I bought several battery packs each of which I intend to fill with 3 non-rechargeable alkaline metal-encased AA batteries and connecting all the packs in parallel.

All the batteries are of the same type, they also have the same nominal voltage, brand and product name.

I wonder, is there any risk that I should know of? I am mainly concerned about the possibility of one of the batteries failing — can we get a short circuit with the batteries possibly catching or causing fire?

Thank you.

EDIT: I use only new unused batteries. I also used my voltmeter and verified that each battery pack individually provides ~4.5 V.

  • \$\begingroup\$ You said it yourself, same capacity and same voltage is important. \$\endgroup\$
    – winny
    Jun 12, 2020 at 6:49
  • \$\begingroup\$ why don't you use a larger cell? \$\endgroup\$
    – jsotola
    Jun 12, 2020 at 7:05
  • \$\begingroup\$ @jsotolo I tested super-life 4.5V cells by the same producer, Varta, and they were even worse then these "long-life". So I will stick with AA. But please, don't get too off-topic here. My question is different to what you are saying. \$\endgroup\$
    – deLock
    Jun 12, 2020 at 7:07

1 Answer 1


The main thing about parallel batteries is the double capacity. It's actually not really cool to put a new battery in parallel with discharged (me thinking about small me now replacing only one battery out of two everywhere lol). The charged (higher voltage) will try to discharge into lower voltage battery, and its chemistry is not designed to be rechargeable. I wouldn't really care much about them failing, never seen anything like that. I would say AA/AAA discharge two quickly in case of some short circuit (don't forget about internal resistance too). So yeah, put a new one with another new one so that voltage difference between them is minimal, and you're pretty much safe.

  • \$\begingroup\$ Yeah. I thought it must be safe also because millions of consumer electronic devices use AA batteries in parallel, too. If it was risky, they wouldn't, right? Thanks for the tip. And yes, I would always replace all batteries (never just some). \$\endgroup\$
    – deLock
    Jun 12, 2020 at 6:28

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