If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #1430
Joined: Sun Apr 06 2008, 11:12AM
Location: Ã…rhus, Denmark
Posts: 102
a few days ago, my dad brought home an old cordless drill, it's a cordless bosch psr color 2.4v.
also, i recently acquired 2 batteries for cordless drills that my school was throwing out(they couldn't find the drills), one is a 12v Ni-Mh outputting 7,55v. the other is a 14,4v Ni-Cd outputting 11,86v.
but i don't have a charger for any of them.
i have a variable power supply and i was wondering if i could use that to charge them. if it's possible: at what voltage do i charge them and is there anything i need to watch out for?
Solidacid
EDIT: i completely forgot, i also have a battery pulled out of a completly destroyed roomba, it's 14,4v 2500mAh and it outputs 2.79v and is made up of 12 cells. any suggestions?
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
similar cells and chemistry *should* work, but be careful. If its NiMH then you *must* use the same cells or the charge circuit could fail causing the cells to vent or worse.
BTW I wouldn't solder to the cells, can block the safety vent and also weakens the seak causing cell failure after about three months or less. Use the tabs if possible.
Registered Member #1430
Joined: Sun Apr 06 2008, 11:12AM
Location: Ã…rhus, Denmark
Posts: 102
Conundrum wrote ...
similar cells and chemistry *should* work, but be careful. If its NiMH then you *must* use the same cells or the charge circuit could fail causing the cells to vent or worse.
BTW I wouldn't solder to the cells, can block the safety vent and also weakens the seak causing cell failure after about three months or less. Use the tabs if possible.
regards, -A
What? these are assembled cells taken from cordless drills. im not going to use them together or anything, just charge them one at a time.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
For manual charging NiCd,NiMH,Li etc A current-limited constant-voltage charging scheme is quite good. 0.1C or C/10 is safe for all common storage batteries. e.g. Charge 2500 mAh cell/battery at 250 mA for more than 10 hours from flat. Do this with current-limit on a psu or just a resistor to limit maximum charging current.
Lithium are the simplest, NiCd should stop charging when the charging voltage 'dips' for a while (c20mV), if not then when the cell(s) feel warm.
Batteries are always best charged as individual cells.
There are all kinds of charging schemes - google for millions of results !
I have come across many failed cheap battery packs often just one bad cell, sometimes the internal thermal fuse, unfortunately though, most manufacturers use really cheap/nasty cells that may give you a false impression of the potential of good rechargeable batteries.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Recharging batteries
