building with a C10 or even better C20 charge would give the longest use of these and then once in a while hit them with a C1 just to wake up the wiskers :-) Wikpedia is very good at giving a global overview, but would be best to find an manufacturer and ask for specifics.
Still waiting to hear what Bribe is needed to get one of these:-<>.. Cheers Bruce S
[ Parent ]
You should never charge a sub C or D battery that hard because you can't add water.
Correct me if i'm wrong, most of the heat is from the recombination of the O2 and H2 during the charge, since the amount of reconbination is the same whether you charge it fast or slow, (within reason, the increased voltage due to cell resistance will increase gasification), the small chargers just assume that if you keep the temperature down, then the internal cell pressure can't be high enough to vent the cell. With vented cell types, there is an order of magnitude less recombination.
Also, the battery should cool upon charging, until it hits end of charge and the oxygen is consumed in the catalyst. This is not necessarily the case for all batteries, the internal resistance varies considerably between manufacturers, for instance, some Nicds can discharge 50C, others are rated only 10C or less. http://www.mpoweruk.com/nicad.htm www.battcon.com/PapersFinal2005/MeisnerPaper2005.pdf
BTW Nimh chemistry is 66% chemically efficient on charge, and Nicd is ~55% on a 16 hour charge, and ~80% on a fast, ~2 hour charge. Both of which lead acid can beat.[ Parent ]
When building or designing for NiCds the best way would be to use the negative slope method. NiMh have this slope too, but not as easy to detect.
Cheers Bruce S[ Parent ]
If you only discharge the first 40%, I bet you could get the efficiency up. This doesn't apply to NIMH though, speaking of which why do they put these in hybrids? they should use NiCds. [ Parent ]
