Good day all,

Here is the scenario. I have a 12v device and a 6 volt device I need to power.

Can this be safely/efficiently accomplished by using 2x4 AA battery holders and run them in series, making a connection in between the two packs to get 6 volts from the first pack to power the 6v device, while powering the 12v device as well by running it in series with both battery packs? This will drain the current on the first pack faster than on the second pack correct? Is this ok?

Thank you!

Edit for clarification:

My 6v device will draw 100ma continuously and be in use for only a few minutes at a time, 5v is its minimum operating voltage. My 12v device will draw 330ma transiently, none when not in use, 12v is its minimum operating voltage.

I plan to use L91 lithium AA for maximum mah.

  • \$\begingroup\$ yes, you can "splice" into a series battery chain for intermediate voltages. \$\endgroup\$
    – dandavis
    Jun 21 '17 at 4:27

In concept the 8x AA cells can nominally provide 12V as you suggest. You could tap into the middle of the stack and pull out the 6V level as well, The main thing I would say is to have the 12V device and the 6V device share the same GND connections back to the common point on the battery pack. This is important in particular because you may have your two devices integrated in some manner where circuitry has to share a common reference point.

Some things to think about when attempting to do this.

  1. AA batteries are limited in the maximum current flow that they can maintain. So make sure that the loads you have are well within what the battery can safely supply.
  2. The AA cells do not have huge energy capacity and you will have to make sure that they can supply power to your devices for the intended working time.
  3. The cells in the 6V part of the pack will be supplying current for both the 6V and the 12V devices so they will discharge sooner than the other four cells. This effect will be minimized of the 6V device draws a fraction of the power that the 12V device consumes.
  4. 12V and 6V levels being discussed are based upon AA battery cell technology that supplies 1.5V per cell. Be aware that there are various technologies that may have different cell voltages. Some of these technologies will do a better job than others at staying fairly close to their nomimal voltage levels as the battery is discharged. On others it will fall to a lower level sooner and may in fact be delivering current to your loads at less than 12V or 6V. You will have to study to check if your devices will continue to work properly when their feed voltage is lowered.
  • \$\begingroup\$ Point 3 was my main concern. How would this effect the integrity of pack 2 and the stability of the 12v device? \$\endgroup\$
    – Lanet Rino
    Jun 21 '17 at 1:34
  • \$\begingroup\$ I have no idea to answer your question in specific terms. You have not told us what batteries you intend to use or even what capacity that they will have. You have also not told us what current draw each device takes when it operates or what voltage range over which they are specified to operate properly. So with the limited information that you did provide I have tried to give you some general guidance. \$\endgroup\$ Jun 21 '17 at 1:41
  • \$\begingroup\$ Edited for clarification \$\endgroup\$
    – Lanet Rino
    Jun 21 '17 at 1:46

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