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Groups > comp.sys.mac.system > #52945 > unrolled thread
| Started by | J Burns <burns4@nowhere.com> |
|---|---|
| First post | 2013-12-04 16:24 -0500 |
| Last post | 2013-12-19 18:59 +1300 |
| Articles | 20 on this page of 83 — 17 participants |
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Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-04 16:24 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 16:38 -0500
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-05 11:01 +1100
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
Re: Why not NiMH? Mike Lane <mike.lane.usenet@ntlworld.co.uk> - 2013-12-05 13:21 +0000
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 09:01 +1300
Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 05:21 -0500
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 09:07 +1100
Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 18:42 -0500
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 11:57 +1100
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:34 +1300
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 17:08 +1100
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 19:19 +1300
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 20:14 +1100
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 13:30 +1300
Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 12:00 +1100
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:24 +1300
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 19:50 -0600
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 15:11 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 16:15 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-04 19:59 -0500
Re: Why not NiMH? Ted Lee <tmplee@mr.net> - 2013-12-04 22:09 -0600
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 00:54 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 00:59 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 02:22 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 02:44 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 03:36 -0500
Re: Why not NiMH? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2013-12-05 04:21 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 16:24 -0500
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 18:37 +0000
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 14:19 -0500
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 13:31 -0600
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 09:07 +1300
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 14:36 -0500
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 22:02 +0000
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 13:26 +1300
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 00:33 +0000
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:36 +1300
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:22 +0000
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 11:49 +1300
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-07 00:11 +0000
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 18:07 +1300
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 08:37 -0600
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 09:52 +1300
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 19:49 -0600
Re: Why not NiMH? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2013-12-05 21:55 -0500
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:40 +1300
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:24 +0000
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 11:49 +1300
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-06 18:43 -0500
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 08:32 -0600
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 09:50 +1300
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 15:50 -0600
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 14:04 +1300
Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 21:02 -0600
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 17:45 +1300
Re: Why not NiMH? Lewis <g.kreme@gmail.com.dontsendmecopies> - 2013-12-06 17:48 +0000
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:25 +0000
Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 05:33 -0500
Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 18:35 +0000
Re: Why not NiMH? Zar Zifodow <zarzifodow@mailinator.com> - 2013-12-04 20:14 -0800
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
Re: Why not NiMH? Siri Cruz <chine.bleu@yahoo.com> - 2013-12-04 20:46 -0800
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 02:22 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 02:44 -0500
Re: Why not NiMH? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-12-04 23:08 -0800
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 03:08 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
Re: Why not NiMH? me@home.spamsucks.ca (Király) - 2013-12-05 14:15 +0000
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 12:43 -0500
Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 12:54 -0500
Re: Why not NiMH? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-12-05 22:44 -0800
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-06 13:19 -0500
Re: Why not NiMH? me@home.spamsucks.ca (Kiraly) - 2013-12-06 22:35 +0000
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-07 02:27 -0500
Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-08 00:10 -0500
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-14 18:57 +1300
Re: Why not NiMH? Fred Moore <fmoore@gcfn.org> - 2013-12-17 12:04 -0500
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-18 09:27 +1300
Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-19 18:59 +1300
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| From | Jolly Roger <jollyroger@pobox.com> |
|---|---|
| Date | 2013-12-06 21:25 +0000 |
| Message-ID | <bgetm0F4mpfU3@mid.individual.net> |
| In reply to | #53035 |
On 2013-12-06, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote: > In message <bgbvg4Fg4nsU2@mid.individual.net> > Jolly Roger <jollyroger@pobox.com> wrote: >> On 2013-12-05, J Burns <burns4@nowhere.com> wrote: >>> On 12/5/13 12:59 AM, nospam wrote: >>>> In article <l7p4em$siq$1@dont-email.me>, J Burns <burns4@nowhere.com> >>>> wrote: >>>> >>>>> My modem and ATA have wall warts for 12VDC. When I went to VOIP, I >>>>> bought 50 feet of zip cord, red on one side to identify positive. I put >>>>> connectors for my modem and ATA on one end and alligator clips on the >>>>> other for my car battery. Now I have phone service when the power is >>>>> out. If I had a laptop, I could check the power company's site and of >>>>> course comp.sys.mac.system. >>>> >>>> or you could buy a ups and run more than only 12v devices. >>>> >>> Some people get only 2 years from UPS batteries. The run time is >>> usually minutes. My last car battery lasted 13 years and gave me all >>> the phone time I wanted in power failures. > >> Uh huh... > >> The rest of us get 5-8 years from our UPS batteries, and size the UPS >> units to give us longer run times. It's always best to use your brain >> when making purchasing decisions, eh? > > The UPS I have my router and cable modem and switch on can run them for > at least 4 hours, maybe more. > > The UPS I have my iMac on can run it for at least an hour, though I will > lose the second screen and the external drives. Nice! >> BTW, I can run my Mac Pro for a full 30 minutes during power outages before >> running out of juice, and my internet connectivity is unafected by >> outages, all thanks to a UPS. > > Also, UPSs generally clean up the power, so your devices last longer > even without power failures. Indeed. That's another benefit of using UPSs. -- E-mail sent to this address may be devoured by my ravenous SPAM filter. I often ignore posts from Google. Use a real news client instead. JR
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| From | Davoud <star@sky.net> |
|---|---|
| Date | 2013-12-05 05:33 -0500 |
| Message-ID | <051220130533190041%star@sky.net> |
| In reply to | #52953 |
Ted Lee: > My laptop works just great in a power failure. > Problem is, my wifi and DSL don't! I have one of these <http://www.generac.com/Residential/GuardianSeries/>, 20kW, and also one of these <http://preview.tinyurl.com/vzw-jet>. No problems. -- I agree with almost everything that you have said and almost everything that you will say in your entire life. usenet *at* davidillig dawt cawm
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| From | Jolly Roger <jollyroger@pobox.com> |
|---|---|
| Date | 2013-12-05 18:35 +0000 |
| Message-ID | <bgbvblFg4nsU1@mid.individual.net> |
| In reply to | #52953 |
On 2013-12-05, Ted Lee <tmplee@mr.net> wrote: > On 12/4/13, 6:59 PM, J Burns wrote: >> >> A laptop might be nice in a power failure or for occasional portability. >> If I ran a lithium battery down in a power failure, I'd be out of >> luck. My NiMH charger uses a 12V wall wart, which means I could hook it >> to a car battery to provide charged cells to run a laptop indefinitely. >> > > My laptop works just great in a power failure. > Problem is, my wifi and DSL don't! So put them on an uninterruptible power supply (UPS). Problem solved. When my power goes out, my internet connectivity is uninterrupted. ; ) -- E-mail sent to this address may be devoured by my ravenous SPAM filter. I often ignore posts from Google. Use a real news client instead. JR
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| From | Zar Zifodow <zarzifodow@mailinator.com> |
|---|---|
| Date | 2013-12-04 20:14 -0800 |
| Message-ID | <l7ouim$6qg$1@dont-email.me> |
| In reply to | #52950 |
On 12/4/13, 4:59 PM, J Burns wrote: > On 12/4/13 4:38 PM, nospam wrote: > Apple says a battery will last the most years if you discharge it about > 50% each day and recharge. What a hassle! If you leave it plugged in, > or unplug it and leave it charged, capacity will decline. If you leave > it discharged, you may be unable to recharge it. You made that up, didn't you.
