Current supply for 1.5v batteries? - Page 1
Forum section: electronics / projects

author: gooseEL34
author_rank: Regular Contributor
timestamp: February 07, 2014, 10:42:32 pm
content: I need to build a mobile 9v supply. Anyone have the current supply ratings for AA AAA and C and D batteries?Tim

author: gooseEL34
author_rank: Regular Contributor
timestamp: February 07, 2014, 10:51:53 pm
content: I am building a mobile guitar rig that uses a Roland cube amp. This will be used to power a Boss GT3 multi effects unit which has an AC to DC wall wart that supplies the 9v source

author: dannyf
author_rank: Super Contributor
timestamp: February 07, 2014, 10:57:01 pm
content: I assume that all aaa/aa/c/d batteries are the same, regardless of make and chemistry,...?

author: gooseEL34
author_rank: Regular Contributor
timestamp: February 07, 2014, 10:59:10 pm
content: Ooh. Good point. I was making an assumption. Guess it is a battery by battery issue.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 07, 2014, 11:08:36 pm
content: QuoteNot off the top of my head but I suspect that Google can find a few datasheets for you.Don't forget that capacity depends on multiple factors including temperature and discharge rate and, of course, chemistry.

author: mariush
author_rank: Super Contributor
timestamp: February 07, 2014, 11:29:24 pm
content: Seehttp://www.batteryshowdown.com- they tested a bunch of batteries at 200mA and 1A :200mA : results and chart with all batteries:http://www.batteryshowdown.com/results-lo.html1A : results and chart with all batteries :http://www.batteryshowdown.com/results-hi.htmlSo it depends on how much current the battery needs to provide and the battery type and the quality of the battery.I don't know the capacity of C or D type batteries but I suspect it would be around 3-4000mAh but then you're probably better off with some lithium 18650 or regular flat batteries.--Now I don't get exactly what has to be powered from 9v, because you talk something about an amp and other things.Measure the current consumption of the device that needs 9 amps then go from there. If that thing only needs 10-100mA, you could do something like I did for my multimeter, a dc-dc boost regulator:https://www.youtube.com/user/HelpediaVideosBasically, the multimeter I have takes a 9v battery but it shows low voltage indicator at around 5.5v so I used a LT1307 to boost 1-3v to about 5.7v (just above the low voltage battery). The boost regulator can output 5v from 1v, from about 1.15-1.2v it can probably do 7-8v, well within a 9v battery range. So you could replace the 9v adapter with as little as one 1.5v alkaline battery (but it would be more efficient to use 2 or 3 batteries) and this boost dc-dc converter, as long as the device doesn't draw more than 100mA (the maximum limit this LT1307 can do)If you need more current, you'd be better off with putting 8 batteries in series and just running it directly, or maybe through a switching regulator in SEPIC configuration.

author: Psi
author_rank: Super Contributor
timestamp: February 08, 2014, 12:15:12 am
content: Modern D cells can be up to 18000mAh but 99% of the D's you see for sale are actually AA or C inside a D container so are more like 2000-4000mAhThey fake them like that because it's cheaper and modern AA and C cells have the power handling capability of the original D cells many years ago.Products are no longer made that need D cells so all the products that people buy D's for are really old and can work fine with modern AA's.I wouldn't recommend making a new product that uses C or D cells, they will start to get hard to find pretty soon.If your product needs to have batteries available for the user to purchase, use AA's.If it needs high current add a sticker that says "use rechargeable only" or have a battery holder that can be wired to have multiple banks of AAs in parallel.If you still need more current use those larger lithium cells you find in cordless drills, i forget their name.But then the device needs a built in charger.I wouldn't recommend those cells that look like AA but are 3.8V lithiums, it's too easy for people to install a normal AA and wonder why it doesn't work.You can also get single use 1.5V lithium AA's which work well for high currents but are expensive.

author: IanB
author_rank: Super Contributor
timestamp: February 08, 2014, 01:22:53 am
content: Quote from: Psi on February 08, 2014, 12:15:12 amIf we are talking NiMH rechargeable cells then it is true that C and D cells often have a compact sub-C cell inside them. I think real NiMH D's can be up to 12000 mAh or so. A genuine (not marketing sham) 18000 mAh is more than I have seen in a D cell.For alkaline cells, the C and D sizes are fully genuine. No way can an AA alkaline handle the load and run time that a D cell can.