×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

# Contact US

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!

*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

# Battery Characteristic

 Forum Search FAQs Links MVPs

## Battery Characteristic

(OP)
Hi,im a fresh bachelor electrical graduate (5 month graduated to be exact).
My company required me to design a power supply system for a microwave system. I done searching for rectifiers & inverters module.

Right now i stucked at choosing battery for the system. I do know Peukert's formula.
But i just need one explanation/clarification from experienced engineers about batteries.

Battery Discharge Constant Current Characteristics Amperes <---- what this means? I got one table from batteries manufacturer:
F.V/TIME 5min 10min 15min 30min 60min 3h 5h 10h 20h
1.60V [indent]775 525 415 265 163 63.9 45.7 25.4 13.4
1.70V [indent]736 499 398 254 156 63.0 45.0 25.2 13.3
1.75V [indent]692 469 378 242 149 61.7 44.1 25.0 13.2

Does it mean if my system drawing 12Vdc 13A - the battery can support the system for 20hours?

I got the table from here: http://www.polluxbattery.com.my/250ah-12v-battery....

### RE: Battery Characteristic

(OP)
I did calculate the data using peukerts, im using 1.2 as the peukerts constant (since the manufacturer didnt give me the exact constant).

What i found the data table and my calculation is way off. Almost 20% - 30% off.

How accurate is peukert`s formula?

### RE: Battery Characteristic

#### Quote (Battery Discharge Constant Current Characteristics Ampere)

Just means testing with a constant current source. Something that varies its resistance as the battery voltage declines to keep a constant current.

Something being run by a linear voltage regulator would work this way. The load would always draw its regulated current and as the battery voltage drops the linear regulator would just be shaving less and less voltage off - current would not change.

Conversely, something more modern, would possibly have a switching supply that pulls a fixed POWER from the battery. As the battery voltage falls the the current draw would steadily increase to compensate.

Keith Cress
kcress - http://www.flaminsystems.com

### RE: Battery Characteristic

(OP)
Thank you guys for the informations

#### 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! Already a Member? Login

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!

Already a member? Close this window and log in.