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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Battery on the ground
Absolutely, unequivocally NOT.
Even if the ground is frozen YET the battery is fully charged, it still will not discharge. I can't believe that this wife's tale still persists and that some will go to their grave arguing that it is true. j/b "SteveB" wrote in message ... I have heard that if you sit a battery on the ground or concrete that it will lose its charge faster. Is this true? Steve |
#2
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Battery on the ground
When I studied chemistry they told me taht H2SO4 and water were
soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman I'm in the same age bracket as Steve and believe in the acid separating from the water in strata due to chilling it. Ionic flow must take place for battery operation to take place. Without the acid mixed in evenly, only small areas of the plates can conduct electrons. If only 5% is available, the effective resistance is excessive and makes it look dead. Mar 21, 6:57 pm, "jusme" wrote: Absolutely, unequivocally NOT. Even if the ground is frozen YET the battery is fully charged, it still will not discharge. I can't believe that this wife's tale still persists and that some will go to their grave arguing that it is true. j/b "SteveB" wrote in message ... I have heard that if you sit a battery on the ground or concrete that it will lose its charge faster. Is this true? Steve |
#3
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Battery on the ground
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#4
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Battery on the ground
On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick
wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... Some of those are thermoclines, regions where temperature (hence density) changes rapidly in a short range of depth. These also occur in some freshwater lakes during the summer, are visible with sonar. |
#5
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Battery on the ground
On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick
wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. -- Ned Simmons |
#6
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Battery on the ground
Don Foreman wrote:
On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... Some of those are thermoclines, regions where temperature (hence density) changes rapidly in a short range of depth. These also occur in some freshwater lakes during the summer, are visible with sonar. And the same thing "cant" happen in an undisturbed battery. ...lew... |
#7
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Battery on the ground
Ned Simmons wrote:
On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! |
#8
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Battery on the ground
In article ,
Lew Hartswick wrote: Ned Simmons wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! Batteries are too small to support much of a thermocline. It takes at least a lake to get anything that will last more than an hour or two. Joe Gwinn |
#9
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Battery on the ground
On Sun, 23 Mar 2008 18:09:57 -0400, Joseph Gwinn
wrote: In article , Lew Hartswick wrote: Ned Simmons wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! Batteries are too small to support much of a thermocline. It takes at least a lake to get anything that will last more than an hour or two. I didn't see any mention of a thermocline. What's been proposed is a temperature gradient in a battery cell that's packed with enough stuff to inhibit convection when set on a relatively good conductor that's at a different temperature than the ambient air. -- Ned Simmons |
#10
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Battery on the ground
In article ,
Ned Simmons wrote: On Sun, 23 Mar 2008 18:09:57 -0400, Joseph Gwinn wrote: In article , Lew Hartswick wrote: Ned Simmons wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! Batteries are too small to support much of a thermocline. It takes at least a lake to get anything that will last more than an hour or two. I didn't see any mention of a thermocline. What's been proposed is a temperature gradient in a battery cell that's packed with enough stuff to inhibit convection when set on a relatively good conductor that's at a different temperature than the ambient air. Lew Hartwick mentioned the thermocline. But anyway, what's the thermal conductivity of the metal battery plates, and of the electrolyte? It has to be 1000 times greater than air, and unless the battery is *huge*, thermal equilibrium will soon be achieved. Joe Gwinn |
#11
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Battery on the ground
On Sun, 23 Mar 2008 20:50:56 -0400, Joseph Gwinn
