Batteries? (Laptop, Cell Phone, Consumer Electronic)
 

There's a lot of conflicting information out there about batteries. So I'd love for someone with some sort of knowledge (or perhaps better Googling skills than I) to set me straight.

I'd like to split this into 3 categories:

• Laptop (Lithium Ion)
• Cell Phone and other consumer electronics like iPods (Also Lithium Ion)
• Rechargeable AA/AAA/etc (NiMH)

Below are the statements I'd like to prove/disprove for each battery but, if possible, I'd love a source. Sure, "sterlingice is a battery engineer" or "sterlingice works in the R&D division for Samsung and talks to the battery guy a lot" (I am neither) are great sources. But I'm tired of hearing the guy at Best Buy trying to sell cell phones, pulling crap out of his ass. I'm looking to try and figure this out with actual facts.

• Lots of batteries advertise X number of recharges. Does that mean you want to run them down to 0% before recharging them since you are limited on your refills. Or is that 400 times for each "piece" inside the battery? So, maybe today, you use battery sections 1-4 on your camera and tomorrow 5-8. If you refill, are you using 1-4 again? Or is there even that level of granularity within a battery?
• But I thought draining a battery down to 0 was bad? I thought it started diminishing the capacity of the battery when you did that. Is this only true if you really, really, really try to drain it like keep taking pictures after your camera has been warning you for 20 photos to change the battery or leave that flashlight on until there's nothing left? Is this even true at all?
• A lot of cell phone places love to talk to you about an initial drain. Drain it to 0, they always say- just so your battery knows how far it can drain. Does a battery have some sort of memory? Doesn't that contradict the previous point about draining things down to 0 being bad?
• What about plugging an item to charge it? I'm not talking about my laptop where I use it plugged in most of the time- I can see that once it's at 100%, it says it's no longer charging the battery and just running on the cord. But how about my phone? I bring it home each day and toss it on the charger, whether it's at 20%, 40%, or 80% so it's at 100% the next morning. Does this shorten my battery life because of the X number of recharges? I suppose this could be cleared up with #1 answered.

So, there we have it. Anyone here a battery guru or know of a nice battery board where these questions have been answered.



SI

Can't offer a ton, but it seems that much of the info that people share is factually incorrect. So good luck in your fact finding. I'll see if I get time to help.

I'll try and make this as to the point as possible. I don't quite understand all the chemistry of it all, but I do have a good idea of understanding.

I'll start with NiCad batteries, the first rechargeable batteries. They were subject to memory issues and if they were constantly recharged the overall usage was much less then if they were allowed to drain out. They were effective but the capacity wasn't all that great, hence the need to constantly recharge.

They were succeeded by NiMH batteries that had 3 to 4 times capacity and were not subject to memory issues. The biggest issue with NiMH was the discharge rate just after charge was quite high on day 1, and slowed after. They are subject to the problem of max discharge destroying the battery (I didn't know this until I read up on it) as the batteries can change polarity trying to keep up. Some electronics like cameras have built in safety guards to help prevent this from happening.

All cell and laptop batteries are Li Ion. They are very high capacity and not subject to memory either, but they do like to be recharged as much as possible to extend the usage cycles on the battery. They are mostly damaged by heat, such as a laptop plugged in will generate heat and can cut the expected life of the battery in half. Li Ion batteries are also exceptionally dangerous outside of the units they are meant to go in. The contacts can short and cause a thermal runaway of the batteries that will feed on itself and is very hot. Water makes it much worse, Ice does the trick.

I'll add this site with lots of info.

Battery Information Table of Contents, Basic to Advanced

Wow! Thanks for the site and the advice, PM!

SI

Okay, since the topic is batteries, here's one that stumps me. How is it that even though I have never seen a car parked in front of either store, my town apparently can support not one, but two retail chains that sell nothing but batteries?

Heh...

I have a similar question about the one in our town.

No idea either. Stubborn old owner who refuses to shut down cause he has a ton of inventory?

Battery retailers are largely supported by commercial accounts that buy dozens of batteries a week.

One other tidbit to add. There is a company in Charlotte, NC (cellguard) . That makes battery components, specifically for cell phone batteries. I used to do significant work for this company as a sub contractor. I learned from asking the same question of one of their engineers one of the reasons for "memory" and for life span.


As I am sure we all know a battery makes electricity by mixing a Chemicals, and specific metals. The rate of this reaction is controlled by a membrane (that is what this company makes) the memory is because if the electrolyte level stays against this membrane long enough at a given level it actually degraDes the membrane while the remaining portion is still in tact. This degraded portion no longer reacts in either direction, likewise when a battery reaches e end of its useful life it is frequently mbecause this membrane has broken down to the point that it can no longer regulate this chemical reaction.

Anyway maybe common knowledge or not interesting to anyone else but I found it interesting.

It's possible that something like hearing aid batteries could be paying the bills, especially if they deliver. Maybe hover-round type batteries as well?

Just as a side note, lithium batteries have been linked to at least fatal 747 crashes in the last 2 years. Thermal runaway is really dangerous.

money laundering?

I've always wondered how many businesses I see around town which seemingly do no business but have stayed in business forever are just fronts for some sort of criminal activity.

SI