I'm having an issue with my SECOND Concorde platinum series battery. I have the extra cranking power version. My ammeter on the panel says I'm charging. My EDM700 shows 14.3 volts with the engine running. At the battery, when the engine is running, we show 14.3 volts. When I land, I don't have enough power to start the engine again.
I have a Battery Minder installed and if I keep it hooked up, the airplane will always start for the flight. When I come back from the flight, after only about 45 minutes, I've got a very weak battery if not dead.
We have checked the battery ground, the alternator ground, the starter ground. The installation of the battery minder is simply one wire with two leads - one for each post on the battery and it is accessed through the aux power plug hole. There is a special plug from the battery minder that plugs into this plug. The battery minder is the aircraft version and has a charge and a float charge (maint) mode. I don't see any damage to the battery and it seems to take a charge from the battery minder that lets me start the airplane for the first flight of the day. It is the 12V system by the way.
One A&P had a theory that the 12" lead for the connector from the battery to the battery minder plug was the source of the drain while flying. This doesn't make any sense to me. Has anyone had any similar issue?
Does it seem possible that my battery (RG-35AXC) could be bad? I had one that was bad not long ago. More history.. I put in an RG-35AXC about a year ago. I used the battery minder for about 6 months with no issue. Then, the "drain while flying" problem started. I replaced the battery and the new one started having the same issue only about two months later. The battery monder I'm using is: "Designated as the 12-V model 12248-AA-S2 (Aviation Specific), it is similar to model 12248-AA-S1 except for its Plug ‘n Run feature, eliminating the need to set neither the output current nor battery type, before operating."
Thanks for any ideas you might have!!!