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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> MRC Charger Product Support (i.e. Super Brain, etc) >> sb 977
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sb 977 - 12/29/2007 2:56:52 AM   
timmaay


 

Posts: 72
Joined: 5/21/2006
From: Monroe, WI, USA
Status: offline 		i reciently purchased a 977 and have had problems right off the back. i cannot get the discharge to work properly. i tried 3 different packs and they all do the same thing: the charger will start the discharge sequence (2 amps, 30mv, 6 cell, 4200mah) at 7+ volts, discharge the first cell then shut off after 10-15 mins still showing 6+ volts. start the sequence the again and stops after 1 minute with no change. am i doing something wrong, or is there a problem?
       Post #: 1

RE: sb 977 - 12/29/2007 3:50:00 AM   
guver


 

Posts: 8974
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		All cells in a pack are being discharged at the same time and if the voltage is 6.?? volts then the pack is considered empty. Restarting will only go for another minute as you have observed.

Hopefuly the packs were'nt full, right? It sounds like they were empty.

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you hear that silence?

(in reply to timmaay)
       Post #: 2

RE: sb 977 - 12/29/2007 4:24:49 AM   
timmaay


 

Posts: 72
Joined: 5/21/2006
From: Monroe, WI, USA
Status: offline 		no, when i started the voltage was around mid to high 7's. when it was done discharging, it said it discharged about 600-700 mah, mid to low 6's, and then read it as a 5 cell.

(in reply to guver)
       Post #: 3

RE: sb 977 - 12/29/2007 4:56:03 AM   
guver


 

Posts: 8974
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		That sounds normal to me.

_____________________________

you hear that silence?

(in reply to timmaay)
       Post #: 4

RE: sb 977 - 12/29/2007 6:13:07 AM   
timmaay


 

Posts: 72
Joined: 5/21/2006
From: Monroe, WI, USA
Status: offline
quote:

ORIGINAL: guver

That sounds normal to me.


how is that normal? shouldn't the voltage go down to nearly nothing, and the discharged mah should be higher as well? not saying you are not right, but it doesn't sound normal to me. thanks for you input though, you are very helpful!!!!!!

(in reply to guver)
       Post #: 5

RE: sb 977 - 12/29/2007 6:58:32 AM   
guver


 

Posts: 8974
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		No, it will discharge to maybe 6 volts or just a touch under 6 volts. You may be able to fool it quickly into thinking it's a 5 cell battery and then it may go down t less than 5 volts.

I'm not clear, were the batts full? anyways, if they were then they should show 4000 or more mah, but yours seemed to have only 600-700 OR a 1 bad cell perhaps.

_____________________________

you hear that silence?

(in reply to timmaay)
       Post #: 6

RE: sb 977 - 12/29/2007 12:53:58 PM   
timmaay


 

Posts: 72
Joined: 5/21/2006
From: Monroe, WI, USA
Status: offline
quote:

ORIGINAL: guver

No, it will discharge to maybe 6 volts or just a touch under 6 volts. You may be able to fool it quickly into thinking it's a 5 cell battery and then it may go down t less than 5 volts.

I'm not clear, were the batts full? anyways, if they were then they should show 4000 or more mah, but yours seemed to have only 600-700 OR a 1 bad cell perhaps.


yes the batts were full. the thing i'm still confused about is that the charger did the samething on three different 6-cell packs.

(in reply to guver)
       Post #: 7

RE: sb 977 - 12/29/2007 4:12:02 PM   
guver


 

Posts: 8974
Joined: 3/7/2003
From: LaGrange, OH, USA
Status: offline 		If they were full then they should hold over 6 volts for the whole 4000 mah and have a bad cell/connection.

_____________________________

you hear that silence?

(in reply to timmaay)
       Post #: 8

RE: sb 977 - 12/29/2007 4:12:35 PM   
Silent-AV8R



Posts: 1782
Joined: 3/16/2004
From: SOCAL, CA, USA
Status: offline 		NiMH cells are considered fully discharged at 0.9 to 1 volt per cell. For a 6 cell pack this is 5.4 to 6 volts.

Lithium cells are fully discharged at 3 volts per cell. Going below either voltage is bad for the cells and in the case of lithium may harm them to the point of rendering them useless.

_____________________________

Reality is Subjective. At least that's what I think.

(in reply to timmaay)
       Post #: 9

RE: sb 977 - 12/30/2007 1:06:54 AM   
timmaay


 

Posts: 72
Joined: 5/21/2006
From: Monroe, WI, USA
Status: offline 		i forgot that .9v was considered dead, and didn't do the math. thanks for the help!!!

(in reply to Silent-AV8R)
       Post #: 10

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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> MRC Charger Product Support (i.e. Super Brain, etc) >> sb 977
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