Repeater Visit April 22, 2011

Tim (KE7TAC) and Dale (K7FW) made a noon trip up to the repeater site. The goals for the trip were: 1) replace temporary fuse in the charge controller, 2) check battery specific gravity and add water, 3) measure opening for door frame and see if new door would easily install.

On our last visit we found that the repeater was off the air due to a blown fuse in the charge controller which prevented the batteries from charging but due to the radios still connected allowed them to discharge down to two volts. We thought that with some good hard charging for a few days we might need to add water and we wanted to check the specific gravity to see how well the batteries were recovering. We found that they had not recovered at all. While we did not need to add water, the specific gravity was not measurable as it was less that 1.1 (water is 1.0). We may find that these batteries do not recover and need to be replaced. We will need to get a low voltage dropout to insert between batteries and radios or get a charge controller with this feature. Clearly we need to protect the batteries from such a complete discharge in the future.

hydrometer reading
When I first checked the hydrometer I
thought that the float might be stuck to
the side of the glass as the float did not
rise at all. After some jiggling I tried a
second hydrometer but found the same
result. The battery acid (such as it is now)
had a specific gravity of less than 1.1,
as low as the hydrometer will read.
I have never encountered a battery
with a specific gravity this low.

Note that the charter (Specialty Concepts, SCI Mark/22) inidcated that it was supplying 12 amps of charging current today. This was the first completely clear and sunny day we have had since our last trip five days ago.

The next order of business was replacing the temporary fuse with the correct form factor. This was quick and easy.

charge controller
The charge controller has two
glass cartridge fuses. On our
last trip we found one of them
blown but lacked a replacement.
Fortunately Ken (WA7PIX) had
a 25 AMP blade fuse and some
small jumpters so we were
able to get the repeater back
on the air.

After replacing the fuse I left
the remainder of the box at
the site so we have some spares
up there.

We went up there with some photos of the replacement door and measurements of the frame. It appears that the replacement frame matches the present door frame so we do not expect that the door replacement will be too difficult.

This was a clear day and gave us a nice view of the coast.

looking west

looking west

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