Waiting for Verizon.. [telecom]

In article ,

Not exactly. The regulator stabilizes the alternator/generator output to an appropriate level. (effectively a constant-voltage, variable-current power supply, "within limits".) The battery 'floats' across the alternator output as it powers the rest of the vehicle's systems.

To use a Clintonism, "That depends on what you mean by 'suitable'."

Standard auto batteries are -not- intended for deep-discharge cycles. Repeated deep discharge *radically* shortens battery life.

Standard auto batteries generally suffer if routinely discharged below 50% of full-charge level. "Deep discharge" batteries, on the other hand are good for 80%-90% discharge without damage.

*IF* you can afford to put in twice the AH you'll use, _and_ have a cut- off when the 50% level is reached, regular auto batteries are 'ok'.

Also, if it is a true =emergency= (only!!) system -- where you just need 'something' for a relatively short, but _unspecified_ time period -- auto batteries do provide some of the least expensive per amp-hour storage, if maintained properly and _not_ drained excessively.

As an 'off grid' power supply, or as part of an 'uninterruptible' grid-based power source, auto batteries are 'medium lousy', to put it charitably.

If you have need to get a specific _duration_ of power, batteries designed for deep discharge *will* provide _more_ power for a _longer_ period, and for _more_ occurrences, than auto batteries.

It boils down to "if you expect to use it", get batteries designed for the task. If you _don't_ expect to use, it get the 'cheap' ones. Batteries do age, and *do* have to be replaced periodically. If the use will be only a few times during the projected lifetime, the benefits of 'deep discharge' designs are probably =not= worth the extra cost.

Analyzing the trade-offs is _not_ a simple process. :)

In article ,

No.

Batteries are typically rated at the total number of A-H they will produce if totally discharged over TWENTY HOURS.

If the discharge rate is higher, the total A-H produced is less.

There is also the issue of 'can you do it _repeatedly_'. (how many times?)

Over the 'lifetime' of an auto battery you'll get a lot _less_ total A-H out (at a given discharge rate) if you run from 100% charge to ~0% charge than if you run from 100% charge to 50% charge. i.e., only pull 1/2 the 'rated' A-H before recharging.

Back when I was more active in the hobby and belonged to W1AQ if we went battery it was deep cycle batteries that we used.

Of course we also used aluminum extension ladders as makeshift towers. I can recall one field day when I was eating lunch in the mess tent during a storm.

I happened to look out and saw the bottom of one of the 'tower's dancing. We had to go out and tie it down in the pouring rain.

When my buddy donated his portable 55' military crank up tower it was a god-send.

***** Moderator's Note *****

That brings up another "what if" question: do LEC's still have microwave backup capability for emergencies? Years ago, when I was working a remote for MIT radio station WTBS on Boston Common, a phone technician unrolled a length of twenty-five pair cable, which went over to a van with a ~1 meter microwave dish on it mounted to a hydraulic lifting stack, and told me which colors were my program and talkback circuits. Do LEC's still maintain a stock of portable short-haul microwave for temporary or emergency use?

Bill Horne Moderator

No, they are not as rugged as any battery gets. They won't last more than two or three deep discharges; the plates will warp and the cells will short out and then you pitch them.

Car batteries are intended for high peak loads for cranking a starter, but they are unable to deal with long-term loads or deep discharge like a backup battery would be used for.

You will notice that most car batteries aren't even _rated_ in amp-hours, only in "cold cranking amps." The fact that they don't have a rating for long-term use is a sign....

--scott

A question about 'deep discharges' for a car battery. If someone leaves their headlights on and the 'battery runs down', is that a "deep discharge" situation? That is, if someone does that, have they ruined their car battery and need a replacement?

One time my alternator died. My mechanic said I'd be ok driving from home to his garage for a fix. While there he had to add water to the battery (this was some years ago). Did a situation like that constitute a "deep discharge"?

Thanks.

Side note 1: My current car has an automatic relay that turns the headlights off if I forget when I open the car door with the motor off. Nice feature. Still, I carry full length jumper cables in the trunk, very useful to have.

Side note 2: I wish I could remember where I read the technical description of dry cells intended for magneto local-battery telephone service or "intermitent use". I recall seeing such No. 6 cells in magneto phones so marked. Such cells had a chemistry intended for such service and was able to replenish itself a bit after a brief use, extending their lifespan. Said description also explained how they made "heavy duty" dry cells. Apparently there were various types of carbon-zinc chemistries for industrial service dry cell batteries that ordinary consumers wouldn't see. Actually, I haven't seen the old style batteries sold in a long time; everything in common consumer stores is alkaline or a newer type. However, the old style type are often included with TV remote units or packaged with cheap flashlights.

