whats the difference between heavy duty and alkaline batteries

I went to buy some batteries today (AA) and i noticed there were 2 kinds. Alkaline and heavy duty. What is the difference? the heavy duty ones were cheaper but i got the alkaline for fear of damaging my equpitment if i’d used heavy duty.

Can you use either in any device that requires batteries or must you stick to alkaline.

“Heavy duty” is a meaningless marketing term. Those batteries are good old carbon-zinc. Just like the ones that leaked and ruined all you cool toys in the 50s. “Heavy-duty” was invented back then to imply a better grade of carbon-zinc batteries.

For almost all applications, alkalines are better than carbon-zinc.

FWIW, I noticed a package of cheap alkaline-looking batteries at the store the other day. Nowhere did it say “alkaline” on the package. I.e., carbon-zincs in sheep’s clothing.

Consumers Reports has tested batteries over the last 20 years.

Results: Always buy alkaline batteries, and the brand makes NO difference.

I’m going to disagree slightly. Off-brand batteries are often made with inferior ingredients, and also tend to sit in warehouses longer. Overall, they don’t last quite as long as major brand alkaline batteries. However, my experience has been that all major brand batteries roughly perfom at the same level.

“Heavy duty” and alkaline batteries only have slightly different chemistries, and slightly different open circuit voltages. Both are very close to the established ‘label voltage’ of 1.5v for the carbon-zinc wet cell (Leclanché, 1868) and later the carbon-zinc dry cell (Gassner, 1888). By comparison, the cell voltage of a lead-acid battery is ~2.0v, and Nicad cells run about 1.4v

However, there are significant differences in practice - mostly length of life (Alkalines last 4-9 times as long), current disscharge properties (alkalines supply more current for longer), voltage drop-off with use (“Heavy duty” drop off gradually as they are drained; alkalines keep a higher voltage until they are nearer their end of life, and then drop off) etc. Sometimes a device requires a certain voltage to operate, and the gradual voltage drop-off of a “heavy duty” cell causes it to fail even when it has significant charge left in it. Therefore, a heavy duty battery that ‘died’ in 10 minutes in one device, may still work fine in others

The term “heavy duty” is a misnomer. It was “heavy duty” in the 60s when I was born (and probably well before) but only in comparison to the older cells. Today, it should be called “pathetic underachiever” but somehow the makers are slow to make the change.

The “regular duty” dry cell was basically a Leclanche cell that mixed the electrolyte into a slurry with black manganese dioxide instead of using a plain liquid. The electrolyte was a slightly acidic mixture of ammonium chloride [and some zinc chloride], and actually had an ‘open circuit voltage’ of 1.55v, that settled close to 1.5v under load.

The anode (- end) is actually the zinc casing itself (hidden under steel end plates for durability and a protective paper shell) The cathode (+ end) is a carbon bar, inserted into the electrolyte, and sealed with insulating wax, to make both sides of the cell accessible from the outside, without shorting out the cell… Some of the zinc in the casing is consumed during use, so a heavily discharged dry cell may ‘break through’ and leak if left in the circuit

(The terms cathode and anode may seem reversed here. That’s because battery designers use + and - relative to the cell chemistry, not the voltage supplied by the battery - or so I’ve read. It still seems silly to me.)

The ‘heavy duty’ battery changed the primary electrolyte to zinc chloride resulting in a slightly higher open cell voltage (~1.6v), and held its voltage better under load, as well as having a longer life (more pronounced under under heavier loads than light loads)

Despite the way the term is used in advertising, alkaline cells are actually chemically carbon-zinc cells with a somewhat improved [predictably, more alkaline] electrolyte. They have a slightly higher open cell voltage, more storage capacity, and less voltage drop during the main part of the discharge curve, but most of its benefits actually come from improved construction.

The casing of an alkaline cell is just protective. The Anode is a gel of zinc and KOH (a potent alkali) inside a polyester cylinder in the middle of the battery. The gel is connected to the external - terminal by a brass spike. The cathode is a shell of carbon+manganese dioxide slurry between the polyester cylinder and the outer casing.

Alkaline cells can last 4-9 times as long as “heavy duty” cells (depending on the application) and have a better discharge curve (they lose less voltage as they are discharged, then drop of more at end of life]. They can’t be recharged (they tend to explode) while the heavy duty cells could be mostly recharged a few times. Standard and heavy duty rechargers were common in the 1970s, though recharging was always recommended against by the manufacturers, because of the risk of leakage/bursting after erosion of the zinc casing, and lost profit from erosion in new battery sales.

However, the Renewal cell (Rayovac) is actually a carbon-zinc cell that is designed to be recharged 25-100 times (using a microprocessor-based recharger). A nicad battery can be recharged 1000 times ideally but its chemistry has a lower open cell voltage of about 1.4v, which is fine for many applications, but won’t work in others. (Carbon zinc cells don’t reach 1.4 until they are mostly dead) Since few people recharged Nicads that often except in specialty uses like laptops, and nicads had other issues, the Renewal was considered a viable alternative to NiCad.

