BMS hookup

[emeraldcoastcamper]

Ok. I am a total noob...but learning. I received two Daly 150 amp BMS today. I have two batteries. I get that the Blue wire goes to the negative terminal of the battery and the small red wires go to 1234 cell positive. Where does the remaining large black wire go? The diagram says Load. Is that the positive connection to the charger, or the negative.?

 

[emeraldcoastcamper]

Can someone please just tell me where to connect the large black wire.

 

[MisterSandals]

Can someone please just tell me where to connect the large black wire.

Oh LARGE black wire. Sorry disregard original version of this answer.

 

[MisterSandals]

The large black wire can go to a couple different places depending if your BMS is on the charge side of the batteries or on the load side of the batteries.

If on the charge side (most common use), then the large black is connected to the negative from the SCC.
If on the load side, then that goes to your <fuse> then load bus or inverter.

 

[Pierre]

I think before you connect anything you need to watch some of Will’s introductory videos.

 

[MisterSandals]

Think of the BMS as a big switch for a negative line. The BMS monitors the battery cells and when it reaches any limits (high voltage, low voltage, temp sensor if available) it opens the contacts (thereby stopping charging (on charge side) or stopping discharge (on load side)).

But yes, watch videos as pierre suggests.

You can test the voltages of the contacts on the loom too. From the 1st pin which is negative put your volt meter negative probe here. Start on 2nd pin and hopefully read ~3.3v. Progress to pin 2 and it should increase by ~3.3v to about 6.6v. Progress across your loom contacts. If it does not progress as described above, its wired wrong and may damage whatever it is plugged in to.

 

[emeraldcoastcamper]

Thanks Cap'n. I am learning. My Daly has the Common port. P- (black thick wire) is connected to my "load" bus bar which is connected
to the Black post on the inverter/charger. B- (thick blue wire is connected to the main negative terminal of the battery. This concurs with the instructions send by Daly.

I should clarify that I have two 12.8V batteries connected together to double the AH. I think the term is Parallel. Each battery has it's own Daly 150 AMP BMS.

I did read somewhere that I should do a couple of discharge and charge cycles for the BMS to function properly. Is that true?

 

[MisterSandals]

Ya lost me. Do you have 3 BMSs?
The one we were talking about and one on each battery?
I would need to see a drawing, there are way too things with vague descriptions for me without more coffee.

 

[emeraldcoastcamper]

Two batteries...two BMS.

And all cells are now balanced at 3.35V

Have a great day and thanks for taking time to reply.