Why are rechargeble batteries only 1.2 volts?

[Red Squirrel]

Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

 

[Colt45]

different chemistry.

 

[RoloMather]

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

 

[Itchrelief]

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

False. For low-current devices where alkaline internal resistance is negligible and shutoff voltage is unusually high, a good alkaline will outlast an NiMH, as alkalines will have something like 3000mAH of capacity at very low current drain rates(vs 2000-2700 for NiMH), and the low current makes alkaline voltage drop irrelevant. Higher drain devices will even the playing field, but the high voltage shutoff behavior is still going to leave a good deal of potential runtime on the table.

9volt rechargeable is only going to compound the low-voltage problem if your devices exhibit it, because they have multiple cells in series. Most Ni based batteries are going to be 7.2-8.4V nominal. I think 9.6V is somewhat rare.

 

[RoloMather]

Originally posted by: Itchrelief

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

False. For low-current devices where alkaline internal resistance is negligible and shutoff voltage is unusually high, a good alkaline will outlast an NiMH, as alkalines will have something like 3000mAH of capacity at very low current drain rates(vs 2000-2700 for NiMH), and the low current makes alkaline voltage drop irrelevant. Higher drain devices will even the playing field, but the high voltage shutoff behavior is still going to leave a good deal of potential runtime on the table.

9volt rechargeable is only going to compound the low-voltage problem if your devices exhibit it, because they have multiple cells in series. Most Ni based batteries are going to be 7.2-8.4V nominal. I think 9.6V is somewhat rare.

False. The original statement that "low voltages makes batteries life shorter" is false because low voltages does not cause low battery life.

 

[Newbian]

False....because I said so.

 

[Itchrelief]

Originally posted by: RoloMather

Originally posted by: Itchrelief

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

False. For low-current devices where alkaline internal resistance is negligible and shutoff voltage is unusually high, a good alkaline will outlast an NiMH, as alkalines will have something like 3000mAH of capacity at very low current drain rates(vs 2000-2700 for NiMH), and the low current makes alkaline voltage drop irrelevant. Higher drain devices will even the playing field, but the high voltage shutoff behavior is still going to leave a good deal of potential runtime on the table.

9volt rechargeable is only going to compound the low-voltage problem if your devices exhibit it, because they have multiple cells in series. Most Ni based batteries are going to be 7.2-8.4V nominal. I think 9.6V is somewhat rare.

False. The original statement that "low voltages makes batteries life shorter" is false because low voltages does not cause low battery life.

So you are going to argue semantics when it is obvious his device is shutting off at the low voltage point?

Go ahead, you win the argument.

If you can't use the capacity, it's useless to you. Unless it makes you happy that you have all this theoretical capacity that your devices never tap.

 

[Jeff7]

Originally posted by: Colt45
different chemistry.

This is pretty much it.

Per cell, there's a voltage that's determined by the chemistry.
For alkaline, it's 1.5V.
NiCad and NiMH: 1.2V
Lead acid: 2V
Li-ion: 3.6-3.7V


Rechargeable 9V's were once 7.2V when NiCad was the main rechargeable battery on the block. The higher capacity of NiMH allows them to use smaller cells, thus they can use 7 cells instead of 6 in each 9V battery. Result: You now get 8.4V in a 9V package, or even 9.6V (8 cells).

My usual advice for batteries is: Avoid Powerizer. I have about a 40% failure rate after less than 1 year with a batch of 24 AAs. Failure means that they either hold MUCH less than their rated capacity (<50%) or else they show a terminal voltage of only 0.10V - quite thoroughly dead. And out of 2 9V batteries, one no longer takes a charge. It registers as an open circuit now.
Maha might be decent; I've used one of their chargers, but never their batteries.

Low-discharge 9V - it's made by Tysonic. I have no idea if they're Made in China or not, or what their quality's like.
My experience with batteries made in China hasn't ever been particularly good; Sanyo's Japanese batteries, either Eneloop or not, have always been good to me. Their standard 1700mAh AAs could usually perform as well as the Powerizer 2250mAh cells, and out of 12 of them I bought more than 5 years ago, they all still work just fine.

Originally posted by: Itchrelief
So you are going to argue semantics when it is obvious his device is shutting off at the low voltage point?

Go ahead, you win the argument.

If you can't use the capacity, it's useless to you. Unless it makes you happy that you have all this theoretical capacity that your devices never tap.

