Mixing 4QD 150 / 200 / 300 series boards

With several ‘caveats’, the control boards and base boards of the 4QD series are interchangeable and may be mixed and matched. However – it is important that you understand the potential problems.

4QD 300: This has slightly diferent values on the control board to that used for the 4QD-150 / 200, so do not mix 300 control  boards with those from the 150/200.

48v controllers : Recent 48v controllers have used low Rds(on) MOSFETs – 5 milliohn, instead of the more usual 10-14 milliohms ones. This necessitates value changes in the current limiting circuits. These notes therefore do not apply to the 48v controllers but only to the 24-36v versions.

This table shows the different versions of the 4QD-300 boards that we have tested together. It’s a work in progress and we’ll update it as we get more data.

Control board 30-15
2000 2001 2002 2003 2004 2005 2007 2010 2011 2016
Base board 30-16 12 13 14 15 16 17 18 18a 18b 19
1998 10 Y Y N
1999 11
2000 12 Y Y Y  Y Y Y
2003 13
2004 14
2005 15
2006 16
2007 17 Y Y Y Y

BDP link

Battery discharge protection was only fitted to the base board from issue 13 onwards. To use control boards at version 15 or later with early base boards it will be necessary to cut the BDP link on the control board [see manual for details of the link location].