wrote: In article , Ned Simmons wrote: Batteries are too small to support much of a thermocline. It takes at least a lake to get anything that will last more than an hour or two. I didn't see any mention of a thermocline. What's been proposed is a temperature gradient in a battery cell that's packed with enough stuff to inhibit convection when set on a relatively good conductor that's at a different temperature than the ambient air. Lew Hartwick mentioned the thermocline. I don't see that in Lew's posts, perhaps I missed one. But anyway, what's the thermal conductivity of the metal battery plates, and of the electrolyte? It has to be 1000 times greater than air, and unless the battery is *huge*, thermal equilibrium will soon be achieved. The heat capacity of a concrete slab and the earth below it is huge compared to the battery, and it may take days to reach equilibrium with the air. In the meantime, if the weather is trending warmer, the bottom of the battery is cooled below ambient by the slab. I have no idea whether the effect is actually large enough to discharge an otherwise healthy battery, but I don't think the possibility can be dismissed without either an experiment or some very messy calculations. In any case, I find the notion more plausible than *'s assertion that, "Electrons WOULD leak through the porous case to ground - eventually discharging the battery." g -- Ned Simmons |
#12
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Battery on the ground
On Sun, 23 Mar 2008 15:25:26 -0600, Lew Hartswick
wrote: Don Foreman wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... Some of those are thermoclines, regions where temperature (hence density) changes rapidly in a short range of depth. These also occur in some freshwater lakes during the summer, are visible with sonar. And the same thing "cant" happen in an undisturbed battery. ...lew... Not to any significant extent, because the battery is only about a foot deep at most. I think the stratification is due to electrochemical action as David Harmon suggested. |
#13
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Battery on the ground
On Sun, 23 Mar 2008 15:26:17 -0600, Lew Hartswick
wrote: Ned Simmons wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! Have you noticed this while wading in a foot of water, or swimming on the surface over deeper water on a calm day? The thermal conductivity of water is not much different than that of concrete -- roughly 0.5 W /(m*K). HDPE is also in the same ballpark. http://www.engineeringtoolbox.com/th...ity-d_429.html Air is about 24 times less. A battery sitting on concrete surrounded by air of different temperature will behave thermally about like a block of concrete sitting on the concrete. |
#14
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Battery on the ground
On Sun, 23 Mar 2008 22:31:12 -0600, Don Foreman
wrote: On Sun, 23 Mar 2008 15:26:17 -0600, Lew Hartswick wrote: Ned Simmons wrote: On Sun, 23 Mar 2008 08:26:00 -0600, Lew Hartswick wrote: wrote: When I studied chemistry they told me taht H2SO4 and water were soluble in each other in all proportions, also that a solution cosisted of two substances that would not separate merely due to differences in density. Has any of this changed? Engineman Did "Chemistry" class ever explain how the ocean has different layers of density that cause the sonor problems that are well documented by submarines? I would think using your logic that it would be one uniform solution. ???? ...lew... There are continuous inputs (e.g., rivers) and ouputs (evaporation) of fresh water to and from the ocean which prevent it from ever reaching equilibrium with respect to solutes, unlike electrolyte which is thoroughly mixed before filling a battery. Similarly, as a result of localized inputs and outputs of heat, most bodies of water are also not in thermal equilibrium, as any swimmer can attest. It seems reasonable that the same could be true of a battery sitting undisturbed on a large heat sink (a concrete floor) while air temp is fluctuating. A-MEN! Have you noticed this while wading in a foot of water, or swimming on the surface over deeper water on a calm day? It's easier to notice on the scale of a couple feet in open water. But one of my favorite places to swim has several ledges covered with rockweed or bladderwrack; at half tide when the seaweed is floating on the surface it inhibits convection and steepens the temperature gradient near the surface. A few extra degrees feels pretty good when the water temperature is in the low to mid 60's. I would expect the plates in a battery to have much the same effect on convection within the cells. The thermal conductivity of water is not much different than that of concrete -- roughly 0.5 W /(m*K). HDPE is also in the same ballpark. http://www.engineeringtoolbox.com/th...ity-d_429.html Air is about 24 times less. A battery sitting on concrete surrounded by air of different temperature will behave thermally about like a block of concrete sitting on the concrete. If one were inclined to calculate what the temp gradient might be, treating the battery as a block, and ignoring convection, seems like a reasonable first pass to me. -- Ned Simmons |
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