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Old 11-09-2011, 02:11 AM   #1
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Default charging AA NIMH ..Help pls

Hi Guy,

I want to seek your expert opinion about charging AA NIMH Battery.
I have InteliPeak Ice Charger. I am charging 4 cells AA Nimh 2700 mAh battery.

Charge current 0.5a
Discharge current o.5a
Peak Sensitive: 9 mV/C

The problem - Before the battery even get warm the charger already give me the message End: Delta Peak" . However, the battery not even reach the full charge capacity
I already tried to readjust the Peak sensitive from 5mV/C. to 9 mV/C

any idea or solution
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Old 11-09-2011, 03:08 AM   #2
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Maybe the battery doesn't have the specified capacity?
Was it completely empty before charging, the charger can only add so much as there is room.
What is the voltage at the end of the charge?


Benjamin
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Old 11-09-2011, 03:13 AM   #3
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Originally Posted by BenjaminX2 View Post
Maybe the battery doesn't have the specified capacity?
Was it completely empty before charging, the charger can only add so much as there is room.
What is the voltage at the end of the charge?


Benjamin
Hi,
the battery was cold and the charger already stop!

4 AA 2700 mah battery only reached 5.5 V ..
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Old 11-09-2011, 05:18 AM   #4
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Originally Posted by ceong View Post
Hi,
the battery was cold and the charger already stop!

4 AA 2700 mah battery only reached 5.5 V ..
That voltage sounds correct for 4 AA bateries at full charge. (1.2V ea X 4 = 4.8V)
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Old 11-09-2011, 05:53 AM   #5
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Originally Posted by AreCee View Post
That voltage sounds correct for 4 AA bateries at full charge. (1.2V ea X 4 = 4.8V)
I even try to discharge the battery.. and it took less than 5 min then it was done! around 5 min to discharged 4 x 2700mah .. normal or abnormal?????
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Old 11-09-2011, 06:43 AM   #6
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If it was fully charged (noty likely) it's abnormal... Theoretically, if the pack was fully charged, it'll take about 5-6 hours discharging them at 0,5 amps... Discharging at one amp, should take about 2,5-3 hours.

Personally, I've always charged my NiMh AA's with 1 amp/discharged at 1 amp. Works fine untill they get very old... But NiMh's definately dont like being stored for prolonged time.

How old is the pack? Has it been stored for a long time? What brand? Might there be some bad connections in the setup? Do your charger work fine with other NiMh's?

Do you have a separate voltmeter? If there's one bad/dead cell among them, this particular one would likely have significantly HIGHER voltage during charge and significantly LOWER during discharge...

If you dont have a voltmeter, you could try charging and then discharging the cells one by one - provided your charger support charging single cells. This might prove if it's only a few or all cells having problems. Do take a while of course, so the next suggestion might work easier

Another option could be that you could leave the pack on trickle charge for 3-4 hours, and then try a regular charge...
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Last edited by Cole Trickle; 11-09-2011 at 06:58 AM.
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Old 11-09-2011, 07:46 AM   #7
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Originally Posted by Cole Trickle View Post
If it was fully charged (noty likely) it's abnormal... Theoretically, if the pack was fully charged, it'll take about 5-6 hours discharging them at 0,5 amps... Discharging at one amp, should take about 2,5-3 hours.

Personally, I've always charged my NiMh AA's with 1 amp/discharged at 1 amp. Works fine untill they get very old... But NiMh's definately dont like being stored for prolonged time.

How old is the pack? Has it been stored for a long time? What brand? Might there be some bad connections in the setup? Do your charger work fine with other NiMh's?

Do you have a separate voltmeter? If there's one bad/dead cell among them, this particular one would likely have significantly HIGHER voltage during charge and significantly LOWER during discharge...

If you dont have a voltmeter, you could try charging and then discharging the cells one by one - provided your charger support charging single cells. This might prove if it's only a few or all cells having problems. Do take a while of course, so the next suggestion might work easier

Another option could be that you could leave the pack on trickle charge for 3-4 hours, and then try a regular charge...
Hi Cole trickle,

1- has been stored for a few months,
2 - Toshiba 4 cells AA Nimh 2700 mah about year old but i hardly use it.
3 - My intelipeak ice charger is in good and working well..
4 - can you be more specific about the trickle charge? from the manual, it is not recommended to trickle charge AA Nimh battery..


thanks
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Old 11-10-2011, 01:56 AM   #8
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Quote:
Originally Posted by Cole Trickle View Post
If it was fully charged (noty likely) it's abnormal... Theoretically, if the pack was fully charged, it'll take about 5-6 hours discharging them at 0,5 amps... Discharging at one amp, should take about 2,5-3 hours.

Personally, I've always charged my NiMh AA's with 1 amp/discharged at 1 amp. Works fine untill they get very old... But NiMh's definately dont like being stored for prolonged time.