Side note 3: With cell phone batteries, do the batteries sold today have the "memory" problem, that is, is it necessary or _prudent_ to discharge them fully before recharging them? It seems most people recharge their cell phones at their convenience, not waiting until the phone is completely drained, and they get a great many charging cycles out of their. (On my current cellphone, a plain vanilla LG, I get four hours of talk time per charge, which I guess is good.)

snipped-for-privacy@bbs.cpcn.com wrote in news: snipped-for-privacy@r27g2000yqn.googlegroups.com:

I carried jumper cables for about 40 years, but now I have a portable car start battery kit in each car. It is much easier to use, and it also has a small air compresser and LED flashlight built in. Anything it can't handle is a job for AAA.

This is partly possible because we all carry wireless phones now (obTelecom).

I have a few batteries (12V), they were made for AT&T and we used them on remote sites, they are about half the size of a car battery. The data on them says they are a 10 year battery, The company would replace them about once a year. I use them on my very old and very very large UPS. I can run it for 5 plus hours on both of my computers and a few other small radios. I guess I'm under using them, but all of them are over 10 years old and still hold the same charge as when I first got them. I have not seen then [for sale] in years, so I guess when [these] do go I'll have to look for something [else] to replace them.

Do that two or three times and your battery won't hold a charge at all. Doing this dramatically shortens the life of your battery.

Possibly. May have been fine, may not have, depending on how far the battery voltage dropped. Used to be cars had a voltmeter on the instrument panel so you could see that you were down below 12V and possibly doing some harm to the battery.

Primary cells and rechargeable accumulator cells are very different things. I think what you're talking about are "heavy duty" batteries which use a manganese-dioxide electrolyte and then a zinc chloride layer around the zinc casing instead of the ammonium chloride that "regular" batteries used. This reduces self-discharge so the batteries don't go bad as quickly in intermittent service, and it also increases the current for brief time spans.

That would be a "heavy duty" battery, which has been pretty much entirely replaced by alkaline batteries today.

No battery has had memory for the past thirty years or so. You're much more apt to damage any sort of battery stack by fully discharging it than not.

Cell phone batteries today usually have computer control inside with a little processor that equalizes the load between the individual cells both on charging and discharging, to make the cells last a lot longer, so none of these issues are a problem.

--scott

These are most-likely lead-iron float cells. Very poor energy density, but amazingly rugged and they will last a lot longer than ten years if you're careful. I have seen fifty-year-old lighting systems that still met original specs.

Float cells are still available for telco applications and emergency lighting systems, but you don't want to know what they cost.

--scott

........

Ni-cad batteries that were in my 1990's phone certainly had "memory effect" issues and would lose capacity quickly if not treated with care.

Things are better now but that started to turn around about 8-10 years ago when Ni-MH cells were becoming more common.

As for "no battery has had memory" etc, Duracell say all batteries do have this characteristic:

Regards, David.

-- David Clayton Melbourne, Victoria, Australia. Knowledge is a measure of how many answers you have, intelligence is a measure of how many questions you have.

I* still do have access to them, Verizon still changes the batteries every 2 years now, they are sent back to supply , but I have been able to get a couple a year, I use them for a month or so, they change them out and keep doing that to not kill them. I still have 2 of the first ones I got in 1984 and they appear to be in vary good condition. Each month I force a power outage and run the batteries for a couple of hours on the UPS, they have a 80% charge after a couple of hours, the UPS was made to run a server and it took 3 of us to get it in place in my den/office.

- - The only good spammer is a dead one!! Have you hunted one down today? (c) 2010 I Kill Spammers, Inc., A Rot in Hell. Co.

***** Moderator's Note *****

The problem with a UPS is that it's not meant to _sustain_ it's loads, only to supply them _temporarily_ until they can shut down gracefully: if, however, the owner has not taken the time to connect the necessary cables and install the vendor's software, then the computers which the UPS was supposed to protect will keep going until they exhaust the UPS batteries.

Don't ask me how I know.

Bill Horne Moderator

+--------------- | As for "no battery has had memory" etc, Duracell say all batteries do | have this characteristic: | That may be true for all *nickel*-chemistry batteries, but it is certainly not true for *all* batteries:

How to prolong lithium-based batteries ... A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges. ... Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.)

Note: Don't be confused by the problem of so-called "digital memory" in "smart" lithium-ion batteries:

Although lithium-ion is memory-free in terms of performance deterior- ation, batteries with fuel gauges exhibit what engineers refer to as "digital memory". Here is the reason: Short discharges with subsequent recharges do not provide the periodic calibration needed to synchronize the fuel gauge with the battery's state-of-charge. A deliberate full discharge and recharge every 30 charges corrects this problem. Letting the battery run down to the cut-off point in the equipment will do this. If ignored, the fuel gauge will become increasingly less accurate.

