Observation about battery voltage after storage

[Gryphon Rider]

Normally I put a charger on my motorcycle batteries over night every couple of months over the winter, but this season I just never got around to it.  In the fall my son bought himself an '83 Honda 650 Nighthawk, so we have two neglected batteries.  Yesterday, before hitting the start button on my son's bike, I put a voltmeter on it to see what the state of charge was.  It measured 13.4 volts, way higher than expected, so I hit the start button.  It made the starter relay buzz, but no cranking action.  I figured the battery needed charging and put a smart charger on it, which lit the "25% charged" light.  This morning it was at 100%, charge completed.  Then I put the meter on my Valk, expecting it to be somewhere around 12 or 12 1/2 volts.  It also was around 13.5, higher than I expected.  The charger, when connected, told me it was at 75% charge.

Have any of you measured a higher-than-expected voltage on a depleted battery?  What might cause this?

[WintrSol]

Sounds like you need a better meter. No lead-acid battery will read that high after resting, the chemistry isn't capable.

[mbramley]

 I second wintrsol on that. I do industrial electrical/ electronic work for a living. The only time you should be reading above 13 volts is when on a charger or being charged while the motor is running. (or possibly immediately after.

[Gryphon Rider]

You two were right.  Battery voltage measured with a different meter was in what I consider to be the normal range.  Maybe time to invest in a professional grade meter.