How old is the pack? Has it been stored for a long time? What brand? Might there be some bad connections in the setup? Do your charger work fine with other NiMh's?

Do you have a separate voltmeter? If there's one bad/dead cell among them, this particular one would likely have significantly HIGHER voltage during charge and significantly LOWER during discharge...

If you dont have a voltmeter, you could try charging and then discharging the cells one by one - provided your charger support charging single cells. This might prove if it's only a few or all cells having problems. Do take a while of course, so the next suggestion might work easier

Another option could be that you could leave the pack on trickle charge for 3-4 hours, and then try a regular charge...
I have tried to Trickle charge at 50mA... Peak sensitive at 8mv
same result ... after 10 minutes End Delta peak message came out ! or I should set the peak sensitive to zero or higher?
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Old 11-10-2011, 02:21 AM   #9
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I dont know your charger, but on all NiMh's I've seen, trickle charge works like this: It kicks in after the fast charge - please check your manual.

Anyway, yes, trickle is not recommended - that is, not recommended for a racepack, which is fully charged during fast charge. But this is not a racepack, and since it's not [I]that[I] old, and a well known brand, it should be able to charge. Sometimes it's a matter of "wake up" / "break in" a pack, though I think this pack might be defective (one or more cells are dead).

The idea behind trickle charge, is that the charge rate is so low, that if the cells are out of sync (one or more is fully charged before the others), then the cells wont be damaged by the slight overcharge.

So - if your charger initiates trickle charge after a normal charge - peak detection don matter. Just let it carge until it shuts off, and let the trickle charge be on for 3-4 hours. With a bit of luck, that might get the pack started, and afterwards you can charge normally (remember to disable trickle charge again).
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Old 11-10-2011, 02:31 AM   #10
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Originally Posted by Cole Trickle View Post
I dont know your charger, but on all NiMh's I've seen, trickle charge works like this: It kicks in after the fast charge - please check your manual.

Anyway, yes, trickle is not recommended - that is, not recommended for a racepack, which is fully charged during fast charge. But this is not a racepack, and since it's not [I]that[I] old, and a well known brand, it should be able to charge. Sometimes it's a matter of "wake up" / "break in" a pack, though I think this pack might be defective (one or more cells are dead).

The idea behind trickle charge, is that the charge rate is so low, that if the cells are out of sync (one or more is fully charged before the others), then the cells wont be damaged by the slight overcharge.

So - if your charger initiates trickle charge after a normal charge - peak detection don matter. Just let it carge until it shuts off, and let the trickle charge be on for 3-4 hours. With a bit of luck, that might get the pack started, and afterwards you can charge normally (remember to disable trickle charge again).
Hi,

Thanks ... i will try again .. i will get back to you o
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Old 11-10-2011, 08:12 AM   #11
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Its very common for NiMhs that have been unused for a while to false peak. Just reset the charger and try again. You may have to do this a few times - keep doing it until the cells are getting warm when the charge is ended. If your cells have been sitting long enough this doesn't appear to be working, try a trickle type charge at C/20 for 14-16hrs. That's often used to revive cells that have not been used for a long time.

Some chargers were so aware of this as a prob, they have a peak delay setting - tells the charger to ignore any apparent peak until beyond th epeak delay.
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Old 11-10-2011, 11:56 AM   #12
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Good advise Duster
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Old 11-11-2011, 04:20 AM   #13
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Originally Posted by Duster_360 View Post
Its very common for NiMhs that have been unused for a while to false peak. Just reset the charger and try again. You may have to do this a few times - keep doing it until the cells are getting warm when the charge is ended. If your cells have been sitting long enough this doesn't appear to be working, try a trickle type charge at C/20 for 14-16hrs. That's often used to revive cells that have not been used for a long time.

Some chargers were so aware of this as a prob, they have a peak delay setting - tells the charger to ignore any apparent peak until beyond th epeak delay.
Hi.. my current charge rate is 0.5 a.. top-off charge 400mah, peak sensitive 9mv

should I increase it a bit higher?By the way, as you have mentioned "tells the charger to ignore any apparent peak" .. I am using Intelpeak Ice charger and I don't think there is way I can turn it off...

Million Million Thanks
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Old 11-11-2011, 04:26 AM   #14
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The ice is a nice charger to verify this "false peak" because it has a very intricate graph.
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Old 11-11-2011, 04:37 AM   #15
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The ice is a nice charger to verify this "false peak" because it has a very intricate graph.
I am ware of that but the problem is that this End Delta Peak happened so fast right after 5 min i put the battery into charging mode.. the battery still cold and not even warm ...


I have try to increase the peak sensitive from 5 mv to 9 mv .. and this End Delta Pean will pop up again within 5 to 8 min and the battery stil cold and not fully charged
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