Hello Victron Community,
For a few weeks now I've been struggling to find the right solution to charge my LiFePO4 batteries from my bus alternator. Here are the relevant technical details:
- Delco Remy 50dn heavy duty alternator (24v 270amps); oil cooled, belt driven, externally regulated
- 2x3 Battle Born batteries (12v 100ah) in seriesxparallel for 300ah at 24v (internal BMS)
- Cyrix-li-ct relay connecting start batteries (2x group8 lead acid)
I consulted Battle Born and a few others in the industry and was told that this setup should work. The alternator is rated for heavy continous use and the Battle Born batteries can take charge from the alternator with the normal caveats (i.e. the alternator voltage will not be able to take the batteries to full SoC, etc.)
In practice, however, what I'm seeing is unworkable and I'm concerned I may actually damage my alternator/system. With the engine on and the relay engaged (solid blue light), I see a cycle that lasts 3-4 seconds and repeats ad infinitum. For a few seconds there is no current flow. Then, for a split second, a large in-rush of current (160+ amps) and a voltage spike of over 30 volts. Followed by no current and a return to 28 volts.
I've recorded the behaviour on video here:
Does anyone at Victron or in the community have an idea as to why this is happening? In the video you can hear the relay making a noise that is a bit disturbing as well.
Thanks in advance for any advice.