RC-Monster Forums  
RC Monster

Go Back   RC-Monster Forums > RC-Monster Area > General Discussion

Reply
 
Thread Tools Rating: Thread Rating: 4 votes, 5.00 average. Display Modes
Lucky?
Old
  (#136)
JERRY2KONE
JERRY2KONE SUPERMAXX
 
JERRY2KONE's Avatar
 
Offline
Posts: 3,452
Join Date: Sep 2006
Location: HAYMARKET VIRGINIA
Lucky? - 08.30.2012, 09:51 AM

If your lucky there might be some kind of a miniature "pot" switch that you can make minute voltage adjustments with. Then you can just calibrate each charger to the same voltage. I was kind of thinking that you might run into this problem, but we never know until someone tries it out. You are the guinee pig here. Thank you. Anyway hopefully you can find a loop-hole with this setup and get it to work right for your application. Good luck.


SUPERMAXX YOUR LIFE.
   
Reply With Quote
Old
  (#137)
mistercrash
Guelph, Canada, eh!
 
mistercrash's Avatar
 
Offline
Posts: 1,083
Join Date: Sep 2007
Location: Guelph, Ontario, Canada
08.30.2012, 10:39 AM

Here's a few pics of the inside. I don't see a pot and Brian, what is a IC?













No brain, no headaches.
   
Reply With Quote
Old
  (#138)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
08.30.2012, 11:16 AM

Starting from the cord side, I see what looks to be a bridge rectifier, cap filter, an opto-isolated simple switching power supply, and the IC (labeled U2) is presumably the actual charger IC, but the top has been sanded to prevent identification.

However, I do notice the resistors used are 5% tolerance (gold 4th band). No big deal if they aren't used to "program" cell cutoff voltage or whatever, but if they are being used in the charging part of the circuit, I would have expected to see 1% or 2% tolerance precision resistors (5 bands).
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#139)
mistercrash
Guelph, Canada, eh!
 
mistercrash's Avatar
 
Offline
Posts: 1,083
Join Date: Sep 2007
Location: Guelph, Ontario, Canada
08.30.2012, 11:57 AM

Do you think changing those resistors would make these chargers more precise? If they are part of the charging like you said. It would be easy enough to change those resistors and then charge a few 18650 cells to find out what the end voltage is. I just need to know which resistors to get. Thanks Brian.


No brain, no headaches.
   
Reply With Quote
Old
  (#140)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
08.30.2012, 12:03 PM

I'm not sure. If the part number of the IC wasn't ground off, you could look up the datasheet for it and see what purpose/effect any support components would have.

I can't quite make out the color code to know what the exact resistor value should be, and you shouldn't measure it while in the circuit because other components could affect the reading. But once you figure out the default resistor value (looks to be under 1k), you can replace it with a pot and adjust it until it matches the exact value as found on the color code on the resistor. But again, if it's not part of the charging circuit, it will have little or no effect on the output. It's all a shot in the dark at this point.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#141)
mistercrash
Guelph, Canada, eh!
 
mistercrash's Avatar
 
Offline
Posts: 1,083
Join Date: Sep 2007
Location: Guelph, Ontario, Canada
08.30.2012, 12:59 PM

I was hoping for something more encouraging but I guess it is what it is. Thanks.


No brain, no headaches.

Last edited by mistercrash; 08.30.2012 at 01:03 PM.
   
Reply With Quote
Old
  (#142)
mistercrash
Guelph, Canada, eh!
 
mistercrash's Avatar
 
Offline
Posts: 1,083
Join Date: Sep 2007
Location: Guelph, Ontario, Canada
09.10.2012, 12:57 PM

This EV thing is turning into a hobby that is worst than RC! I went 72V 30Ah just two weeks ago and I am having so much fun with it that I already want to go 100V 40Ah.


No brain, no headaches.
   
Reply With Quote
Old
  (#143)
snellemin
2 KiloWatt RACER
 
snellemin's Avatar
 
Offline
Posts: 2,496
Join Date: May 2007
Location: Houston
09.10.2012, 05:02 PM

Do it man. Just be careful with 100V DC and your fingers.


6 KiloWatt A123 Racer
GTP-Pletty Big Maxximum+RX8. GTP-C50-6L Hacker+RX8. CRT.5-Pro4+ZTW esc.
24s2p EVG SX 49.6mph Ebike.
18s4p Raptor 60mph Ebike. 11.5KW
   
Reply With Quote
Old
  (#144)
mistercrash
Guelph, Canada, eh!
 
mistercrash's Avatar
 
Offline
Posts: 1,083
Join Date: Sep 2007
Location: Guelph, Ontario, Canada
09.11.2012, 08:55 PM

Tell me about it, this 72V battery I made bit me a couple times during the construction. My fault, I was in a hurry trying to get it done and I really shouldn't work like that. 100V 40Ah would be with genuine A123 prismatic cells from A123RC. So I need the money before I worry about the fingers. Maybe next year.


No brain, no headaches.
   
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 On

Forum Jump



RC Monster




Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Skin developed by: vBStyles.com