Thus spake Arfa Daily:
Snipped
The NiCad suggestion for a car battery is interesting. Apart from the
fact that NiCads are being phased out as part of the RoHS thing
anyway, I have seen it suggested that nickel metal-hydride batteries
could be used, as these are so good now, that manufacturers can
easily produce a 40AH 12v battery to fit in a car, and make it the
same size as the current lead-acid type. The trick is that you can't
make one that will do ten times the nominal max discharge rate, for
brief periods. Remember, that your starter motor, particularly if on
a diesel engine on a cold day, is looking for around 400A from that
battery ...

I ordered 18 Yuasa Pb 12V 7A/hr batteries from RS to repair the 2 server
UPSs at work with 2 spares set aside. ~£480's worth after volume discount.
Some UPSs do use NiCads & as has been mentioned, probably a high majority of
Pb from vehicle batteries gets recycled. However, how many PCBs get dumped
each year, with their lead straight into land-fills?

As for NiCads, I thought they were exempt from the RoHS directive (much to
my disgust). NiMH batteries aren't perfect though; their internal resistance
is higher, they won't take so many recharge cycles (as NiCads) & they
self-discharge more quickly. There greatest advantage is their energy
density (AAs up to 2.6A/hr & increasing). I hear the amount of cadmium is
tiny - albeit still toxic, so none is still an advantage.

http://www.batteryuniversity.com/partone-4.htm
Compares Ni batteries

For this reason alone, the lead acid battery, as the primary source of
stored electrical energy in a car, has been deemed an irreplaceable
technology, and as such, exempted from the RoHS directive. Because
lead-free solder makes crap joints, and is attempting to replace a
tried, tested, mature, and above all reliable technology, it is my
contention that this is irreplaceable as well. Sadly, I carry no
weight with the EU ...

I think you're right in the short term - learning curve & all that. I'm not
sure if lead-free is considered to be inherently less reliable but does
require better bonding of Cu onto glass fibre etc due to the elevated temps
& will be more problematical to rework.


I wonder if anyone has actually worked out the additional energy
budget, world wide, to run all those thousands of production solder
lines 50 degrees hotter, and all of the millions of hand soldering
irons. The overall pollution from that is likely to be, I think,
rather more seriously damaging to the planet, than the small risk of
environmental or personal poisoning from a leakage of the tiny lead
quantity in solder, into the ecosystem, particularly if proper
recycling mandates and procedures are in place.

the world as a whole faces 2 environmental challenges. Fresh water & energy
production. Electronics does use vast amounts of water during production & I
suspect legislation for factory based recycling will increase. Power
generation is another one. We will have to get used to using much less.
Trying to calculate the increase in power caused by Pb-free solder in
production is too complex when you factor in stuff like gains by LCD panels
over CRTs, when you factor in the energy used by disposing of those CRTs,
transportation...