×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

How to monitor the remaining energy in a Lithium based battery

How to monitor the remaining energy in a Lithium based battery

How to monitor the remaining energy in a Lithium based battery

(OP)
Hello,

I am working on wireles sensor networks topic and I need to monitor the battery level of my sensor nodes in the network. However, as far as I know, lithium based batteries have a flat voltage over time curve, so it is not possible to simply measure the voltage of the battery output. Am I correct?

My sensor nodes are low capacity ones and they dont (and most probably they cannot) have any hardware mechanism attached to them to monitor the battery. What I need to know is to detect whether the battery level of a node is in a critical situation or not. Is it possible to do it without adding any additional hardware?

Regards,

Cagri

 

RE: How to monitor the remaining energy in a Lithium based battery

No battery has a perfectly flat profile with a perfectly sharp cutoff.  You just have to pick a spot, and take the lumps for replacing batteries that might still be quite full.  

Lithium batteries nominally have 3V at the start.  According to Duracell's Li battery bulletin, they are essentially completely discharged at a 2V output, so 2.5V might be a good stopping point.  According to the curves in the bulletin, 2.5V would put you at about 90% of capacity.  

TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Chinese prisoner wins Nobel Peace Prize

RE: How to monitor the remaining energy in a Lithium based battery

(OP)
Thanks for the response, I will consider that.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources