# Best place to buy battery-tester, and best kind to get **URL:** \ **Category:** Factual Questions\ **Created:** [October 14, 2013, 10:20pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257 "2013-10-14T22:20:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Came\_in\_like\_a\_Wrecking\_Ball](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@Came\_in\_like\_a\_Wrecking\_Ball](https://boards.straightdope.com/u/Came_in_like_a_Wrecking_Ball)\ **Post date:** [October 14, 2013, 10:20pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/1 "2013-10-14T22:20:46Z")
My Xbox controller eats AAs like PAC man eats ghosts on Live Arcade. Problem is, when controller dies you don’t know if both batteries are dead. So I need a battery power tester to see which one still has juice. Unless I’m completely wrong and multiple batteries die at the same time. I don’t know how batteries work. Lemme know. Anyways- where can i buy a battery power tester? What type is best? ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [October 14, 2013, 10:32pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/2 "2013-10-14T22:32:15Z")
Almost any model from Radio Shack is a good buy. A battery tester, even a cheap and simple one, is one of the most valuable household tools you can have. It will keep you from replacing good batteries - and, as you surmise, not all toys and tools wear down their batteries at the same rate. I’ve had many things that would eat one or two batteries (perhaps to power motors, etc.) while the adjacent batteries (for the circuitry) remained good. You can also sort your batteries among dead (toss 'em) and new (use for the fussiest and most demanding gear) and the slightly run down (good for flashlights, motorized things and other undemanding uses). I’ve had a lot of gear that will only work properly on the top 10-20% of a battery’s power, but it’s foolish to discard those batteries when other gear will work just fine for hours on them. Get a tester. Even a slightly 'spensive one ($20), if it’s more accurate or more convenient to use, will pay for itself in a very short time. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [October 14, 2013, 10:33pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/3 "2013-10-14T22:33:58Z")
If the batteries are coupled together, and I guess they are, then if one dies they are all dead. Can you switch to rechargeables? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 14, 2013, 10:59pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/4 "2013-10-14T22:59:23Z")
If you have two identical batteries in a controller they are typically wired in series, and the same current goes through both. They will be drained at exactly the same time. Since batteries may not be exactly identical you may end up with one that has a little bit of juice left in it when the other is completely dead, but they’ll usually be pretty close. If you don’t use identical batteries, then when one dies the other one will try to charge it. This can be particularly bad for alkaline batteries, as they can swell and leak when charged. Always use identical batteries and replace them both at the same time. ETA: And bob++'s suggestion of rechargeables will save you a fortune in the long run. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [October 14, 2013, 11:10pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/5 "2013-10-14T23:10:59Z")
I use my digital multimeter. ---
**Author:** ![Came\_in\_like\_a\_Wrecking\_Ball](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@Came\_in\_like\_a\_Wrecking\_Ball](https://boards.straightdope.com/u/Came_in_like_a_Wrecking_Ball)\ **Post date:** [October 14, 2013, 11:26pm UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/6 "2013-10-14T23:26:20Z")
> [@engineer\_comp\_geek](#): > > If you have two identical batteries in a controller they are typically wired in series, and the same current goes through both. They will be drained at exactly the same time. Since batteries may not be exactly identical you may end up with one that has a little bit of juice left in it when the other is completely dead, but they’ll usually be pretty close. > > If you don’t use identical batteries, then when one dies the other one will try to charge it. This can be particularly bad for alkaline batteries, as they can swell and leak when charged. > > Always use identical batteries and replace them both at the same time. > > ETA: And bob++'s suggestion of rechargeables will save you a fortune in the long run. Okay where do I buy rechargeable a and how many devices does it all take and what’re best kind to buy? ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [October 15, 2013, 12:42am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/7 "2013-10-15T00:42:35Z")
My favorite rechargeables are Sanyo brand eneloops. They hold the majority of their charge even if stored for 2 years, and can be recharged 1000+ times. ---
**Author:** ![Came\_in\_like\_a\_Wrecking\_Ball](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@Came\_in\_like\_a\_Wrecking\_Ball](https://boards.straightdope.com/u/Came_in_like_a_Wrecking_Ball)\ **Post date:** [October 15, 2013, 12:50am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/8 "2013-10-15T00:50:00Z")
> [@Ferret\_Herder](#): > > My favorite rechargeables are Sanyo brand eneloops. They hold the majority of their charge even if stored for 2 years, and can be recharged 1000+ times. Where buy, how charge, what needed? ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [October 15, 2013, 1:20am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/9 "2013-10-15T01:20:59Z")
> [@DrFidelius](#): > > I use my digital multimeter. Which won’t give you an accurate reading unless it has a battery test mode that puts a small load across the battery. An effectively dead battery will often read near full voltage with no load. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [October 15, 2013, 1:21am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/10 "2013-10-15T01:21:13Z")
> [@Ferret\_Herder](#): > > My favorite rechargeables are Sanyo brand eneloops. They hold the majority of their charge even if stored for 2 years, and can be recharged 1000+ times. When i used to use rechargeable battery’s in my portable C B radio’s I had to use 8 Alkaline battery’s or 10 Ni-Cad’s. Are the Sanyo’s you use full power battery’s? > [@](#): > > engineer\_comp\_geek If you have two identical batteries in a controller they are typically wired in series, and the same current goes through both. They will be drained at exactly the same time. Since batteries may not be exactly identical you may end up with one that has a little bit of juice left in it when the other is completely dead, but they’ll usually be pretty close. > > If you don’t use identical batteries, then when one dies the other one will try to charge it. This can be particularly bad for alkaline batteries, as they can swell and leak when charged. > > Always use identical batteries and replace them both at the same time. I certainly am not saying the Good Engineer is wrong, but just this morning I was pre-triping my bus and my rechargeable flashlight was home in the charger so i had to use the cheap flashlight in the bus. I was not working very well so I did what i have done for over 30 years and that was to switch battery’s front to back and i had enough light to complete my daily. Yes new battery’s are in order but swapping them does work in a pinch. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 15, 2013, 1:25am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/11 "2013-10-15T01:25:23Z")
I personally bought Energizer NiMH rechargeable batteries at Walmart, mostly because Walmart is cheap, close, and convenient to where I live. You can get a pack of four AA batteries plus a charger for something like $12 or so. Lithium ion batteries are lighter and have a better energy density than NiMH but lithium ion batteries don’t age well. They tend to die an early death no matter how well you treat them. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 15, 2013, 1:29am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/12 "2013-10-15T01:29:21Z")
> [@Gbro](#): > > When i used to use rechargeable battery’s in my portable C B radio’s I had to use 8 Alkaline battery’s or 10 Ni-Cad’s. Ni-Cd and NiMH batteries are both 1.2 volts per cell instead of the 1.5 you get from an alkaline. For some devices that does make a difference. 8 alkalines in series is 12 volts and 10 ni-cads in series is also 12 volts. 8 ni-cads in series would only be 9.6 volts. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [October 15, 2013, 1:58am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/13 "2013-10-15T01:58:02Z")
> [@Came\_in\_like\_a\_Wrecking\_Ball](#): > > Where buy, how charge, what needed? You buy them anywhere they sell batteries. If your controller uses AA’s, you buy AA’s. If your controller uses AAA’s, you buy AAA’s. They are often sold with a charger; avoid the quick chargers and use the ones that take 3-4 hours. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [October 15, 2013, 2:06am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/14 "2013-10-15T02:06:14Z")
> [@Gbro](#): > > When i used to use rechargeable battery’s in my portable C B radio’s I had to use 8 Alkaline battery’s or 10 Ni-Cad’s. > Are the Sanyo’s you use full power battery’s? I have no idea what you’re asking. [These](http://us.sanyo.com/Battery-Products) are the batteries I use. (The standard ones listed, not the XX version that’s the first product.) ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [October 15, 2013, 2:31am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/15 "2013-10-15T02:31:14Z")
> [@Amateur\_Barbarian](#): > > Which won’t give you an accurate reading unless it has a battery test mode that puts a small load across the battery. An effectively dead battery will often read near full voltage with no load. Yes, I was first thinking about a VOM or DMM and then remembered the no-load voltage issue. I do think a DMM is a useful thing to have anyway and I think if you can just put a resistor across the battery terminals and measure across the R you’d have it. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 15, 2013, 2:39am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/16 "2013-10-15T02:39:11Z")
> [@Ranger\_Jeff](#): > > I think if you can just put a resistor across the battery terminals and measure across the R you’d have it. Yep, that’s pretty much all a battery tester is, a voltmeter with a built-in load resistor. And technically you can tell how discharged the battery is even with a voltmeter and no load, but you’ll have to get the battery discharge curves from the manufacturer’s web site and look up the voltage. It doesn’t drop much over most of the battery’s range but it does drop. ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [October 15, 2013, 2:39am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/17 "2013-10-15T02:39:11Z")
> [@Gbro](#): > > When i used to use rechargeable battery’s in my portable C B radio’s I had to use 8 Alkaline battery’s or 10 Ni-Cad’s. > Are the Sanyo’s you use full power battery’s? > I certainly am not saying the Good Engineer is wrong, but just this morning I was pre-triping my bus and my rechargeable flashlight was home in the charger so i had to use the cheap flashlight in the bus. I was not working very well so I did what i have done for over 30 years and that was to switch battery’s front to back > and i had enough light to complete my daily. Yes new battery’s are in order but swapping them does work in a pinch. and the swapping could have as much to do with creating new connection points that allow the current to flow better - kinda like ‘spinning’ the AA batteries in the seats of the mouse or ‘smacking’ the flashlight - you don’t think you’re really waking it up do you? ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [October 15, 2013, 5:40am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/18 "2013-10-15T05:40:09Z")
> [@Came\_in\_like\_a\_Wrecking\_Ball](#): > > Where buy, how charge, what needed? buy a kit that includes the charger and the batteries you need. Look for the highest mAh rating as that is that amount of stored energy. [Example](http://www.ebay.com/itm/28x-AA-3000mAh-1-2V-Ni-MH-Enecell-Rechargeable-Battery-White-Cell-Charger-/190839237559?pt=US_Rechargeable_Batteries&hash=item2c6ee7abb7) I’m not recommending these particularly but you get the idea of what is out there. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [October 15, 2013, 5:56am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/19 "2013-10-15T05:56:36Z")
When I was suing things a lot, I went the rechargeable route. Bought quality chargers & batteries. Found in stuff that had heavy loads for short times used up rechargeable much faster than fresh alkaline. especially “D” in my game camera that is set for 3 picture bursts with regular flash & IR flash. If I had to not be able to check it every other day, I would use the alkaline because I could usually get 2-4 days out of them. The cheap prices of batteries is such that the only place I am using alkaline is in my TV head individual head sets as that is what came in them & they get recharged every day. With a regular charging routine, rechargeable on much used equipment works pretty good but for a lot of the things I use & the frequency of use, rechargeable is not the best economy. YMMV ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [October 15, 2013, 6:45am UTC](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257/20 "2013-10-15T06:45:33Z")
Yeah, the [eneloops](http://www.amazon.com/eneloop-Capacity-Pre-Charged-Rechargeable-Batteries/dp/B008LTJJJA/ref=sr_1_9?ie=UTF8&qid=1381819204&sr=8-9&keywords=eneloop+aa) are great. They work fine with the Xbox controller and last forever. The XX ones have more capacity (2500 MAh vs 2000) but can only be recharged about 500 times instead of the 1500 or so for regular eneloops. The regular ones are honestly fine and cheaper. Just buy the 4 pack with charger and you’re good to go, including a spare pair to hot-swap in when the controller starts blinking. [Next page](https://boards.straightdope.com/t/best-place-to-buy-battery-tester-and-best-kind-to-get/671257.md?page=2)