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| From | nospam <nospam@nospam.invalid> |
|---|---|
| Date | 2013-12-04 23:38 -0500 |
| Message-ID | <041220132338257109%nospam@nospam.invalid> |
| In reply to | #52950 |
In article <l7oj51$k05$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > > you aren't actually suggesting making a laptop to run on a bunch of aa > > eneloops, are you? > > You caught me. I'll admit it. That's what I was suggesting. i don't think you've thought through all of the downsides, or realize how good lithium ion batteries are. what you're describing is *not* marketable. > > right now, a macbook air can get as much as 15 hours of run time on one > > charge, all in a 2 pound laptop. there's no need to worry about running > > low. > > > > using aa batteries would be more than twice the bulk, ridiculously > > inconvenient and probably not that much cheaper, if it is at all. > > > Apple says ideally you might get 5 years or 1,000 cycles from a lithium > battery. Then you have the problem of getting it to an Apple center, > where they will charge $130 - $200. most people replace their laptop in less than 5 years (3-4 is typical), which means the battery outlasts the computer. they won't be replacing the battery. they'll be upgrading to a new computer. also, apple says that rating means 80% capacity is left, which is still very useful. it's not as good as new but it's not totally dead either. > You'd need 6 Eneloops and 6 more to swap, for about $36. They'd have > about 2,000mah, compared to 5400 for a lithium battery. If you had > battery trouble, you could buy new ones without travel, downtime, or > much expense. swapping batteries sucks. the early powerbooks used nimh batteries and they didn't get anywhere near the battery life of today's laptops, and they were way the hell thicker and heavier. something you're also forgetting is that the energy density of lithium batteries is higher, which means for the same capacity, lithium is a lot lighter. people don't want heavy laptops, nor do they want to carry multiple battery packs. > Apple says a battery will last the most years if you discharge it about > 50% each day and recharge. What a hassle! that's not needed. what they're saying is to not leave it plugged in all the time. the battery needs a little exercise. > If you leave it plugged in, > or unplug it and leave it charged, capacity will decline. If you leave > it discharged, you may be unable to recharge it. lithium batteries are designed to shut down before they get to the point of total discharge. however, if it's discharged to where the computer shuts off and you don't charge it relatively soon (i.e., months), there is a possibility it will self-discharge to where it can't take a charge. however, that's not a normal thing to do. you'd really have to work at it, actually. > A desktop would almost always suit my needs. With a detachable battery > pack, a laptop could be used as a desktop without impairing battery > performance. then get a desktop. if you are going to use a laptop as a desktop, then its battery type does not matter and you don't need to spend the $130-200 to replace its battery either, nor do you need to worry about leaving it plugged in. > A laptop might be nice in a power failure or for occasional portability. > If I ran a lithium battery down in a power failure, I'd be out of > luck. My NiMH charger uses a 12V wall wart, which means I could hook it > to a car battery to provide charged cells to run a laptop indefinitely. you can get a backup ups for a desktop to use during a power outage. if you ran a nimh battery down in a power outage, you'd be out of luck too. there are car chargers for laptops, and that means lithium batteries can be recharged. > And NiMH cells don't seem to catch fire or bulge. it's rare that a lithium ion battery does that.
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| From | Siri Cruz <chine.bleu@yahoo.com> |
|---|---|
| Date | 2013-12-04 20:46 -0800 |
| Message-ID | <chine.bleu-8996AA.20464004122013@news.eternal-september.org> |
| In reply to | #52957 |
In article <041220132338257109%nospam@nospam.invalid>, nospam <nospam@nospam.invalid> wrote: > > And NiMH cells don't seem to catch fire or bulge. > > it's rare that a lithium ion battery does that. Battery fires are due more to the amount energy in the battery rather than its composition. Low energy battery defects can radiate the extra heat without noticing it; high energy battery defects create heat too quickly to safely disperse. -- :-<> Siri Seal of Disavowal #000-001. Disavowed. Denied. Deleted. They hung there dependent from the sky Like some heavy metal fruit These bombers, ripened, ready to tilt
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-05 02:22 -0500 |
| Message-ID | <l7p9ji$gb7$2@dont-email.me> |
| In reply to | #52957 |
On 12/4/13 11:38 PM, nospam wrote: > In article <l7oj51$k05$1@dont-email.me>, J Burns <burns4@nowhere.com> > wrote: > >>> you aren't actually suggesting making a laptop to run on a bunch of aa >>> eneloops, are you? >> >> You caught me. I'll admit it. That's what I was suggesting. > > i don't think you've thought through all of the downsides, or realize > how good lithium ion batteries are. > > what you're describing is *not* marketable. It was marketable when NiMH batteries weren't nearly as good as Eneloops. > > > most people replace their laptop in less than 5 years (3-4 is typical), > which means the battery outlasts the computer. they won't be replacing > the battery. they'll be upgrading to a new computer. If I had to ship my laptop to Apple and pay them $200, I'd be tempted to replace it, too. Should I throw my 3-year-old laptop in the trash? If I spent the money for a laptop, I'd want to keep it to get online in a power failure or have files available where there was no outlet. > > > > the early powerbooks used nimh batteries and they didn't get anywhere > near the battery life of today's laptops, and they were way the hell > thicker and heavier. I wouldn't have bought one. > > something you're also forgetting is that the energy density of lithium > batteries is higher, which means for the same capacity, lithium is a > lot lighter. people don't want heavy laptops, nor do they want to carry > multiple battery packs. Why do you think I'm forgetting that? I believe a Macbook Pro battery weighs 24 ounces and holds 60 watt hours. Six Eneloops weigh 6 ounces and hold about 7 watt hours. Battery life would matter if you spent all day computing in lecture halls, but the laptops I've seen used were close to outlets. > > >> A desktop would almost always suit my needs. With a detachable battery >> pack, a laptop could be used as a desktop without impairing battery >> performance. > > then get a desktop. > > if you are going to use a laptop as a desktop, then its battery type > does not matter and you don't need to spend the $130-200 to replace its > battery either, nor do you need to worry about leaving it plugged in. Battery type matters if I want to be ready for a power failure. Eneloops can sit ready on the shelf for years. If I run them down, I swap and keep right on using my computer by the fire while the other batteries charge in the car.
