12V system down (Smart Battery Protect - disabled by remote)

DIY
,
1

Need some help with troubleshooting a weird issue. My entire 12V system shut down unexpectedly after running fine for 1.5 years. The Multiplus inverter is on, and I have 120V (US) available, but all 12V is down. I traced the power flow to the Smart BatteryProtect and the Smart BMS CL 12-100.

Power goes into the Smart BatteryProtect, but does not come out. I have a single blue LED on the device. The smart BatteryProtect shows “output disabled by remote” inside the Victron app. Then, power goes into the Smart BMS CL 12-100, but does not go out. No control lights are active at all on the device. The fuse on the Smart BMS CL 12-100 has power on both sides of the fuse.

The batteries are currently at about 70%. All systems in the Victron app seem fine. No red exclamation points. The MPPT controllers (2) show zero incoming watts, but I assume that is due to the BMS not working. I did power off the entire system for 24 hours, hoping it would drain the current from everything (but the batteries), but that did not change anything. There is a large fuse in the lower compartment (see picture), but I have power on both sides of the fuse.

As mentioned, the system ran fine for about 1.5 years and there has been no recent work inside the compartment for several weeks. I am in a bit of a loss why the system shut down. The only thing I am not able to check easily is the inverter due to the way it is installed, but since it is working fine and shows a green light, there is no need to look into the inverter more deeply. I am in contact with the builder of the system as well and I relayed more information to them this morning after checking on the fuse on the BMS. Not shown on the pictures is a Victron Digital Multi Control 200/200A GX. I installed that 12 months ago to be able to control the inverter.

Any thoughts on where to go from here with troubleshooting?

PXL_20260512_163538658
PXL_20260512_1635386581920×1440 392 KB

PXL_20241123_022844862
PXL_20241123_0228448621920×1446 637 KB

PXL_20250820_181740424
PXL_20250820_1817404241920×1446 472 KB

2

Yeah a wiring digram would definitely help.

Check the remote on the bms

Screenshot2026-05-16-20-57-40-696com.android.chrome-edit
Screenshot2026-05-16-20-57-40-696com.android.chrome-edit954×530 63.8 KB

Is this on because of shore power? If the battery is not outputing anything then that can be the only way it is on.

Its possible the bms is switching the battery protect off (hence the error) and the mppts might not be charging for the same reason.

Ofcourse youcan verify of the remotes are there.

It is an option in the manual

Replece the loop on the battery protect for test purposes to eliminate the long remote back cable as an issue. As a secondary item.

3

Thanks for the help.

Update in case you are interested. The situation has been resolved. I was digging around the official Victron support community, went down a rabbit hole, and found this discussion where someone was pointing out that the BMS CL 12-100 is actually not powered by the house batteries, but the vehicle batteries. At the same time, the person I was talking to at the builder mentioned that there is an additional terminal fuse in the engine bay on the driver side battery. Dummy me did not even know what a terminal fuse looks like, but I do now. Of course, this one was installed in a way you could not see the fuse “window” from the outside. Got my tools out, took it off and sure enough it was blown.

Ordered a new one from Amazon and I am back in business. Learned a lot along the way and I am thinking of replacing the BMS CL 12-100 with a Lynx Smart BMS and two Orion XS DC-DC chargers. Have not been impressed with the alternator charging of the BMS.