It's only RoloMather. Don't bother wasting much time - he's likely just doing his usual trolling of the boards.

 

[mugs]

Originally posted by: Colt45
different chemistry.

This.

Also, alkaline batteries spend most of their life closer to 1.2v than to 1.5v.

Alkaline batteries drop quickly to 1.4v, then they drop steadily to 1.0v as they drain.
http://www.candlepowerforums.c...showthread.php?t=64660

NiMh batteries start around 1.4-1.5v, drop quickly to 1.2v, they stay at 1.2v until they're depleted. They drop off abruptly when they're almost fully drained.
http://www.candlepowerforums.c...showthread.php?t=79302

 

[RoloMather]

Originally posted by: mugs

Originally posted by: Colt45
different chemistry.

This.

Also, alkaline batteries spend most of their life closer to 1.2v than to 1.5v.

Alkaline batteries drop quickly to 1.4v, then they drop steadily to 1.0v as they drain.
http://www.candlepowerforums.c...showthread.php?t=64660

NiMh batteries start around 1.4-1.5v, drop quickly to 1.2v, they stay at 1.2v until they're depleted. They drop off abruptly when they're almost fully drained.
http://www.candlepowerforums.c...showthread.php?t=79302

:thumbsup:

 

[Red Squirrel]

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

I always figured the more amps you draw, the faster the life goes so when there is less voltage it will draw more amps to make up wattage. Guess that makes no sense, that's why I'm not in EE.

I decided to test that for myself by replacing one of the 1.2v batteries in my flashlight with a 1.5 duracell (tested voltages to ensure the batteries were actually that voltage and they were within 0.05) and yeah, guess I was in fact wrong, in fact, the light bulb takes more watts when I give it more volts but guess that makes sense because it's also brighter, hence, producing more watts. (most being heat)

two rechargeables:
2.539v * 0.652a = 1.655w

one rechargeable and one duracell alkaline:
2.866v * 0.867a = 2.4842 (brighter)

I don't have proper battery holders or I'd do more experiments such as add a 3rd battery, or see what kind of readings I get if I try to light a 120v bulb. (did this as a kid once, with like 30 D batteries, DC shocks hurt more then AC imo)

 

[RoloMather]

Originally posted by: RedSquirrel

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

I always figured the more amps you draw, the faster the life goes so when there is less voltage it will draw more amps to make up wattage. Guess that makes no sense, that's why I'm not in EE.

I decided to test that for myself by replacing one of the 1.2v batteries in my flashlight with a 1.5 duracell (tested voltages to ensure the batteries were actually that voltage and they were within 0.05) and yeah, guess I was in fact wrong, in fact, the light bulb takes more watts when I give it more volts but guess that makes sense because it's also brighter, hence, producing more watts. (most being heat)

two rechargeables:
2.539v * 0.652a = 1.655w

one rechargeable and one duracell alkaline:
2.866v * 0.867a = 2.4842 (brighter)

I don't have proper battery holders or I'd do more experiments such as add a 3rd battery, or see what kind of readings I get if I try to light a 120v bulb. (did this as a kid once, with like 30 D batteries, DC shocks hurt more then AC imo)

:laugh: A real world test is not permitted in these hallowed halls.

V = IR so it make sense that current goes up with increase voltage given same resistance.

Anyways, most of the time your alkaline battery will have more mAh than your NiMH battery.

 

[mugs]

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

 

[Red Squirrel]

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

 

[Modelworks]

They could make a true 9v rechargeable battery, but the problem would be it would no longer fit where the chemical 9v battery do.
Just like the companies that try to make their battery run longer than the competitor by increasing the battery size slightly. They fit, but very very snug.

 

[Hacp]

Originally posted by: RedSquirrel

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

I always figured the more amps you draw, the faster the life goes so when there is less voltage it will draw more amps to make up wattage. Guess that makes no sense, that's why I'm not in EE.

I decided to test that for myself by replacing one of the 1.2v batteries in my flashlight with a 1.5 duracell (tested voltages to ensure the batteries were actually that voltage and they were within 0.05) and yeah, guess I was in fact wrong, in fact, the light bulb takes more watts when I give it more volts but guess that makes sense because it's also brighter, hence, producing more watts. (most being heat)

two rechargeables:
2.539v * 0.652a = 1.655w

one rechargeable and one duracell alkaline:
2.866v * 0.867a = 2.4842 (brighter)

I don't have proper battery holders or I'd do more experiments such as add a 3rd battery, or see what kind of readings I get if I try to light a 120v bulb. (did this as a kid once, with like 30 D batteries, DC shocks hurt more then AC imo)

You've seriously never taken a physics class?

