Originally Posted by Sebach
Well, the effect on my Pb/acid battery's run time isn't so extreme that I need to stick the coke bottle-sized mofo in my jacket. Besides, I'm sure the sulfation process taking place right now will increase the exothermic properties of the cells during discharge as a function of increased resistance, thereby keeping my battery warmer, muhaha, it's a win-win situation! Not really, but I like saying it is.
All in all, I'd say that of my available choices for power sources (NiCd, NiMH, Pb/acid, Li-ion), taking into consideration the conditions of use (high drain, cold temps, weight being no issue) I'd have to go with either Li-ion or Sealed Pb/acid cells. NiCd are cheap and can handle high drains great but they do horribly in cold temps. NiMH don't suffer the memory effects of NiCd and can hold more charge but they can't handle the high drains. Li-ion has an awesome charge-weight ratio but I'm not sure how long it can sustain a constant current in cold conditions.
So here's my vote (preferred to least):
1: (tie) Li-ion, Pb/acid (Li-ion gets vote for LED light or Xenon, Pb/acid for Halogen)
2: NiMH (awesome if you need a single Christmas light for a couple hours)
3: NiCd (awesome if you need a batsignal for 2 seconds, bad if you need it for 5)
Any thoughts?
I've never used Li-ion but I have used Pb/acid, NiMH and NiCd. I find the NiMH to be a very poor performer in anything below about 35F and they tend to be rather delicate. I've also used Pb but found it to be a poor performer too as well as not being that rugged either. I do find the comment about NiCd being a poor cold weather performer to be curious since that's all that I use. Most of the stuff that I've read about them also state that they work well down to -40F. I do charge and store my batteries indoors and take them out to the bike just before I leave but I don't put them anywhere special on the bike and I certainly don't put them under my jacket. I do have 2 7Ahr NiCd that do very well during the cold but that might just be a function of their mass.