UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to alt.engineering.electrical,sci.electronics.equipment,sci.chem.electrochem.battery,uk.d-i-y
external usenet poster
 
Posts: 22
Default How long intelligent charger remembers previous cells?

At home I charge my NiMH AA cells for everyday use.

I have an rapid "intelligent charger" which senses delta-V and it
measures current/voltage/whatever.

Let's say I start to charge some cells. After an hour, they are not
fully charged but I take them out and immediately replace them with some
different cells.

(1) Would the charger still remember the first set of cells and seek to
find delta-V based on its reading of the previous cells?

(2) How long should I leave an intelligent charger when swappig
batteries like this to make it forget the previous cells?

(3) Would I need to actually disconnect the charger from the mains power
to make it forget?
  #2   Report Post  
Posted to alt.engineering.electrical,sci.electronics.equipment,sci.chem.electrochem.battery,uk.d-i-y
external usenet poster
 
Posts: 19
Default How long intelligent charger remembers previous cells?

Alex Coleman wrote:
At home I charge my NiMH AA cells for everyday use.

I have an rapid "intelligent charger" which senses delta-V and it
measures current/voltage/whatever.

Let's say I start to charge some cells. After an hour, they are not
fully charged but I take them out and immediately replace them with some
different cells.

(1) Would the charger still remember the first set of cells and seek to
find delta-V based on its reading of the previous cells?

(2) How long should I leave an intelligent charger when swappig
batteries like this to make it forget the previous cells?

(3) Would I need to actually disconnect the charger from the mains power
to make it forget?


Sensible designs will detect the removal of the cells and reset the
charger.

Many (most?) use standard chips that do this.

However, if you don't like assumptions, either take measurements, open
the thing up and see what chip is used, or go for (3).

--
Sue




  #3   Report Post  
Posted to alt.engineering.electrical,sci.electronics.equipment,sci.chem.electrochem.battery,uk.d-i-y
external usenet poster
 
Posts: 9,045
Default How long intelligent charger remembers previous cells?

Alex Coleman wrote:
At home I charge my NiMH AA cells for everyday use.

I have an rapid "intelligent charger" which senses delta-V and it
measures current/voltage/whatever.

Let's say I start to charge some cells. After an hour, they are not
fully charged but I take them out and immediately replace them with some
different cells.

(1) Would the charger still remember the first set of cells and seek to
find delta-V based on its reading of the previous cells?


No.


(2) How long should I leave an intelligent charger when swappig
batteries like this to make it forget the previous cells?


a millisecond.

(3) Would I need to actually disconnect the charger from the mains power
to make it forget?


No.

Chargers have no memory. Normally there is a 'fast charge' button, which
initates the charge - the machine simply waits to see when the output
voltage falls by a few mV instead of rising. Normally it then goes to
'trickle current' mode.

If you disconect the battery, it should sense that and go to trickle
anyway when a new battery is connected. You normally restart the fast
charge with a button.

In the case of a charger that is dedicated to a particular pack, (e.g.
for a cordless) I suspect that there is a combination of voltage and
delta V sensing..fast charge will be applied below a certain level,.
otherwise its trickle charging. IN that sense its merely using the pack
voltage to 'push' the notional 'restart button'.
  #4   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 49
Default How long intelligent charger remembers previous cells?



(3) Would I need to actually disconnect the charger from the mains power
to make it forget?


I would go for this option, having just destroyed 4 NimH AA cells on a
Goodman's intelligent charger, that now all read about 10 Mohms in both
directions, plus its psu has failed.
So I think its chip was a couple of cells short of a full battery.


john2

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Resurrecting a 'bad' rechargeable cell? Lobster UK diy 8 May 10th 06 05:34 PM
NICD vs NIMH batteries [email protected] UK diy 12 January 28th 04 01:09 PM
Silent thermostat Dave Gibson UK diy 13 January 5th 04 12:02 PM
Intelligent NiCd/NiMH charger John Stumbles UK diy 5 August 4th 03 11:50 PM


All times are GMT +1. The time now is 06:21 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"