MacBook Pro Retina (Retina, Mid 2012), Battery issues.

Hello there, GregNYR89.

It sounds like you're having issues with your battery life and your system shutting off unexpectedly. The following Knowledge Base article offers up some great recommendations for troubleshooting:

About Mac notebook batteries

Troubleshooting batteries

A great place to start when troubleshooting battery issues is the built-in diagnostics that are available on your Mac notebook. Review the following articles for more information on using diagnostics.

• Using Apple Diagnostics
• Using Apple Hardware Test

Note: The additional troubleshooting recommended below assumes you have run the above diagnostic appropriate for your computer and that no issues were found.

My battery runtime is low

1. Identify what the battery life should be for the product you're using.The Tech Specs site provides Apple's battery life expectations for battery usage. The specifics for wireless web usage and standby time are included in the Tech Specs article for each product.
2. Learn how to minimize common causes of battery drain:
   • Optimize your battery life using the Optimizing Battery Life section earlier in this article.
   • Learn how apps can affect Mac battery performance. Check Activity Monitor for any malfunctioning software processes, especially after installing software updates or a new operating system. Installing updates is important to ensure optimal performance for all applications.
   • If you're still having battery runtime issues after optimizing your computer's performance and checking for malfunctioning software processes, test in Safe Mode. Safe Mode limits the active items on the system and allows testing in a more minimal environment. If the battery life is better in Safe Mode, you may need to do further software isolation for the items disabled by Safe Mode to determine what the power draw is while not operating in Safe Mode.

Additionally there is some great information on servicing your battery:

Servicing the battery in your Mac notebook

MacBook, MacBook Air, and MacBook Pro computers with built-in batteries should only have their batteries replaced by an Apple Authorized Service Provider or Apple Retail Store. Attempting to replace a built-in battery yourself could damage your equipment, and such damage is not covered by warranty.

These Mac notebooks have built-in batteries:

• MacBook (13-inch, Late 2009) and later
• All MacBook Air computers
• All MacBook Pro computers with Retina display
• MacBook Pro (13-inch, Mid 2009) and later; MacBook Pro (15-inch, Mid 2009) and later

Most older Mac notebooks have removable batteries you can replace yourself. Contact an Apple Authorized Service Provider or Apple Retail Store for assistance servicing a removable battery.

Thanks for reaching out to Apple Support Communities.

Cheers.

With 958 cycles on your battery, it is far from new condition and you should seriously consider replacing it. You might try a SMC reset which may improve the situation, but view that as a temporary measure:

https://support.apple.com/en-us/HT201295

Ciao.

Greetings Greg,

It looks like your battery cycle count is nearing the end of it's life per this article: Determining battery cycle count for Mac notebooks - Apple Support

Remember that your MacBook Pro Retina Display is slated for 1000 cycles so it's nearing consumed on your end.

Here is the price list:

Ciao.