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Author Topic: Cobbled together PV in W.Sussex  (Read 153081 times)
eabadger
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« Reply #300 on: October 10, 2016, 11:57:10 AM »

the two i lost were both after storms, but who knows, i have now wirelessly decoupled the incoming telecom from the lan as this seemed most likely point of entry, but i also considered the issues discussed on web, morningstar were better than the dealers at accepting fault, dealer tried to make out it was over voltage but morningstar said unit was protected against over current and voltage so could not be the issue!!
i already use the morningstar software was just looking at seeing combined but now think that is what the hub1 does but not by tcp/ip

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
biff
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« Reply #301 on: October 10, 2016, 11:59:48 AM »

I would not know a lot about Mppt controllers,
                                             However, i have a decent memory for installation failures and noticed that Mppt controllers had been present in almost 90% of the hassled ones.
     My base voltage is 120volts not 48volts and that does make a difference. Grin.
   So I do not use tristars or Xantrex or big names at all. Instead, i use 2kw Chinese w/t controllers that take 600watt in solar as well. So if they take 2kw from the wind and 600watt from the sun,
   they should be cushy with 2.2kw from 2 strings of solar pv. 1100watt each,
   In their normal use these wind turbine controllers divert the power to two big resistors but in our installation The resistors are bypassed and our 2 x 2kw x 138vdc immersion heaters make use of
   anything above this 138vdc. So instead of using the W/T controllers 3 phase entry i use the solar entry and the amps and the volts come up on the dash giving me an excellent indication of how
   each pair of arrays is performing. It is really simple and easy to understand. The 120volts system allows me to group different panels together and if their voltage amounts to something between
   130vdc or 150vdc,then I can chain then in series as long as the amp ratings are withing .3 of each other which generally speaking has been the case with me.
   I think what happens with the Mppt controllers is that the original installation was set up and calculated to work within a certain safe parameter, giving a certain safe tolerance but then something
   in the installation would be changed and the Mppt controller which would have organised its own way of coping with the Original installation would cope with the added power for a certain length
   of time until the power coming in over loaded the system and then the Mppts get confused and bad things would happen.
   This is the impression that I formed over the years. I may be wrong but my assumed that if these members who were a lot more clued up on Electricity toys than I was, were having all this hassle
   then there was not much hope that I was going to get away Scott Free, because back then I was always fiddling  and poking at things.
   At present there are 3 x 2kw controllers in the system including the one that handles the 2kw charger input if needed, If ever one of these controllers gave up,the others would have no problem
   coping,The whole installation is module based, I can remove any controller and the system will still perform, We might have one tank remaining cold for a short while until the controllers is replaced.
  Maybe if I took the time to try and understand the Mppts a bit better I might be a fan but they seem to be that bit too complicated for me.
                                                                   Biff
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Outtasight
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« Reply #302 on: October 10, 2016, 07:01:39 PM »

Basically, whatever works for you, works.

The TS-MPPT-60 is pretty robust though. I connected about 2.8kW of PV to the controller that is only designed to output 1.6kW. It just limits the output current, sitting pegged at 60A for hours in summer.

All grid tied solar inverters use MPPT inputs so it's no longer a "dark art". Many inverters sport two independent MPP trackers, for those who have split east-west arrays.

The new Tristar TS-MPPT60-600 is a result of advances in power electronics (solar and electric cars) with the ability to accept a 100-525VDC input from a solar array. The normal working voltage of all residential grid tied solar inverters with 14x 60 cell modules in a single series string is about 420Vmp at just 9 Amps (making cabling very easy but requiring a lot of respect for wiring terminals).

Soon nobody will do an install with an array at 35VDC and use 25mm2 cable runs and big parallel junction boxes, like what I dun  facepalm

I say "soon" because there is the matter of cost. The new 600V Tristar is over double the price of the 150V model at 1400 and still only charges at 60A into a 48V or 60V battery.

My PV array is such a Frankenstein work of random sized panels that it will pretty much only work at 35VDC, even though I should now reconfigure it for 105VDC operation to cut the distribution losses. The little 15A chargers are only good to 70V input. I'd have to bin the entire array and start again to use a single 420V string.

The other trend is towards very high voltage batteries, again borrowed from electric cars that use 400V batteries.  Now we're full circle and the 420V PV array is a good match for charging a 400V battery without lots of expensive DC-DC conversion power electronics. It remains to be seen how many fires we see from the long series-parallel strings of tiny (3-4Ah) battery cells used. Historically, a bad idea in battery bank design.

Tesla have almost cracked it, with only a handful of incendiary batteries but Samsung are struggling at the moment to keep ONE cell under control in their Note 7 phone with a 15 watt USB charger. stir
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http://solarbodge.blogspot.com/
3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
Tiff
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« Reply #303 on: October 10, 2016, 07:57:51 PM »

Great stuff, pleased to see this thread still going.

I wonder how many on here have started out with a small experimental system that has grown incrementally?

Sometimes I wish I could go back in time knowing what I know now and start again.
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« Reply #304 on: October 10, 2016, 10:14:02 PM »

I've always said that collecting solar panels was akin to collecting garden gnomes.

