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Hi K. This is likely just the Multi 'filling it's caps', and the instantaneous surge is enough to trip the bms. If you wanted to test this theory for yourself, try with a separate wire and watch for the *spark*. With a bigger Multi and higher V (say 48), it can be quite spectacular (underwear change level).

Best to leave the Multi connected to the batts, and if you need to turn off inverting do it from the front panel.

There are workarounds, like a resistor (or even a lightbulb) in a wire to precharge, but practicality might impinge there.

Can't speak for your 'buzzing', but symptoms suggest overloading..

@Kaplan78

"Temperature Compensation: Temperature compensation is not needed with our batteries and in some cases, may trigger the built in BMS to go into protect mode. For this reason, we recommend that temperature compensation be shut off or set to 0."

Is this a possibility?

Interesting I'll try leaving it connected and turning it off at the panel. I was just trying to prevent phantom draw since I rarely ever need the multiplus. It does seem like some kind of surge issue.

As far as temperature compensation, I'll have to look but it should be zero. I set the exact specifications recommended by Battle Born for the Multiplus. However, everything is cold when I'm doing this, everything has been off so there is zero heat. Not sure if that matters with this setting. I will double-check the setting though

With the buzzing I have never heard a Multiplus run so it may be normal, of course, the battery tripping is not. I have other say that inverters of this size are just really loud. I would say it's loud enough if someone walked in my van when it was running they would say what the heck is that noise?

Battleborn sells CSLs. I had two installed for this. I ended up removing them, didn’t need them. Let me know if you want pics.

You should install a pre-charge resistor to charge the compasitors in the Multiplus before turning on the main switch. I have my Multiplus 24/3000 set up this way and just use a 7watt 120ohm resistor.

Ok thanks everybody for the help. I really hit a wall. I went back trough and reconnected wires to the inverter AC input and output. I also found out that when I was updating my Multiplus I didn't seat the CAT5 cable all the way back into the GX panel so it was disconnected. Upon doing all this everything is running smooth and the inverter is super quiet while inverting. Per Johnc I'm going to keep the Multiplus connected to the battery and not use my on/off switch. I will turn off the Mulitplus using the GX panel. It only seems to pull one extra watt leaving it on which isn't terrible. I'm hoping the tripping doesn't come back, but for right now everything seems solid. If it does come back I'll look at the other suggestions here. Thanks for all the help this is a great community!

4.2 Connection of Battery cables In order to fully utilize the full capacity of the product, batteries with sufficient capacity and battery cables with sufficient cross section should be used. See table. 12/2000/80-50 24/2000/50-50 Recommended battery capacity (Ah) 350–1000 200–500 Recommended DC fuse 300A 200A Recommended cross section (mm2 ) per + and - connection terminal 0 – 5m 70mm2 35mm2 Remark: Internal resistance is the important factor when working with low capacity batteries. Please consult your supplier or the relevant sections of our book “electricity on board”, downloadable from our website. Procedure Proceed as follows to connect the battery cables: Use an insulated box spanner in order to avoid shorting the battery. Avoid shorting the battery cables. Connect the battery cables: the + (red) on the left and the - (black) on the right, to the battery see appendix A. Reverse polarity connection (+ to – and – to +) will cause damage to the product. (Safety fuse inside the Multi Compact can be damaged) Secure the nuts tightly in order to reduce the contact resistance as much as possible.

Battleborn sells a CSL (current surge limiter). Call them and order one.

Battle born sells a device for this exact reason so that the MP cap charging doesn’t trip it. Call BB.

I just encountered this problem. I have 2 Battle Born batteries and a Multiplus 2000. The batteries are in parallel. My testing shows that if the MultiPlus has been disconnected for a while the stored or residual charge disapates over time. If the residual voltage gets to 0.5v the initial current surge causes the battery BMS to shut down the batteries. I have had the system restart successfully with the residual voltage as low as 2v. My temporary solution is to connect the batteries via a switch, measure the battery voltage and if less than it should be immediately disconnect, remove the negative cable to reset the BMS, quickly reconnect the cable, and reconnect the batteries. In multiple attempts this has worked to get the MultiPass going. Apparently there is enough residual charge so the second try does not trigger the BMS protective shutdown.

While not an ideal solution it is a repeatable. If necessary the rate of charge decay can be slowed by turning the switch on the MultiPass to OFF. The rate of charge decay may depend on the amount of vampire devices connected to the DC side of the MultiPass.

I’m actually considering installing a voltage meter in my battery compartment and a switch in my negative battery cable to allow rapid BMS reset. Then I can prime the MultiPlus, reset the BMS, and start it without tools.

I'm in the same situation here. 2 x 100ah BB batteries in parallel connected to a victron MultiPlus 2K inverter. As soon as the inverter is connected to the lynx distributor, the BB BMS triggers. I'm using short cable runs for batteries to lynx (less than 2 feet) and using 2/0 wire. Inverter runs are also less than 2 feet and I'm using 2/0 wire.

Rather than do what @Streborg has done (longer runs of 1/0 cable), I'm considering installing a 3 way switch on my negative run between inverter and negative busbar, where I hardwire a pre-charger resistor as switch 1 (allowing me to pre-charge caps for a few seconds) and then switch 2 will be the normal path between inverter and busbar. Has anyone else done this? Thanks in advance!

BB tech support has not been very helpful thus far. I've shared photos of my install and my wiring diagram. They've not offered up any solutions yet. I'm really not impressed with their customer service yet.

The 1/0 cables mentioned in my answer above were more than sufficient to provide all the power I needed and never show any signs of even warming up. Once the 1/0 cables were in place the battery BMS never again shut down.

I recently decided to increase my battery capacity to 4 100AH Battle Born batteries. Because the battery compartment was too small I relocated the batteries to a new location in the RV. This required about a 15 foot cable run so I went back to 2/0 AWG cable. The extra length of the 2/0 was enough to prevent the the initial surge from tripping the BMS.

It must be very difficult for the manufacturers like Victron and others to handle the really strange fault conditions that are appearing as a result of the batteries that are purchased from the local toy store.

From an engineering design perspective a pre-charge resistor is a far better choice than increasing the impedance of supply cables.

Is the CSL the same as a pre-charge resistor? How can you figure out whether you'll need one or not ahead of time? If I know how many batteries I will have and their configuration and which inverter I will use, other than finding someone with exactly the same setup, is there a way to figure out the required wire for length x and whether it will trip?