We had this very same "digital memory" problem in spades at a PPoE where we were using LIon laptop batteries to power a DRAM to create a "non-volatile" memory to protect data in case of mains power failure. The battery was almost never discharged at all [since power failures are quite rare] -- *and* the charging circuit was unable to charge the battery all the way to 100%[1] -- so the built-in "fuel Gauge" [readable via the I2C bus] got less & less accurate over time. After a system had been running continuously for several months, the built-in "fuel gauge" would report *zero* charge remaining, yet if you then took the battery out and discharged it on a lab bench with a reference load, it was indeed fully charged (well, as charged as it ever got, see [1]) and would deliver the expected number of amp-hours!! [That is, there was no observable "memory effect" at all.] We finally had to change our system software to completely ignore the built-in "fuel gauge" and instead developed our own software model of charge remaining based on the battery voltage, current, and temperature [all of which could be read over the I2C bus]. It wasn't perfect, but it was *much* better than the battery's built-in "fuel gauge", which got horribly confused by our peculiar operating conditions. ;-}

-Rob

[1] The particular battery we were using needed to be charge to 12.6 V to get a 100% full charge [and thus reset the "fuel guage"], but the system only had a +12.0 V supply. Losing that last 0.6 V cost us nearly *30%* of the rated charge, but other than that caused no operational problems with the battery itself [except the above- mentioned fuel gauge issue]. In fact, the battery's manufacturer told us that only charging to 12.0 V would actually extend the life of the battery somewhat.

----- Rob Warnock

627 26th Avenue San Mateo, CA 94403 (650)572-2607

I agree that is what they are made for, but as I said, this UPS was made to run a very larger server an all I have running on it are a small Mac Powerbook and my old Apple //e which has my old BBS on it; the BBS is down, but I have been working on some Apple software; there is a lot of interest in this old computer again. I have the software that will start shutting down the computer, at least the PowerBook.

I started running the BBS in 1986 and only took it down in 2004. At that time we had UUP newsgroups, network e-mail, and being able to send files;between 10 other Apple II BBS's around the US. I have been doing updates to the software to fix the 2000 date problem, that is now done and a way to network it to the Internet, that will take moving it to a Apple IIgs or linking it via a doors program on a Mac. I had several months to work on it, but I'm now doing work again and Verizon and AT&T is keeping contractors busy, so any work will have to wait until the end of this year.

I used Powerware UPS's previously and the software they provide does this.

One machine has the direct control cable connection to the UPS (the "Master") and other devices plugged into the UPS have software that uses a LAN connection for control, so when the power drops the Master sends a signal to the others to shut down.

You need your LAN infrastructure that *all* these devices use on a UPS as well!

-- Regards, David.

David Clayton Melbourne, Victoria, Australia. Knowledge is a measure of how many answers you have, intelligence is a measure of how many questions you have.

In article ,

This is generally *TRIVIAL* to do.

UPS monitoring software for UNIX-type boxes generally runs a shell script when the power-fail is detected and/or when it it time to shut down. postulating the other machines are on the LAN, it is trivial to have the LINUX box send a shut-down directive to those other machines. For unixeqsue boxes, it's a simple matter or logging in and running a shutdown script. Numerous ways to do this, one of the easiest is the freeware comms program KERMIT, which can make a fully scripted telnet connection, and do the deed. For Windows boxes, see the freeware tool 'poweroff.exe'. A Unix box can easily tell a poweroff-equipped windows box to power down. (Not just "shut down", but 'hibernate', so *nothing* is lost on a power-fail.)

About the only viable solution is SNMP.

Googling ``snmp ups software'' finds:

and

among others; the above two look useful.

Highly dependent on what you specify for the UPS install. For example at my last regular job I had specified a 15 minute run time for 125 servers and telecom gear.

We had 70 so that 15 minute limit became 45 minutes of power. Took two full size racks to do that, one the power controller, the other the battery bank.

But that was all just belt and suspenders to keep critical apps up and running. The UPS was backed up by a 125kW natural gas fired generator.

That was spec'd to come on within 10 seconds of power fail and also set to do monthly exercise, etc.

It always helps when you have several hundred thousand dollars to do a server room rigt.

Thanks for the explanation. But now I'm confused: What is the best way to maximize battery life in a cellphone? Wait until it runs down, or, recharge it at a different level? (I don't use my cellphone very much, so my recharge cycles are about 1-2 months apart. So far I'm getting four hours of talk time on a charge. I usually have the phone turned off unless I'm expecting a call, so my standby time is brief).

--J.