On 11/27/05, jeff <jdavis70@tampabay.rr.com> wrote:
> On Sunday 27 November 2005 07:40 pm, steve szmidt wrote:
> >
> > One thing to be aware of is that the electronics is built to handle a
> > certain load. Putting a much larger battery, and load, could result in
> > overloading the circuitry. Also the charging circuit has to be able to
> > charge your batteries of course.
> >
> > Granted, I've never done it with a much larger batteries, and I don't
> > know what kind of margins these circuits are built with. But I would
> > imagine that if you connected a car battery to one of these 500W, put
> > over 500W load on it and then turned off the AC you could eastoast it.
>
> Adding a larger battery (or more batteries) doesn't pose a problem to the
> UPS. It (the UPS) will still draw the same wattage at the same rate
> regardless of the battery capacity. Recharging a larger capacity battery
> will take longer, but unless the battery has an internal fault the UPS will
> happily charge whatever size battery that you plug into it.
Yes the charger is current limited because the battery appears as a low
impedance device who's impedance changes as the battery takes on
charge, so at maximum discharge the charger MUST be self limiting or
it would self destruct even on a small battery.
>
> Plugging more devices (or higher current draw devices) into the UPS can
> overload it. Plug a laser printer into a 300VA UPS, pull the power cord and
> print a letter and you will no longer have a UPS.
Normally the overload will cause the machine to quite powering the equipment,
that has been my experience with them. As soon as the overload is removed
and the machine restarted it will again work as designed. Most of them will
handle about a 100% overload to take into account inductive loads like motors
and thermalreactive loads like a large incandescent lamp (looks like a
short when
the filament is cold but as it warms up to incandescence the resistance goes
up accordingly). The key is sizing them according to the equipment needs.
-- Chuck Hast To paraphrase my flight instructor; "the only dumb question is the one you DID NOT ask resulting in my going out and having to identify your bits and pieces in the midst of torn and twisted metal."----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.
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