I just have a battery issue where my battery just does at some point before it's anywhere near low. I overcharge it and still nothing. What do I do to prevent my laptop from just turning off at times like 45% 90% and such?
If your laptop turns off without warning when powered on battery there are some issues:
Battery is old, running in high or low temperature or damaged
Battery smart calibration failed for some reason
Battery connector is damaged or dirty
OS setup is not managing battery properly and do a silent shutdown
Further analysis should me made but probably I can't ask you to check battery info from kernel or use a multi-meter to measure battery voltage and shunt resistor voltage from laptop mainboard.
If you believe that's a software problem try to run it on every OS you have but if your battery is older than three years and used a lot you should consider replacement.
By the way a Li-Ion battery can last longer on partial charges and discharges keep in mind if you buy a new one: a good approach is to limit charge and discharge between 40% and 80% charge level.
Then it looks like battery got too old and fails to provide enough voltage under load spikes. Formal remaining % is one thing. Ability to cope with high-current load spikes without dropping voltage on the floor is another. Old batteries could behave like this due to increased internal resistance. If battery not very old (just few years), you kept laptop fully charged nearly all the time and sure of battery quality, you can try to perform several full charge-discharge cycles and see if it improves state of things. If it does, well, Li batteries could be a bit strange if left "unused" (witout cycling charge and discharge on regular basis) for a while due to "passivation". Passivation is reversible, few full charge-discharge cycles would undo it. Wouldn't help if your battery just turned too old and got increased internal resistance and lost capacity - at this point you have to replace it I guess.
Never leave batteries unused for long regardless of their technology. Keep those charged every three or six months and in a cool storage. Lithium Ion/Polymer batteries seems especially sensible to overdischarge.
