Draw power from one of two batteries in series - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 2nd April 2013, 10:10 PM   #1
diyAudio Member
 
Join Date: Feb 2013
Location: Copenhagen
Default Draw power from one of two batteries in series

This might be an odd question, but I was wondering if you have two 12v sla batteries in series to supply 24v for one part in for example a preamp, and have another part that needs just 12v, could you with no problem draw 12v from just one of batteries
even though it is connected in series with another?
  Reply With Quote
Old 2nd April 2013, 10:25 PM   #2
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Yes, you can. Just remember that the battery with the largest draw will run down first.
Do you charge them in series, or in parallel?
  Reply With Quote
Old 3rd April 2013, 05:35 AM   #3
diyAudio Member
 
Join Date: Feb 2013
Location: Copenhagen
Thanks for the reply Pano, I charge them in series with a standard 24v charger, so I guess I need to make it so the 12v part is disconnected from the one battery when charging right?
  Reply With Quote
Old 3rd April 2013, 06:46 AM   #4
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
Not necessary to disconnect if the 14.X volts is not damaging your load(12v part). However charging may differ for the individual batteries.

Gajanan Phadte
  Reply With Quote
Old 3rd April 2013, 07:30 AM   #5
diyAudio Member
 
sofaspud's Avatar
 
Join Date: Nov 2005
Location: San Antonio
Quote:
However charging may differ for the individual batteries.
If the 24V supplies a preamp, and the 12V supplies a power amp, the discharge will be significantly different between the two batteries. If recharged in series, the current required by the more-discharged battery will have to pass through the less-discharged battery. That is probably a situation to be avoided, as the charge current will continue well past the full-charge point of the one battery.
I would definitely do some research on the possible effects. Maybe a switching circuit or bipolar charge circuit could provide a workable solution.
__________________
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine
  Reply With Quote
Old 3rd April 2013, 10:22 AM   #6
diyAudio Member
 
Join Date: Feb 2013
Location: Copenhagen
Sofaspud I hear you, as long as I stick to powering things like a relay or any part that draws a very low curren I shouldn't be in trouble connecting the part directly to one of the batteries in a series (given that the part can take the 14.x charge current as well).
  Reply With Quote
Old 3rd April 2013, 12:23 PM   #7
diyAudio Member
 
Join Date: Feb 2013
Location: Copenhagen
Quote:
Originally Posted by sofaspud View Post
If the 24V supplies a preamp, and the 12V supplies a power amp, the discharge will be significantly different between the two batteries. If recharged in series, the current required by the more-discharged battery will have to pass through the less-discharged battery. That is probably a situation to be avoided, as the charge current will continue well past the full-charge point of the one battery.
I would definitely do some research on the possible effects. Maybe a switching circuit or bipolar charge circuit could provide a workable solution.
After reading about a bit, as you said it gets a bit more complicated, as it seems this tiny imbalance that will happen between the batteries will not be corrected when charging them in series, and so the difference between the batteries will only grow larger and eventually become a real problem over time and could result in overcharging...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
joule thief (draw more power from a power supply?) realflow100 Solid State 11 7th November 2012 12:06 PM
Power tube maximum current draw from a power supply razorrick1293 Tubes / Valves 4 4th November 2011 10:48 PM
Orion 2150GX power draw Dr Zeus Car Audio 4 27th June 2011 02:59 AM
Thought experiment: A thousand 12V car batteries in series bigwill Everything Else 6 21st June 2007 03:56 AM
charging 3x 12V batteries in series. RichJones Solid State 7 24th September 2003 10:10 AM


New To Site? Need Help?

All times are GMT. The time now is 10:51 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2