fresh batteries not yielding peak power

[ixfd64]

I'm not sure where I should post this topic, since it has to do with both lasers and batteries. However, I'm posting it here, since I think that it is more related to batteries.

Anyways, I know that fresh batteries tend to have a higher voltage, which generally allows lasers to perform better. I have a set of Toshiba batteries, which I measured to have a total of 3 V. However, when I use the batteries in my laser, it performs as if it's using old batteries. I even put aluminum foil between the batteries and the contact springs, but this does not help.

I don't think it is a problem with my laser, because all other sets of fresh batteries (3 V total) yield an optimal ouput.

Does anyone know why this might be happening?

 

[Curious_character]

I'm not sure where I should post this topic, since it has to do with both lasers and batteries. However, I'm posting it here, since I think that it is more related to batteries.

Anyways, I know that fresh batteries tend to have a higher voltage, which generally allows lasers to perform better. I have a set of Toshiba batteries, which I measured to have a total of 3 V. However, when I use the batteries in my laser, it performs as if it's using old batteries. I even put aluminum foil between the batteries and the contact springs, but this does not help.

I don't think it is a problem with my laser, because all other sets of fresh batteries (3 V total) yield an optimal ouput.

Does anyone know why this might be happening?

The open circuit voltage is a poor indicator of how much energy a battery has left, for most kinds of batteries. If the voltage is very low, you can be sure the cell is essentially dead, and for an alkaline cell if it measures around 1.55 volts it's probably fairly fresh. But if you measure anything in between, you just can't tell the state of charge. Considering that the laser works ok on on other batteries, I'd be pretty certain that the cells in question really are nearly dead.

c_c

 

[Marduke]

Would these happen to be Toshiba Super Heavy Duty cells??

 

[TorchBoy]

I've noticed that super heavy duty cells - much more so than alkalines - can have a reasonably high resting voltage, but if they're a little old their voltage plummets when they're asked to do anything, even light jobs (no pun intended).

 

[Illum]

Toshiba doesn't make alkalines as far as I know. if it says anything like "0% mercury" or "heavy duty" on them its most likely a carbon zinc cell. These batteries are intended for low current consumption and using them in lasers or digital peripherals puts a heavy load on them and causes the voltage to sag, sometimes from 1.5V to 1V

it may appear as 1.5V open circuit but the minute a load is applied its no where near 1.5V. Your better off with Alkalines :thumbsup:
Cells like cr123a are essentially "dead" to lights would still have ~3V open circuit. you really shouldn't use measurable voltage as your only criteria in measuring remaining life of batteries

 

[ixfd64]

Thanks for the information. I was always uder the impression that lasers perform better when the batteries have a higher voltage. It seems that I was wrong.

By the way, I do think the batteries were indeed the Toshiba "super heavy duty" ones.

 

[Mr Happy]

Thanks for the information. I was always under the impression that lasers perform better when the batteries have a higher voltage. It seems that I was wrong.

No, they might indeed perform better. However, the voltage that matters is the operating voltage when the batteries are in the laser and it is switched on. If you were to measure that voltage you would find it is no longer 3 V. Every battery has a lower voltage when you pull current out of it to power something, and some batteries do better at keeping up their voltage than others. In general rechargeables do better than alkalines, which in turn do better than zinc-chloride cells.

 

[Curious_character]

This article might help you understand why battery voltage doesn't tell you as much as you might think. Especially note the graphs showing the voltages of both NiMH and alkaline cells. "Heavy duty" cells will be droopier than alkalines -- a lot droopier at high currents.

You can get a 12 volt battery that's not much larger than a shelled peanut. A car battery is also about 12 volts. The car battery can easily power a pair of automobile headlights. Would you expect the peanut sized battery to light them up too?

c_c