Started by in sci.electronics.basics5 years ago 8 replies

I was measuring torque required to drive various drill bits and incidentally found that my cordless drill was delivering way less torque than...

I was measuring torque required to drive various drill bits and incidentally found that my cordless drill was delivering way less torque than it was spec'd for. 80in-lbs measured vs 250 spec'd. If this wasn't a Milwaukee drill, I would have dismissed it as a spooky torque spec. But 80 vs 250 for a Milwaukee doesn't figure. The thought that came to me was maybe the battery couldn't de...

## Converting Large Vessels To Na-S Battery Electric

Started by in sci.electronics.basics5 years ago 11 replies

Knowing ship owners are the cheapest folk on the planet, it's 100% certain similar calculation have been done before: Vessel displacement: ...

Knowing ship owners are the cheapest folk on the planet, it's 100% certain similar calculation have been done before: Vessel displacement: 1,000 kilo ton (~300 m LOA) Prop power: 80 MW Na-S battery density: 0.150 MW-hr/ton Voyage time: 720 hours 57,600 MW-hrs 80 X 720 / 0.150 = 384 kilotons ~ 38% of the weight of the loaded ship The ship loses about a quarter of it's ca...

## Formula for calculating run time of apc ?

Started by in sci.electronics.basics4 years ago 3 replies

I am looking for a formula for calculating the run time of my APC battery system. I did a search but what I found required a particular model...

I am looking for a formula for calculating the run time of my APC battery system. I did a search but what I found required a particular model of apc. Total watts of computer and monitor is about 120 watts. Battery in my apc is 12V 18 Ah Thanks, Andy

## Ahmed Mohamed

Started by in sci.electronics.basics7 years ago 21 replies

I assume everyone has heard of this kid and his clock. http://truthuncensored.net/wp-content/uploads/2015/09/ahmed-mohamed-clock.jpg The...

I assume everyone has heard of this kid and his clock. http://truthuncensored.net/wp-content/uploads/2015/09/ahmed-mohamed-clock.jpg The picture of the clock shows a 9V battery hookup but no battery. That means the kid either had to plug the clock in or it does have batteries that are not shown. If we assume that there are no batteries, can this clock store it's alarm time? I say no, bu...

## Refrigeration To Reduce Battery Size / Overall Energy Storage Costs

Started by in sci.electronics.basics5 years ago 29 replies

90% of the electric bill in the desert at this time of the year is HVAC. The rest of the house doesn't need so much power and only requires a...

90% of the electric bill in the desert at this time of the year is HVAC. The rest of the house doesn't need so much power and only requires a small low cost battery for night time. Freeze about 2 tons of water during the day and then sink heat into the ice at night. Maybe 2/3rds of the solar power goes to running the conventional AC or heat pump during the day and 1/4 goes to freezing water...

## OT: Solar Charging 12V Car Battery

Started by in sci.electronics.basics10 years ago 44 replies

OT: Solar Charging 12V Car Battery... My son, Aaron, software engineer turned farmer, has acreage in the San Tan Valley with no source of...

OT: Solar Charging 12V Car Battery... My son, Aaron, software engineer turned farmer, has acreage in the San Tan Valley with no source of electric power. He'd like some artificial light for his chicken coop to increase the egg output. Lighting and timers are easy to find off-the-shelf, but I need some pointers toward finding a good quality solar panel that can charge a 12V car batter...

## Calculate run time of battery to a specified voltage

Started by in sci.electronics.basics3 years ago 11 replies

I want to calculate approx run time of a D cell with a capacity of 13,000 Mah. I assume that Time(H) = Capacity(Ah)/Current(A) equals a final...

I want to calculate approx run time of a D cell with a capacity of 13,000 Mah. I assume that Time(H) = Capacity(Ah)/Current(A) equals a final battery voltage of 0 volts which will not work in my case. I need a calculation for an ending voltage of around 2.0 volts. (At 2.0 volts, my clock starts losing time.) Thanks

## What is your opinion of this 9 volt 900maH li-ion battery?

Started by in sci.electronics.basics7 years ago 6 replies

...

http://www.ebay.com/itm/Etinesan-Big-capacity-900mAh-9v-li-ion-lithium-Rechargeable-9-Volt-Batte ry-/390967934161?pt=LH_DefaultDomain_0&hash=item5b07813cd1 Claims the nominal voltage is 8.4 and it's good for 1200 cycles. Made in China by Etinesan. Priced at \$9.59 with free shipping. Sounds like a deal to me. --- news://freenews.netfront.net/ - complaints: news@netfront.net ---

## Charge gel cell with car charger?

Started by in sci.electronics.basics9 years ago 57 replies

A friend has a battery powered Ryobi lawn trimmer ("weed whacker") which doesn't work. The 12vdc wall wart puts out only ~ 12.4v. I charged...

