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 #1792
Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527
It looks like the Max1555 wants to charge a lithium ion battery to a 4.2V cell voltage. Is that the chemistry and cell voltage of the battery you're trying to charge?
Generally you can always charge a battery at a lower rate without a problem, in fact slower charge rates can result in longer cell lifetimes, And 280mA on a 6AH battery will be a nice and slow C/20 charge rate. Most of the problems with battery charging come from charging too fast or applying too much voltage to the cells.
Full charge in20 hours? So you go a day and have half a day of music? also you said it works manually charging it. can't you make a v-reg circuit that manually charges the battery?
Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
The problem with lithium batteries is that they can burst into flames if not charged correctly so only people that really know what they are doing should attempt to make their own chargers.
MAX1555 is a nice little chip and I use it on most of my batteries up ot 17 Ah. It is important to get the capacitors close enough to the chip like described in the datasheet.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
It has one capacitor already on the PCB itself, as part of the existing switch mode supply.
I'll add them just to be safe then.. Best to use disc rather than SMD ceramics here good to 50V?
Also added the appropriate LED so I can see the charge status, it turns off when "full"
It also seems to have a failsafe on the battery itself, consisting of a little PCB on each cell and evidently a LVCO circuit too. Batteries are labelled REC4351122P, 3Ah.
Shame Maxim don't make a 5 pin LiFePO4 charger, that would be very useful indeed
EDIT:- They do, its just not SOT23. EDIT 2- Need to move charger IC and add reverse protection diode as it is attempting to power itself from the USB output pin when battery voltage rises above 3.7V which resulted in an epic fail and squealing SMPS noises Luckily I noticed the problem before it could do any damage..
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.
Safe to use a MAX1555 to charge 6AH battery?
