Devices to store chemical energy and convert it to electrical energy.

learn more… | top users | synonyms

0
votes
3answers
83 views

Capacitance: How to increase total charge drawn from a battery?

I can't seem to find any information about how parallel capacitors or capacitors in a series affect how much a capacitor can charge, not in my textbook or online. Here is the question I am trying to ...
0
votes
1answer
93 views

How to calculate cost of AA accumulator charge? [closed]

I would like to calculate how much it will cost to change AA accumulator. Is it really cheaper than usage of batteries (don't consider ecology question as of now)? Let's say I have the following ...
0
votes
1answer
132 views

What is the difference between a battery and a “polarized” charged capacitor?

I know that the main difference between the two is that a battery can provide a constant voltage whereas a capacitor's voltage decreases as the charge stored decreases. But what about the internal ...
0
votes
1answer
2k views

Calculate the UPS Capacity in amp-hours [closed]

I am trying to find out the UPS capacity in amp-hours for my HP UPS system. I've already done some calculations based on the UPS information from the HP Power Manager software. Bellow are my ...
0
votes
2answers
626 views

Can a battery charger be too powerful for a rechargeable battery?

I got the impression that a regular iPhone charger can charge the iPhone and the iPhone won't become too hot while charging, and the charging time is standard, but if using the 10W iPad charger to ...
0
votes
1answer
223 views

How does battery cell size affect voltage drop for a fix current load? [closed]

For a fixed current load, will the voltage drop be larger in a small cell or a big cell battery? Why?
0
votes
2answers
101 views

Batteries connected in Parallel

"If we connect two batteries in parallel, the battery with higher voltage will discharge into the other one." What is the intuition behind this?
0
votes
1answer
57 views

Cell connections

I have an UPS with two 6V batteries connected in series. Is it possible to use the same system (UPS) to charge another two pieces of 6 volts battery if all the batteries are connected in parallel to ...
0
votes
1answer
140 views

Battery fully loaded, pull out the chord?

I recently bought a new phone (Samsung Galaxy 3) and when the battery is fully loaded, it says like "Battery fully loaded, pull out the chord". Is this a typo from Samsung, or would there ...
0
votes
2answers
152 views

Does using batteries in a series raise the overall Wh's of the batteries used? Why/Why Not?

If one has 2 batteries of 6 Volts each with 500 mAh each, then separately the batteries should provide 6 Volts * 500 mAh = 3 Wh each or 6 Wh total. However would it be the case that if someone where ...
0
votes
0answers
44 views

Why are magnets attracted to negative side in battery

I have been experimenting with magnets, and built an Homopolar motor however it works but the magnet only attracts the negative side of the AA battery (the flat side of a battery) which I thought was ...
0
votes
2answers
382 views

What do we mean exactly by the positive/negative charges in cathode and anode?

In batteries, what exactly do we mean by negative and positive charges? My understanding is that the negative charge of the anode is basically an atom with an extra electron in the last orbital and a ...
-1
votes
1answer
3k views

Can I use AA batteries to charge iPhone? [closed]

Technically, 4 AA batteries will give out ~5V, which is equivalent to USB. Can you use 4 AA batteries to charge an iPhone, without messing up the Li-Ion cells used on iPhone? So my question really ...
-1
votes
1answer
33 views

High Current at first and then steady from a battery

I just came up with a question, When a battery is connected to a circuit, the current first suddenly peaks up and slowly goes down to a steady value. Why is it so? I have not actually observed this, ...
-2
votes
1answer
42 views

What happens when a battery is in space? [closed]

What would happen If you take a battery in a space ? Would the current flow between terminals being it in vacuum of space?
-2
votes
1answer
322 views

Hard circuit problem [closed]

I want to find the p.d. between points A and B. I'm not sure how to approach this problem though, could I have a hint?
-3
votes
1answer
161 views

Whether a battery store energy or simply it makes energy? [closed]

There're some easy concepts which I don't get exactly in my mind. I've been studying these things for two years of my engineering but they still bother me. Battery is one of them. Can someone explain? ...
-4
votes
2answers
355 views

Basic Physics Question [closed]

I'm having a difficult time answering this question. I think I'm just converting the units wrong somewhere: You're the CEO of a courier company, and you decide to select an electric car for your ...