Trying to repair/hack logitech diNovo Edge keyboard ....

• Trying to repair/hack logitech diNovo Edge keyboard ....
  Posted by scince! on 19 Jul, 2015 09:35
• I am a big noob in electronics but I like to thinker a lot and watching EEVblog.
  
  So I have a keyboard Logitech diNovo Edge for 8 years and my original battery died it can hold charge for 2-3 hours. I bought a new replacement battery. I installed the new battery but it`s not charging. When I put my keyboard on the charging station its blink once green and after that it blinks red. I switch it with the old battery and it works so I was sure the problem was in the battery. I emailed ElectroPapa.com and received a second battery for free but it has the same problem...
  
  My theory : The battery for the keyboard have 3 pins (+,- and T) and the "T" on my new batteries is not working properly so the keyboard protection decides not to charge them so I want to bypass the protection. Pictures bellow show my idea will it work, will it explode , what do you think I have to do?
  
  Greetings from Bulgaria and cheers to the professionals!
  

  ---

  

  
• #1 Reply
  Posted by PA0PBZ on 19 Jul, 2015 10:13
• DON'T DO IT!
  
  There is most likely a charging circuit between the charger connector and the battery connector, bypassing that will almost certainly kill the battery in no time 
  
• #2 Reply
  Posted by scince! on 19 Jul, 2015 10:18
• I think the charging circuit is in the charger ?
  
  
• #3 Reply
  Posted by Rasz on 19 Jul, 2015 10:56
• dont know about this keyboard, but logi mouses have charging circuit inside them, charging base is just a holder with connector
  
  quick test if its the thermistor - wire up old battery ground and T  + new battery ground and vcc at the same time
• #4 Reply
  Posted by PA0PBZ on 19 Jul, 2015 11:33
• This could be the charger circuit:
  
  

  ---

  
• #5 Reply
  Posted by scince! on 19 Jul, 2015 11:35
• Rasz i dont fully understand you...
  you want me to connect the new battery + , - and only connect the old battery T and see if its charging ?
  I made some photos hope they are helpful close up of the suspected charger board on the keyboard and two photos of the insides of the docking station charger.

  ---

  

  

  
• #6 Reply
  Posted by PA0PBZ on 19 Jul, 2015 11:57
• The fact that you have a T connection going to the board points to at least some part of a charge circuit there, it is supposed to stop charging when the temperature rises too high. when you measure the voltage on the T for both for the old battery and the new one (while under charge) it could provide a clue why the new battery isn't charging.
• #7 Reply
  Posted by Rasz on 19 Jul, 2015 22:00
• Quote from: scince! on 19 Jul, 2015 11:35

  Rasz i dont fully understand you...
  you want me to connect the new battery + , - and only connect the old battery T
  

  and ground
  
  looks like your holder has smoothing cap and diode bridge
• #8 Reply
  Posted by scince! on 23 Jul, 2015 21:08
•       I wrote an email that the second battery was defective and got a refund ... so now i am wondering to buy a new battery from a different manufacturer or buy a cell phone battery same Voltage but 2x the capacity and half the price? Will it start working and if not maybe I can modified it to use the +,- of the cell phone battery and the T of the original? Will it charge correctly or explode 
  
  thanks for the help so far
• #9 Reply
  Posted by Rasz on 24 Jul, 2015 04:19
• why are you asking us? you have all the parts to test it
  + I didnt suggest connectoing thermistor of original battery as a permanent solution, just to check if your 'new' chinese batteries are ok
• #10 Reply
  Posted by scince! on 27 Jul, 2015 11:05
• I connected the T of the old battery and tested with the two chines batteries its works ... got refunded and order from a different manufacturer now I will wait for two weeks and post an update