Low Battery Error?

[Doug Rutherford]

I have a Garmin 820 XS chart plotter. Where can I download a complete instruction manual?
I received an Error message “Low voltage 11.2 volts”
The unit promptly shut down leaving me to navigate on my own. This time it did not present any issue.
My question is this error referring to ships battery? All ships systems remained working. Started engine and this did not rectify shutdown.
Is there an internal battery? I could not find where this is installed.
Your help would be appreciated as the unit is not working now.

[Kelkara]

Since it sounds like your battery is actually fine ... you may have a high-resistance connection in the power cable leading to the plotter.


After double checking that the battery really is properly charged, the first thing I'd check would be any terminals/crimps/wires between the battery and the plotter ... although poor connections can be tricky to track down, especially if you can't turn the plotter on, since a voltmeter won't always detect them if the circuit isn't loaded.

[Bycrick]

Digital volt meters are generally much more accurate than los analog meters, but they can be horribly misleading if you’re trying to locate a high-resistance in a power feed circuit. Because DVMs have a very high input resistance, they draw almost no current. That means that almost any wire/connection will allow it to read the voltage, even if that wire will only pass micro amps of current. It’s usually far easier to look for bad wires/connections with an old-fashioned test light that draws some measurable current.