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Author Topic: Tigo TSA-O Optimizers  (Read 2044 times)
nowty
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« Reply #15 on: April 04, 2020, 04:59:34 PM »

Panels now in full shade, voltage is now 20v and current is 0.7A, water has now cooled down slightly to 50 degrees so I think the time to end the experiment.
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12kW+ of PV installed and 65+ MWh's generated.
Useable home battery storage of 50+ kWh's.
Hot water storage of 15+ kWh's.
Storage heaters of 15+ kWh's.
EV BMW i3 (another 30+ kWh's of storage).
6kW+ Ground source heatpump.
310,000+ litres of water harvested from underground river.
pj
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« Reply #16 on: April 04, 2020, 05:07:00 PM »

That's a really interesting set of results - I think we're onto something here.

Can I give you your job sheet for tomorrow? Since it looks like we are in for some more sunshine, repeat as today, but try removing the Tigo units to give a comparison of the power transfer from panels to kettle direct?
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North Hampshire
nowty
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« Reply #17 on: April 04, 2020, 08:36:35 PM »

Can I give you your job sheet for tomorrow? Since it looks like we are in for some more sunshine, repeat as today, but try removing the Tigo units to give a comparison of the power transfer from panels to kettle direct?

OK, I probably wont bother with more photos and I will post the results once later in the day.

I will run the test twice at the same times as today to see how long it takes to boil on the first test and what temp the second test gets to at the end of the day.
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12kW+ of PV installed and 65+ MWh's generated.
Useable home battery storage of 50+ kWh's.
Hot water storage of 15+ kWh's.
Storage heaters of 15+ kWh's.
EV BMW i3 (another 30+ kWh's of storage).
6kW+ Ground source heatpump.
310,000+ litres of water harvested from underground river.
nowty
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« Reply #18 on: April 05, 2020, 05:04:48 PM »

PJ,

I have done some more experiments today and the surprising result (or maybe not that surprising) is that it made no difference if I used the Tigos or not.

Voltage and current where practically the same, the kettle still boiled in 15 mins in full sun. I even shaded parts of the panels and again voltage and current where practically the same, with or without the Tigos.

To restore my sanity, I reconnected everything to the string and shaded parts of the panels and the Tigos worked perfectly. I.e. dropping the string voltage and maintaining the current. So I think you need the dynamic help from an inverters MPPT to make the Tigos work properly.

So where does that leave running resistance loads direct from PV ?

As I said earlier the two panels I used were already reasonably matched to the kettles load. I.e. At max power voltage of the panels at 120v gave a current through the kettle (28 ohms) of 4.3A which is just a little lower than the panels current at max power of the panels.

So I think you just have to try and match a set of PV to a load by making up a string with series and parallel elements in such a way as to arrive at a working current roughly equal to the PV strings max power current. As to the making of a working DC thermostat, you could just use a standard one which then operates a DC disconnect power contactor.

But for me, I prefer AC connecting all the PV and using Immersuns to dump surplus power. My Immersuns have transferred over 20kWhs to hot water and storage heaters today.
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12kW+ of PV installed and 65+ MWh's generated.
Useable home battery storage of 50+ kWh's.
Hot water storage of 15+ kWh's.
Storage heaters of 15+ kWh's.
EV BMW i3 (another 30+ kWh's of storage).
6kW+ Ground source heatpump.
310,000+ litres of water harvested from underground river.
pj
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« Reply #19 on: April 05, 2020, 11:26:38 PM »

Hi Nowty,
Interesting and I guess disappointing results. I'd looked at the spec for your panels, and agree that they do match your kettle very closely for impedance, hence it works nicely without the TIGO in circuit. Great that you could do these experiments, now we know the Tigo does not do the job I was hoping.

I agree, if the grid is available, then AC is generally a better route. I still think though there are scenarios whereby PV direct to immersion would be a good solution - just need that impedance matching Black Box.

Thanks again for doing the testing.
regards PJ
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North Hampshire
stannn
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« Reply #20 on: April 06, 2020, 08:55:47 PM »

Nowty, I suspect that it is the first picture ever published of a mains kettle in the act of boiling water whilst connected directly to PV. Well done.
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2.45 kWp PV (Navitron supply), 40 evacuated tubes (Navitron supply), Clearview 650 log burner with back-boiler heating cottage and water, 2 off 50W border collies, 1 off 35W cat, 1 off 25W cat.
daveluck_uk
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« Reply #21 on: April 06, 2020, 09:10:57 PM »

If it is just for the immersion

http://techluck.com/


I'm 100% sure this has been highlighted here before but I can't find the thread!
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