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alkaline batteries connected in parallel, quick question Answered

Okay, doing some throwie-inspired LED "artwork" and I'm using alkaline AA batteries instead of the CR2302s or similar smaller cells to get way more mAh and extend the life of my display. I've got all the proper resistors and AAs connected in series to get the right voltage, etc... but I want to rig up a second set of AAs in parallel. I've found a few posts and websites talking mainly about lithium cells and/or specifically rechargeables connected in parallel, but nothing on alkalines. I know to make sure they're of the same make, type, not to mix new and old (aka the same mA)... but will leaving parallel alkaline batteries connected until they are all used up cause any problems, possible fires, leakage, plagues, end of the world? I've found one web page talking about if one of the cells in parallel was lower in mA (or maybe only if it's faulty?) it could drain faster and possibly short, draining the energy from the other cells, possibly causing a fire hazard... Not good for my artwork or the places it will be displayed. Any thoughts would be greatly appreciated. Thanks for the help!

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Ruy Liu

8 years ago

Maybe our Li ion 32650 3.6V 5500mAh and 26650 3.6V 4500mAh battery can be helpful. if you need, can contact me by ruy@gebattery.com.cn

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11010010110

9 years ago

if the cells are in identical condition you should have no problem - as lemonie allready said the 3 resistors for a led is mega overkill. the led won't blow up on just the 47 ohm resistor alone or the 2 X 18 in series usually (when batteries are not energizer / duracell) you can use 2 batteries instead of 3 to power without resistor at all resistor with the leds can give significantly longer life for significant drop in brightness if you use more than 1 leds series connection and some experimenting may give you the same extra life at reduced brightness w2ithout using resistors. thats good cause resistors work by wasting energy

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shanepollard11010010110

Reply 9 years ago

Thanks! I may try experimenting with how much lower a resistance I can go with before it pops. I'm new to circuits though so I'm sorta learning as I go. The LED I'm using is a 3.5Vtypical and I tried running it on 3V, but it does shine a good deal brighter with the 3.5V... which, with AAs, meant 4.5V. Then did the (Vs-Vn)/I equation and ended up with 50ohms. Then with a 5% tolerance I figured I should clear 52.5ohms so I figured on a 56ohm resister. (I did all this cause the first time I started messing around with LEDs I just hooked the LED straight to the batteries and it popped with a good size spark... woops). Is that too conservative? It's just that the LEDs are going to be near impossible to replace once everything is put together and I'd hate for the LEDs to burn out. Thought about maybe doing a 6V setup with two 3.5V LEDs... they'd each be running .5V shy but I was thinking that with the two together, it would be brighter than the one alone at full power... plus more of my power would be going to light than heat.

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11010010110shanepollard

Reply 9 years ago

a led needs very high current to pop high current to melt a bubble in it and then pop quite high current to just melt moderately high current to overheat and die a bit high current to overheat and have shorter life in series setup you can play at quite high precision by adding / removing a battery. try your leds 2 in series with 6 Vand 7.5 V warning - very small over voltage without current limitation can kill a led. i connected once 3.3 V led to 3.7 V phone battery and it hissed and melted a bubble

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shanepollard11010010110

Reply 9 years ago

That just made everything click for me. I was doing the math for the circuit and it made sense to me, but I didn't completely understand what was happening. I don't know why I wasn't thinking in terms of current flow. Thank you!!

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shanepollard

9 years ago

Actually I was just reading something that gave me the idea to take the light resistor out of an old mobile phone I have and some parts from an old radio, and make the entire thing light-sensitive... Haha, we'll see how that goes. But then perhaps I could push the LEDs a bit more because they wouldn't be on 24/7? Like I said I'm new to all of this so basically I don't know what I don't know, ha. I've got a few books I'm learning from but I can't always find the answers I'm looking for in them. Do LEDs only "pop" at a point of too much power? Or if continuously running a little hot will they also "wear out"?

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lemonie

9 years ago

See this link for 192 AA batteries powering a car. Some of them must have been in parallel.

If the cells are matched / identical you shouldn't have a problem

L

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shanepollardlemonie

Reply 9 years ago

Ha and to think I was concerned with hooking up 3 in parallel. Great link, thanks! (did you read any of the comments on the page? there are some gems)