Did I waste my time?  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       


FISHER FUEL PRODUCTS 5 GALLON & 2.5 GAS FUELERS
Seller:  hunternfla
Details:   $220.00   |  10/2/2008   |  Classified Ad
We will rotate YOUR AD in this spot if you select "Forum Featured" when placing or editing your ad!

All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Did I waste my time?
Page: [1]

Login
Message << Older Topic   Newer Topic >>
Did I waste my time? - 9/27/2003 2:13:37 AM   
YS-I-DO


 

Posts: 246
Joined: 8/3/2003
From: Lewiston, ID, USA
Status: offline 		After purchasing a 5 cell 2700mah NiCad battery from my LHS, and being reassured by the salesman that my Futaba 4 volt 50mah charger would handle it, I had a rude awakening. Browsing some recent RCU posts, I realized that the salesman was blowing smoke up my..... Anyway, not wanting to spend a lot of money on a new charger, I built a current limiting circuit like the one here - www.screaminet.com/~marvintm/Reg_1.jpg , and powered it with a Radio Shack selectable voltage wall wart, capable of up to 9v and 300mah. I set the wall wart at 7.5v, and then used my digital ammeter to set the current regulator at .27amps, or .1C of by battery pack. Now, if I understand everything that has been said in this forum, I can leave it on the charger for 16 hours to get a full charge, no matter what the charge state of the pack. Also, I can turn down the regulator to .13amps, or .05C, and use it as a trickle charger. Did I just waste my time and money, or will this thing work??
       Post #: 1

RE: Did I waste my time? - 9/28/2003 12:30:45 AM   
JPMacG


 

Posts: 1179
Joined: 1/2/2002
From: Ivyland, PA, USA
Status: offline 		Sounds like you got it right to me.

(in reply to YS-I-DO)
       Post #: 2

RE: Did I waste my time? - 3/4/2004 2:14:32 AM   
marvintm



Posts: 77
Joined: 9/3/2003
From: Cleveland, OH,
Status: offline 		My link for the regulator has changed location:

http://users.adelphia.net/~marvintm/images/regulator.jpg
enjoy

< Message edited by marvintm -- 5/13/2004 1:57:43 PM >

_____________________________

The sun was in my eyes.

(in reply to YS-I-DO)
       Post #: 3

RE: Did I waste my time? - 3/4/2004 11:34:00 AM   
Geistware



Posts: 12946
Joined: 4/9/2002
From: Locust Grove, GA, USA
Status: offline 		Hey Marvin, Can I use this on my site???



quote:

ORIGINAL: marvintm

My link for the regulator has changed location:

Constant Current Regulator

enjoy


_____________________________

Aircraft Proving Grounds
http://www.rcaircraft.net/
Information on the building and flying of Radio Control Aircraft.
Site for hobbyist in the R.C. Aircraft modeling world.

(in reply to marvintm)
       Post #: 4

RE: Did I waste my time? - 3/4/2004 3:08:47 PM   
crownvic



Posts: 653
Joined: 3/30/2003
From: Mc Cleary, WA, USA
Status: offline 		The salesperson wasnt BSing you. you just need to leave it on longer.



Lonnie

(in reply to YS-I-DO)
       Post #: 5

RE: Did I waste my time? - 3/4/2004 6:29:05 PM   
beavertail



Posts: 713
Joined: 12/2/2002
From: SOUTH, TX, USA
Status: offline 		Wouldnt 1C be 2.7 Amps? I might be wrong, If so, pretend you didnt read this.

_____________________________

Hows my flying???
Call 1-800-EAT-(Censored by Moderator)

(in reply to crownvic)
       Post #: 6

RE: Did I waste my time? - 3/4/2004 8:58:09 PM   
Hangtime



Posts: 346
Joined: 6/5/2002
From: Babylon, NY, USA
Status: offline 		Ouch.

quote:

ORIGINAL: crownvic

The salesperson wasnt BSing you. you just need to leave it on longer.
Lonnie



sorry.. but a stock 4.8v 50ma wall wart charger ain't an appropriate choice for charging a 2700ma 6v pack correctly or fully.. even if you left it on fer 3 days. It IS possible to modify that charger and get it to do the job.. from the Tx side of it. Check Reds Battery Clinic for details.

http://www.rcbatteryclinic.com/

quote:

Wouldnt 1C be 2.7 Amps? I might be wrong, If so, pretend you didnt read this.


Yup. I get lost in the number myself sometimes... I pretty sure he meant c/10 or 10% rated capacity.

_____________________________

Steve Anthony
www.hangtimes.com
NoBS Batteries

(in reply to crownvic)
       Post #: 7

RE: Did I waste my time? - 3/5/2004 4:39:40 PM   
crownvic



Posts: 653
Joined: 3/30/2003
From: Mc Cleary, WA, USA
Status: offline 		Thats very strange! Because I have 8 planes on charge all the time using wall warts all with 6V packs and MA ranging allthe way from 1000 ma all the way to 3200ma and they all cycle out just fine and have been doing so for over 15 yrs. Alot of this battery stuff and charging stuff I think is a bunch of voodo crap


Thats my take on it!

