On Mon, 15 Jun 2020 16:40:33 +0100, Brian Reay wrote:

We've got one of the old Friedland 'ding-dong' chimes- it was fitted
when we bought the house and, as strange is it seems, we love it. It
isn't electronic, just a nice, pure, 'ding dong'. Plus, it works like a
Rolex- it just keeps going. I assumed for years it ran off transformer
until someone used it when the power was off and I don't recall even
even changing the batteries. We bought the house in 1997 so they've not
done badly. I do check they aren't corroding etc now I know it isn't
mains powered!

From the above, the reasons we'd like to keep the chime should be obvious.

I also don't want to mess around charging the battery in the Ring Unit
but, it seems, in theory, you can (sometimes) keep the old chime and
charge the Ring Unit- if you have a transformer bell which is compatible.

However, as Ring is really aimed at the US market, compatible for an
older chime seems to mean a chime than runs off a higher voltage than
many UK ones- including ours- the Ring wants 16-24VAC, our chime is more
like 8VAC as far as I can tell.

I've an idea how to solve this- a relay which runs of, say 18-24VAC
which the Ring 'sees' as the bell with the contacts acting as the bell
push for the existing chime, running off 8VAC.

Looking on the Internet, it seems others have done this and it works BUT
as I suspected, there is a problem. The resistance of the relays is
higher than bell coils so the standing current through the relay (to
charge the Ring battery, causes a problem. I suspected this - I'd
worked done some calculations using a best guess of the standing current
drawn by the Ring unit.

It seems this problem crops up elsewhere (not sure where) as Ring can
supply a 'box' which you would connect across the relay coil. (I assume
when used normally, ie not in 'work around' set ups, it would go across
the chime coil).

Said box obviously provides, in simple terms, an alternate current path
for the standing current to charge the Ring unit. I suspect it is no
more than a simple resistor, probably wire wound, able to handle the
power etc. Needless to say, the box has a fancy name the "Ring Pro Power
Kit".

I get the impression they supply these boxes free if you need one but
I'm not adverse to buying one- the Ring itself isn't cheap and a few
quid more for a box, especially as I need to buy other bits etc, isn't
an issue.

HOWEVER, I'd like to understand exacting what is in it, especially as
it seems I'm not using it quite as intended (even though someone else
has has the same idea and used the box etc.)

So, my question to the group, or at least anyone who has fitted a Ring
and used the "Ring Pro Power Kit"- What is in it? It seems to be
(about) the size of a large match box and has 2 wires.

I have now read all 9 pages on the Ring website of users comments
about their wired bells not working, and I recommend you do the same.
One of them even says he got his Friedland ding-dong working and it
didn't mind 24V instead of its 16V max spec.

There seem to be three problems.
1. The Ring app has three settings for external bells - None, Digital,
and Mechanical. When the bellpush is pressed, the power contacts are
shorted by a solid-state relay for the Digital and Mechanical options.
For Digital, the contacts are shorted for a fixed time that triggers
the digital bell to play its tune. For Mechanical, the contacts are
shorted for as long as the button is held pressed.
2. The power terminals make contact with the inner PCB via springs,
which probably corrode after a time in the wet outdoors, so need
cleaning and tweaking after a time.
3. The Ring website gives wiring diagrams for various bell
arrangements, and the 'Ring Pro Power Kit' is only needed across the
bell unit if it is the only bell. One of the commenters opened up the
unit and found a LCB710 normal-closed solid-state relay and a varistor
of some kind. The Friedland man said the chimes passed sufficient
current not to need it.

It could be that without it, the charging current might be enough to
ring an electronic bell continously. Or perhaps one electronic bell
does not pass enough charging current. The unit should look like a low
resistance at the charging current level, but go high resistance when
the Ring button shorts its power terminals, supplying the full 24V to
the bell.

If you keep the batteries in your Friedland and use a 24V transformer
for the Ring, you would need a 24VAC relay in series with the Ring
button and its contacts across the Friedland wires. You would need the
'Ring Pro Power Kit' across the relay coil for the reasons above.
--
Dave W