# Is there a better way to discharge a battery? **URL:** \ **Category:** Factual Questions\ **Created:** [February 28, 2005, 5:41pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317 "2005-02-28T17:41:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![BarnOwl](https://avatars.discourse-cdn.com/v4/letter/b/e95f7d/32.png) [@BarnOwl](https://boards.straightdope.com/u/BarnOwl)\ **Post date:** [February 28, 2005, 5:41pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/1 "2005-02-28T17:41:13Z")
I bought another of those Radio Shack cordless phones with a NiCad battery that looks sort of like No. 23-962 at… [http://www.radioshack.com/search.asp?cookie\_test=1&find=60AAS38MX&hp=search&image1.x=30&image1.y=39&image1=submit&SRC=1](http://www.radioshack.com/search.asp?cookie%5Ftest=1&find=60AAS38MX&hp=search&image1.x=30&image1.y=39&image1=submit&SRC=1) The directions say: “About once a month ago, fully discharge the battery by keeping the handset off the base until **Low Battery** flashes on the display. Otherwise, the battery pack loses its ability to fully recharge.” My question: Is there a better, more efficient way to fully discharge the battery, than simply taking it off the base? Wires run off the battery that clip to the phone innards. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [February 28, 2005, 5:58pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/2 "2005-02-28T17:58:40Z")
I’m not sure how an alternate method is more “efficient.” If you mean faster that can be a problem. Using too high a load (too low resistance) will discharge the battery quickly but may cause the cells to overheat which can damage then and reduce charge capacity. You could use a resistor that discharges them in about the time thte phone takes but what’s the point? Consider too that if you discharge them in the phone you can still use the phone while this is going on. IMO doing this once a month is at best overkill. Memory isn’t as big a problem as everyone used to think and the instructions are just following what I think is obsolete conventional wisdom. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [February 28, 2005, 6:15pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/3 "2005-02-28T18:15:31Z")
I have an experience not with a cell phone battery, but the batteries to my cordless drill. It is a Black and Decker Firestorm 12 volt drill/driver. A few months ago the both batteries would hold a charge for only a few weeks, even if not used. I was told to fully discharge the batteries then give them a full charge and that would fix my problem. Yeah, it fixed my problem all right. I rigged up a 12 vdc light bulb and clipped it to the battery terminals till the batteries were dead then gave each a full charge of at least 2 days. Now the batteries might last an hour or 2. The cost of a replacement battery was more than I paid for the drill with 2 batteries so I upgraded to a Makita 15.6 volt drill driver. I am guessing the quick drain on the batteries supplied by the light bulb permantly ruined them. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [February 28, 2005, 6:38pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/4 "2005-02-28T18:38:26Z")
I don’t think it was the quick drain that ruined your pack but that you discharged them until they were dead. Completely discharging is an almost surefire way to destroy a rechargable pack. Driving it too far into discharge can actually reverse one or more cells which ruins the pack. That’s another reason Radio Shacks to discharge only until you get a low voltage warning. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [February 28, 2005, 9:40pm UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/5 "2005-02-28T21:40:21Z")
I used to overhaul (big) nicad batteries in a previous job. You should never completely discharge a battery, it can damage some of the cells. The proper procedure is to disassemble the battery into individual cells, complete discharge each cell at a safe rate, charge and test each cell, replace any bad cells, reassemble the battery, charge and test the battery. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [March 1, 2005, 1:09am UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/6 "2005-03-01T01:09:34Z")
> [@Padeye](#): > > Memory isn’t as big a problem as everyone used to think and the instructions are just following what I think is obsolete conventional wisdom. Agree. I’ve never experienced memory problems with NiCADs. I’ve never known anyone who has. I think it’s a non-issue, for the most part. ---
**Author:** ![BarnOwl](https://avatars.discourse-cdn.com/v4/letter/b/e95f7d/32.png) [@BarnOwl](https://boards.straightdope.com/u/BarnOwl)\ **Post date:** [March 1, 2005, 1:46am UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/7 "2005-03-01T01:46:40Z")
Racer72 and Padeye… I posted a thank you to both of you quite awhile ago, and it got lost!!! So, I’ll do it again. 😛 Thank you very much for your excellent advice. I’ll discharge the pack the slow way, as recommended, but I’ll do it every other month, perhaps. Or maybe never. Damn phone’s been off the hook and on my desk since a little before i opened the thread. Still no Low Battery alert. I’ll put it back tomorrow, and then to hell with this crap. 😃 ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [March 1, 2005, 2:12am UTC](https://boards.straightdope.com/t/is-there-a-better-way-to-discharge-a-battery/292317/8 "2005-03-01T02:12:18Z")
How about a 3 month severance package? Sorry, it’s been that sort of day. I’ll stop now.