My Mac 'dies' if it has less the battery level is below 3%. Is it possible to force it to hibernate when the charge is at 5%?
I have a Mid-2009 MacBook Pro with 683 load cycles and the latest SMC available (1.47f2)
The SMC and device firmware control power management and I've not seen any parameters you can simply adjust to change the thresholds but clearly, Apple could program that and push an update if you had infinite money or influence.
That being said, it's quite easy to run a background command to log the battery levels to a file and parse that file. Whether you prefer python or perl or simpler shell commands would influence the solution you implement.
So yes, it is possible to program such a tool, but you'd need some basic scripting knowledge to implement a higher limit to enter hibernation.