Quote:
Originally Posted by Andrew B
I found that PP3 batteries come in 2 flavours, one type contains pile cells and the other type has 6 "AAAA" cells inside.
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There are many kinds!
- Zinc layer cells (Only one kind, though some may be labelled "Chloride"
- Alkaline cells close enough to AAAA to fit an AAAA holder, slightly shorter
- Alkaline cells like AAAA but shorter.
- 6 rounded rectangle flat Alkaline cells, stacked, similar to button cell construction.
- Lithium Iron. No idea what is inside.
The layer cell type (1) at low current is better value, if shelf life isn't important as the cells fit case better than the common type (3) Alkaline. Much less difference in capacity than AA Zinc Carbon and Alkaline (which is about x2, the x5 life is special case).
The Rechargeable are again stacked "button cell" (NiCd and some NiMH) or NiMH similar to AAAA, but a little shorter.
The stacked type come in 6 cell (better capacity) or 7 cell (better voltage), i.e. 7.2V or 8.4V nominal for NiCd and 7.5V or 8.75 nominal for NiMH.
Capacity is terrible at low current draw compared to regular layer cell or Alkaline.
Use only Alkaline in Smoke detectors, intermittently used test gear etc.
Only use Rechargeable for motorised or things charged before use due to low capacity and high self discharge.
Unlike cylindrical based Zinc Carbon/Zinc Chloride vs Alkaline the Layer type are far better value for regularly used low current drain such as a transistor set or 45V to 90V miniature valve HT pack used regularly.