K100D Power Problems

Sean Nelson · 03-09-2009, 07:39 PM

Originally posted by UnknownVT

The optimal charge rate for any NiMH (including eneloops) - is 0.5 - 1C.

Since AA eneloop capacity is 2000mAh (1900mAh minimum) -
that is between 1- 1.9Amps (1,000-1,900mA)
so batteries are charged in about 1 to 2 hours.

Reason: end of charge -dV is more easily detected with 0.5-1C charge rates, below about 0.3C it is almost impossible to detect the -dV end of charge.

The higher the charge rate, the harder it is on the battery chemistry. I charge my Eneloops at 200ma (about 0.1C) and my La Crosse BC-900 charger has never had a problem detecting the battery full condition.

UnknownVT · 03-09-2009, 08:28 PM

Originally posted by Sean Nelson

The higher the charge rate, the harder it is on the battery chemistry. I charge my Eneloops at 200ma (about 0.1C) and my La Crosse BC-900 charger has never had a problem detecting the battery full condition.

Sorry, it's a myth that lower charge rates are somehow "kinder" on batteries.

There have been many discussion of this over at CPF Batteries section. (please see this post and A look at slow charging )

Battery University on Charging nickel-based batteries from the quote above:

" Nickel-metal-hydride should be rapid charged rather than slow charged. Because of poor overcharge absorption "

0.1C is fine for the initial forming charge - this is normally timed termination at about 12-16 hours - but it is not recommended for regular charging - most cheap dumb chargers are about 0.1C timed (if one's lucky) at 12-16 hours -
one of the most prevalent problems is a tendency for people to charge partially discharged batteries -
then a timed charger will over-charge those batteries......

Fnarf · 03-09-2009, 10:19 PM

All this stuff about charging rate and so on is way over my head. My Maha charger has a conditioning mode so I'm taking it on faith that it will work for me.

As for my Li-Ions, here's what Thomas says about them: "The Moby Power rechargeable lithium battery also has a Rechargeable Battery Safety Unit built in for reliability and safety. This Safety Feature prevents damage to your equipment due to over voltage, unlike other rechargeable CR-V3 rechargeable lithium batteries on the market. This battery is designed to operate within the safe voltage range of an actual CR-V3 lithium battery."

I hope that's safe.

UnknownVT · 03-10-2009, 08:55 AM

Originally posted by Fnarf

My Maha charger has a conditioning mode so I'm taking it on faith that it will work for me.

It most probably is fine-
the conditioning mode is supposed to be only for occassional use after about 10+ full discharge/recharge cycles.
Let us know the model #

Originally posted by Fnarf

As for my Li-Ions, here's what Thomas says about them: "The Moby Power rechargeable lithium battery also has a Rechargeable Battery Safety Unit built in for reliability and safety. This Safety Feature prevents damage to your equipment due to over voltage, unlike other rechargeable CR-V3 rechargeable lithium batteries on the market. This battery is designed to operate within the safe voltage range of an actual CR-V3 lithium battery."
I hope that's safe.

The advert sounds fine.
I think some people may have used these in the K100D -
so may be able to give you direct experience.

Fnarf · 03-10-2009, 10:14 AM

The model number is MH-C800S, as recommended earlier in this thread.

UnknownVT · 03-10-2009, 11:02 AM

Originally posted by Fnarf

The model number is MH-C800S, as recommended earlier in this thread.

The MH-800S is a very nice charger with 8 independent charging channels.

It has Fast/Rapid and "Soft" charge cycles.

For AA batteries
Fast/Rapid is rated at 1Amp
"Soft" at 0.5Amp.

The Rapid/Fast charge current is preferable as it is exactly 0.5C of the eneloop AA's.

I know this may make people's eyes glaze over -
but from the Duracell Technical document on NiMH batteries -

(and from the various references already given earlier) -
or just trust me on this -
0.5C charge current (=1Amp) is about the ideal for eneloops.

Just a note of interest - the "Soft" charge current of 0.5Amps is 500/2000C of the eneloops = 1/4C - which Duracell Tech Bulletin (Download PDF) says is not recommended for NiMH batteries.......

