Why default discharge value 3V per cell?

Chris Burton · Nov 04, 2009, 10:07 AM

Hey guys,

Just a short questions from someone who wants to store a dozen or so lipos for the upcoming winter season.

This will be my first time discharging lipos for storage, so I was wondering:
My Mystery B6 discharging function shows 9V for 3S, 6V for 2S and 3V for 1S - how the hell can this be good or am I missing something? Isn't this waaaay to much for a lipo? And yes, I am using the LiPo function (since it supports other battery types as well).

I just really wanted to ask before destroying most of my lipo collection

Thanks for your input!

Terry Rigden · Nov 04, 2009, 10:48 AM

Yes that's way to low and will probably kill them. I store mine at 3.85V/cell and that seems to work.

Regards

Terry

Chris Burton · Nov 04, 2009, 10:56 AM

Cheers man, 3.85V sounds about right. Why the hell would they include that as a default program? The lipo program won't let me change any values for discharging, so I should probably just keep them in the cycle, eh?

RC Man · Nov 04, 2009, 11:11 AM

Most all the high-end chargers and some of the low cost chargers have a storage charge or discharge mode. Sometimes you have to read the manual to know for sure.

Terry Rigden · Nov 04, 2009, 11:18 AM

Just interupt the charge when the voltage is about 3.9V/cell they will then settle back to around 3.85V/cell

Terry

Dave H. · Nov 04, 2009, 11:23 AM

It sounds like there's some confusion between a storage charge (~50%) and a discharge. The latter is usually not recommended for LiPos. As for why it offers that for LiPos, maybe that's why the charger is called a "Mystery"

videocruzer · Nov 04, 2009, 11:42 AM

you cant go wrong if you store them at the nominal voltage.

Chris Burton · Nov 05, 2009, 03:03 AM

Right, gotcha. Thanks for the input guys, much appreciated!

everydayflyer · Nov 05, 2009, 07:04 AM

The 3 V per cell for discharge capacity checks was from many years ago when most LiPolys were 3 to 6C rated and also most were under 1000 mAh . The combination of a low rate discharge such as most charger are capable of,newer 20c and greater cells and 3 V per cell will dmage them.

Years ago I used one of my Triton chargers to place LiPolys in storage by using the Ni setting. For a 3S set to Ni discharge and 11.4 volts. When the discharge is done the voltage will rise some but anything between 3.7 and 4.0 is fine.

Charles

Nov 04, 2009, 10:07 AM	#1
Chris Burton Registered User Join Date: Jan 2009 Posts: 214	Why default discharge value 3V per cell? Hey guys, Just a short questions from someone who wants to store a dozen or so lipos for the upcoming winter season. This will be my first time discharging lipos for storage, so I was wondering: My Mystery B6 discharging function shows 9V for 3S, 6V for 2S and 3V for 1S - how the hell can this be good or am I missing something? Isn't this waaaay to much for a lipo? And yes, I am using the LiPo function (since it supports other battery types as well). I just really wanted to ask before destroying most of my lipo collection Thanks for your input!

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Nov 04, 2009, 10:48 AM	#2
Terry Rigden Registered User Join Date: Apr 2004 Location: East Anglia England Posts: 1,193	Yes that's way to low and will probably kill them. I store mine at 3.85V/cell and that seems to work. Regards Terry

Nov 04, 2009, 10:56 AM	#3
Chris Burton Registered User Join Date: Jan 2009 Posts: 214	Cheers man, 3.85V sounds about right. Why the hell would they include that as a default program? The lipo program won't let me change any values for discharging, so I should probably just keep them in the cycle, eh?

Nov 04, 2009, 11:11 AM	#4
RC Man A man with too many helicopter Join Date: Feb 2001 Location: Illinois Posts: 10,713	Most all the high-end chargers and some of the low cost chargers have a storage charge or discharge mode. Sometimes you have to read the manual to know for sure.

Nov 04, 2009, 11:18 AM	#5
Terry Rigden Registered User Join Date: Apr 2004 Location: East Anglia England Posts: 1,193	Just interupt the charge when the voltage is about 3.9V/cell they will then settle back to around 3.85V/cell Terry

Nov 04, 2009, 11:23 AM	#6
Dave H. Registered User Join Date: Feb 2008 Posts: 51	It sounds like there's some confusion between a storage charge (~50%) and a discharge. The latter is usually not recommended for LiPos. As for why it offers that for LiPos, maybe that's why the charger is called a "Mystery"

Nov 04, 2009, 11:42 AM	#7
videocruzer Registered User Join Date: May 2008 Location: Victoria BC Canada Posts: 431	you cant go wrong if you store them at the nominal voltage.

Nov 05, 2009, 03:03 AM	#8
Chris Burton Registered User Join Date: Jan 2009 Posts: 214	Right, gotcha. Thanks for the input guys, much appreciated!

Nov 05, 2009, 07:04 AM	#9
everydayflyer Southern Pride Join Date: Oct 2004 Location: Haralson County GA. USA Posts: 24,267	The 3 V per cell for discharge capacity checks was from many years ago when most LiPolys were 3 to 6C rated and also most were under 1000 mAh . The combination of a low rate discharge such as most charger are capable of,newer 20c and greater cells and 3 V per cell will dmage them. Years ago I used one of my Triton chargers to place LiPolys in storage by using the Ni setting. For a 3S set to Ni discharge and 11.4 volts. When the discharge is done the voltage will rise some but anything between 3.7 and 4.0 is fine. Charles