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domwild
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Joined: 16/12/2005
Location: AustraliaPosts: 873 |
| Posted: 10:59pm 25 Apr 2022 |
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Fronius build more expensive inverters, but give you a 12VDC signal from the Data Manager card to drive at least one consumer, like the H/W system or pool pump. Can be programmed to switch on when production is more than 2,700W for my 2,400W element for x hours and desired for y hours stopping at 3PM when FIT goes to a very generous 10c/kWh in WA!
Problem is that it switches the H/W in once production goes above 2,700W, but at that time the dishwasher (2,000W) may be on by mistake, so I would like to switch the H/W system off in that case. Assuming at 9:30 it reaches 2,700W, it will stay on 1.5 hrs until 11AM, never to switch on again - manual control here is also desirable.
If Fronius uses a contact-based relay to send 12VDC to my 40A H/W SSR, I can see no problem should I send 12V to the SSR relay as the Fronius circuit is open and I want to switch the H/W on in parallel. If it switches electronically, my knowledge of electrickery is insufficient to know if it is safe to send 12V. Thanks.
P.S.: Plumbing-based solar H/W systems cost probably $2,000 or so, with the Fronius being about $700 dearer (?) and fan cooled, IMHO it looks like a clever solution?
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phil99
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Joined: 11/02/2018
Location: AustraliaPosts: 1781 |
| Posted: 12:35am 26 Apr 2022 |
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A diode between the inverter 12V out and the SSR will protect it from back-feed.
Anode to inverter, cathode to SSR. Manual switch from Bat+ to SSR.
A three position switch will give "Man. On". "Auto" and "Man. Off".
Connect Common terminal to SSR, Position 1 to +12V, Pos. 2 to inverter and Pos. 3 O/C.
No need for a diode with this as the inverter control is isolated in the other positions. |
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domwild
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Joined: 16/12/2005
Location: AustraliaPosts: 873 |
| Posted: 10:49pm 26 Apr 2022 |
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Thanks Phil for help. Sorry, still confused! For convenience I prefer remote switching and not having to go to the switchboard to switch ON/OFF manually.
I know Fronius is suggesting a Finders DIN relay with those three positions, but that would mean opening the lid on the switchboard, switching and closing. I can work on 12VDC, but not with 240VAC.
To make it idiot proof for me and without a manual switch if possible, is there a solution? If so, which diode by number, etc.? Thanks.
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phil99
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Joined: 11/02/2018
Location: AustraliaPosts: 1781 |
| Posted: 04:46am 27 Apr 2022 |
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If the solid state relay is already installed there is no 240V wiring involved. The switch only controls the 12V DC supply to the SSR photo diode.
The switch can be as remote as you like by using 4 core cable of the type used for alarm systems.
If the solid state relay isn't already installed then you will have to get someone to do it. The hot water system is 240V, to control it you must connect to it. I can see no way around that. |
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domwild
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Location: AustraliaPosts: 873 |
| Posted: 08:19am 27 Apr 2022 |
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Thanks Phil for further info. The 240V SSR is installed and the robo system works already with the 12V signal from the Fronius, but as I said before, with my new 12V 133MHz relay I need that manual override.
When the Fronius switches the H/W on, I would like to be able to switch it off and vice versa.
I am not worried about my 12V supply TO the SSR, I am worried about the Fronius side.
Fronius says OFF: If my relay is connected as NC, then my 12V to the SSR via the remote will switch the H/W on and my relay will open, which is OK.
I realize now I have to do a bit more thinking (which hurts!) how I connect as my relay can be in the NO or NC state. If the Fronius 12V signal is ON to the SSR and I also send 12V to the SSR in parallel, then something may go wrong?
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phil99
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Joined: 11/02/2018
Location: AustraliaPosts: 1781 |
| Posted: 01:15pm 27 Apr 2022 |
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A diode between the inverter 12V out and the SSR will protect it from back-feed.
Anode to inverter, cathode to SSR. Your new 12V 133MHz relay contacts connect from Bat+ to SSR. |
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domwild
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Joined: 16/12/2005
Location: AustraliaPosts: 873 |
| Posted: 09:32pm 27 Apr 2022 |
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Thanks once again, Phil. As I am ignorant what sort of a diode I would need here from Jaycar, may I ask you to suggest one?
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
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phil99
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Location: AustraliaPosts: 1781 |
| Posted: 10:57pm 27 Apr 2022 |
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Any general purpose diode will do. Eg 1N4001 to 1N4007, 1N914 etc. The SSR input is probably less than 10mA and almost all diodes can handle 12V |
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domwild
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Location: AustraliaPosts: 873 |
| Posted: 11:02pm 27 Apr 2022 |
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Thanks Phil, very much appreciated.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Winston Churchill |
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domwild
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Joined: 16/12/2005
Location: AustraliaPosts: 873 |
| Posted: 11:04pm 09 May 2022 |
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Thanks Phil. If I understand it correctly, the diode as a one-way switch on the Fronius feed side of the + positive will stop my 12V signal from back feeding to the Fronius?
Assuming the Fronius sends the 12V to the SSR and I send 12V in parallel to the SSR by mistake, is that going to upset the SSR, which by the way triggers from 3V to 25V roughly?
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
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