From DIYWiki
Revision as of 23:37, 19 July 2008 by NT (talk | contribs) (→‎Computers: pic)
Jump to navigation Jump to search
D, C, AA, AAA, PP3 & button cells


historic name for a rechargeable battery. More or less always refers to lead acid.
A battery means a quantity of cells used together. These may be housed in one container, such as with 6v and 9v consumer batteries, or they may be separate containers only electrically connected, as is common with large lead acid installations.
Total output ability measured in amphours, current x time.
a single electrochemical unit producing electricity, usually from 1.2v to 3v (commonly 1.5v).
C/20 etc
charge rate. C/20 means capacity divided by 20, C/10 means capacity divided by 10 etc. Eg C/10 charge rate for a 1Ah battery would be 100mA.
one charge & discharge
Deep discharge battery
lead acid battery optimised for deep discharge applications
taking power from the cell
Dry cell
Historic term for zinc carbon cells. Today there are also other dry types, so usage of the term sometimes refers to these as well.
the liquid, gel or paste in the cell
Energy density
amount of energy stored per weight
Float charge
low current charge to keep battery topped up. See trickle charge
Emission of liquid content from the cell. Zinc carbon and zinc chloride are prone to this. Leaked electrolyte is corrosive.
Primary cell
non-rechargeable cell
Secondary cell
rechargeable cell
Sealed lead acid.
Starting battery
lead acid battery optimised for engine starting, eg car battery
Trickle charge
very slow (low current) charge. See float charge

Battery chemistries

Zinc carbon
low cost, can leak.
Zinc chloride
improved performance version of zinc carbon
greater capacity than zinc carbon. However high drain apps dramatically reduce the capacity they can deliver. Ill suited to high drain use (ironic that they're marketed for this).
Not prone to leakage
Longer shelf life than ZnC
Ideal for low to medium drain apps, where they can give much longer service life than ZnC.
long service life of upto 10 years if drain very low. Capacity and price both much higher than alkalines. 3v per cell.
Lead acid
Rechargeable, typically heavy high capacity batteries.
Sealed lead acid (SLA)
Spillproof lead acids.
NiCd (nickel cadmium)
Popular rechargeables, small light low capacity
NiMH (nickel metal hydride)
As nicad, but higher capacity & cost, and require NiMH chargers
Iron carbon
DIYable batteries. Indefinite storage dry, short lived when wet. Power backup, camping etc
Silver oxide
Coin cells, 1.4v per cell
Li-ion (lithium ion)
Most expensive type of rechargeable with high energy density. Used in laptops and very few cordless tools.

Coin cells


Widely used in PCs, watches, and miniature battery appliances. The smaller ones are also known as button cells.

With tiny capacity and max load current, these cells are only suited to micropower uses.


3 types of chemistry are popular in coin cells:

  • alkaline - 1.5v per cell, lowest cost
  • silver oxide - 1.4v per cell
  • lithium - 3v per cell, highest cost

Common sizes

There are a large number of sizes still in production. A small range are much more popular than the rest, and are listed here. If you don't know what battery is needed, these are the first to look at.

Nearly all these battery sizes have various other names as well.

Most popular

  • AAA 1.5v
  • AA 1.5v aka penlight
  • C 1.5v
  • D 1.5v
  • PP3 9v
  • PJ6 6v - spring top lantern battery

1960s & 70s appliances

4.5v 3R12
  • PP6 9v
  • PP9 9v
  • other PP sizes are occasionally seen, eg PP7, PP10, PP11
  • ? 3v
  • 3R12, 3396? 4.5v, strip terminals

Cordless tools

sub-C Nicad 1.3Ah - 2Ah



CR2032 (3v lithium) is the most common BIOS battery in desktops. These retain BIOS settings when mains is unplugged.


12v 30-60Ah lead acid battery, either round or flat posts.


  • AA 1.5v
  • 123 3v
  • CR2 3v

Burglar alarms, UPSes

Sealed lead acid, 6v or 12v, various capacities


  • AA
  • PP3
  • N

Battery capacity

These are typical figures only, in real life capacity varies according to brand and use conditions. Ref

          alkaline   nicad
N    1.5v  1Ah
AAA  1.5v  1.2Ah
AA   1.5v  2.8Ah     0.7Ah
C    1.5v  8Ah       2 Ah
D    1.5v  20Ah
PJ6   6v   26Ah
PP3   9v   0.6Ah     0.2Ah

Note that although alkaline cells have higher Ah ratings than nicads, they perform poorly in high drain apps, and nicads give more time of use in these apps. capacity Ref


See Also