A friend has a battery powered Ryobi lawn trimmer ("weed whacker") which doesn't work. The 12vdc wall wart puts out only ~ 12.4v. I charged the lead-acid gel cell using a car charger. The charge rate (selectable) was 0.5A. Afterward the trimmer seemed to work as new. Can the car charger be used to charge this battery? He can install a timer to limit charge time if that's something req...

## Solar charger

Started by in sci.electronics.basics12 months ago 10 replies

I have a solar charging I am using with my car battery. The current voltage of the battery is 12.7 volts. And the charger is still...

I have a solar charging I am using with my car battery. The current voltage of the battery is 12.7 volts. And the charger is still charging. Here are some specs for the charger. Rated power output = 5W Operating power voltage = 18V Operating power current = .33A Trickle charging current = .2A Floating charging Voltage = 13.8 Overcharge Protection Voltage = 14.1 Voltage At what ...

## Transistors

Started by in sci.electronics.basics9 years ago 60 replies

Ok, this is a question that is not so battery-charger specific, but is obviously related. So here's a circuit fragment: 18V ...

Ok, this is a question that is not so battery-charger specific, but is obviously related. So here's a circuit fragment: 18V +----+--------__^------/\/\/-----------+ | 2n3055| 0R5 | | | 5W / | | \ 5R10W | | / |_______|>

## The danger of battery-powered wearable frames with A.I. software

Started by in sci.electronics.basics5 years ago 2 replies

## mystery tool

Started by in sci.electronics.basics4 years ago 4 replies

In a hardware store, I saw a rectangular bar, 10" long, with two through holes, labeled "MAGNETIZE" and "DEMAGNETIZE". Presumably it has a...

In a hardware store, I saw a rectangular bar, 10" long, with two through holes, labeled "MAGNETIZE" and "DEMAGNETIZE". Presumably it has a battery compartment, though I didn't check. What's inside? -- Rich

## No schematic for boiled potatos

Started by in sci.electronics.basics9 years ago 2 replies

...

http://blogs.smithsonianmag.com/ideas/2013/12/a-potato-battery-can-light-up-a-room-for-over-a-mo nth/?utm_source=smithsoniantopic&utm_medium=email&utm_campaign=20131208-Weekender

## Conductivity of rechargeable battery

Started by in sci.electronics.basics10 years ago 7 replies

Would the stuff inside ever become an insulator and stop conducting electricity? -- @~@ Remain silent. Nothing from soldiers is...

Would the stuff inside ever become an insulator and stop conducting electricity? -- @~@ Remain silent. Nothing from soldiers is real! / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (Fedora 15 i686) Linux 3.3.4 ^ ^ 22:50:01 up 6 days 2:36 0 users load average: 0.00 0.01 0.05 ä¸å??è²¸! ä¸è©é¨?! ä¸æ´äº¤! ä¸æ??äº¤! ä¸æ??å?«! ä¸è?ªæ®º! è«?è?

## Cost of Carbon Fuel Goes Up & Down But Generally Up

Started by in sci.electronics.basics8 years ago 8 replies

Cost of solar PV just keeps dropping. Even EV battery costs have dropped 30% in 5 years. Anyone who this fundamental truth will change needs...

Cost of solar PV just keeps dropping. Even EV battery costs have dropped 30% in 5 years. Anyone who this fundamental truth will change needs to join a drinking club, i.e., the "Man will Never Fly" society. Bret Cahill

## White LEDs for strobing?

Started by in sci.electronics.basics10 years ago 13 replies

I was thinking about making a little battery powered strobe using one of the really bright white LEDs now available. But I don't know how long...

I was thinking about making a little battery powered strobe using one of the really bright white LEDs now available. But I don't know how long the phosphor glows after the LED turns off. Anybody here know? Thanks, Eric

## Speaker id needed

Started by in sci.electronics.basics3 years ago 15 replies

This is from a cordless phone. I think it is a speaker. Phone uses 2.4 volt battery. I was wondering if it would work in a 9 Vdc...

This is from a cordless phone. I think it is a speaker. Phone uses 2.4 volt battery. I was wondering if it would work in a 9 Vdc circuit? https://www.dropbox.com/s/yy6rwm0vib91010/PhoneSpeaker.jpg?dl=0

## Component ID??

Started by in sci.electronics.basics8 years ago 6 replies

Hello all, Can anyone ID the component in the picture with the marking FD218-3055?? Or is there an alternative replacement for the...

Hello all, Can anyone ID the component in the picture with the marking FD218-3055?? Or is there an alternative replacement for the device. It is part of a battery charging circuit. As you can see the one on the left popped it top and let the smoke out. https://www.dropbox.com/s/y1b6hzhh47w583p/Component%20ID.jpg?dl=0 Thanks, Les

## LED lights when circuit broken

Started by in sci.electronics.basics10 years ago 15 replies

Hi, What is the simplest (cheapest, lowest energy) way to get an LED to light if the circuit from a 1.5v battery is broken? Thanks, Rod

Hi, What is the simplest (cheapest, lowest energy) way to get an LED to light if the circuit from a 1.5v battery is broken? Thanks, Rod