inverter outputs

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inverter outputs

Postby dinkum » Mon Nov 13, 2017 7:46 pm

hi,just a basic ?, which is why i posted here. please feel free to move it, if you like gordon.
my ? is is it ok to use solid state relays on the outputs of selectronic se32 inverter or any inverter for that matter.it has open collector transistors max 100 Ma.reason is they have very low current draw and i have some very light telco wire.distance is approx 70 meters i will insert small image to show what i mean...thanks dennis
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Re: inverter outputs

Postby Gordon-Loomberah » Thu Nov 16, 2017 3:31 pm

Why do you have 2 SSRs in parallel with the 240V switching in series? I take it that the DC output is turned on at float, or at some other point you can set?

That's not how I do it here, I use a pressure switch at the pump so that I don't have to run a cable all the way up to the tank. The pressure switch is set to turn off at a pressure that is very quickly reached after the float valve at the tank inlet closes. The inlet is at the top of the tank, connected to a T at the bottom outlet, which has a flap valve to prevent the tank filling from the bottom. I set the cut-in pressure as close as I could to the cut-out pressure, and just running a high flow tap briefly (which is done regularly anyway) enables it to reset.

I was using a Morningstar relay driver to power the pump's flow switch on after the battery had been in the absorb stage for a while, but these days just turn it on manually when there is excess charging current available every week or so. You could use your inverter controlled SSR to do the same thing, and avoid the long cable run.
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Re: inverter outputs

Postby dinkum » Thu Nov 16, 2017 8:24 pm

the reason for 2 ssr's parallel/series is if a ssr fails it is usually in short circuit [on],so one will still switch off. might save floods, pump, etc.the pump is controlled by pl40 load terminal,"on @ float , off @ < 25V , through a relay to switch 240V on/off . i was just thinking if i could control either this relay or the 240V power to pump via limit switch to turn pump off when full. i did think of a pressure switch, but with only a couple of psi diff, full to empty, and a submersible pump it would be easier and cheaper with a level switch.
Gordon-Loomberah wrote: I set the cut-in pressure as close as I could to the cut-out pressure,
does this mean you are cycling your pump often or am i reading this the wrong way. the reason i asked about the ssrs is,i dont want to damage inverter and void the lifetime warranty .lol. thanks..
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Re: inverter outputs

Postby Gordon-Loomberah » Thu Nov 16, 2017 9:45 pm

Only running the pump once per week or so, the 5000l tank will normally last well over a week.
As I mentioned earlier, turning on a large tap will briefly drop the pressure enough (it takes some time for the water to start moving down the pipe after a sudden opening of a tap, as the negative pressure wave travels up the pipe), which resets the pressure switch at the pump.

The difference between a full and empty tank here is only ~20kPa (~3 psi), at 28m head from the pump (~280kPa).

The instruction manual for the inverter should say what is ok to connect to it.

I'm more inclined to trust the reliability of a float valve plus a pressure switch at the pump, than a float level switch at the end of 70m of thin wire + an SSR (or 2)... which is why I did it that way in the first place.
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Re: inverter outputs

Postby dinkum » Fri Nov 17, 2017 7:43 am

appreciate your replies gordon , i will experiment with a pressure switch to see if i can get 1 to work at my pressures.in the meantime i got onto some heavier wire and am digging trench this w/end to run cables and power out to paddock so will have 2 options. in regards to outputs, manual only mentions relays or direct small loads.i'm not sure ssrs were even around 21 years ago.i'll try and contact selectronics advice, and as an afterthought just now, maybe ask about capacitors drying out, as i have read about somewhere.they might be covered by warranty.ha.ha....thanks again.
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