Excessive voltage (16v) at switch panel.

[fredrussell]

Here’s a strange one. Engine off. Boat plugged into shore power. Battery on “storage” at 13.3v (Victron charger) tested with multimeter. Tested voltage at nav light switch panel (same multimeter) and getting 15 to 16 volts. With the charger switched off voltage at switch panel drops to 14.3v despite voltage at battery being 13v.

Discovered this whilst trying to work out why masthead tricolour and anchor lights not working. Am I right to assume excessive voltage has blown the (incandescent) bulbs?

Any idea where this excess voltage is coming from? I’m baffled.

 

[ChromeDome]

Which Victron model and what battery setup?
What do you get on the multimeter, at different points, when the Victron is off - and when it's been off for 3-4 hours?

 

[ChromeDome]

Is the multimeter confirmed reliable? Tested a different meter?

 

[penberth3]

Here’s a strange one. Engine off. Boat plugged into shore power. Battery on “storage” at 13.3v (Victron charger) tested with multimeter. Tested voltage at nav light switch panel (same multimeter) and getting 15 to 16 volts. With the charger switched off voltage at switch panel drops to 14.3v despite voltage at battery being 13v.

Discovered this whilst trying to work out why masthead tricolour and anchor lights not working. Am I right to assume excessive voltage has blown the (incandescent) bulbs?

Any idea where this excess voltage is coming from? I’m baffled.

I don't think a 12V lamp would blow. It might if it was running at 15/16V for a long time, or if it's had higher voltages than you've measured.

 

[fisherman]

If the internal battery in a multimeter is flat some will register extra 1 or 2 volts.

 

[fredrussell]

Is the multimeter confirmed reliable? Tested a different meter?

I was just about to amend my opening post but you beat me to it. Used another multimeter and voltage is now correct. First multimeter was reading incorrectly.

Nowt to see here folks! Cheers for replies. I’ll get up the mast and check bulbs, need to replace them with LED anyway.

 

[ChromeDome]

If the internal battery in a multimeter is flat some will register extra 1 or 2 volts.

Most multimeters have a low battery notification somewhere.
E.g.

 

[fredrussell]

Yes, it was low battery - but no indication of this on screen. This meter is at the opposite end of the quality spectrum from Fluke. I think it cost £3.99 at Wilkinsons!

Lesson learnt there anyway.

 

[William_H]

Just to explain A multimeter has a voltage reference type diode which sets a reference voltage perhaps around 6v. (not sure) anyway as battery gets low in voltage it can not maintain the reference voltage at correct level. So low reference voltage makes tested voltage look bigger when compared. Even though stille nough battery power to operate screen. ol'will

 

[fredrussell]

Cheers Will, this was a new one to me.