NiMh Battery Charger? - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th January 2003, 11:45 PM   #1
Banned
 
Join Date: Nov 2002
Location: Adelaide, Australia
Send a message via MSN to SkinnyBoy
Default NiMh Battery Charger?

I have two 5volt @ 2amp switchmode plugpacks and would like to make a battery charger able to charge 2 AA NiMh batteries, They are 1.6amps each.. I would also like to include a feature to be able to select the charge rate (slow/normal/fast) anyone know of a circuit?? I have looked EVERYWHERE for a circuit.. well, nearly... also, a timer would be good... a simple one to select the charge time.. anyhelp would be GREAT!!
  Reply With Quote
Old 12th January 2003, 11:50 PM   #2
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default Try Maxim

a circuit featuring these MAX712, 713 etc. chips was a staple in the ARRL Handbook, you can find it here at Maxim's site:
http://www.maxim-ic.com/quick_view2.cfm?qv_pk=1666
  Reply With Quote
Old 12th January 2003, 11:54 PM   #3
Banned
 
Join Date: Nov 2002
Location: Adelaide, Australia
Send a message via MSN to SkinnyBoy
Ok thanx, I think I saw it before... or maybe not... Anyway, my problem is (I have many, but not relevent to this project ) is that I am not sure if I can connect the cells in series due to the lowish input... one schematic I saw needed 7 volts I think to charge to cells in series...
  Reply With Quote
Old 14th January 2003, 12:49 AM   #4
diyAudio Member
 
Join Date: Nov 2002
Location: Michigan, USA
NiMh can be tricky to charge properly. Usually they use a microcontroller, and monitor voltage, current and temperature. They are very sensitive... ...you can charge them with a simple power supply, but will shorten the life/capacity of the cells.

-Dan
  Reply With Quote
Old 14th January 2003, 09:27 PM   #5
diyAudio Member
 
Join Date: Feb 2002
Location: Belgium
The max713 is very foolproof. Monitors dv/dt, Icharge, switches to trickle charge and has a timeout. If I remember you need 2V more than the max voltage during charge. So for 2 cells that would be 2V+2V+2V=6V. So a 7V adapter would be right.

Never charge cells in parallel! They will always charge uneven.
  Reply With Quote
Old 14th January 2003, 09:34 PM   #6
Banned
 
Join Date: Nov 2002
Location: Adelaide, Australia
Send a message via MSN to SkinnyBoy
Quote:
Originally posted by Havoc
The max713 is very foolproof. Monitors dv/dt, Icharge, switches to trickle charge and has a timeout. If I remember you need 2V more than the max voltage during charge. So for 2 cells that would be 2V+2V+2V=6V. So a 7V adapter would be right.

Never charge cells in parallel! They will always charge uneven.
Could I use 2 controller ICs and have a seperate circuit for each cell... I only have a 5volt plugpack.... I bought it with teh hope of making a battery charger.. I already had the batteries... I bought then 2 years ago, but had no way of charging them... The reason I want to use the 5volt plugpacks is bacause they are small, very small, and give 2amps out, which is good.... I suppose I may be able to modify one to get 7volts, rather that 5.... A voltage divider on the feedback line.... but I can't even get it open.. :P lol They are well regulated, they still give "5 volts" (about 5.2volts) even with a 2.1amp load..... So, I think these were a good find at only $5.50AU... I only bought 2.... I was going to buy 5.... or... what else could I do with them?
  Reply With Quote
Old 14th January 2003, 09:59 PM   #7
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
the MAX713 is a little expensive to use 2 of them -- about $7 -- but with Maxim you get a lot of utility for the USD or AUD.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery Charger for 15V Li-ION Battery Pack ??? Jan Dupont Parts 2 11th April 2009 02:18 PM
R/C battery and charger jaudio Power Supplies 3 18th February 2009 07:27 PM
Simple and safe NiMH charger? antomas Power Supplies 21 28th March 2008 05:38 PM
Battery Charger ThSpeakerDude88 Everything Else 13 6th September 2006 10:40 PM


New To Site? Need Help?

All times are GMT. The time now is 09:23 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2