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Design => Engineering board => Topic started by: frank mccune on May 16, 2017, 04:48:51 PM
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I remember a bit of basic electricity from my youth and what I remember is this. If one connects two 5 amp, 1.5 volt batteries in parallel, the capacity will increase with the square of the number of batteries connected. In this case, the capacity would be 25 amps. Of course the voltage would remain the same at 1.5 volts. I think that Ohms Law stated that I squared was responsible for this result. If we hooked our No. 6 Lantern Batteries this way, they would last a much longer and provide a great glow to the plug.
Am I correct? What is the rest of the formula E=IR and how is I squared arrived by using basic algebra? I just can not get my head around this idea at this time.
Suggestions and or comments?
Tia,
Frank McCune
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You've got a couple of different things mixed in your head, I think. Which is excusable as the decades pass. At any rate, the maximum current draw is just plain old linear per cell, so two 5A cells in parallel will deliver 10A. The current-squared thing has to do with power dissipation in a resistor.
Just as a side note, alkaline cells are so much better at delivering current than plain old carbon-zinc cells that a pair of "D" cell batteries in parallel will light up an engine better than a nicad glow-starter, and they'll last forever, too. I put banana plugs on the end of my glow-starting lead, and use the magic size of brass tube (I think it's 5/32", but I won't swear to that) into which they fit. I just solder two batteries together in parallel with lengths of the tube, wrap it in electrical tape, and tra-la, I have a battery.
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Just as a side note, alkaline cells are so much better at delivering current than plain old carbon-zinc cells that a pair of "D" cell batteries in parallel will light up an engine better than a nicad glow-starter, and they'll last forever, too. I put banana plugs on the end of my glow-starting lead, and use the magic size of brass tube (I think it's 5/32", but I won't swear to that) into which they fit. I just solder two batteries together in parallel with lengths of the tube, wrap it in electrical tape, and tra-la, I have a battery.
Paul Walker used to do that. He may have used 3 or 4 D cells. They would last him a season, and he flew a lot of stunt in a season.
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Hello:
Thanks for the prompt replies! I think that I "remember" that I was taught that one forgets 80% of everything that one has learned. I wonder at what age this information was determined. Lol
If I remember correctly, the No.6 Lantern battery was nothing more than four D cells wired in parallel providing a great starting battery for our glow engines. I did see some of the older more prosperous fliers using two No. 6 batteries connected in parallel. That was a good as it got back in the days! Oh yes. there was the long cylindrical 1.5 volt battery that could also be used for our purposes. These were less common than the No. 6 battery. I did see two of these wired in parallel as a child. Is there any old timers remember having your buddy hold the wires of the glow plug alligator clips to each end of a single "D" cell while attempting to start an engine? Talk about being provincial!
Be well my friends,
Frank McCune
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Hi Tim:
You are probably correct. What I may have been thinking was the formula of E=I squared R. That is burned into my mind as firmly as reactive capacitance! Lol.
All of the best,
Frank McCune
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We sure had fun with the old "Left Hand Rule"...or was it the "Right Hand Rule"? ;) Steve
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I^2*R is the power, not the voltage. P=IV, V=IR, substitute for V -> P=I*IR = I^2*R.
Brett
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Just as a side note, alkaline cells are so much better at delivering current than plain old carbon-zinc cells that a pair of "D" cell batteries in parallel will light up an engine better than a nicad glow-starter, and they'll last forever, too. I put banana plugs on the end of my glow-starting lead, and use the magic size of brass tube (I think it's 5/32", but I won't swear to that) into which they fit. I just solder two batteries together in parallel with lengths of the tube, wrap it in electrical tape, and tra-la, I have a battery.
Do you have a picture of this getup?
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Do you have a picture of this getup?
Alas, no. I would take a picture of what I have now, but it looks remarkably like a black blob with a couple of banana plugs shoved into it.
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Alas, no. I would take a picture of what I have now, but it looks remarkably like a black blob with a couple of banana plugs shoved into it.
Take pictures wile you take it apart ;D
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Take pictures wile you take it apart ;D
Oh, fine. The thread is right here (http://stunthanger.com/smf/open-forum/dry-cell-glow-starter/) -- I figured many would be interested, which is why I started a new thread instead of hiding the topic in here.
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Just a quick note. You can write exponents with the "sup" (superscript) editing function above the edit box.
P = I2R
SK