One of the main reasons I got into Ham was for emergency communications.  I got to wondering, what do repeater owners generally use for back up power?  I would imagine many are located atop mountains, and thus susceptible to long term power outages. In the case of an emergency, such as Hurricane Sandy, where power outages are long term, how long do repeaters have provisions for power?

In my experience, usually a couple of deep cycle marine batteries that are floated by a charger connected to commercial power. Sometimes solar panels, but for high remote sites, you run into problems with snow and dust collecting on the panels. Most emergencies that they prepare for (usually a major storm) will be fixed within a few days, since usually there are cell repeaters at the same location. Otherwise the repeater maintainers either let it die until power is restored or drive up there with a generator to top off the batteries (or swap them for charged ones).

the answer is a firm "it depends".

for example, an amateur repeater used for RACES/ARES or similar may have battery backup for 24 hours of EMCOMM use, and the club/organization may have purchased a generator (Honda EU2000i or equivalent) which can be pressed into service for long term use during an extended utility power outage.  so the answer in this case is days/weeks of backup.

in other cases the amateur repeater may be installed in a location which is leased space with a common power system for many customers.  depending on many factors, this may result in no backup time to unlimited backup time.

in still other cases the amateur repeater may have no provision whatsoever for backup power.  no utility power translates to no repeater operation.

ar-jedi

Good info guys thanks!

Our local repeaters here have a large deep cycle storage battery on each repeater.  In previous power outages they've lasted for 48 hours, with heavy usage during that time... never had an outage long enough to find out how long they would truly last.  Long term contingency planning involves visiting the site at intervals to swap depleted battery for a charged one, with the depleted battery recharged via auto, home generator, etc.

Here is my future repeater

Off the grid 24/7 since 2002









And here is its power supply (6) 6v batteries charged by 5 panels






It powers a fire dept vhf repeater, 2 meter, 1.25 meter, and 70 cm. Something I didn't think of till we went up there is due to our height that our VHF repeaters only radiat about 12 watts and the uhf is about 16 watts and they cover about 100 miles each. The low power used plus the fact they don't get to much traffic keeps them charged pretty well.

our man repeater as well as the two remote receive sites are powered by stand by gennys. all are located on the same towers as the EOC uses for there systems so we always have coverage.

my last club had repeaters colocated at the city's radio sites for PS stuff.  There was a big ol genset outside, and this inside:



Of course we had to share it with umpteen 800MHz radios and microwave links and there was probably a VHF fire repeater in there too, but that's still a lot of juice.  The tall rack in the corner housed all of our gear.

Depends on the site

Some have nothing, while others nay have solar, batteries or a generator (or a combo)

Wow, I don't know what most of that equipment is, but apparently I completely underestimated what repeater setups looked like.

I think this is more like what I thought most repeaters looked like.

Our club has a 3kw propane generator with a 500 gal tank. The genny and tank was donated to the club and it does come in handy, our club repeater is also the local ARES repeater and by estimation the repeater would be able to run for 3 weeks or more if the grid went down.

Don't forget to check/fill/change the oil in that period. That would be my biggest worry with a genset hooked to a large fuel tank is that I would forget to check the oil. On a small tank the oil would be checked during fill-ups (every 4-5 hours).