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Subject: Re: Deep discharge
From: Joris van den Heuvel (joris.bass_at_planet.nl)
Date: 2003-03-07


----- Original Message -----
From: Chris Holt <amiga2k_at_cox.net>
To: <rockbox_at_cool.haxx.se>
Sent: Thursday, March 06, 2003 5:57 PM
Subject: Re: Deep discharge

| You are thinking about Li-Ion batteries. NiMH likes to be fully
| discharged just like NiCad, it's just not as critical. With NiMh the
| biggest advantages are high current and energy/weight ratio and
| resistance to "memory effect". Notice I say resistance and not immunity.
| They do benefit from occasional conditioning (full discharge to ~1v/cell
| followed by full charge).
|
| chris
|

To comment on your "high current" remark: as far as I know, NiCd have the
best "high current" capacity. That's why you never see NiMH batteries in
power tools. An 800 mAh NiCd battery will outperform a 1600 mAh NiMH when
loaded with a few amperes.

This is how I understand it:

NiCd vs. NiMH
- high current vs. high energy/weight ratio
- sensitive to memory effect vs. low sensitivity
- low sensitivity to overcharging vs. high sensitivity
- environment unfriendly vs. relatively clean

BTW it's a misconception to believe that Li-ion batteries are memory-effect
free, and they seem to wear out faster than NiMHs.

Regards,
Joris.



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