Welcome guest. Before posting on our computer help forum, you must register. Click here it's easy and free.

Author Topic: 12V -> 5V 1A using L7805CV  (Read 3465 times)

0 Members and 1 Guest are viewing this topic.

Geek-9pm


    Mastermind
  • Geek After Dark
  • Thanked: 981
    • Gekk9pm bnlog
  • Certifications: List
  • Computer: Specs
  • Experience: Expert
  • OS: Windows XP
Re: 12V -> 5V 1A using L7805CV
« Reply #15 on: October 02, 2017, 12:56:06 PM »
People come to CH for answers.
Sometimes the best answer is to tell the OP not to do what he wants to do.
However, it is helpful if both the OP and anybody reading a post get the sense of why one method is better than another.
He asked about the 7805 regulator, and he got some answers.
He said he wanted to use a 12 volt motorcycle battery.
He said he wanted to power his smartphone. He did  say  which phone.  Most often a smartphone uses a small lithium-ion battery, about 4 volts, which should not be overcharged.  Overcharging a small cell-phone battery is a mistake.
He was told to use a fuse close to the battery. Good advice.

Or else, just don't try to make a DIY external battery thing for a cell phone. You can get them already made.

This is information people need to know.
This risk is more that just loss of property. Bodily harm can come from a DIY project that involves a lithium-ion battery. Even some commercial designs have under estimated the volatility of this type of battery.

This is a serious subject and should not be trivialized.
This is from a government agency.
http://www.nfpa.org/news-and-research/fire-statistics-and-reports/research-reports/hazardous-materials/lithium-ion-batteries-hazard-and-use-assessment
There is a video to watch.  :)
Yes the video is about storage problems. From that one can see that these batteries have some  issues. Using the battery improperly may cause the batter overheat and catch fire. If a battery does catch fire, you can try to stop it with water. 

The OP did not make it clear if he  was going to leave the battery inside the cellphone. Some cell phones do not work without the battery in place and a changer connected. And some cell phones have a battery that is wired internally and you can not remove it.

patio

  • Moderator


  • Genius
  • Maud' Dib
  • Thanked: 1692
    • Yes
  • Experience: Beginner
  • OS: Windows 7
Re: 12V -> 5V 1A using L7805CV
« Reply #16 on: October 02, 2017, 04:09:58 PM »
Hence my observation earlier...it's a bad silly project to begin with...
   
 
" Anyone who goes to a psychiatrist should have his head examined. "

Geek-9pm


    Mastermind
  • Geek After Dark
  • Thanked: 981
    • Gekk9pm bnlog
  • Certifications: List
  • Computer: Specs
  • Experience: Expert
  • OS: Windows XP
Re: 12V -> 5V 1A using L7805CV
« Reply #17 on: October 02, 2017, 05:51:57 PM »
Hence my observation earlier...it's a bad silly project to begin with...
True.
If anybody needs to extend the use of his cell phone for a number of days while in a remote area with no vehicle, he can carry spare batteries.