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| From | nospam <nospam@nospam.invalid> |
|---|---|
| Date | 2013-12-05 02:44 -0500 |
| Message-ID | <051220130244075635%nospam@nospam.invalid> |
| In reply to | #52963 |
In article <l7p9ji$gb7$2@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > >>> you aren't actually suggesting making a laptop to run on a bunch of aa > >>> eneloops, are you? > >> > >> You caught me. I'll admit it. That's what I was suggesting. > > > > i don't think you've thought through all of the downsides, or realize > > how good lithium ion batteries are. > > > > what you're describing is *not* marketable. > > It was marketable when NiMH batteries weren't nearly as good as Eneloops. it was marketable when lithium ion batteries were more expensive than they are now. and there's nothing special about eneloops other than low self-discharge which isn't an advantage in a laptop because the laptop is either running from wall power or running from battery, neither of which is self-discharge. > > most people replace their laptop in less than 5 years (3-4 is typical), > > which means the battery outlasts the computer. they won't be replacing > > the battery. they'll be upgrading to a new computer. > > If I had to ship my laptop to Apple and pay them $200, I'd be tempted to > replace it, too. it can be done while you wait in the store, or you can do it yourself if you are handy with a screwdriver. you *might* need to do it once in the lifetime of the computer. it's not a big deal. > Should I throw my 3-year-old laptop in the trash? who said anything about throwing in the trash? it's still usable, just with reduced battery runtime. the battery is not dead. if you replace it with a new computer, sell the old one. > If I spent the money for a laptop, I'd want to keep it to get online in a > power failure or have files available where there was no outlet. you can do that, because laptops have batteries. and that's assuming your modem has backup power and the cable or phone company hasn't lost power either. > > the early powerbooks used nimh batteries and they didn't get anywhere > > near the battery life of today's laptops, and they were way the hell > > thicker and heavier. > > I wouldn't have bought one. nobody is going to buy what you're suggesting. > > something you're also forgetting is that the energy density of lithium > > batteries is higher, which means for the same capacity, lithium is a > > lot lighter. people don't want heavy laptops, nor do they want to carry > > multiple battery packs. > > Why do you think I'm forgetting that? I believe a Macbook Pro battery > weighs 24 ounces and holds 60 watt hours. Six Eneloops weigh 6 ounces > and hold about 7 watt hours. using your numbers, you would need 9 battery packs to match the macbook pro battery, for a total of 54 ounces, more than twice as heavy. nobody is going to get 9 battery packs. a macbook pro is rated for 9 hours, so each of your battery packs would last one hour. nobody is going to tolerate that. > Battery life would matter if you spent all day computing in lecture > halls, but the laptops I've seen used were close to outlets. then why are you so fixated on batteries? > >> A desktop would almost always suit my needs. With a detachable battery > >> pack, a laptop could be used as a desktop without impairing battery > >> performance. > > > > then get a desktop. > > > > if you are going to use a laptop as a desktop, then its battery type > > does not matter and you don't need to spend the $130-200 to replace its > > battery either, nor do you need to worry about leaving it plugged in. > > Battery type matters if I want to be ready for a power failure. > Eneloops can sit ready on the shelf for years. If I run them down, I > swap and keep right on using my computer by the fire while the other > batteries charge in the car. nope. eneloops self-discharge like everything else. it's not as fast as a regular nimh but it sure ain't 0, and it won't last 'years'. and as i said, you can get a car adapter. you don't need a battery in the laptop.
