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NiMH battery charger questions
How can I find out if a charger (i.e. one I already have) is a so-called
intelligent charger (i.e. one which monitors the batteries and starts charging with a trickle current once they are nearly charged)? And, are all intelligent chargers mostly equal, or is there some very good reason for some of them selling for £10 and some selling for more than four times that price? Daniele -- Apple Juice www.apple-juice.co.uk Chapter Arts Centre Market Road Cardiff CF5 1QE |
In article
, D.M. Procida wrote: How can I find out if a charger (i.e. one I already have) is a so-called intelligent charger (i.e. one which monitors the batteries and starts charging with a trickle current once they are nearly charged)? Look inside it? If it appears to have electronics - like an IC - it's likely to be reasonably intelligent. Basic ones - like supplied with some cheap drills merely use a DC power supply and a series resistor. And, are all intelligent chargers mostly equal, or is there some very good reason for some of them selling for £10 and some selling for more than four times that price? Dunno. I stick to charging at the 1/10th capacity rate which takes overnight. Batteries last a long time with this. -- *Two many clicks spoil the browse * Dave Plowman London SW To e-mail, change noise into sound. |
"D.M. Procida" wrote in message ... How can I find out if a charger (i.e. one I already have) is a so-called intelligent charger (i.e. one which monitors the batteries and starts charging with a trickle current once they are nearly charged)? And, are all intelligent chargers mostly equal, or is there some very good reason for some of them selling for £10 and some selling for more than four times that price? Daniele -- Apple Juice www.apple-juice.co.uk Chapter Arts Centre Market Road Cardiff CF5 1QE Look for delta or peak in description. Make sure timer not mentioned. |
D.M. Procida explained on 25/08/2005 :
How can I find out if a charger (i.e. one I already have) is a so-called intelligent charger (i.e. one which monitors the batteries and starts charging with a trickle current once they are nearly charged)? And, are all intelligent chargers mostly equal, or is there some very good reason for some of them selling for £10 and some selling for more than four times that price? The intelligent ones are usually the fast/rapid charge type, charging in about 60 to 90 minutes. They will also have some sort of indication (LED) when a cell is fully charged. Delta-V (voltage sensing end of charge), or delta-T (Temperature sensing end of charge) should be mentioned somewhere. Avoid the ones which simply trickle charge [1] or use a fixed timer. The later are only useful with the set of batteries supplied with the charger. [1] These are not so bad, if you know the charge rate and are willing to carefully supervise the charging session to prevent overcharge. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.org |
In article ,
Harry Bloomfield wrote: Avoid the ones which simply trickle charge [1] or use a fixed timer. The later are only useful with the set of batteries supplied with the charger. [1] These are not so bad, if you know the charge rate and are willing to carefully supervise the charging session to prevent overcharge. Accepting the limitations - and 14 hours is basically overnight - IMHO batteries last far longer charged like this than by any other method. Which may or may not matter for some applications, but to me it's important. I have a charging 'station' in the workshop with a 14 hour timer feeding multiple outlets. -- *Always borrow money from pessimists - they don't expect it back * Dave Plowman London SW To e-mail, change noise into sound. |
On Thu, 25 Aug 2005 21:50:10 +0100, "Harry Bloomfield"
wrote: The intelligent ones are usually the fast/rapid charge type, charging in about 60 to 90 minutes. They will also have some sort of indication (LED) when a cell is fully charged. Delta-V (voltage sensing end of charge), or delta-T (Temperature sensing end of charge) should be mentioned somewhere. All of these damage the cells to a greater or lesser extent. Avoid the ones which simply trickle charge [1] Actually these are by far the best as far as battery life is concerned. You can happily charge at 1/10th of the cell capacity for a day or 1/20th of capacity for days without causing harm. Neither require careful supervision. The most damaging chargers are usually the cheap "5 hr" ones supplied with some power tools. These have no worthwhile regulation and overheat cells badly. As a rough guide - if the cell/battery gets hot it is being damaged. Nearly all fast chargers make the cells get hot. -- Peter Parry. http://www.wpp.ltd.uk/ |
Peter Parry wrote:
The intelligent ones are usually the fast/rapid charge type, charging in about 60 to 90 minutes. They will also have some sort of indication (LED) when a cell is fully charged. Delta-V (voltage sensing end of charge), or delta-T (Temperature sensing end of charge) should be mentioned somewhere. All of these damage the cells to a greater or lesser extent. Avoid the ones which simply trickle charge [1] Actually these are by far the best as far as battery life is concerned. You can happily charge at 1/10th of the cell capacity for a day or 1/20th of capacity for days without causing harm. Neither require careful supervision. But what happenes when you forget about them, and leave them much longer than the appropriate time? Daniele -- Apple Juice www.apple-juice.co.uk Chapter Arts Centre Market Road Cardiff CF5 1QE |
Dave Plowman (News) wrote:
Look inside it? If it appears to have electronics - like an IC - it's likely to be reasonably intelligent. Basic ones - like supplied with some cheap drills merely use a DC power supply and a series resistor. Laptop battery chargers seem much more intelligent. Mine switches off when the battery is full, as I can see from the computer, which seems to have considerable knowledge of the battery - what its original maximum charge is, what is the maximum charge it has recently had, etc. (Incidentally, I can put batteries holding different charges in my laptop - a Sony Picturebook.) Are there chargers which will give you similar information about standard rechargeable batteries? I do find chargers have a kind of "black box" behaviour - it rarely seems to be explained what they are doing, or when they will stop charging. -- Timothy Murphy e-mail (80k only): tim /at/ birdsnest.maths.tcd.ie tel: +353-86-2336090, +353-1-2842366 s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland |
Timothy Murphy wrote: Dave Plowman (News) wrote: Look inside it? If it appears to have electronics - like an IC - it's likely to be reasonably intelligent. Basic ones - like supplied with some cheap drills merely use a DC power supply and a series resistor. Laptop battery chargers seem much more intelligent. Mine switches off when the battery is full, as I can see from the computer, which seems to have considerable knowledge of the battery - what its original maximum charge is, what is the maximum charge it has recently had, etc. (Incidentally, I can put batteries holding different charges in my laptop - a Sony Picturebook.) It's more likely the battery pack which is "intelligent" with a charge monitoring chip that can be interrogated by the laptop. MBQ |
On Fri, 26 Aug 2005 11:47:55 +0100, Timothy Murphy
wrote: I do find chargers have a kind of "black box" behaviour - it rarely seems to be explained what they are doing, or when they will stop charging. A concept known as "user transparency". You nees not know anything about electrons or holes to use a semiconductor device any more than how telephone exchanges and mobile cells work to make a 'phone call. I was going to have a look in my charger, but it has screws needing a bifurcated screwdriver to remove them. Maybe when the workshop is open, I'll cobble one together. John Schmitt |
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