Panel Monitor for House Battery Voltage

[MustangGT]

Sorry if this has been asked before. I searched and got nothing.
Anyway, my house batteries are toast (7 years old, so no big deal), but could have lasted longer if I hadn't been trusting the panel monitor that has always, and STILL DOES, show a full charge. What is that stupid thing reading? Shore power? Charging level?
1997 Fleetwood Southwind Storm.

[crasster]

Yes as others have said, battery voltage is only showed. If they lack amps try a battery minder to desulfate the batteries. I've brought batteries back that I thought were long gone.

[Matt_Colie]

Mark,

Could you please clarify: What kind of meter and what readings are you seeing?

If it is an analog meter with a 0-15 scale, you will be hard pressed to see the difference between charged and depleted.

DrewE is correct, but such instruments are not cheap (I should know). They are, however, very cost effective and can prevent other expensive like having to replace a house bank.

Matt

[DrewE]

Unless it's a trimetric sort of battery monitor that counts charge in and out of the battery, all it can measure is the DC voltage at the battery. If connected to an active charger, this will be the charge voltage, which will always look like at least fully charged.

If you're looking at a little three or four light bargraph sort of display, there are some voltage thresholds where the lights turn on or off, but you'd have to experiment with a real voltmeter to find out what they are. Often one light down means you should think about charging, two lights down means you're well lower than you want to be, and three lights down is approaching battery killing discharge levels. They rarely if ever provide sufficient information to be very intelligent about battery management.

[scrubjaysnest]

It senses what voltage is at the batteries, this maybe the converter output if on shore power, and is somewhere in the ball park.
The best way to check batteries is fully charge them, then disconnect all loads and let them rest about 6 hours. The using a hydrometer measure the specific gravity of each cell and correct for battery temperature. This is a pita.
Simpler and what a lot of us do; after the batteries rest with no load or charging voltage a couple of hours measure the voltage. A 12 volt system should be around 13 volts.