New Batteries on Princess V39 Quickly Discharge

[mag040]

Hello together,
I have a Princess V39 2017, and my new batteries quickly discharge and then show a normal voltage of 12.5V when I toggle the "on" switch of the domestic batteries on the main panel. After a short time, the voltage drops again, but it returns to normal when I toggle the switch. Did anyone encounter a similar issue before? I would guess there is something wrong with the indicators or sensors, but I haven't found a solution yet.

Best, Max from Mallorca

 

[KompetentKrew]

My initial reaction was to suggest fitting a Victron SmartShunt (or similar) to see what's really going on. This is surely always a good investment, but if I'm understanding correctly it may just be a problem with the voltage displayed on the meter by the chart table. Use a multimeter across the terminals of the battery - does the handheld multimeter show the same as the boat's voltmeter at each stage of your observations?

 

[Obi]

Might be worth a read before doing anything else. It is an excellent resource.
BU-903: How to Measure State-of-charge

 

[Alex_Blackwood]

Hello together,
I have a Princess V39 2017, and my new batteries quickly discharge and then show a normal voltage of 12.5V when I toggle the "on" switch of the domestic batteries on the main panel. After a short time, the voltage drops again, but it returns to normal when I toggle the switch. Did anyone encounter a similar issue before? I would guess there is something wrong with the indicators or sensors, but I haven't found a solution yet.

Best, Max from Mallorca

You don't say where, or from what, you are reading this voltage or what is switched when you toggle the switch. I would suspect that you have dodgy connection in that circuit.

 

[PaulRainbow]

Hello together,
I have a Princess V39 2017, and my new batteries quickly discharge and then show a normal voltage of 12.5V when I toggle the "on" switch of the domestic batteries on the main panel. After a short time, the voltage drops again, but it returns to normal when I toggle the switch. Did anyone encounter a similar issue before? I would guess there is something wrong with the indicators or sensors, but I haven't found a solution yet.

Best, Max from Mallorca

If it's the main battery switch that you are toggling, that operates a heavy duty relay. It sounds like there could be a bad contact across the relay contacts. You need to get this properly checked, it could cause a fire.

 

[mag040]

Thank you, everyone! We checked it and it’s definitely the battery switch on the main panel.
We took it apart and it worked perfectly afterward. Now the problem is back. I try to order a new part.

best regards, max