Navitron Renewable Energy and Sustainability Forum

SOLAR PHOTOVOLTAIC => Solar Photovoltaic Systems => Topic started by: nowty on March 28, 2020, 12:29:51 PM



Title: Tigo TSA-O Optimizers
Post by: nowty on March 28, 2020, 12:29:51 PM
I thought I would share my experimentation with using Tigo Optimizers here at Nowty Towers. Similar to Solar Edge but you can use them on almost any inverter, you donít need any monitoring hardware and you only need to use them on panels where they are needed. The spec is also good enough to use on higher panel wattages (up to 475w) or higher voltage panels (up to 90v open cct V).

They work by adding a variable voltage from zero to the open circuit voltage of the panel to the string at the full existing string current in order to boost the overall string power even if they are partly shaded or in a non-optimal position. So they have their own MPPT for the panel and I presume a step down converter to reduce down the voltage and boost the current to match the existing string current.

There are a few places on my property where an extra panel would fit or an existing difficult string could be enhanced with one of these.


(https://i.postimg.cc/ryvWGCPF/Tigo-1.jpg) (https://postimages.org/)



I added this 325w (60v) panel to an afternoon sunny facade of my car port in series with four existing 250w (30v) panels.

(https://i.postimg.cc/HsXM6cq0/Tigo-2.jpg) (https://postimages.org/)



I added this 325w (60v) panel to a morning sunny wall in series with three existing 245w (42v) panels.

(https://i.postimg.cc/0yCwsg2b/Tigo-3.jpg) (https://postimages.org/)



I added a Tigo to an existing panel (top right) which temporarily shades from my garden fence and added another two panels (with Tigo's) in series (bottom two), both different panel type and slope.

(https://i.postimg.cc/NjtHSGt3/Tigo-4.jpg) (https://postimages.org/)



I first started with just one on the facade of my car port and I was very pleasantly surprised how well it worked. So from there I bought a few more and tried them in several different places. With all the changes I have monitored the string voltage, current and power in different conditions and have frequently disconnected and re-connected the new panel(s) to see the differences.

I have found that the overall string current is slightly reduced, but only slightly, typically 0.1A. The string voltage is always higher and the power is almost always higher. The only conditions I have found it slightly worse is in very heavily overcast conditions when there would hardly be any production anyway.

Everything works best in constant illumination whether that's full sun or overcast. If the conditions are rapidly changing, i.e., full sun, followed by heavy cloud shading, back to full sun again, then it works fine with just a single panel added but where I have more than one panel added, the tracker in my inverter sometimes loses the peak but regains it again within a few minutes when it does its global peak scan. Still overall its much better than before so I am happy with the results.


Title: Re: Tigo TSA-O Optimizers
Post by: kdmnx on March 28, 2020, 02:51:21 PM
I used 2x Tigo optimisers with the two panels I fitted yesterday. I have been wondering how I could know if theyíre doing a good job. Glad you are happy with yours.

How much did you pay for them?


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on March 28, 2020, 03:53:26 PM
How much did you pay for them?

£45 delivered.

I have found them as cheap as £35 but they tend to be the older model with slightly lower spec so you need to be careful if using with a Panasonic higher voltage panel.


Title: Re: Tigo TSA-O Optimizers
Post by: pj on April 03, 2020, 12:24:44 PM
These devices would seem ideal for directly connecting two PV panels to a 3kw immersion heater giving a simple and complete standalone Hot Water solution.
The max output of 90v gives 3000*90*90/(240*240) = 420W max. Current at this wattage would be about 4.5A, easily switched by a regular thermostat.
The device takes care of impedance matching, delivering max power from the panels at any level into the heater.
Also, they are ideal in that they are fully autonomous, with no setup needed, and no ongoing control required.

I know that directly driving immersion heaters from PV has been discussed on other threads - this would seem to provide an answer?


Title: Re: Tigo TSA-O Optimizers
Post by: stannn on April 03, 2020, 06:20:15 PM
These devices would seem ideal for directly connecting two PV panels to a 3kw immersion heater giving a simple and complete standalone Hot Water solution.
The max output of 90v gives 3000*90*90/(240*240) = 420W max. Current at this wattage would be about 4.5A, easily switched by a regular thermostat.
The device takes care of impedance matching, delivering max power from the panels at any level into the heater.
Also, they are ideal in that they are fully autonomous, with no setup needed, and no ongoing control required.

I know that directly driving immersion heaters from PV has been discussed on other threads - this would seem to provide an answer?
This seems to be a very important observation pj as it could presumably also be used to power a storage heater.
Stan


Title: Re: Tigo TSA-O Optimizers
Post by: pj on April 03, 2020, 06:36:27 PM
@Nowty - are you in a position to try an experiment? Take one panel, with one TSA-O and connect it to a regular kettle full of water?


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 03, 2020, 08:18:49 PM
@Nowty - are you in a position to try an experiment? Take one panel, with one TSA-O and connect it to a regular kettle full of water?

What else am I going to be doing in this virus ridden world ? wackoold, I might have a go this weekend, :crossed

I could rig up my 2 x 325w Kuro Panasonic panels (140v Open Circuit Voltage, 120v Max Power Voltage), which already have the Tigoís connected. So thatís 325w + 325w = 650w of solar panels.

The kettle I have is a 2kw one with a 28 ohm resistance element.

So 120v of panels would give 120v / 28 ohm = 4.3 Amps which matches the Panasonic panels nicely as they have a max power current of around 5.5 Amps.

I will have to make up some sort of cable with MC4 connectors. :ballspin


Title: Re: Tigo TSA-O Optimizers
Post by: rogeriko on April 03, 2020, 11:02:00 PM
Thermostats are not designed to switch DC current. Even at 90 volts you will get an arc. Dont forget arc welders operate at only 30v.