 

[Modelworks]

Originally posted by: RedSquirrel

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

It started because people were putting chemical batteries, with NiCd into chargers , which resulted in fires. So they started warning people about not mixing battery types to stop the confusion.


The old and new battery mix isn't harmful, just wastefull. If you don't have a tester it is hard to know which battery in the series of 2 or more needs replacing. If you start with all new near the same charge you can replace them all .

Cadmium in NiCd has an interesting history. It was once used as the metal in early canned food. They sealed the cans with lead solder. Yum !


Also, batteries have to be measured under load, just putting a volt meter to it when not in use isn't all that useful.

 

[Red Squirrel]

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

It started because people were putting chemical batteries, with NiCd into chargers , which resulted in fires. So they started warning people about not mixing battery types to stop the confusion.


The old and new battery mix isn't harmful, just wastefull. If you don't have a tester it is hard to know which battery in the series of 2 or more needs replacing. If you start will all new near the same charge you can replace them all .

Cadmium in NiCd has an interesting history. It was once used as the metal in early canned food. Yum !

That reminds me I actually have some old panasonic 1.5v nicd rechargeables. BEST batteries EVER. Unlimited charges unlike today's "1000 charge" ones. I grew up with those batteries, they were used in my baby toys, then later on "big kids toys" remote controls etc... they're still in a box somewhere, and last I checked, they STILL work. When I was around 10-15 is where they received the most abuse, such as me connecting 5 of them in series to power electromagnets and other stuff (which is basically a short circuit). I used to play a lot with electrical stuff as a kid.

 

[Red Squirrel]

Originally posted by: Hacp

Originally posted by: RedSquirrel

Originally posted by: RoloMather

Originally posted by: RedSquirrel
Why is it that AA and other normally 1.5v batteries are always 1.2 or 1.3 volts when rechargeable? I find this can sometimes cause issues in some applications that require a set voltage to work. I like using rechargeables as it's better for the environment, but having such low voltage makes then last less long.

Any places where I can buy them in 1.5 volts?

What about 9 volt rechargeable. Never used them, are they decent?

False.

I always figured the more amps you draw, the faster the life goes so when there is less voltage it will draw more amps to make up wattage. Guess that makes no sense, that's why I'm not in EE.

I decided to test that for myself by replacing one of the 1.2v batteries in my flashlight with a 1.5 duracell (tested voltages to ensure the batteries were actually that voltage and they were within 0.05) and yeah, guess I was in fact wrong, in fact, the light bulb takes more watts when I give it more volts but guess that makes sense because it's also brighter, hence, producing more watts. (most being heat)

two rechargeables:
2.539v * 0.652a = 1.655w

one rechargeable and one duracell alkaline:
2.866v * 0.867a = 2.4842 (brighter)

I don't have proper battery holders or I'd do more experiments such as add a 3rd battery, or see what kind of readings I get if I try to light a 120v bulb. (did this as a kid once, with like 30 D batteries, DC shocks hurt more then AC imo)

You've seriously never taken a physics class?

I did way back in high school, and that's where I learned that devices will draw more amps if you give it less volts. But like any school material, that's probably false and outdated information by today's standards.

The only thing I really remember well which still holds true is that van degraff generators are very fun toys.

 

[Modelworks]

Originally posted by: RedSquirrel

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

It started because people were putting chemical batteries, with NiCd into chargers , which resulted in fires. So they started warning people about not mixing battery types to stop the confusion.


The old and new battery mix isn't harmful, just wastefull. If you don't have a tester it is hard to know which battery in the series of 2 or more needs replacing. If you start will all new near the same charge you can replace them all .

Cadmium in NiCd has an interesting history. It was once used as the metal in early canned food. Yum !

That reminds me I actually have some old panasonic 1.5v nicd rechargeables. BEST batteries EVER. Unlimited charges unlike today's "1000 charge" ones. I grew up with those batteries, they were used in my baby toys, then later on "big kids toys" remote controls etc... they're still in a box somewhere, and last I checked, they STILL work. When I was around 10-15 is where they received the most abuse, such as me connecting 5 of them in series to power electromagnets and other stuff (which is basically a short circuit). I used to play a lot with electrical stuff as a kid.

