Backup power for cell sites

Haven't we had this discussion before?
At minimum, battery power provides a few hours to most every site. This is the standard solution for T-Mobile and Sprint. After those few hours, either they roll in a generator to the sites that don't have it, or they go dark.
AT&T and Verizon more often than note have backup generators on site. I've seen diesel, propane, in shelter and out of shelter. Naturally, the primary site we use back in NY doesn't seem to have any backup power, lol.

 

It really depends on load. It could be 45 minutes under extremely heavy use, or maybe 4 hours.

 

Oh, uh....well I guess they would want it to go for as long as possible, but there is no minimum that they establish. Some sites don't have any backup at all. They probably shoot for about 4 hours, as that will last for the duration of the average power outage. Then again, there are times where you see an entire cabinet full of batteries:

http://forums.wirelessadvisor.com/a...8-gallery-hot-link-thread-ignore-p1060206.jpg

 

What I am posting below is company confidential material, please don't show it to anyone outside of this forum, because I could lose my job.

Here is a schematic taken from a major cellular operator, diagramming in detail their back-up power supply. There are some variables to consider, like size of the dog, how much food he has, etc, but generally, they can last for more than 4 hours, so I assume this is what was being used during the power-outtage in your neck of the woods last night.




The cheaper USB ones will only last maybe an hour at best....

 

No minimum. The US government tried to mandate 8 hours minimum, but that did not work. Some sites go beyond backup generators, I think Sprint has some fuel cell and solar sites.
The only time I have seen built in generators are on Verizon sites, where the generator was built into the shelter. Most sites have either permanent or portable outdoor generators. Here are a few examples.

Built in:
http://gallery.wirelessadvisor.com/showimage.php?i=4277&catid=searchresults&searchid=6264
http://gallery.wirelessadvisor.com/showimage.php?i=4278&catid=searchresults&searchid=6264

Here is one on a roof in Manhattan:
http://gallery.wirelessadvisor.com/showimage.php?i=6768&catid=searchresults&searchid=6267

Permanent on site, non-shelter:

 

Yea, there is no set standard really. Generally speaking, the operators usually have a few back-up batteries on-site to handle short power outtages, like in the range of a few hours at best. Usually, there's not much room on-site for generators, and then there's the added cost of them as well.

Cellular networks, like most other civilian communications systems, aren't really designed for major disasters or long-term power failures. In distaster scenarios, like massive flooding, mobile cell-sites would be rolled out with satellite up-links to switches in non-disaster areas. Or military could be brought in with their own self-supporting communications networks. Satellite phones like Iridium or INMARSAT are also very useful in cases like that.

 

Charlyee,

You are right - there currently is no mandated requirement on whether or not carriers must provide any backup power at their cell sites. In 2008, the FCC wanted to mandate carriers to have a minimum of 8 hours of backup at every cell site, but they were quickly shot down by various wireless carrier coalitions. VZW was the only (or one of the only) carriers actually in favor of this FCC mandate.

As far as built in generators go, in some states VZW has generators at ~90% of cell sites, in others (mostly metro areas where space is an issue), the figure drops. NEXTEL had generators at many of their sites. From what I see and hear, at&t has generators at sites in some of their higher usage areas (along major thoroughfares, etc.) but generators are not the norm.

For many years now, VZW has used shelters with generators enclosed inside the shelter, whereas older sites have a generator sitting outside the shelter. at&t I have not seen build generators inside their shelters (they are either on the outside or there is none), same for NEXTEL. In areas where Sprint 'synergized' on NEXTEL sites with generators, Sprint has often connected their equipment to the existing backup power as well, which was an advantage to the NEXTEL merger considering Sprint had very few sites with generators.

 

Very good post! I fully agree with everything said. I have never seen a Sprint CDMA only site with a generator, only at sites that are shared with Nextel. Verizon goes out of their way to install generators, as I have seen them on the roof of adjacent buildings multiple times. (except my local NY tower, of course).