NiMH [Nickel Metal hydride] rechargeable cells have more capacity than NiMH but have an open cell voltage fo ca. 1.2 v - not suitable for many applications. For this reason many devices specify alkaline cells (heavy duty should work, due to the similar open cell voltage, but they’ll have a much shorter life

Motorcycle, car and UPS batteries use 3 or 6 lead acid cells (2v each) in series to achieve their rated voltage of 6v or 12v; the rectangular 9v “transistor” battery contains six 1.5v batteries in series inside it. You may have never seen a “B” cell, because in the US, it was a stacked series of cells that added up to 45-90v, and was used for vacuum tubes. It’s called a B cell because “B voltage” was an existing term in vacuum tubes. In Asia, however, there was a B cell that was about as long as a D cell, but narrower than a C cell. Kind of like a supersized A cell. I have one, but it’s been dead for 20 years.

Don’t even get me started on the Lead-acid gel cells, and the various lithium technologies

Ditto on the off-brand alkalines being inferior. Bought some of Wal-Greens alkalines last year and they didn’t last more than a couple months in remotes. In remotes!

While many discount batteries come from the same factories that make the name brands, not all batteries coming out of a factory are of the same quality. The good ones get the name brand labels, the poor ones get the generic labels. Life is a bell curve.

In fact, each of those six cells inside a 9 V battery are AAAA size cells, and can be separated and used as such. Not that AAAA is terribly common, but if you need them, that’s one source for them.

*Originally posted by ftg *

Probably just a single instance of a problem.

do you know that for a fact? How?

Oh, please. What are the odds of ftg grabbing the one bad set of batteries on the shelf? In any case, he said remotes, as in more than one. Obviously this was not a single occurrence.

Since we’re into using anecdotal evidence as proof, I submit the following.

I’ve bought Walgreens alkaline batteries as well as Energizer batteries from the same source(Walgreens) over the last 5 years. My kids and I have used them in portable radios, CD-players, remotes, etc. I have yet to notice a difference.

Your mileage may vary. MIne didn’t. And I’m talking about 100 assorted AA/AAA/D cells over a five year period.

Therefore, I submit there is no difference. Since I, no doubt ,used MORE batteries in the time period in question, that lends MORE weight to my evidence.

QED

Jesus KP. Can you fill me in with more info on rechargable batteries? I use a CD player when exercising and it burns through AA’s really fast so i am wanting to buy some rechargables.

Should i get the Renewal cell alkaline type?

Again, from Consumer Reports.(2002)

Rechargeable NiMH batteries are the most economical overall. Make sure your player can use Nickel-metal hydride batteries. And the charger costs about $30 or so. But, in the long run, it’s the most economical.

Nooooooo! Those things are pure crap. Invest in a good set of NiMH cells and a charger. Preferably an overnight trickle charger, as these don’t overheat the batteries causing loss of capacity. Rapid chargers cause too much heating which can shorten the useful life of the batteries for both NiCd and NiMH types. NiMH cells are a bit more expensive, but they exhibit a higher capacity and longer useful life than NiCd cells. Plus they are less picky about recharging conditions.

So KP what type of batteries were you using to write your post?

:smiley:

KP said NiMH only provide 1.2 v when a 1.5v battery is needed. 2 AA batteries would only get 2.4v from NiMH batteries so i dont know if that would work.

Do NiMH batteries work on a CD player?

Yes, most of the time they do. He was wrong about NiCds however. They have an open-circuit cell voltage of 1.2 V also, not 1.4V.

What about batteries labeled “industrial use only: not for consumer sale”? They seem much heavier than alkaline batteries.

Anecdotally, I seem to notice that OEM jap cells (included) with remotes or other devices seem to last a HELL of a long time compared to domestic brands, it’s not unusual (for me) for them to last several years. Anyone else ever notice that?

I’m struggling to think of devices that would benefit from using standard carbon-zinc cells or be preferable compared to alkaline and can’t think of any, especially the way modern electronic devices suck the current with all the bells and whistles.

adding to the above Consumer Reports said that name brand alk. bats. do last longer then no-name ones BUT the cost of the name brand does not justify the extra run time.

This has been my experence with a gps that has a battery timer where I would get apx 19h ± 45min with name brand and 18h ± 1h30min with no name brand.

A really good charger (Like the SAITEK Eco Charger) is worth the coin you spend on it.

It will recharge Alkalines and Carbon Zinc ones too. As long as they are not too dead.

Re: Rechargables: I just buy the cheapest I can find. When they crap out, I re-cycle them at the battery depot.

I buy the cheapest alkaline too, except I always have 1 set of lithium AA and 1 set of Energizer e2 AAA’s around, in case it HAS to work.

But get a good charger. It makes a difference.

Phil

(Who, when his shaver died, took it apart and salvaged 2 good AA rechargables, and is still using them!)