03-09-2009, 08:28 PM	#32
UnknownVT Veteran Member Join Date: Sep 2007 Location: USA Posts: 1,812	Originally posted by Sean Nelson The higher the charge rate, the harder it is on the battery chemistry. I charge my Eneloops at 200ma (about 0.1C) and my La Crosse BC-900 charger has never had a problem detecting the battery full condition. Sorry, it's a myth that lower charge rates are somehow "kinder" on batteries. There have been many discussion of this over at CPF Batteries section. (please see this post and A look at slow charging ) Battery University on Charging nickel-based batteries from the quote above: " Nickel-metal-hydride should be rapid charged rather than slow charged. Because of poor overcharge absorption " 0.1C is fine for the initial forming charge - this is normally timed termination at about 12-16 hours - but it is not recommended for regular charging - most cheap dumb chargers are about 0.1C timed (if one's lucky) at 12-16 hours - one of the most prevalent problems is a tendency for people to charge partially discharged batteries - then a timed charger will over-charge those batteries...... Last edited by UnknownVT; 03-09-2009 at 09:03 PM.

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03-09-2009, 07:39 PM	#31
Sean Nelson Veteran Member Join Date: Sep 2008 Location: Vancouver BC Canada Posts: 353	Originally posted by UnknownVT The optimal charge rate for any NiMH (including eneloops) - is 0.5 - 1C. Since AA eneloop capacity is 2000mAh (1900mAh minimum) - that is between 1- 1.9Amps (1,000-1,900mA) so batteries are charged in about 1 to 2 hours. Reason: end of charge -dV is more easily detected with 0.5-1C charge rates, below about 0.3C it is almost impossible to detect the -dV end of charge. The higher the charge rate, the harder it is on the battery chemistry. I charge my Eneloops at 200ma (about 0.1C) and my La Crosse BC-900 charger has never had a problem detecting the battery full condition.

03-09-2009, 10:19 PM	#33
Fnarf New Member Join Date: Mar 2007 Location: Seattle, USA Posts: 18 Original Poster	All this stuff about charging rate and so on is way over my head. My Maha charger has a conditioning mode so I'm taking it on faith that it will work for me. As for my Li-Ions, here's what Thomas says about them: "The Moby Power rechargeable lithium battery also has a Rechargeable Battery Safety Unit built in for reliability and safety. This Safety Feature prevents damage to your equipment due to over voltage, unlike other rechargeable CR-V3 rechargeable lithium batteries on the market. This battery is designed to operate within the safe voltage range of an actual CR-V3 lithium battery." I hope that's safe.

03-10-2009, 08:55 AM	#34
UnknownVT Veteran Member Join Date: Sep 2007 Location: USA Posts: 1,812	Originally posted by Fnarf My Maha charger has a conditioning mode so I'm taking it on faith that it will work for me. It most probably is fine- the conditioning mode is supposed to be only for occassional use after about 10+ full discharge/recharge cycles. Let us know the model # Originally posted by Fnarf As for my Li-Ions, here's what Thomas says about them: "The Moby Power rechargeable lithium battery also has a Rechargeable Battery Safety Unit built in for reliability and safety. This Safety Feature prevents damage to your equipment due to over voltage, unlike other rechargeable CR-V3 rechargeable lithium batteries on the market. This battery is designed to operate within the safe voltage range of an actual CR-V3 lithium battery." I hope that's safe. The advert sounds fine. I think some people may have used these in the K100D - so may be able to give you direct experience.

03-10-2009, 10:14 AM	#35
Fnarf New Member Join Date: Mar 2007 Location: Seattle, USA Posts: 18 Original Poster	The model number is MH-C800S, as recommended earlier in this thread.

03-10-2009, 11:02 AM	#36
UnknownVT Veteran Member Join Date: Sep 2007 Location: USA Posts: 1,812	Originally posted by Fnarf The model number is MH-C800S, as recommended earlier in this thread. The MH-800S is a very nice charger with 8 independent charging channels. It has Fast/Rapid and "Soft" charge cycles. For AA batteries Fast/Rapid is rated at 1Amp "Soft" at 0.5Amp. The Rapid/Fast charge current is preferable as it is exactly 0.5C of the eneloop AA's. I know this may make people's eyes glaze over - but from the Duracell Technical document on NiMH batteries - (and from the various references already given earlier) - or just trust me on this - 0.5C charge current (=1Amp) is about the ideal for eneloops. Just a note of interest - the "Soft" charge current of 0.5Amps is 500/2000C of the eneloops = 1/4C - which Duracell Tech Bulletin (Download PDF) says is not recommended for NiMH batteries.......