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 04, 2020, 01:55:48 PM
Thermostats are not designed to switch DC current. Even at 90 volts you will get an arc. Dont forget arc welders operate at only 30v.

True but if you used them with Storage heaters, then they might never get hot enough to need the thermostat to turn them off.


Title: Re: Tigo TSA-O Optimizers
Post by: JohnS on April 04, 2020, 02:50:41 PM
I would never trust them to switch off without arcing and welding..

Too much of a fail dangerously risk.

Probably invalidates any insurance.


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 04, 2020, 03:09:08 PM
@Nowty - are you in a position to try an experiment? Take one panel, with one TSA-O and connect it to a regular kettle full of water?

What else am I going to be doing in this virus ridden world ? wackoold, I might have a go this weekend, :crossed

I could rig up my 2 x 325w Kuro Panasonic panels (140v Open Circuit Voltage, 120v Max Power Voltage), which already have the Tigoís connected. So thatís 325w + 325w = 650w of solar panels.

The kettle I have is a 2kw one with a 28 ohm resistance element.

So 120v of panels would give 120v / 28 ohm = 4.3 Amps which matches the Panasonic panels nicely as they have a max power current of around 5.5 Amps.

I will have to make up some sort of cable with MC4 connectors. :ballspin

When PJ suggested this yesterday I initially thought that's crazy talk, but after giving it some thought, it might just work so I agreed to do the experiment. And it went as well as you could expect. Now you could argue that the panels I used in full sun are already matched quite nicely to the kettle but I think those Tigo's will allow it to efficiently boil the kettle even in weak or cloudy conditions. Obviously it will take longer but I think quicker than just directly connecting the panels to the load.

I used my 2kW kettle with the switch taped down as I donít think it would latch correctly using DC. I cut the plug off an extension lead and added the MC4 connectors directly to the live and neutral. I disconnected two 325w Panasonic panels (with their Tigoís) from the string and reconnected them to the extension lead.

I simply plugged the kettle into the extension and timed it to boil whilst measuring the current and voltage to the kettle.

As a control I timed how long the kettle takes to boil one litre when plugged into the mains and it took 3.5 mins. The two panels with very shallow angle will not get full power even in todays sun so its going to take at least 4 or 5 times to boil if it works.

Test Panels 2 x 325w Kuro Panasonic Panels (the two all black ones)
(https://i.postimg.cc/D0Z4L5Kg/Panels.jpg) (https://postimages.org/)


The two Tigos
(https://i.postimg.cc/7L3zkfVg/Tigos.jpg) (https://postimages.org/)


Health and safety manager checking everything is ok :crossed
(https://i.postimg.cc/qRp3M4bW/Health-and-safety-check.jpg) (https://postimages.org/)


Open circuit voltage 132V
(https://i.postimg.cc/6pGRMH4b/Open-circuit-voltage.jpg) (https://postimages.org/)


On load voltage 115V
(https://i.postimg.cc/tCcWt0JV/On-load-voltage.jpg) (https://postimages.org/)


On load current 4.9A
(https://i.postimg.cc/1zhF2ppm/On-load-current.jpg) (https://postimages.org/)


Tea Time in 15 mins ! wacko
(https://i.postimg.cc/FRGJY8wz/Kettle-Boiling.jpg) (https://postimages.org/)

Now I wonder how long it would take to boil with a string of 15 of these ?  :o sh*tfan:


Title: Re: Tigo TSA-O Optimizers
Post by: pj on April 04, 2020, 03:29:01 PM
 :genuflect :genuflect :genuflect
Wow that's brilliant Nowty. Certainly proof of concept. As far as using a thermostat for DC goes, you can use contact suppressors to suppress the arc, so a regular cylinder thermostat would work, your measured current of 4.9A well inside the thermostat's limit.

As an afterthought - could you repeat this with less sunshine (what am I saying), maybe in the evening? I'm interested to see that voltage/current output of the Tigo is under less light as you suggest.


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 04, 2020, 04:24:30 PM

As an afterthought - could you repeat this with less sunshine (what am I saying), maybe in the evening? I'm interested to see that voltage/current output of the Tigo is under less light as you suggest.


OK, its on again now at 4:30pm, sun is now way off the SSE facing panels and one is half shaded.

Voltage is 61v and current is 2A, not much but water is still warming up. The panels may shade up completely before the water is boiled but we shall see.

(https://i.postimg.cc/cHR4Cbkj/Shaded-Panel.jpg) (https://postimages.org/)


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 04, 2020, 04:38:30 PM
Shade now over more than one panel, voltage has dropped to 50v and current now at 1.8A, water temp is 50 degrees and 20mins have passed.

(https://i.postimg.cc/rs7hHfMV/More-shaded-Panel.jpg) (https://postimages.org/)


Title: Re: Tigo TSA-O Optimizers
Post by: nowty on April 04, 2020, 04:52:15 PM
Its now 30mins and there is only about 1/4 of one panel left in the sun and at a very poor angle.

Voltage is now 30v and the current is 1.4A.

Water temp is now about 55 degrees.

I don't it will get any higher as its fairly chilly out now and what it gains, it loses to the atmosphere. But I think this shows that it still works even in non optimal conditions.


Title: Re: Tigo TSA-O Optimizers
Post by: nowty 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.


Title: Re: Tigo TSA-O Optimizers
Post by: pj 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?


Title: Re: Tigo TSA-O Optimizers
Post by: nowty 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.


Title: Re: Tigo TSA-O Optimizers
Post by: nowty 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.


Title: Re: Tigo TSA-O Optimizers
Post by: pj 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


Title: Re: Tigo TSA-O Optimizers
Post by: stannn 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.


Title: Re: Tigo TSA-O Optimizers
Post by: daveluck_uk 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!