Fw: Parallel charging

[JOddino]

A warning to all:
Here is a real potential problem.  We are talking about NiCd and NiMH charging.  Recently two guys have burned up packs in their planes. I get called because they think it was caused by my switch harnesses.  I got suspicious when I found out both were using parallel packs and switch harnesses.  I remember when Chip Hyde first started using the original Duralites in parallel he found he could not charge both at the same time if they were both plugged into the receiver.  We found it was due to the sensing resistors in the return wires from the batteries being charged, being short circuited by the connection in the receiver.  This confuses the charger.  I wasn't sure if the Schulze and the other sophisticated chargers used low side current sensing so I asked.  I didn't get a perfectly clear answer but you can see the German approach.
If you don't know if your charger has this potential problem don't charge simultaneously unless you unplug one from the receiver.
For those of you following the discussion of the NMP Li-Ion charger, it does not have low side current sensing, it has a meter in the high side, and it is perfectly okay to charge in parallel simultaneously in the plane.
Jim
----- Original Message ----- 
From: hotline at schulze-elektronik-gmbh.de 
To: JOddino at socal.rr.com 
Sent: Saturday, May 08, 2004 4:00 AM
Subject: Re: Parallel charging


you ALWAYS have to charge batteries directly and all alone connected to the charger.


Best regards
Matthias Schulze

Schulze Elektronik GmbH
Prenzlauer Weg 6
64331 Weiterstadt
Germany

Fon: +49-6150-1306-5   (sales + answering machine) 
Fon: +49-6150-1306-98 (hotline daily 14:00-16:00 local time CET)
Fax: +49-6150-1306-99

eMail: sales at schulze-elektronik-gmbh.com for your order(s)
eMail: hotline at schulze-elektronik-gmbh.com for technical support
Homepage: http://www.schulze-elektronik-gmbh.com


        Original Message        processed by Tobit InfoCenter  
        Subject:  Parallel charging (07-Mai-2004 4:24) 
        From:     JOddino at socal.rr.com 
        To:       hotline at schulze-elektronik-gmbh.com 


  Is it possible that the charger gets confused if two batteries are being charged simultaneously with two chargers and the batteries being charged have their returns connected as they are when they are plugged into a single receiver through typical R/C switches?

  Is there some type of current sensing in the return line that would not function properly with two in parallel?

  Thanks in advance.
  Jim Oddino
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