![]() It’s best to have backup charging devices, especially on the go, so if the batteries run on empty, you could still have at least one of the best portable chargers as a spare source of power. Unfortunately, they didn’t perform well on high drain devices like cameras or flash units. We were impressed with how long they lasted before becoming completely discharged. That makes these best for items like clocks, remotes, flashlights and toys. The AmazonBasics C cell batteries offer 1.5 volts and 7,000 mAh of capacity, making them a perfect fit for everyday use on items that don’t drain a lot of power. Packaging is a little frustrating to open.↳ Is this connected to that? Use a homemade electronic tester to find out if electricity can flow between two objects.↳ Investigating the 'Mpemba Effect': Can Hot Water Freeze Faster than Cold Water?.↳ From Dull to Dazzling: Using Pennies to Test How pH Affects Copper Corrosion.↳ Forensic Science: Building Your Own Tool for Identifying DNA.↳ Electrolyte Challenge: Orange Juice vs.↳ Do Oranges Lose or Gain Vitamin C After Being Picked?. ![]() ↳ Math & Computer Science Sponsored by Hyperion Solutions Corp.↳ Grades 9-12: Getting Ready for the Science Fair.↳ Grades 6-8: Getting Ready for the Science Fair.↳ Grades K-5: Getting Ready for the Science Fair.↳ Science Teachers: Fairs, Projects, and General Support.↳ Advanced Science Competitions (Intel ISEF, Intel STS, Siemens Competition, JSHS, etc.).↳ Grades 9-12: Math and Computer Science.↳ Grades 9-12: Life, Earth, and Social Sciences.↳ Grades 6-8: Math and Computer Science.↳ Grades 6-8: Life, Earth, and Social Sciences.↳ Grades K-5: Math and Computer Science.↳ Grades K-5: Life, Earth, and Social Sciences.Active Forums (Make all new posts here).We have actually noticed that with some of our robotics projects, where Energizer or Duracell last much longer than off-brand ones. The toy car will draw much more power, draining the batteries quicker. You can also find plenty of multimeters on Amazon, or get one at a Radio Shack if you have one nearby.ģ) You might not have time to do this now, but for future reference, you might be able to see the results "faster" if you use something like a toy car that has motors or other moving parts, instead of a tiny flashlight. ![]() Note that you would need to take the readings in a dark room where the lux meter's reading will not be contaminated by other light sources, like ceiling lights or windows.Ģ) If you decide to go with a multimeter and voltage readings instead, we have an entire tutorial on how to use one (just in case you haven't before). So, if you wanted to quantify "how bright" the flashlight is with a number (instead of just looking at it with your eyes and assigning values like "really bright, bright, medium, and dim"), you could use one of those. I just wanted to throw in a couple more things:ġ) You can get "lux meters", which are used to measure the intensity of light, pretty cheap on Amazon. Howard has provided some great advice so far. All kids love flashlights - even us grownup kids! It would be wonderful if you had access to a multimeter and could measure the current draw to make some calculations. From their data, their AAA batteries should have had trouble lasting a full day - so something is odd. heets.jspx (your son may want to include some charts if he's making a report or entering this in a fair). But yes, I'm a little surprised you got more than 2-3 days.ĭuracell publishes all sorts of test results for their batteries. It may linger with a very dim glow for a while longer if it's lasted this long. You have to determine at what point you'll call the test completed. I'll wager that after 4 days of bring on, your batteries are technically 'dead'. The battery manufacturers consider the battery to be pooped out when it drops from 1.5V to 1.1V with a load on it. I'm actually surprised it's still lit after 4 days but I'll bet it's a lot dimmer than it was. So the rough mAh capacity calculation is still somewhat reasonable. It gets a little more complicated when you go from one red/yellow/green LED to a white one and to two batteries, but a white LED requires a higher voltage. A AAA battery typically can provide 1000 mAh which at 20mA is (more or less) 1000/20 or 50 hours. Many of these cheap LED flashlights pull perhaps 20mA through the LED. The question is how much light does the flashlight put out and consequently, how much power/current is the LED drawing? Except for the cheapest junk batteries, most AA or AAA batteries are pretty similar across brands.
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