Lonnie

(in reply to Hangtime)
       Post #: 8

RE: Did I waste my time? - 3/5/2004 11:59:49 PM   
Hangtime



Posts: 346
Joined: 6/5/2002
From: Babylon, NY, USA
Status: offline
quote:

Alot of this battery stuff and charging stuff I think is a bunch of voodo crap


LOL Lonnie!!

Yup.. you could be right.. there's voodoo at work here..

I'm offering advice garnered from professional first hand experience. Working inside mfg guidelines and following accepted industry proceedures established by engineers with impeccable credentials when dealing with systems that folks rely upon to keep their investment flying safe ain't 'voodoo'...

...but using a 4.8v 50ma wall wart to recharge a discharged 6.0v 3200ma pack fer 15 years probably is.



_____________________________

Steve Anthony
www.hangtimes.com
NoBS Batteries

(in reply to crownvic)
       Post #: 9

RE: Did I waste my time? - 3/6/2004 2:07:23 AM   
crownvic



Posts: 653
Joined: 3/30/2003
From: Mc Cleary, WA, USA
Status: offline
quote:

ORIGINAL: Hangtime

quote:

Alot of this battery stuff and charging stuff I think is a bunch of voodo crap


LOL Lonnie!!

Yup.. you could be right.. there's voodoo at work here..

I'm offering advice garnered from professional first hand experience. Working inside mfg guidelines and following accepted industry proceedures established by engineers with impeccable credentials when dealing with systems that folks rely upon to keep their investment flying safe ain't 'voodoo'...

...but using a 4.8v 50ma wall wart to recharge a discharged 6.0v 3200ma pack fer 15 years probably is.


IT works for me but I am special the battery GODS like me because I buy new packs every 2 to 3 years and charge them with wall warts! cant tell you why it works? but it does

(in reply to Hangtime)
       Post #: 10

RE: Did I waste my time? - 3/6/2004 1:59:01 PM   
KB9STD


 

Posts: 215
Joined: 4/26/2002
From: Evansville, IN, USA
Status: online 		The set-up sounds good to me NEWBIE. I'm not so sure about setting the "wall wart" output at 7.5 volts though.The regulator needs some voltage across it to work (seems like I have heard 3 volts). With the input at 7.5 volts(5 cells times 1.5 volts) the regulator has no voltage to work with, and I think the current will fall as the battery voltage increases. I would suggest, 5 cells times 1.7 volts=8.5 Plus 3 volts , or 11.5-12 volts.Try setting the output at the 9 volt setting and see how it works.

(in reply to YS-I-DO)
       Post #: 11

RE: Did I waste my time? - 4/10/2004 5:44:19 AM   
marvintm



Posts: 77
Joined: 9/3/2003
From: Cleveland, OH,
Status: offline 		Geistware,

Sure you can use the diagram. Its just my drawing based on the National Semiconductor datasheet information located here:
http://www.national.com/ds.cgi/LM/LM117.pdf

It contains this application for using the voltage regulator as a current regulator.

Nice Web Site BTW
See ya

< Message edited by marvintm -- 4/10/2004 12:45:10 AM >

_____________________________

The sun was in my eyes.

(in reply to Geistware)
       Post #: 12

RE: Did I waste my time? - 4/10/2004 2:19:04 PM   
JoeAirPort



Posts: 7155
Joined: 8/11/2003
From: Milwaukee, WI, USA
Status: online 		Is the stock Futaba 50 ma charger really only 4.8 volts output? Have you measured it while your charging the 5 cell pack? Maybe I'll try that at home with one of mine to see what it outputs. I'm curious.

< Message edited by JoeAirPort -- 4/10/2004 8:26:25 AM >

_____________________________

Joe AP

(in reply to YS-I-DO)
       Post #: 13

RE: Did I waste my time? - 4/10/2004 5:46:50 PM   
FHHuber



Posts: 4931
Joined: 1/1/2003
From: gone, , USA
Status: offline 		All AC/DC transformer-rectifiers will have a voltage and current range of operation.

The nominal 4.8 volt 50 ma output of the wall-warts supplied with the radio systems is way the heck off. (It has to be or the batteries wouldn't charge to thier peak)

If you do some testng, the current and voltage output of the wall-wart will vary when charging a typical 4.8 v 4 cell pack. You can get close to 75 mah at the start of charge. The voltage measured at the terminals of the pack will range from 4.6 (if you drained it to 4.4... and immediately put it on the charger) to 6.7 volts at peak (this is ON the charger). If you pull the pack off the charger you can VERY briefly read it at up to 6.5 volts. (that drops to 5.6 within a couple of minutes)

Take apart some old Wall-wart that you don't need... its VERY simple. Some of the single output ones just have the transformer and a diode.

(in reply to JoeAirPort)
       Post #: 14