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| From | Kevin McMurtrie <mcmurtrie@pixelmemory.us> |
|---|---|
| Date | 2013-12-04 23:08 -0800 |
| Message-ID | <mcmurtrie-3766AD.23082204122013@c-61-68-245-199.per.connect.net.au> |
| In reply to | #52945 |
In article <l7o6ih$a9r$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > I've avoided laptops because of the hassles and expense of lithium > batteries. > > I started using NiMH AA cells for a camera in the 1990s. They were > quirky. > > For several months, I've been using Eneloop AA NiMH cells. They vastly > better. I can count on them for a device that requires 1500ma. They > take only an hour to charge and always seem to charge fully, about > 2,000mah. They're supposed to be good for 1500 cycles and hold a charge > for years. (I don't use the latest ones, which have slightly more > capacity but a much shorter service life.) > > Why not uses them for a laptop? For a given amount of energy, a battery > pack would probably have twice the bulk of lithium, but they're cheap > and foolproof. If you run low, pop in a set of charged cells! You're mistakenly comparing only amp-hours. NiMH have an average output of just 1.1 volts per cell while LiPo is 3.7 volts per cell. That makes the watt-hours per volume much higher for LiPo. Compare watt-hours per weight and NiMH starts to look like a very bad idea. The little 13" MacBook Pro has 71 watt-hours of batteries inside. That would be about the power of 30 top-quality AA sized NiMH cells. NiMH cells are also a major pain in the ass to charge properly. It can only be done with a very steady current and a very steady temperature so that a very tiny voltage dip may be detected. Any other conditions require a powerful overcharge so that rapid heating may be used for detection. It doesn't work well in a laptop. LiPo can be charged to 80% capacity with a constant float voltage or charged to 100% with a straightforward top-off algorithm. It's much easier.
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-05 03:08 -0500 |
| Message-ID | <l7pc9i$rjd$1@dont-email.me> |
| In reply to | #52961 |
On 12/5/13 2:08 AM, Kevin McMurtrie wrote: > In article <l7o6ih$a9r$1@dont-email.me>, J Burns <burns4@nowhere.com> > wrote: > You're mistakenly comparing only amp-hours. NiMH have an average output > of just 1.1 volts per cell while LiPo is 3.7 volts per cell. That makes > the watt-hours per volume much higher for LiPo. Compare watt-hours per > weight and NiMH starts to look like a very bad idea. The little 13" > MacBook Pro has 71 watt-hours of batteries inside. That would be about > the power of 30 top-quality AA sized NiMH cells. I was thinking of watt-hours. According to Wikipedia, the energy density of lithium polymer batteries is 300 Wh/L. The energy density of NiMH is 140-300 Wh/L. Wikipedia says LiPo produces 130-200 Wh/kg, and NiMH produces 60-120 Wh/kg. One thing I used to dislike about NiMH was that sometimes the voltage under a load was only 1.1. Eneloops do much better. > > > NiMH cells are also a major pain in the ass to charge properly. It can > only be done with a very steady current and a very steady temperature so > that a very tiny voltage dip may be detected. Any other conditions > require a powerful overcharge so that rapid heating may be used for > detection. It doesn't work well in a laptop. LiPo can be charged to > 80% capacity with a constant float voltage or charged to 100% with a > straightforward top-off algorithm. It's much easier. > My charger has a circuit for each cell. It charges Eneloop AAs at 2000ma, a much higher rate than NiMH cells used to accept. I use them mostly for a one-cell headlamp. With 1500ma, it will light a wall 500 feet away. I couldn't get that kind of power from the NiMH cells available in the past. Normally I run it at 450ma and get about 4-1/2 hours. The NiMH cells available in the past didn't give me such consistent run times.
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| From | nospam <nospam@nospam.invalid> |
|---|---|
| Date | 2013-12-05 11:29 -0500 |
| Message-ID | <051220131129544832%nospam@nospam.invalid> |
| In reply to | #52966 |
In article <l7pc9i$rjd$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > One thing I used to dislike about NiMH was that sometimes the voltage > under a load was only 1.1. Eneloops do much better. no they don't. they're the same nimh, but with lower self-discharge. the voltage is the same.
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| From | me@home.spamsucks.ca (Király) |
|---|---|
| Date | 2013-12-05 14:15 +0000 |
| Message-ID | <l7q1p9$6us$1@dont-email.me> |
| In reply to | #52945 |
J Burns <burns4@nowhere.com> wrote: > For several months, I've been using Eneloop AA NiMH cells. They vastly > better. I can count on them for a device that requires 1500ma. They > take only an hour to charge and always seem to charge fully, about > 2,000mah. They're supposed to be good for 1500 cycles Not if you're pumping 2 amps through them to charge them in an hour. You will drastically reduce their life if you do that. You'll get closer to the published 1500 cycle life if you charge them at a low current over a longer time, like 200ma over 10 hours. -- K. Lang may your lum reek.
