Hey guys, my PC 680 appears to have gone bad after only 18 months since I replaced it. The other one was about 8 years old before I replaced it. The only reason I replaced it was it seemed that it was not turning the prop as fast during start and I felt it was time to replace it. My charge voltage is about 14.2-14.4 during cruise RPM. At idle its 12.6 to 13, Oddessy recommends 14.4-14.8 volts. I fly about 1-2 times a week usually less than 1 hour each flt. I have a Ducatti VR installed in cockpit. When I take the battery home to charge (I do have the proper charger) it charges up quickly but will run down to 85% after sitting two days. Is there a better battery available that's not so sensitive to having 14.4-14.8 charge volts? Or could it be that I just had an inferior battery?
From ODYSSEY? Battery Technical Manual:
All ODYSSEY batteries can be quickly charged. Figure 7
on the next page shows their exceptional fast charge
characteristics at a constant 14.7V for three levels of inrush
current. These current levels are similar to the output
currents of modern automotive alternators. Table 6 and
Figure 7 show the capacity returned as a function of the
magnitude of the inrush3 current.
Standard internal combustion engine alternators with an
output voltage of 14.2V can also charge these batteries.
The inrush current does not need to be limited under
constant voltage charge. However, because the typical
alternator voltage is only 14.2V instead of 14.7V, the
charge times will be longer than those shown in Table 5.
The above may explain it somewhat...
Our alternators are putting out 14.2 or so and our typical GA flight is an hour or less.....we may be slowing discharging our batteries.