DC Ripple / Low Battery alarms

DIY
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1

Hi there,

Last year I purchased a sailboat which got converted to electric powered in 2021. During this winter, I had an emergency which kept me from visiting the boat for some time and the batteries onboard were deep discharged. I therefore took them home to charge both of them and clear any faults using the Victron BlueSmart Charger.

When the time came a month ago to put the old boat at sea again, I installed back the batteries, precisely the same as before. Then I noticed the installed VE bus smart were completely dead. So I purchased a new one, updated the new VE bus smart and figured that everything was in order. However, when I tried to turn on the engine and a few RPM, the propeller turns an 8th of a turn and then the Multiplus 24/1600/40-16 warns for Low Battery and Ripple Alarm. Furthermore, when I have it connected to 230VAC Shoreconnection the propeller will turn. Once then the RPM is set on neutral, the Multiplus will turn off (indicating Alarm) and then reset itself. Once reset, you can go forward/backward.. which also is odd. I’m completely new at this, and I hope I can get some support regarding this fault. I’m pretty desperate.

Batteries: LiFePO4 12,8V/200Ah Smart + 1x supportbattery to utilities
Measured over batteries: approx. 26.6VDC
Measured at Inverter: approx. 29VDC.

The propulsion has worked well before this winter and I’m confused what could be the fault.
I will upload the wiring diagram of the system (excluded the support battery).

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Let me know if there is anything that needs to be clarified which I might have missed or if there are any questions.

Best Regards,
Anton

2

The fact that there are two different voltages suggest a fuse has blown.
Or the cyrix has a problem?

Anyway just check all connects and disconnects between the inverter and battery.

3

Thanks! Cyrix is indicating blue which suggest that it is functioning properly. I will check fuse and connections today.

4

Update:
Measured from battery to cyrix = 26.6VDC
From cyrix to inverter= 20-29VDC fluctuations.

Solution: I reset the Cyrix and now the voltage from Cyrix to inverter matches the battery and is stable and everything is working as intended. Curious why the fluctuations occurred in the first place, but that can be a topic for another time. Thanks.