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-05 12:43 -0500 |
| Message-ID | <l7qdvh$nml$1@dont-email.me> |
| In reply to | #52974 |
On 12/5/13 9:15 AM, Király wrote: > J Burns <burns4@nowhere.com> wrote: >> For several months, I've been using Eneloop AA NiMH cells. They vastly >> better. I can count on them for a device that requires 1500ma. They >> take only an hour to charge and always seem to charge fully, about >> 2,000mah. They're supposed to be good for 1500 cycles > > Not if you're pumping 2 amps through them to charge them in an hour. You > will drastically reduce their life if you do that. You'll get closer > to the published 1500 cycle life if you charge them at a low current > over a longer time, like 200ma over 10 hours. > NiCd manufacturers used to recommend C/10 for 14 hours. My first set was GE cells with a GE charger. Instead of 500 cycles, I got about 50. When I went to NiMH, manufactures said C/10 wouldn't work. I got a charger that worked in about 2 hours. After 10 years and hundreds of cycles, 8 cells of 2 brands were still going strong. I discovered that my NiCds also held up much better with the faster charging. Later, I read the reason. With slow charging, salts build up in nickel cells. That leads to faster self-discharge and eventually shorts. I think it also increases internal resistance. With faster charging, I was apparently not producing salts. I got another charger because it charged each cell on its own circuit. I think 700ma was typical. Sanyo recommends not more than C/2. I thought my charger would give them C/3. Instead, it was C, or 2,000ma. These cells charge faster because they have much less internal resistance than those I've had in the past. Then I noticed that on their tests, Sanyo charges at C. I've probably charged my cells 35 times at C, and I haven't seen any deterioration. Maybe Sanyo recommends C/2 because they don't know if the consumer's charger will cut off properly. Overcharging at C/2 would be better than overcharging at C.
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| From | nospam <nospam@nospam.invalid> |
|---|---|
| Date | 2013-12-05 12:54 -0500 |
| Message-ID | <051220131254218810%nospam@nospam.invalid> |
| In reply to | #52980 |
In article <l7qdvh$nml$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > When I went to NiMH, manufactures said C/10 wouldn't work. I got a > charger that worked in about 2 hours. After 10 years and hundreds of > cycles, 8 cells of 2 brands were still going strong. bullshit.
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| From | Kevin McMurtrie <mcmurtrie@pixelmemory.us> |
|---|---|
| Date | 2013-12-05 22:44 -0800 |
| Message-ID | <mcmurtrie-1984CE.22445505122013@c-61-68-245-199.per.connect.net.au> |
| In reply to | #52980 |
In article <l7qdvh$nml$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > On 12/5/13 9:15 AM, Király wrote: > > J Burns <burns4@nowhere.com> wrote: > >> For several months, I've been using Eneloop AA NiMH cells. They vastly > >> better. I can count on them for a device that requires 1500ma. They > >> take only an hour to charge and always seem to charge fully, about > >> 2,000mah. They're supposed to be good for 1500 cycles > > > > Not if you're pumping 2 amps through them to charge them in an hour. You > > will drastically reduce their life if you do that. You'll get closer > > to the published 1500 cycle life if you charge them at a low current > > over a longer time, like 200ma over 10 hours. > > > NiCd manufacturers used to recommend C/10 for 14 hours. My first set > was GE cells with a GE charger. Instead of 500 cycles, I got about 50. > > When I went to NiMH, manufactures said C/10 wouldn't work. I got a > charger that worked in about 2 hours. After 10 years and hundreds of > cycles, 8 cells of 2 brands were still going strong. You can only detect a full charge in NiMH using voltage depression when charging near the C/3 to C rate. Other rates require other methods that aren't as accurate. Repeated undercharging is fine, but too much overcharging ages the battery. > I discovered that my NiCds also held up much better with the faster > charging. Later, I read the reason. With slow charging, salts build up > in nickel cells. That leads to faster self-discharge and eventually > shorts. I think it also increases internal resistance. With faster > charging, I was apparently not producing salts. > > I got another charger because it charged each cell on its own circuit. > I think 700ma was typical. Sanyo recommends not more than C/2. I > thought my charger would give them C/3. Instead, it was C, or 2,000ma. > These cells charge faster because they have much less internal > resistance than those I've had in the past. > > Then I noticed that on their tests, Sanyo charges at C. I've probably > charged my cells 35 times at C, and I haven't seen any deterioration. > > Maybe Sanyo recommends C/2 because they don't know if the consumer's > charger will cut off properly. Overcharging at C/2 would be better than > overcharging at C.
