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HP97 battery pack rebuild
02-11-2016, 01:47 PM
Post: #10
RE: HP97 battery pack rebuild
(02-11-2016 11:57 AM)Hans Brueggemann Wrote:  i agree with you that longer charging times will get you more mileage. however, i managed to kill several of those battery packs over time by being "too generous" on charging times. so, i always keep charging below 120% of rated amp-hours.

Actually 1,2 is the "official" factor for NiCd and NiMH for average charging rates (let's say 0,1...0,5 C). Since new high-quality batteries usually have somewhat more true capacity than nominally rated (+5...10% is quite common) and low charging rates around 0,1 C are quite relaxed, the manufacturers often state an 1,4x factor which leads to the ubiquitous "14 hours at 0,1 C" recommendation.

Example: Although rated at 2450 mAh ("minimum capacity") Panasonic's HHR260SCP has an average capacity of 2600 mAh and the recommended standard charge is 260 mA (=0,1 C) for 16 (!) hours. This would translate to 24 h in the HP97.

It's good to hear that you measured the 97's actual charging current. For a 2400 mAh battery, these 170 mA are merely 0,07 C. If you take a look at the manufacturers' data sheets you'll often find the statement that permanent trickle charge can be applied with 0,03...0,05 C without harming the battery. Some battery types (especially those designed for high loads and fast charge) even have no problems with a permanent 0,1 C charge.

So I think in this case we can see things quite relaxed here. For hard facts simply consult the manufacturer's data sheet of the battery type actually used.

Dieter
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Messages In This Thread
HP97 battery pack rebuild - Jlouis - 02-10-2016, 06:47 PM
RE: HP97 battery pack rebuild - d b - 02-10-2016, 07:33 PM
RE: HP97 battery pack rebuild - Jlouis - 02-10-2016, 07:41 PM
RE: HP97 battery pack rebuild - d b - 02-10-2016, 09:26 PM
RE: HP97 battery pack rebuild - rprosperi - 02-11-2016, 12:12 AM
RE: HP97 battery pack rebuild - Dieter - 02-11-2016, 11:23 AM
RE: HP97 battery pack rebuild - Dieter - 02-11-2016 01:47 PM
RE: HP97 battery pack rebuild - TASP - 02-11-2016, 12:42 AM
RE: HP97 battery pack rebuild - rprosperi - 02-11-2016, 03:08 PM
RE: HP97 battery pack rebuild - Jlouis - 02-11-2016, 03:42 PM
RE: HP97 battery pack rebuild - Dieter - 02-11-2016, 11:15 PM
RE: HP97 battery pack rebuild - rprosperi - 02-11-2016, 11:23 PM
RE: HP97 battery pack rebuild - Jlouis - 02-12-2016, 12:55 AM
RE: HP97 battery pack rebuild - d b - 02-12-2016, 04:01 AM
RE: HP97 battery pack rebuild - Jlouis - 02-16-2016, 04:11 PM
RE: HP97 battery pack rebuild - Dieter - 02-16-2016, 07:28 PM
RE: HP97 battery pack rebuild - Jlouis - 02-16-2016, 07:42 PM
RE: HP97 battery pack rebuild - Jlouis - 02-18-2016, 01:49 PM
RE: HP97 battery pack rebuild - quantalume - 02-18-2016, 07:18 PM
RE: HP97 battery pack rebuild - d b - 02-19-2016, 07:04 AM
RE: HP97 battery pack rebuild - Dieter - 02-19-2016, 07:11 PM



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