I have the option of replacing my aging and almost dead lead acid batteries with Li-ion to run a 24 volt motor. The data sheet for the Li-ion cells report the cells as having a nominal voltage of 3.8 volts. If I use 6 of these cells in series, the average voltage will be slightly lower than what the lead acid provided, but if I use 7 cells in series, the average voltage will stay above 24 volts, (starting at 29.4 volts).
The lead acid batteries are rated and 18Ah and the Li-ion are rated at 30Ah and tested at a 100 amp discharge rate to provide 28.3 amps, so they can handle a high current!
I am leaning toward the 6 cell battery because when I look at the datasheet for the battery, the discharge curve shows the voltage to stay at about 3.8 volts or higher (at a 20amp discharge) until the last 15 minutes out of a 1.5 hour discharge, and for my purposes, it wouldn't be discharged that low. So this would keep the voltage at around 22 volts.
So is it better to run a DC motor with more volts than rated or less? - if you have no choice?