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-06 13:19 -0500 |
| Message-ID | <l7t4f7$1vd$1@dont-email.me> |
| In reply to | #53026 |
On 12/6/13 1:44 AM, Kevin McMurtrie wrote: > In article <l7qdvh$nml$1@dont-email.me>, J Burns <burns4@nowhere.com> > wrote: > >> On 12/5/13 9:15 AM, Király wrote: >>> J Burns <burns4@nowhere.com> wrote: >>>> For several months, I've been using Eneloop AA NiMH cells. They vastly >>>> better. I can count on them for a device that requires 1500ma. They >>>> take only an hour to charge and always seem to charge fully, about >>>> 2,000mah. They're supposed to be good for 1500 cycles >>> >>> Not if you're pumping 2 amps through them to charge them in an hour. You >>> will drastically reduce their life if you do that. You'll get closer >>> to the published 1500 cycle life if you charge them at a low current >>> over a longer time, like 200ma over 10 hours. >>> >> NiCd manufacturers used to recommend C/10 for 14 hours. My first set >> was GE cells with a GE charger. Instead of 500 cycles, I got about 50. >> >> When I went to NiMH, manufactures said C/10 wouldn't work. I got a >> charger that worked in about 2 hours. After 10 years and hundreds of >> cycles, 8 cells of 2 brands were still going strong. > > You can only detect a full charge in NiMH using voltage depression when > charging near the C/3 to C rate. Other rates require other methods that > aren't as accurate. Repeated undercharging is fine, but too much > overcharging ages the battery. > Thanks. I see overcharging at C/10 is supposed to be okay for NiCd, but C/20 should be the limit for overcharging NiMH. I've read that it may be better to undercharge than to fool with overcharging. I used to check capacity with a 1.5V analog clock in parallel with a resistor. The capacity of a NiCd could stay good for years, but self-discharge would get bad. I didn't see that after I went to a fast charger. A NiMH that had sat idle for weeks or months would show reduced capacity and high internal resistance. Apparently the electrolyte wasn't evenly distributed. It was likely to improve with each cycle. I imagine it's less of a problem with some of the newer NiMH cells. I've read that if a cell heats up while charging, the charger may not detect a voltage drop when it's charged. I've had that happen at least once. The charging light stayed on and the cell got unusually hot. So far, the Eneloops have stayed cooler than cells in the past while charging.
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| From | me@home.spamsucks.ca (Kiraly) |
|---|---|
| Date | 2013-12-06 22:35 +0000 |
| Message-ID | <l7tjf2$ss1$1@dont-email.me> |
| In reply to | #52980 |
J Burns <burns4@nowhere.com> wrote: > NiCd manufacturers used to recommend C/10 for 14 hours. My first set > was GE cells with a GE charger. Instead of 500 cycles, I got about 50. A typical capacity of a NiCD AA cell is about 700maH, and so NiCD chargers put out about 50mA, which would charge them over 14 hours. > When I went to NiMH, manufactures said C/10 wouldn't work. C/10 is just fine for NiMH. In fact, most NiMH chargers put out exactly that amount, which is 200-250mA. (AA NiMH capacities are tpyically 2-2.3 AH.) I think you were misunderstanding what the manufacturers were saying. NiCD chargers aren't any good for charging NiMH. Too little power for the increased capacity. -- K. Lang may your lum reek.
