Originally Posted by Baloo
I've charged the battery, read 12VDC. Installed, hooked up cables and the batt dropped to 10VDC. Hooked up shore pwr. and still reads 10VDC. It's been hooked up now several days with no draw on it, still reads 10VDC.
Reading 12 volts on a charged battery does not mean the battery is "good." With no load, you should be reading over 13 volts when it is fresh off the charger. As SOON as you put a load on it it should start dropping.
However it should never drop lower than 12.8 or 9 until it is used for a while. If it drops quickly to 11 or so you have a bad battery.
Each cell in a 12 volt Lead Acid battery produces approximately 1.5 volts.
One cracked plate will cause the problem you are having (as well as a converter). Plates crack for a lot of reasons including vibrations from road travel and freezing (being discharged will allow the water to freeze since the acid that would have protected the water is plated onto the battery plates as sulfate).
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW