Most low voltage bulbs are designed to operate on 12 volts or less. Excessive voltage reduces lamp life due to excess heat generated from that voltage.
Here are the approximate values of voltage effects …
- 13.0 volts … 50% of rated life
- 12.5 volts … 65% of rated life
- 12.0 volts … as rated by manufacturer
- 11.0 volts … 2x rated lamp life
- 10.0 volts … 3x rated lamp life