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-07 02:27 -0500 |
| Message-ID | <l7uikv$5sj$1@dont-email.me> |
| In reply to | #53050 |
On 12/6/13 5:35 PM, Kiraly wrote: > J Burns <burns4@nowhere.com> wrote: >> NiCd manufacturers used to recommend C/10 for 14 hours. My first set >> was GE cells with a GE charger. Instead of 500 cycles, I got about 50. > > A typical capacity of a NiCD AA cell is about 700maH, and so NiCD > chargers put out about 50mA, which would charge them over 14 hours. > >> When I went to NiMH, manufactures said C/10 wouldn't work. > > C/10 is just fine for NiMH. In fact, most NiMH chargers put out exactly > that amount, which is 200-250mA. (AA NiMH capacities are tpyically 2-2.3 > AH.) > > I think you were misunderstanding what the manufacturers were saying. > NiCD chargers aren't any good for charging NiMH. Too little power for > the increased capacity. > If C/10 works, why not C/20? When I first bought NiMH, every website I checked said I'd need a special charger. I think I've found the answer. Battery University says overcharging is worse for NiMH than for NiCd. According to Panasonic's 2005 "Charge Methods for Nickel Metal Hydride Batteries," "the overcharging of nickel metal hydride batteries, even by trickle charging, causes a deterioration in the characteristics of the batteries." They recommend a charge of C/2 to C until cell voltage reaches 1.8, or it drops by 5-10mv, or the temperature rises at 1 or 2 degrees C per minute. Then you switch to a timed trickle at C/30 to C/20. For backup batteries, they recommend a voltage sensor. When cell voltage drops to 1.3, a timer tops them off at 0.1 lt. (I don't know what lt is.) I used to charge NiCds in pairs, 16 hours at C/10. This would probably mean overcharging, particularly if one cell was still partially charged when I started. I think those accumulated hours of overcharging caused the deterioration I saw. I got better service when I switched to a charger that shut off when the voltage dropped.
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| From | J Burns <burns4@nowhere.com> |
|---|---|
| Date | 2013-12-08 00:10 -0500 |
| Message-ID | <l80v0u$kvb$1@dont-email.me> |
| In reply to | #53050 |
On 12/6/13 5:35 PM, Kiraly wrote: > J Burns <burns4@nowhere.com> wrote: >> NiCd manufacturers used to recommend C/10 for 14 hours. My first set >> was GE cells with a GE charger. Instead of 500 cycles, I got about 50. > > A typical capacity of a NiCD AA cell is about 700maH, and so NiCD > chargers put out about 50mA, which would charge them over 14 hours. > >> When I went to NiMH, manufactures said C/10 wouldn't work. > > C/10 is just fine for NiMH. In fact, most NiMH chargers put out exactly > that amount, which is 200-250mA. (AA NiMH capacities are tpyically 2-2.3 > AH.) > > I think you were misunderstanding what the manufacturers were saying. > NiCD chargers aren't any good for charging NiMH. Too little power for > the increased capacity. > After reading your message, I think I've learned something significant. LaCross has a charger that will charge 4 NiMH or NiCd AA or AAAs on independent circuits. You can choose 200, 500, or 700ma, but it's in pulses of 800, 2000, or 2800ma. When it reaches the voltage drop, it switches to a timed trickle charge as Panasonic recommends. It monitors temperature. It will recondition a cell by cycling it until the capacity stops increasing. It will check capacity, which I've done with a clock and a resistor in the past. With great NiMH cells and chargers available, I'll try to avoid products with built-in rechargeable batteries.
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| From | Your Name <YourName@YourISP.com> |
|---|---|
| Date | 2013-12-14 18:57 +1300 |
| Message-ID | <141220131857424155%YourName@YourISP.com> |
| In reply to | #52945 |
In article <l7o6ih$a9r$1@dont-email.me>, J Burns <burns4@nowhere.com> wrote: > I've avoided laptops because of the hassles and expense of lithium > batteries. > > I started using NiMH AA cells for a camera in the 1990s. They were > quirky. > > For several months, I've been using Eneloop AA NiMH cells. They vastly > better. I can count on them for a device that requires 1500ma. They > take only an hour to charge and always seem to charge fully, about > 2,000mah. They're supposed to be good for 1500 cycles and hold a charge > for years. (I don't use the latest ones, which have slightly more > capacity but a much shorter service life.) > > Why not uses them for a laptop? For a given amount of energy, a battery > pack would probably have twice the bulk of lithium, but they're cheap > and foolproof. If you run low, pop in a set of charged cells! Rather than AA batteries, why not try brussel sprouts ... <http://www.techadvisor.co.uk/news/digital-home/how-power-christmas-tree- lights-using-brussels-sprouts/> Of course, they have to use 1000 brussel sprouts to (supposedly) power a measly 100 LED Cristmas tree lights ... so you'd likely need a couple of truck loads to power a laptop. ;-)
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