# Charging a rechargeable battery with a different voltage adaptor (Need Answer Fast!)

**URL:** <https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718>\
**Category:** Factual Questions\
**Created:** [May 8, 2009, 3:46am UTC](https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718 "2009-05-08T03:46:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![picker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/picker/32/13969_2.png) [@picker](https://boards.straightdope.com/u/picker)\
**Post date:** [May 8, 2009, 3:46am UTC](https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718/1 "2009-05-08T03:46:42Z")

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I have a Coleman camp lantern with a rechargeable battery. The power converter (120 VAC --\> 12 VDC) has gone missing however.

What I do have is two other chargers. One is 8 VDC and the other is 18 VDC. I can plug either into the lantern and the charging indicator comes on.

My question is this: Will they both actually work? Is it just that the 8 VDC will take just over twice as long to charge the lantern’s battery as the 18 VDC one?

Or am I totally misunderstanding how this all works?

Trying to charge the lantern prior to the wife’s camping trip tomorrow night. How can I do this without blowing something up?

Thank you for fighting my ignorance.

P

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [May 8, 2009, 3:55am UTC](https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718/2 "2009-05-08T03:55:17Z")

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The 18v one is likely to fry something - either itself or the charge circuitry in the lantern.  
The 8v one _might_ work, but probably not.

BTW, doing this (plugging random chargers into sockets that happen to fit) is a really bad idea.

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**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\
**Post date:** [May 8, 2009, 4:45am UTC](https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718/3 "2009-05-08T04:45:03Z")

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The 8 VDC will charge the battery to 8 volts. That means the battery is still discharged.

The 18 volt charger will attempt to charge the battery to 18 volts. The high voltage will over amp the battery. Over heat it and probably cook it.

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**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\
**Post date:** [May 8, 2009, 12:13pm UTC](https://boards.straightdope.com/t/charging-a-rechargeable-battery-with-a-different-voltage-adaptor-need-answer-fast/495718/4 "2009-05-08T12:13:07Z")

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Go buy a new DC adapter and don’t use the 18 volt or you’ll start a fire. The 8volt just won’t charge the lamp.