What is an AA cell capacity?

[ericmark]

I see standard, 70%, 100%, 150% and 200% extra, but what is the base line?

 

[jj4091]

I would have thought it woulld be 100%. Are you talking about mAh's

 

[JohnD]

I see standard, 70%, 100%, 150% and 200% extra, but what is the base line?

I think the baseline is the old zinc-carbon batteries that nobody uses any more.

It's disappointing that rechargeable batteries are marked with their capacity, and alkaline aren't

Though from my use in low-current devices, alkaline seem to last about four times as long.

The rechargeable are economical, but I have to change them much more often.

Which do comparative tests from time to time, and the Lidl and Aldi alkaline usually give most hours per pound.

Lithium are most expensive, but give the most power in a high demand device like a camera flash.

 

[denso13]

I think the baseline is the old zinc-carbon batteries that nobody uses any more.

Funnily enough my new wall clock a few years back was losing time and when I checked it advised zinc carbon only. Started using them and it hasn't missed a beat.

 

[Munroast]

I see standard, 70%, 100%, 150% and 200% extra, but what is the base line?

there can't really be a baseline ( a mAh capacity) for alkaline batteries as they are very load dependant, half the load and the same battery may last 3 or 4x longer.
Look up Peukerts Law, its particularly relevant to alkalines

I have seen ratings for them such as AAA 720 -> 1400 mAh as a guide, but if it was a tiny drain it may give 2000mAh

I once swapped a AAA for a D Cell on something that ran the battery down every couple of months - I have just went and cheked, that was nearly 4 years ago and it is still showing 1.31v

 

[JohnD]

Funnily enough my new wall clock a few years back was losing time and when I checked it advised zinc carbon only. Started using them and it hasn't missed a beat.

The voltage is slightly higher.

 

[ericmark]

The Leclanché Cell was originally a wet cell, it was adapted into a dry cell, and like the lead acid, there is nothing to stop it having a Ah assigned where we have the 10 hour rate or 20 hour rate, but it will without any use, slowly degrade, so it would need to have a use by date, to assign a Ah rate.

We call them an alkaline cell, which is a bit pointless as all versions are alkaline cells, but the chemicals have been changed, and lithium is used in the higher output cells.

There were some 1.5 volt versions of AA rechargeable cells, but these seem to have vanished, main problem was they needed a special charger, so in the main rechargeable are 1.2 volt, with old CB radios one had two shorting bars, so 8 x 1.5 volt, or 10 x 1.2 volt, but most items even if it could have 5 cells with rechargeable (secondary) and 4 cells with primary cells, this option is normally not given.

Since a cat flap is often fitted in a door, they don't seem to have the option of using a mains powered transformer, at least not this one. in my case door rarely used by us, so it could have been mains powered.

However, it does not matter, TRV, wall thermostat, cat flap, light switches we to decide, how much to spend on them, and we have a whole host of batteries with no real way to compare.

I tend to use expensive versions mainly to ensure they don't leak, but put them in a draw as not used whole pack, and a date of 03/35 on batteries bought today, means in real terms, we could be using 8 year old batteries which are still in date, but likely well past their best.

The problem is the more expensive cells, do not move in the retailers as fast, so they could be older.

5 volt USB is same voltage as 4 cells at 1.25 volts each, old cells 1.18 each, new 1.68 volts. So it would seem the flap could be USB powered, but to use rechargeable they would be rather fast become under voltage.

The flashing red was too late, by time it was flashing, it would not let the cats in.

 

[CountryFan]

Funnily enough my new wall clock a few years back was losing time and when I checked it advised zinc carbon only. Started using them and it hasn't missed a beat.

Funnily enough, as you’re probably aware, zinc batteries behave poorly in battery operated thermostats

 

[SUNRAY]

We have a number of clocks in the house using AA's and the first call for a replacement is always a Zinc due to their longer life. Added to them often being 12-16 for the same price as 8 Alkalines it makes perfect sense to me.

However It's increasingly difficult to find them for sale, Home bargains and Lidl have stopped the Kodaks and JCB's some time ago

 

[ericmark]

I had a temperature corrected pendulum clock that would drift with small batteries, but kept good time with large batteries, but most of my clocks, did not seem to mind what type used.

Main reason for expensive batteries was so they don't leak, the odd one out was camera flash, if the battery was too good, it could burn out the SCR, as when it fired it shorted out the battery for a very short time. Also had to be careful as some used a high voltage on the hot shoe, and could damage a DSLR camera.

I am sure the claims on 70%, 100%, 150% and 200% extra are correct under set use, but today there does not seem to be a standard battery, I know I use to buy them on the street market, but where I live now, no street market.

In the main the app shows battery level
But the icon

is rather small, and as to ¼, ½, ¾, or full, I would think it is looking at voltage, which can change battery to battery, this one actually shows battery voltage, but I have no idea as to how long a pair of cells will last when showing 2.59 volts, they will need changing soon, and that make needs a screwdriver to change them.

Even the Nest Gen 3 shows battery voltage

not sure why, as a rechargeable battery fitted and always on charge from the hub.