No problem there, that's normal for a Lithium array. 37 volts is the nominal operating voltage for the system. Most Lithium chargers output 42 volts, with the fully charged battery showing 40-41 volts.
In the case of 36 volt lead-acid arrays, a fully charged battery will actually show around 39.5 volts fresh off the charger.
It would be very interesting to know how your three-year-old Sanyo battery is performing regarding the miles per charge compared to when it was new.
Regards
Bob
Oops, crossed with d8veh
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