Tell Telstra to stop sending you dead trees.

They are essentially 700ma for 3.5 hours, which doesn't go far really if it is a significant blackout.

The real problem with any battery is they do not like being left on trickle charge for months. You really need a system to give them a workout every month(who remembers that more than once or twice).

Reply to
terryc
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silly

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Modern ones need a boost charge then lower float than older style, depends which technology they use, they may also need proper initial setup or forming, but there's less info on that floating about the web. Some manufacturers quote the method, but it takes a week or so, don't expect a supplier to perform that function. Reason is that less formed batteries have a much longer shelf life, so it's good for the resellers.

Those poor things don't survive many outages as PC UPS, but at least a phone or telecomms UPS would not be asked for the same power delivery amount as a PC backup would be.

Snap! OUCH! Sparks. No house burn down? Give one a fright, maybe the battery explode it one reacts the wrong way --> weld contacts to metal cover -- surely case designers would do a better job? Hmmm.

An old UPS I retired wasn't very good in the battery compartment.

Not have a UPS at the moment, want a decent 24V one, or fulltime inverter and charger style, not sure, not done a technology survey for a few years.

Grant.

Reply to
Grant

Got to be automated? Float too high corrodes the cells, under float sulphates, so one needs under float with the occasional light discharge/charge cycle to exercise the things (something like that?).

Not at all like the old flooded cell equalising overcharge they used to do decades ago on traction batteries.

Grant.

Reply to
Grant

But solar nicely fits with modern airco usage. Because people demand their summer comfort cooling? My electricity peak is winter heating, only a couple fans for summer.

Grant.

Reply to
Grant

I suppose I was more thinking about careless handling prior to installing, or indeed careless handling of the battery being replaced, which presumably won't actually be dead. People are so used to things being idiot proof that they don't know how to handle things that aren't.

I currently have two UPSs as a result of buying a replacement, and then figuring out how to repair the one it was replacing. Both use 24V by running two of the above batteries in series (which is actually a slightly questionable practice).

I don't really see the point of paying extra for a fulltime version - the switch over time for the part time versions is much too small to be noticed by a PC power supply. Assuming that's what you're using it for, of course.

Sylvia.

Reply to
Sylvia Else

The spec sheet linked to from the Jaycar page I posted indicates 648mA for 10 hours.

My UPS runs on battery for about a minute once a month. The primary goal appears to be to test that the batteries are still up to the task, since the UPS starts beeping if they're not, but it exercises them a bit as well.

Sylvia.

Reply to
Sylvia Else

The correlation between sunlight availability and airconditioning demand is certainly high, but it's nothing like 100%, meaning that provision would still have to be made for high airconditioning load at times when the sun is sufficiently obscured to compromise solar power generation.

Photovoltaic solar power generation would also be an exceptionally expensive way of supporting the demand for air conditioning if it were only used when airconditioning was required.

In practice of course, the power solar panels generate is used whenever it is available, displacing the grid power generation with the highest marginal cost, thus decreasing the economic viability of that generation plant, which in turn feeds into higher electricity prices. Greenies also need to be aware that it would change the finances of natural gas powered generators, with the result that less efficient (i.e. more CO2 releasing) plants would be built.

A much cheaper solution is for people to own petrol generators capable of providing occasional power, and for those to be used at time of high airconditioning loads. I looked at buying one a while back out of concern that the grid would fail to handle peak loads during heat waves, though I couldn't quite convince myself of the need, and it didn't happen - that summer at least.

Sylvia.

Reply to
Sylvia Else

SNIP : :I can imagine people burning their houses down by shorting them out :while changing them. : :Sylvia.

I doubt that homeowners will be allowed (technically) to change their own battery. The UPS forms part of the equipment supplied by the service provider and it may be the case (I haven't yet seen anything on this subject though) that only licensed ACMA installers or electricians are allowed to perform this task. I estimate that even if a prime quality battery is used and a licensed installer is used, it will cost around $100 - $140 every 5 years.

Of course, most homeowners will do the job themselves or get somebody who can do it for them.

Reply to
Ross Herbert

Well, perhaps, but the Telstra document cited by you earlier would certainly lead me to expect to change the battery myself. It says "you must regularly check the battery indicators and replace it as recommended by the manufacturer."

I suppose the manufacturer might say "get a qualified technician to replace it" or words to that effect, though my UPS manuals provide detailed instructions on how to do it, with no suggestion that it's a task for a professional.

Sylvia.

Reply to
Sylvia Else

Snip : :The SLA's described in the Telstra page appear to be these : :

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This is the UPS which Telstra was using on their Velocity service

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It is now superseded so I don't know what they are using now, but it will be similar.

: :The discrepancy in the height relates to whether the connection tabs are :included. : :My UPS uses them. The problem is they're not cheap, as you can see, :about $35 retail, and I get only about three year's use out of them even :though they spend almost all the their fully charged, and are rarely :called on to deliver power. : :I can imagine people burning their houses down by shorting them out :while changing them. : :Sylvia.

Reply to
Ross Herbert

Feel free to do that. It is your battery.

Reply to
terryc

OK, so you're talking about the effect that deep cycling has. But blackouts of that extent are rare in any given place, and these batteries only last a few years even when not being deeply cycled.

Sylvia.

Reply to
Sylvia Else

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