around 3.68V. I knew I wasn't flying again for about a week, so I figured I'd put it at Storage voltage, and be done. I threw it on the charger on Storage mode, and left it at its initial .1A charging rate. It took it around 2 hours or so to finally get to Storage voltage! What would have taken probably a half-hour max, ended up taking way longer.

It'd be nice if I didn't have to wait that long for storage charging (especially because I need to be around to monitor the charging, since it's a LiPo, afterall). But I'm not 100% sure on how it should be done, and didn't want to bump up the rate if that would be a problem.

Thanks!
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Old May 22, 2012, 03:01 PM
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What is the capacity of your 3S lipoly? .1A is very likely significantly less than 1C charge rate for any 3S lipoly so the 2 hours it took to reach storage is entirely reasonable.

Feel free to bump up the storage charge rate up to the maximum permissible charge rate and your time to reach 'storage' voltage will be dramatically reduced.

Mark
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Old May 22, 2012, 03:25 PM
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Originally Posted by mrforsyth View Post
What is the capacity of your 3S lipoly? .1A is very likely significantly less than 1C charge rate for any 3S lipoly so the 2 hours it took to reach storage is entirely reasonable.

Feel free to bump up the storage charge rate up to the maximum permissible charge rate and your time to reach 'storage' voltage will be dramatically reduced.

Mark
Mine's a Turnigy Nanotech 850mAh. It's a pretty small battery.

Should I bump it up to .8A (1C) when under voltage, and leave it at .1A when over voltage (going to storage voltage)?

Thanks!
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Old May 22, 2012, 04:27 PM
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Doesn't matter.
For almost all purposes set the DC to max (1A). If the charger can't do it, it throttles down. As it nears the 'goal' it slows down anyway. Remember, in real flight you are DC these batteries WAY more than 1A and most lipos nowadays can be charged at 2-3C without any problems at all.

For that matter EXACTLY 3.85v (50%) is not magic. Anywhere from 40-60% is fine.
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Old Jun 04, 2014, 12:17 PM
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This is an old thread; however, it has some information that concerns me.

> So, with my 3S, 11.1V battery.
I have the same Accucell 6 and a 3S 2.2Ah Lipo and want to put the Lipo in storage mode.

All the information I have read says a three cell should not go below 11.4v (3.8v per cell)
The Accucell 6 has a default value of 11.1!

How do I change the default value to 11.4v

Thanks.
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Old Jun 04, 2014, 12:32 PM
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How do I change the default value to 11.4v

Thanks.
You cannot change it. And, it doesn't matter. Storage is not a 'delicate balance' or critical point. It's more than 'dead' and less than 'full'. For short term I tolerate anything from 20% to 80%, though I usually bump up low cells to minimize charging the next time out.
I only go for closer to storage-50% for long term.

Yes, the AC-6 and similar 50W charger all have low-slow storage ability. That's just the way it is.
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Old Jun 04, 2014, 01:59 PM
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I have 10 3s lipos and an Accucell 6 charger that I have been using for 5 years. My batts are usually close to 3.7v when I am done flying. I put them away that way until I am ready to use them again. I tried the storage charge mode once and only once. Takes to long and isn't that critical.

All my batteries are in good shape and still going strong. If I need to discharge a battery I use an array of 3 auto light bulbs.
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Old Jun 04, 2014, 03:08 PM
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Originally Posted by flydiver View Post
You cannot change it. And, it doesn't matter. Storage is not a 'delicate balance' or critical point. It's more than 'dead' and less than 'full'. For short term I tolerate anything from 20% to 80%, though I usually bump up low cells to minimize charging the next time out.
I only go for closer to storage-50% for long term.

Yes, the AC-6 and similar 50W charger all have low-slow storage ability. That's just the way it is.
If they all go as low as 11.1 they are not set correctly and for a novice like me we need to be warned not to use this function?

>Proper storage :
Approx. 3.85 volts per cell in a cool location. IMO with today's fast charge capable LiPolys and high rate capable chargers there is little sense in leaving LiPolys charged just in case the weather turns nice.

The above comes from http://www.rcgroups.com/forums/showthread.php?t=1330647
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Old Jun 04, 2014, 03:30 PM
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What do you mean 'not set correctly'?
It's STORAGE, not full, not dead.....somewhere around the middle of the range. Good enough however you get there > fly, charger, lightbulbs....whatever.

The AC-6 storage function, and setting, will NOT hurt anything. It is s....l....o.....w but way better than leaving your batteries fully charged for extended time.

Everydayflyer (Charles) is excellent. He's giving your great advice but 3.85 is not, repeat not a 'magic' number. Just get it somewhere around there.
Notice, he says [Approx. 3.85 volts per cell]
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Old Jun 04, 2014, 11:29 PM
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Originally Posted by TrueBuld View Post
If they all go as low as 11.1 they are not set correctly and for a novice like me we need to be warned not to use this function?

>Proper storage :
Approx. 3.85 volts per cell in a cool location. IMO with today's fast charge capable LiPolys and high rate capable chargers there is little sense in leaving LiPolys charged just in case the weather turns nice.

The above comes from http://www.rcgroups.com/forums/showthread.php?t=1330647

Nothing wrong with 11.1 volts. This is the voltage most manufactureres store and send to customers.
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Old Jun 05, 2014, 11:46 AM
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For a 3s pack, 11.1V (3.7V/cell) is the 80% discharged voltage. Packs from the manufacturer are in the 3.8-3.85V range (40-50% charged).
For me, anything between 3.7 and 3.85V is OK.
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Old Jun 05, 2014, 11:55 AM
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Nothing wrong with 11.1 volts. This is the voltage most manufactureres store and send to customers.
Really? As far as I can recall every pack I've gotten has been around 3.8v per cell.
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Old Jun 06, 2014, 03:24 AM
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Really? As far as I can recall every pack I've gotten has been around 3.8v per cell.
My brand new Tunigy 2.2 arrived with 11.55V = 3.85 per cell.

Voltage measured with a CellLog 8M
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Old Jun 06, 2014, 07:35 AM
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Interesting? I guess each manufacturer has their own basic level of storage charge. I have received batteries with voltages all over the board but usually in the neighborhood of nominal voltage.
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Old Jun 06, 2014, 01:35 PM
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The old merry-go-round again ...........

3.7 - 3.9v is range ... with anywhere in middle fine ...

So if you fly and end up with a pack which is rested and shows any of 3.7 .. 3.7x ... 3.8 .. 3.8x volts per cell ............... put it in your storage place and leave nicely till next flight session when you charge it up and enjoy.

No rocket science ... no mumbo-jumbo ...

As to the original OLD OP .... does it really matter what rate you set on such a 50W charger for storage ? IT's so slow and limited as to be painful. I have two B6 chargers and never bother with the storage function ... I built myself a discharger for less than $15 ... that does it in minutes instead of hours.

Nigel
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