Dear All,
I am wiring up a Blue Sea ML-RBS Remote Battery Switch with Manual Control - 12V DC 500A contactor with a REC-ABMS as recommened by my marine electrician. I have tested the contactor and it works as expected. However, I can not get the REC-BMS to pull the contactor closed when the BMS poweres. Any suggestions are appreciated.
Hello Bill, System design is a choice from components.
You didnt mention which ML relay you use. Looks like the ML 7700.
I didnt install this with the REC prechargeV3. But install them with the older latching relay drivers from REC.
The ML 7700 needs a positve trigger signal. What I see in the REC manaul prechargeV3, is that the drawing shows a latching relay with 2 coils. The ML7000, is slightly different in operation as the latching relay in the drawing. The are many different latching relays!!
It could that the PREchargeV3, switch only the negative inside, and NOT the positive to the coil. Maybe RICK or others here on the forum knows. BUT you can easily check this yourself with a multi meter. Post it here, good info for others.
If the REC prechargeV3 switch internally the negative, then you could use a extra signal relay to convert the negative trigger, to positive trigger.
If you like to use blue sea relays, why not use the ML 7713/ML 7717, more easier to wire.
My personal choice is relays from the brand TBS(Netherlands), there RBS makes a nicer compact installation, together with there Tfuses and busbars.
It looks like you are missing a jumper between pins 3 and 4 for your pack power. I would try that first.
I used the info from both of you. If you look at this drawing, you will see that:
(1) Jumpered pins 3 and 4 on the Pre-Charge module, but am wondering if that is only required to use the active balancing.
(2) Connected pin 5 "Relay DCHF" from the REC ABMS to the bus bar ground.
(3) But the above did not work until I changed the DIP switches to OFF-OFF-ON "Single pole contactor/relay 2 second pre-charge delay"
(4) I also tried the setting the DIP switches to OFF-OFF-OFF "Single pole contactor/relay 1 second pre-charge delay" but it did not work. I'm not sure why.
So at this point the REC BMS is working as expected and is driving the Blue Sea ML-RBS 7700.
I used this figure from the REC ABMS manual on page 8 to help me.
@Ben This is the switch that I using. It is highly recommended by the electrical engineer that is overseeing my design. It also meets all of the required certifications for my MARINE application, which is important. 
@Ben Here are the important specs.
@Bill I know this switch, but have a look at the ml7713!!!
@Ben @Bill good that it works.
But looks like strange settings you made.
Not sure or it is easy for you to do a test, or the "setcoil +". Or the "setcoil-" is the one that gives the trigger signal?
As this is not in the manual, good to know for others.
Many times one off the 2 wires is a constant - or +, the other ones gives the trigger pulse.
@Ben
Thanks so much for posting about the TBS - it looks like a great solution which made me go looking some more!
(I'll be posting in a new thread about this)
@Bill C. First of all, thank you for sharing your project!
I have the REC ABMS 4S as yours and I want to add the Bluesea bi-stable contactor ML-RBS 7700 driven by the ABMS Main internal relay, as you did.
In all the REC diagrams I saw, the REC Pre-Charge unit 3.1 is connected to the "System side + pre-charge" (pin 5 > 15 Ohm, pin 10 > 30 Ohm).
Why did you not connect System DC+ to one of these pin?
