Need to turn on DC-DC charger when oil pressure is sensed

[ashrun4fun]

Twin Cummins 6 BTA 330hp in 1998 Bayliner 4788. I have just installed 4 Battelborn 100ah LiFePO4 batteries with Victron components including DC/DC chargers between each start battery and the LifePO4’s. Everything is working great, temps are great voltages/amps all as expected both on shore power, underway, and at anchor.  When I went to add a separate charger for the start batteries (and Gen battery) to keep them topped of while at the dock on shore power, I ran into the issue of the DC/DC chargers detecting the voltage from that new charger and turning on.  It has been suggested that I run a sensor wire (16 guage) from the DC/DC charger (remove the bridge terminal) to the oil pressure sensor on each engine from each DC/DC charger to signal them to turn off and on. (they are not paralled)  My question is, would this cause any issues for the oil sensor function? And if not, does it matter which side of the pressure sensor I connect the wire to?

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[Clark Leighs]

If you are still here  Tony is correct.                   

 Just thought I would add this for anyone else with a similar question.

 

However you do not want to use the oil pressure sensor.   It is a resistive device meant to operate the dash guage and that will throw off the guage reading and may still not deactivate the chargers properly.

 

What I think you need is an oil pressure switch that is ON or OFF.      You will need a N.O.  switch of about 15 PSI turn on.     THat way when the engine is off the switch will be off breaking the connection to the charger. When the engine is operating with pressure beyond 15PSI the chargers will get the signal and  operate.   

Stewart Warner, Cole Hersey among others offer these.      

[Tony Athens]

You really need to post a wiring diagram  of what you are doing.. 

 

Do you mean a 2-wire single pole “pressure switch”?  .. If so, no,  it does not matter.

 

 

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