[RE-wrenches] DC Ripple (was Odd Outback FNDC/Mate issue)

[Allan Sindelar]

Dick,
Hmmm... now you have me thinking, thank you. I generally have three
additional wire functions carried in the same conduit as the battery cables.
Have done it this way for years and never thought about it, or had any
problems that I have become aware of. I carry the temperature sensor wires
for both the charge controller and inverter temperature sensors in the
conduit, and usually a length of float switch cable (18/1pr shielded type
TC) through the battery box to the Zephyr Power Vent. 

Has anyone ever had temperature compensation issues that could be traced to
DC ripple from the magnetic field of the battery cables?

Thank you,
Allan at Positive Energy

-----Original Message-----
From: re-wrenches On Behalf Of Richard L Ratico

Howie,
Very high, rapidly fluctuating, DC currents are carried by battery cables.
These
produce powerful, local magnetic fields. Many sources recommend twisting the
cables together to reduce RFI. I have found this twisting hard to do well.
Steel
conduit accomplishes the same thing, more effectively. Resist the temptation
to
put any other wiring in that conduit. This would most likely be a code
violation
in any case; wires of different voltage ratings in the same conduit are
generally prohibited.

Dick

Dick Ratico
Solarwind Electric

--- You wrote:
Outback has now determined that somehow this induced current from the
battery cables into the voltage sensing wires for the FNDC can cause the
communication system to get overwhelmed, but they are not quite sure how. 
None-the-less, as of this week, they are recommending to run the FNDC
voltage sensing wires (plus and minus) *not* along side the inverter
cables.

Hopefully, this is the end of this story...

Has anyone experienced any similar symptoms?  This seems a first for OB,
but I thought I'd ask here.