Is It Safe to Use This Battery with the Raspberry Pi Zero?

Safe? YESWill it work? NO you need 5V

1. Is there a way for the dealership to revive a dying battery?

Answers to your 3 questions:1) No, there is no such "magical" device. If there were, everyone else would know about it too. When a battery is past the end of its service life there is no process to revive it. 2) Moot question in light of the first question.3) I am going to speculate that the initial test was faulty. The dealer likely charged the battery and after that it was "good". I suspect the initial diagnosis was based on the age of the battery and not a diagnostic test. It's not uncommon for a dealer to note that a battery is older than some arbitrary age and recommend a replacement to save the owner of the car the trouble of a breakdown at some inconvenient time

2. my psp battery life weakens why?

Many reasons why it is weakening (most probable to least probable) 1. Batteries are made of chemicals and compounds, and to create electricity that you use, it create chemical reactions inside your battery. As you use your battery, the chemicals get less and less, until the reactants (chemicals) are obsolete and cannot generate electricity. Solution: Leave your battery in a relatively cool/room temperature area or there's a rumor that putting your battery in the freezer will help it or purchase a new battery. Also, discharge your battery completely then recharge completely--this often helps. 2. Your PSP was left on for extended amounts of time, which can be taxing for your battery. Solution: Leave your battery in a relatively cool/room temperature area or there's a rumor that putting your battery in the freezer will help it or purchase a new battery. 3. Your PSP has been revealed to extreme heat/pressure, this can damage the battery or lead to acid leaks. Solution: If the battery dies, dispose of it and replace. 4. Your Li-ion (Lithium Ion cell) battery has been punctured or damaged (often happens to PSP users when they try hard-modding (modifying hardware) their battery to use custom firmware (CFW). This can lead to battery meltdowns, leaks and explosions, all are dangerous. Solution: Dispose safely and replace. Good luck.

3. what battery is better. Energizer or duracell?

They are only like a few cents different, I doubt that there is any measurable difference

4. Way to boot laptop without CMOS battery?

Your BIOS needs that battery to remember the settings for the system. I see you asked this question several days ago, so this point is probably moot, but you should take the 30 minutes it takes to get the battery changed.

5. 9V Battery gauging

Battery voltage does not change very fast compared to the time of a A/D reading. One solution is therefore to enable the voltage divider only for just long enough to take the A/D reading, then do this infrequently.For example, turning on the divider for 10 s every second makes it draw 100,000 times less than when left on all the time. Now you can use a lower impedance divider too. Let's say the divider draws 10 mA (a lot) when on. The average divider current is now 100 nA, which is well below what the micro draws likely the self-discharge current of the battery. To switch the divider when the input voltage is higher than the micro's power voltage, you have to switch the top side. A P-channel FET is one way

6. Dim laptop monitor on battery power?

Try entering the BIOS when the computer starts (known as entering setup.) Usually the key is F12 or delete, although it can be other keys also. Then you can default brightness settings for when its plugged in and when it's running off the battery.

7. Chosing a battery for a small sailboat?

(LOL - the "thumbs down bandit strikes again. . . I am sure he will thumb me down too - always does. . . ) Nothing wrong with their answers, it's just that some of us do things differently. . . As for your answer - a marine battery charging solar panel is pretty cheap - I suggest you get one. In addition, I would look to "two" (that's 2) medium priced marine batteries vs one expensive one. Connected in parallel, you are doubling the capacity (amp hours) of the battery while maintaining the voltage of one. This is done by connecting (negative to negative, positive to positive) and it not only doubles your amp hours, it will double the life of each battery both short term (between charges) and long term years. If you are more or less a weekend boater, a good solar battery charger will keep charge both batteries charged. In addition, I would NOT put them on a battery selector switch as this defeats the entire purpose of a parallel connection. Your 5 hp motor (as are all small outboards) are lousy at charging or keeping batteries charged - this is not saying they do not do it - just that they are lousy at doing it - on a sailboat, it requires you to run the motor a long period of time - thus, why I suggest 2 batteries with a solar charger. If you do this, I highly suspect you will never have to take a battery home to charge. I have this set up (x 2) on my sailboat and never had to use a 110v charger. Furthermore, I do not have to worry about my bilge pump running my batteries down and then having my boat flooded. My second bank of batteries runs my auxuliary power for my laptop, & TV. etc. but my 1st bank is set up to run navigational lights, anchor light, cabin light, GPS, depth finder, VHS radio and start my 10hp engine. Only difference is, I have some heavy duty solar panels on my 2nd bank of batteries. . . but, I live and cruise on my boat full-time. PS. a battery box is required - but I guarantee you that you can buy on cheaper then buying fiberglass cloth & resin and going through all that mess explained by CMV - I built boats for over 40 years, and had all that stuff 'laying around' and would never go to that trouble.