Biggest problem with NiCd is the memory effect. If you take a NiCd and drain it to .75 volts and do that over and over then that is where the battery will cease to function. It remembers what the charge/recycle charge is and that is all it will produce. To fix it there are some chargers that have a setting to try to repair. Basically just puts the battery under a higher than normal voltage pulse, sometimes causing them to fail completely . So if you use them run them empty before recharging.

That was a huge problem with laptops and cell phones. People were always recharging them so they wouldn't run out but really the more they charged them the worse they charged.

 

[alkemyst]

damn even drunk this thread hurt my brain.

MAH!

 

[Red Squirrel]

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

It started because people were putting chemical batteries, with NiCd into chargers , which resulted in fires. So they started warning people about not mixing battery types to stop the confusion.


The old and new battery mix isn't harmful, just wastefull. If you don't have a tester it is hard to know which battery in the series of 2 or more needs replacing. If you start will all new near the same charge you can replace them all .

Cadmium in NiCd has an interesting history. It was once used as the metal in early canned food. Yum !

That reminds me I actually have some old panasonic 1.5v nicd rechargeables. BEST batteries EVER. Unlimited charges unlike today's "1000 charge" ones. I grew up with those batteries, they were used in my baby toys, then later on "big kids toys" remote controls etc... they're still in a box somewhere, and last I checked, they STILL work. When I was around 10-15 is where they received the most abuse, such as me connecting 5 of them in series to power electromagnets and other stuff (which is basically a short circuit). I used to play a lot with electrical stuff as a kid.

Biggest problem with NiCd is the memory effect. If you take a NiCd and drain it to .75 volts and do that over and over then that is where the battery will cease to function. It remembers what the charge/recycle charge is and that is all it will produce. To fix it there are some chargers that have a setting to try to repair. Basically just puts the battery under a higher than normal voltage pulse, sometimes causing them to fail completely . So if you use them run them empty before recharging.

That was a huge problem with laptops and cell phones. People were always recharging them so they wouldn't run out but really the more they charged them the worse they charged.

Hmm that's good to know, so I should let them drain completely before charging then?

 

[RoloMather]

Originally posted by: RedSquirrel

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: Modelworks

Originally posted by: RedSquirrel

Originally posted by: mugs

Originally posted by: RedSquirrel
one rechargeable and one duracell alkaline:

Don't do that. I can't explain it in scientific terms, but my understanding is that you shouldn't use batteries with mismatched voltages together.

I've heard this too, but always just ignored it. I think it's just some marketing tactic to force you to buy more batteries so they all match up.

It started because people were putting chemical batteries, with NiCd into chargers , which resulted in fires. So they started warning people about not mixing battery types to stop the confusion.


The old and new battery mix isn't harmful, just wastefull. If you don't have a tester it is hard to know which battery in the series of 2 or more needs replacing. If you start will all new near the same charge you can replace them all .

Cadmium in NiCd has an interesting history. It was once used as the metal in early canned food. Yum !

That reminds me I actually have some old panasonic 1.5v nicd rechargeables. BEST batteries EVER. Unlimited charges unlike today's "1000 charge" ones. I grew up with those batteries, they were used in my baby toys, then later on "big kids toys" remote controls etc... they're still in a box somewhere, and last I checked, they STILL work. When I was around 10-15 is where they received the most abuse, such as me connecting 5 of them in series to power electromagnets and other stuff (which is basically a short circuit). I used to play a lot with electrical stuff as a kid.

Biggest problem with NiCd is the memory effect. If you take a NiCd and drain it to .75 volts and do that over and over then that is where the battery will cease to function. It remembers what the charge/recycle charge is and that is all it will produce. To fix it there are some chargers that have a setting to try to repair. Basically just puts the battery under a higher than normal voltage pulse, sometimes causing them to fail completely . So if you use them run them empty before recharging.

That was a huge problem with laptops and cell phones. People were always recharging them so they wouldn't run out but really the more they charged them the worse they charged.

Hmm that's good to know, so I should let them drain completely before charging then?

Who even uses NiCd these days? If it's NiMH then don't worry about battery memory. Instead, it would cause the batteries to fail faster if you drain them repeatedly.