Battery

[mstechca]

I am going to try another approach with my radio.

I have went through 4 dead batteries, and each one that I have used has turned my radio (after a few seconds of opeation) into an high-pitched oscillator that slowly decreases in pitch.

This makes me think that low voltage is not a good way to go.

I have been buying low priced batteries from the dollar store in the past, and I wonder if I could get at least 6 hours of operation out of them. It would be a royal pain for me to buy the more expensive (duracell, energizer, etc) batteries and find out they die after 1 hour.

My radio does not use alot of current. The absolute highest current consumption would be about 20ma because I am feeding the voltage to the LED through a 470 ohm resistor. All the other pull-up resistors have higher values.

so what is the best 9V square battery to buy if I am looking for long time voltage stability?

 

[bloki]

First check your radio current consumption. Current consumption has to be below 50mA. If battery is dead after few seconds radio can have some fault.

 

[mstechca]

According to the worst case scenario, the current consumption is just under 25ma. This result came from determining all pull-up resistors in parallel.

I doubt it will be that high, because my radio also has a couple of pull-down resistors.

 

[bloki]

Dont take calculations. Measure current from battery. At 25mA battery can not get empty after few seconds. Maybe your batteries were allready dead.

 

[audioguru]

I've seen the Chinese batteries at the dollar store.
How old are they? It's a long boat trip plus warehousing time.
What's in them? Some say "alkarine". What's that?
Some have a gold top like a Duracell, but it is only paint.
Don't they leak?

You get what you pay for.
If Energizer still made their cheap "Classic" (the red one) carbon-zinc 9V battery, a new one would supply 25mA for only 5 hrs at 25mA. They haven't made them for years but I still see them in stores. What is the shelf life of a carbon-zinc? 1 year?

An Energizer alkaline 9V battery supplies 25mA for about 25 hrs and its shelf life exceeds 5 years.

An Energizer lithium 9V battery (I haven't seen them in Canada, but their AA cells are great) supplies 25Ma for about 70 hrs and its shelf life exceeds 20 years.

Go to www.energizer.com yourself and look at their battery spec's. :lol:

 

[Klaus]

Dont take calculations. Measure current from battery. At 25mA battery can not get empty after few seconds. Maybe your batteries were allready dead.

Yes, and measure it with the volume set at your usual level as well.
You can't realistically 'calculate' the power drain of something that uses a speaker (or headphones).

 

[ljcox]

If your radio oscillates when the battery goes down a bit, then it may need a bypass capacitor.

Try a 10 uF or greater electrolytic across the power rails. You may also need a 100 nF in parallel with it since electros have relatively high ESR.

Len

 

[Joel Rainville]

If Energizer still made their cheap "Classic" (the red one) carbon-zinc 9V battery, a new one would supply 25mA for only 5 hrs at 25mA. They haven't made them for years but I still see them in stores.

Are those still stocked at the big Z stores in Canada?

I buy cheap Panasonic "Super Heavy Duty" 9 volts at the dollar store, and I seem to get pretty decent life out of them. The one I am using right now is stamped 2009, so they look pretty recent. Might not be the case of all cheap 9 volts... especially at Dollaramas!

But I think we're just kidding ourselves by buying cheap 9 volts. A decent alkalyne isn't $5 and I wouldn't be surprised if they lasted at least 5 times longer than the $1 cheapies in most of my applications...

 

[audioguru]

If your radio oscillates when the battery goes down a bit, then it may need a bypass capacitor.

Hi Len,
His "radio" is a super-regen. It is supposed to be a blocking oscillator at an ultrasonic frequency, but maybe MStechca has its frequency set a little low, and maybe the frequency of the blocking decreases with reducing battery voltage.
The design of a regen uses positive feedback of the RF signal to increase its sensitivity and reduce the bandwidth of its single tuned circuit. The "super" part is the blocking oscillator which cuts-off the RF just after it creates RF oscillations. They call the blocking oscillations "squegging". :lol:

 

[audioguru]

I buy cheap Panasonic "Super Heavy Duty" 9 volts at the dollar store, and I seem to get pretty decent life out of them.

Hi Joel,
I looked at Panasonic's website and played their stupid car-race game to try and win some of their new Oxyride batteries. I got my race car up to 180mph in the dark tunnel. I also hit just about every obstacle they had!
Anyway, they don't have any spec's for their new batteries and the only spec's for their Super Heavy Duty ones are dimensions, weight, and that the blue ones are made in Indonesia and the black ones in Japan. They are (old-fashioned) carbon-zinc.

I haven't seen Panasonic batteries at the dollar store. Many of the Chinese batteies there are leaking in their packages. :lol:

 

[eblc1388]

Come to think of it, now its year 2005. New designs, nano technology....

And we still have to put up with battery leaks. Many things contain liquid don't leak, why is that so difficult to package batteries that doesn't leak?

The most annoying thing is to find out that your equipment damaged by a leaking "leak proof" name branded battery.

 

[Joel Rainville]

I haven't seen Panasonic batteries at the dollar store. Many of the Chinese batteies there are leaking in their packages. :lol:

I'm pretty sure they use that brown-gold color on purpose for their batteries so you can't spot the leaks too easily

My Panasonics Super Heavy Duty are the black ones, marked Panasonic Ind. Co./Panasonic Canada Inc./Made in China S-006PNP...

 

[Nigel Goodwin]

And we still have to put up with battery leaks. Many things contain liquid don't leak, why is that so difficult to package batteries that doesn't leak?

The most annoying thing is to find out that your equipment damaged by a leaking "leak proof" name branded battery.

Batteries generally leak because they are flat, the chemical action in a conventional battery eats through the casing once it's gone flat.

Most leaking batteries are caused by allowing the batteries to go flat, OR by mixing different types and makes of batteries, OR even more so, mixing old and new batteries. You should NEVER do any of the above!.

Alkaline batteries only very rarely leak, and conventional batteries are so poor anyway, I would suggest ALWAYS using alkaline ones.

 

[audioguru]

I'm pretty sure they use that brown-gold color on purpose for their batteries so you can't spot the leaks too easily

He, he. Yeah man! :lol: :lol:

My Panasonics Super Heavy Duty are the black ones, marked Panasonic Ind. Co./Panasonic Canada Inc./Made in China S-006PNP...

Panasonic tells lies on their website.

When were carbon-zinc batteries invented? A couple of centuries ago? :?: