Go Back  R/C Tech Forums > General Forums > Electric On-Road
pulse chargers & nimh cells >

pulse chargers & nimh cells

pulse chargers & nimh cells

Old 01-07-2004, 07:03 AM
  #16  
Tech Adept
 
Join Date: Nov 2003
Posts: 140
Default

Maybe someday I'll take some of my 1st generation GP-3300 and do some testing...

I've read all the stuff about how pulse charging was suposed to be so great, etc... as far as I know it never really played out that way on the track... but then I was taking a break from RC about the same time it was the really hot thing. So I don't have much direct experiance with it myself. It seems by the time I got back into RC no one was using it any longer.

For the most part, I've always felt that most of what RC racers think they know about charging, is based on information that is very far from scientific. But then it would be etreemly hard to do anything truely scientific and would be very expensive. I have a little more trust in RC battery guys today, mainly because I've read a little more about what some of the people are doing to determin the best ways of charging and such. Even so, I do think much of what is 'known' about RC battery charging is a lot like magic... if you look very closely from all angles, you generaly will see things aren't always what they appear to be.

Having said that... the realtively scientific testing of batteries and charging methods, that gets done by battery manufactures and even NASA., is of almost no value to the RC racer... Those guys typicaly want long life, and us racers typicaly want POWER at any cost... We basicly abuse our batteries and if we get 50 good cycles out of a pack then we are generaly pretty happy... NASA and others would never put up with the life expectancy that we will... So, their testing really is almost meaningless to us...

At this time, and for the forseeable future, I fully admit my battery knowlege is not all that great... I know a little based on what I've read, and a little based on my own experaince, but all this added up doesn't mean much really

Just for kicks, I may try and do some comparison of charging with pulse vs. chargin with linear on some old GP3300s, but my plate is very full right now, and I wouldn't make any promises as to if/when I might get around to it.
DynoMoHum is offline  
Old 01-07-2004, 11:56 AM
  #17  
Tech Elite
 
Cole Trickle's Avatar
 
Join Date: Sep 2001
Location: Denmark / Europe
Posts: 2,571
Default

Originally posted by DynoMoHum
Just for kicks, I may try and do some comparison of charging with pulse vs. chargin with linear on some old GP3300s, but my plate is very full right now, and I wouldn't make any promises as to if/when I might get around to it.
I recognise this situation....

By the way, an "advantage" to pulse chargers, is they are cheaper to produce. Simply because they run cooler and thus require less cooling.

Another point: In some magazine (probably on the internet) I read an article about those linear chargers. Actually, they are not always true linear... The magazine did some measurement on these chargers (with good reputation), and they were far from linear. Probably, they should result in better charging. But maybe it's too hard to marketing non-linear chargers????

Another thing: LRP's Pulsar is claimed to be linear, though they also claim they use PWM technology for more efficiency. But PWM is pulses.... Maybe I dont know enough about electronics, but it seems a little foggy to me....
Cole Trickle is offline  
Old 01-07-2004, 12:02 PM
  #18  
Tech Fanatic
 
etzkev's Avatar
 
Join Date: Jan 2004
Location: Northville, MI
Posts: 790
Default

A quasar pro is a linear charger right? I am almost POSITIVE, but I'm just making sure.

Thanks,
etzkev
etzkev is offline  
Old 01-07-2004, 12:24 PM
  #19  
Tech Adept
 
Join Date: Nov 2003
Posts: 140
Default

I agree with you Cole that some chargers lead you to beleive they are linear when they are not. If I am not mistaken, Hank from Hobbytalk did a test of several chargers a year or two ago, and many did indeed have pulses... He's probably still got the articles posted somewhere.


Really the only way to know for sure would be to look at the output with a osilliscope.

A for Quasar Pro??? I don't know if it's truely linear or not.
DynoMoHum is offline  
Old 01-07-2004, 08:43 PM
  #20  
Tech Elite
iTrader: (12)
 
rough512's Avatar
 
Join Date: May 2002
Posts: 3,455
Trader Rating: 12 (100%+)
Default Pulse charger???

So is this Linear or Pulse charger????

I have a charger that charges for nearly a second, stops for a few ms, then measures the battery voltage then charges for nearly a second, stops for a few ms, measures battery voltage, then repeats the cycle...

This is a desktop charger for a Bosch cellphone fitted with NiMH battery. It is OEM which means, Bosch is confident it is safe for charging NiMH...

I think it is the reverse pulse chargers that are not suitable for the NiMH. Pulse chargers should be fine as long as the 'chopped' Supply Voltages are in the region of 12-15V. This way, the pulses are softer and gentler on the battery plates... Reversepulse charging are not encouraged on NiMH, although Tekin used to say their PF1 (power flex) profile is gentle enough for NiMH. I use the PF1 on the first charge then go linear for the rest of the day.

just my opinion of course.

rough512 is offline  
Old 01-08-2004, 05:40 AM
  #21  
Tech Adept
 
Join Date: Nov 2003
Posts: 140
Default

You may very well be right rough512.... it may be that a charger with pulses that all go in the positive direction is not what used to be refered to as 'flex' charging... As I said before, I wasn't really around when 'fex' or whatever it was called was popular, and I have never attempted to see if there were negitive voltage pulses introduced or not...

I do have a ossilicope somewhere, and could see if my CE T35 puts out any negitive pulses when it's in 'flex' mode...

I'll see if I can find the O-scope and see what really happens on a couple chargers I have...
DynoMoHum is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.