James Knott wrote:
Per Jessen wrote:
Depends on how many you have. The typical battery used in large scale UPS's (for bridging whilst the generators get going) is a 24v truck battery. I have no idea how much such a collection can deliver, but when it needs to run cooling, lighting, disks and e.g. 3-4 IBM 3090s of the old kind, it's quite a bit. Usually they're only designed to hold the load for 5-10minutes though.
Batteries used for starting cars & trucks are not suitable for that type of service.
Hmm, well, that's how I saw them used in the late 80s in a large datacentre installation. The generator was about the size of a large train engine. Maybe they weren't regular truck batteries.
Starting batteries are designed for high current, short term loads. Batteries for UPS are designed to be floating on the rectifier output and be ready to take over the load immediately and sustain it for as much time as required.
We're just now inthe process of getting a new 40KVA UPS installed, the batteries are standard 12V, nothing special about them. Looking at our much smaller per-rack 6KVA units, the batteries are also standard 6V or 12V units.
Typical UPSs, as used with personal computers only last several minutes. Those used for telecom etc. have to carry the load for several hours or even days.
Because they don't use generators?
Using the wrong type of battery may work in the short term, but premature failure is pretty much guaranteed.
I'm not sufficiently knowledgeable to discuss this, but Schneider/APC seem to disagree with you, they use standard lead accumulators. -- Per Jessen, Zürich (18.1°C) http://www.dns24.ch/ - your free DNS host, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org