Hi, I am using two SBPs for charger control (SBP-65) and load control (SBP-220) in a system setup same as shown in chapter 3.3.5 page 8 in the Victron SBP manual.
Problem is that the fuse (1A) in the GND cable blows directly once the SBP is connected to the accu (Victron 25,6v LFP NG). Even if the plus cable of the charger (Victron Phoenix 24v/25A) is not connected.
The SBP in&out are for sure correctly connected as in the shown setup and configured in mode C (lithium) with 24v system voltage. The GND pin is directly connected via a separate cable to the minus pole and is fused with 1A. The Load protect SBP220 works well. Replacing the SBP-65 doesn’t solve the issue.
First, Check your wiring carefully to ensure it follows the manual. If this is the case, then disconnect the battery positive from each of the BP-65-s in turn to discover which is the defective unit No loads or chargers should be connected to the terminal of the BP65 that is not connected to the battery.
Mike, thanks for your reply. I doublechecked again. I have replaced the BP-65 by a Cyrix Li Load relais and it works now. I understand why it works with an Cyrix relais but don’t understand why it doesn’t work with an BP-65. The BP-65 even goes wrong permanently. I can only imagine that a polarity issue breaks the (MosFet) BP-65, but the in&out of the BP-65 are connected as shown in the scheme of the Victron manual.
One possible wiring error would be to connect the battery to both ‘in’ or ‘out’ terminals of the SBP65. for the setup on p8, this would likely cause problems in one of the units. However, if you now have a working solution, this is academic.