[rescue] Any recommendations on rack-mount UPS?

velociraptor velociraptor at gmail.com
Sun Oct 18 13:02:19 CDT 2009

On Mon, Oct 12, 2009 at 1:19 PM, Robert Darlington
<rdarlington at gmail.com> wrote:

> A friend of mine worked with the state of Florida on some railway project.
> By random luck he noticed that there were service techs at railway
> changing batteries for the lights that are used in case there is a power
> outage.  He chatted them up about it and found out that they changed their
> SLA batteries out roughly once a month.  Pat worked with them to come up
> with a solution.  The first part was to add a heat shield (just a piece of
> aluminum over the box, spaced an inch or two over the box) and paint the
> white (NOT silver).  The other part was to replace the batteries with AGM
> batteries.  Most of the batteries have now been in use for 26 years
> continuously.  Gel cells can't take the heat, but AGMs don't like to be
> cycled.  There are trade-offs, and I prefer to shut down servers before
> depleting the batteries (which results in just a delay before the cord gets
> yanked)  This keeps the AGM batteries happy and it sure beats trying to pry
> out swollen batteries.

AGMs handle all temp variation better, from what I understand.  I only
use AGM in my motorcycles now, especially in Vegas.  Normal lead-acid
cannot take the LV summer at all.


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