[MarinTeams] Channel 7 Repeater power outage restored

Wed Jan 11 02:41:23 EST 2023

All,

First of all let me express my gratitude for your interest in building up and sustaining the K6BW repeater system!  Unfortunately there isn’t a cost-free solution.

Richard, thank you for establishing the turn-on date for the West Marin repeater (November, 2016).  I think you submitted a picture, but our present email newsgroup server allows text messages only.  I have been watching the use of Slack by San Francisco Radio Club and looked into its use for our club, but ran into an expensive subscription plan, per month, per user.  I see that Richard Dillman may be using Slack in West Marin and wonder how the two clubs are able to use Slack, presumably at a cost that we can compare to our present free service.  If anyone knows, or knows of a newsgroup (other than Facebook or Google) that might encourage better discourse among members, please let me know.

On to comments regarding emergency power.  In spite of the drama stirred up by the local news, our present storm system has been IHMO fairly benign.  There hasn’t been much damage in marin (e.g. fallen trees, landslides. etc.), only minimal flooding, and after many years of draught we are finally filling up our reservoirs.  The water table is still in need of further replenishment.  There has been only one power outage at San Pedro and the two other repeaters haven’t lost utility power even though they are in need of radio maintenance.   Yes, there has been quite a spell of rain in January and can be considered a shot over the bow, e.g. we may not be as lucky in the future.

Concentrating on San Pedro, my thoughts are we ultimately need some sort of solar power generation if we intend to harden the site.  We have a gasoline generator there, but it can only run for something like 18 hours continuously.  Also, it is fully manual, has to be pull-started and we would have to power the radio equipment with extension cords.  There aren’t any gas cans to replenish gasoline, either.  Still, it is a little better than nothing.  We have access to 12V, 7-1/2A sealed lead-acid batteries and have some 15-20 charged in reserve at San Pedro.  But there isn’t any way at present to hook them together or to connect equipment.  At the West Marin site, which is fully solar powered, we have a charge controller to maintain battery charge and limiters for both over voltage and low-voltage cut off to prevent battery damage from excessive discharge.  A lot has happened in the last 8 years with solar technology, much of which I am not familiar, but the basic model of considering charging resources vs discharge (power demand) is as far as I know the same.

At the very minimum, I suppose we could consider a battery system with a charge controller (they now have the limiters built-in), where we could specify, say 2 weeks, of repeater operation and rely on a gasoline generator to recharge the batteries.  That was the basis of our solar power assembly at West Marin.  We tallied the (continuous) receiver power needed and added an estimated a number of hours of active transmitter operation.  That was multiplied by 14 days to arrive at total demand.  In West Marin, there is quite a bit of fog and cloud cover from proximity to the ocean.  That, battery charge efficiency, battery life, available power from the sun, and a number of additional de-rating factors were added together to determine the ability of the solar panels to charge the batteries.  In the case of San Pedro, we also are supporting the AREDN broadband network.  We have 7 dishes and two routers at present, and expect that complement to grow.  The dishes don’t take a lot of power, but the demand is continuous and adds up quickly.  At any rate, all of this can be listed in a spreadsheet and become a design model that will indicate the needed battery capacity, and the solar charge current and become a basis to measure how the system will perform and for how long.  Unfortunately, we have very limited access to our example West Marin repeater and have not been able to compare the design model with actual use.  Suffice to say, the repeater has been humming along for the last 6 years without issue.  Perhaps, thankfully it has not had a lot of use as with all the de-rating, the 4 250AH AGM batteries are barely sufficient.

A kill-o-watt monitor might be a good starting point at San Pedro, although repeater use has been practically only that of the ½ hour Monday night net.  It wouldn’t hurt to update the spreadsheet developed for West Marin to incorporate the AREDN network and arrive at a base line to estimate battery reserve.  There is also an emergency lighting circuit at San Pedro that we should consider updating.  It presently uses 36 volt (!) incandescent bulbs which could be switched to something like +12V LED bulbs (or what is commonly available for boat lighting).  Also, there is a HF station with room for good antennas outdoors.

If you are interested in the project, perhaps the first thing to do is haul out the checkbook and send the club your $25 associate membership dues.  Or more!  There is a lot of possibility at the site, and we need your help, both physical and monetary.  

And we are still hunting around for a club meeting place.

73 de Bill, AB6MT

  _____  

From: Harlen [mailto:hmallis at comcast.net] 
Sent: Tuesday, January 10, 2023 8:56 PM
To: George Shea
Cc: Bill; marinteams at mailman.qth.net
Subject: Re: [MarinTeams] Channel 7 Repeater power outage restored

Agreed

Bill probably knows or if not, we can put a kill a watt on there and see what it uses over 24 hours or even a week if usage is not consistent 

Out

On Jan 10, 2023, at 7:21 PM, George Shea <geoirishbox at yahoo.com> wrote:

At this time, in order to analyze the issue would be to determine how many amp hours are needed to keep the repeaters going given the kinds of transmission outages likely to occur. How many amps does the current repeater draw? In use or in standbye? Then, a decision for a generator/inverter that is either autostart or internet start might be considered is the money is there. Solar is also being used quite well. Show me the money.

Otherwise, end of discussion buy new batteries, I hope lithium.

I am replacing my "house" batteries on my sailboat with lithium bought through home depot.

George J. Shea

415-999-9358

On Tuesday, January 10, 2023 at 05:43:29 PM PST, Harlen <hmallis at comcast.net> wrote: 

Charging would be done either through a generator auto start, which they do make.

Or a C, which is the problem as it goes out then what?

It’s nice having multiple systems so you have a little bit more of a failsafe set up

Question, depends on how important the scenario is so you know how much money to throw at the solution

On Jan 10, 2023, at 4:32 PM, George Shea <geoirishbox at yahoo.com> wrote:

LFPs are lighter, they deep cycle, most have internal controllers to avoid over/under charging, can get at least 4,000 recycles, NO MAINTENANCE, still work fine way past the 50% discharge limitation all other batteries etc. A little expensive, but getting cheaper, especially if stored inside. Maintenance free other than charging, and easily convert to solar when available.

I suggest solar unneeded if reliable source of power to charger keeping batteries topped up.

George J. Shea

On Tuesday, January 10, 2023 at 04:13:39 PM PST, Harlen <hmallis at comcast.net> wrote: 

Agreed and there’s some maintenance on them too.

At this point other than the expense, LFP batteries are so much better of a long-term solution.

On Jan 10, 2023, at 3:48 PM, George Shea <geoirishbox at yahoo.com> wrote:

AGMS that are recycled many times (as in solar installations) easily die after four years especially in cold weather.

George J. Shea

On Tuesday, January 10, 2023 at 10:17:24 AM PST, Bill <wbs at hbco2.com> wrote: 

We have four AGM batteries at the site in West Marin.  It has been solar powered from the beginning and has been running uninterrupted for 4 years, I believe.  Will have to check, can't count that high..

-----Original Message-----
From: Harlen [mailto:hmallis at comcast.net] 
Sent: Tuesday, January 10, 2023 9:57 AM
To: wbs at hbco2.com
Cc: marinteams at mailman.qth.net
Subject: Re: [MarinTeams] Channel 7 Repeater power outage restored

That’s tough with all the gray weather we’ve had two you’re talking about a lot of batteries. It’s the storage that makes all the systems work.

> On Jan 10, 2023, at 9:50 AM, Bill <wbs at hbco2.com> wrote:
> 
> Power is back on at San Pedro.  All of Santa Venetia was knocked out during
> last night's storm, but apparently has been restored.
> Would be nice to have solar backup!
> 73 de Bill, AB6MT
> 
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