You get one, then another, then a few. Then you're featured on BBC South Today as the guy in the  "And finally..." story.
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biff
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« Reply #305 on: October 11, 2016, 11:07:40 AM »

Orrible bad news from Samsung this morning,
                                 Everyone has been asked to switch off their phones,even the replacement ones, sh*tfan   arrrghhhh. No I don,t have one but I know who does. Grin
  On the subject of solar panels. I bought some of the earliest PV panels almost 10 years ago,2 x 80watt x 12volt jobbies. I removed them from the roof of our house last week with the i
  intention of cobbling them together(great word that Outta,)with other used but newer pv panels. I have enough to reach the magic figures 137vdc+ but one thing I noticed was that these
 older pv panels were quite amaturish  and not in the same class as the newer pv panels. So vast improvements were made. The old panels had a smaller area,, 30mm right around and the frames,
 junction boxs and the cables were rather poor quality. I cannot deny that they worked first class while we used them on our old original 12volt house system. They did indeed do a great job but
 the newer panels are without doubt much better all round.
  Folks might wonder what on earth I am doing working PV with W/T controllers but it is not as daft as it first seems. The W/T controllers have a built in "Divert to dump" which is 138/9vdc and
 would be the same as 14volt in the corresponding 12volt installation, That is a bit low but what happens is,that it takes the best voltage for heating water,any lower would prevent the bank
 from getting a fair charge and any higher would needlessly spend excess energy pushing uphill for no real gain. I can boost the bank by dropping one of the dump load immersions for a few hours
 each month or running the charger @ at 147vdc x8amps, bearing in mind that our bank very seldom drops below 123/4 under load.
 Then there is the problem of trying to remember, how we put these works of art together. For a while I was stumped to remember some of my own moves, In fact it took me a few days to figure out correctly
 how I strung the whole lot together. I had Mrs Biff in mind and wanted her to be able to start the charger and bring it onstream. It is now a very simple matter but i had to strip out a lot of  unused
 wiring,take the 230 generator another 100ft away from the house and the charger another 20ft beyond that. The RE ac cables are colored white and the 230 generator cables are colored orange
 The 120volt charger is permanently connected and delivered direct to the Bank meaning that it does away with the need to switch over. We just start the Charger and carry on as before, The
 charger automatically ups the charge in dc the more power we take from the bank. So anyone listening to the engine of the charger would note that it sounded more relaxed the more load put
 on the bank which would be the complete opposite to the AC generator.
   There was a time back in 2010 when i could not even walk out the front door into the sunshine. i was quite ill in fact. The system ran itself but the batteries were without care all summer, by the
  time I was able to walk down and have a look inside the cells,they were all bone dry on top freeze. I filled the 60 cells to the top with rain water and went back to bed. Yes i break a few rules .
  I could maybe have one of those self watering jobbies installed into the bank but unlike the smaller banks, it does not need water near as often and a monthly check is suffice. The summer sun does
  speed up the evaporating process but that is to be expected. I now use proper cell water.
  So If I were to give anyone advice on this type of installation, i would simply say. "Map everything and color code it all"  "Document and date all changes"." Beware of the month of March,especially
  if you have been futtering and improving over the previous winter". March has caught the best of us out.
                                                                               Biff
   
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« Reply #306 on: October 12, 2016, 05:48:44 PM »

Good advice man, and I hope you're fine now.

I've got the same motivation to automation as you - the missus! She doesn't like touching anything to do with the solar stuff. When I had the two battery banks separated, I did train her to press an "enable" button on the inverter and flip a AC change-over switch to select it.

But now I've got the two 400Ah banks in parallel in one bank - another experiment in li-ion battery behaviour. What happens when you parallel two battery strings, one with 1000 cycles on it and the other, brand new. So far, the answer is - no problem. It didn't work out well for my old lead acid bank of random strings of batteries paralleled.

But today's post is a warning to would-be purchasers of new kit. If you're buying anything American, buy it NOW!

The Pound fell to a 168 year low today against the Greenback so I ordered a LCD display front panel for my new Morningstar charger. When UK stocks run out, they'll be buying it in from the US at the new exchange rates.
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http://solarbodge.blogspot.com/
3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
Tinbum
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« Reply #307 on: October 12, 2016, 11:37:20 PM »

the two i lost were both after storms, but who knows, i have now wirelessly decoupled the incoming telecom from the lan as this seemed most likely point of entry, but i also considered the issues discussed on web, morningstar were better than the dealers at accepting fault, dealer tried to make out it was over voltage but morningstar said unit was protected against over current and voltage so could not be the issue!!
i already use the morningstar software was just looking at seeing combined but now think that is what the hub1 does but not by tcp/ip

steve

I had a problem with a Morningstar MPPT and they were excellent about it. Within a week I had received a replacement direct from America. They were very interested in the actual sequence of events of how it failed and of the physical fault within the unit. I didn't have to return the old unit and in the end I repaired it (less than 5 in parts) and I am still using it 2 years later.

With these controllers I think its a case of turning of the PV before the battery- which goes against the sequence for most inverters.
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« Reply #308 on: October 13, 2016, 08:39:46 AM »

Yes, that's the sequence recommended in the user guide. Disconnect the PV first (and I'd only do that when the power input is low or off at night).

I guess one feature that they could add is a "shut down" command from the LCD screen menu or a special way of pressing the reset button. If it commanded the charger to stop charging (so there was no current flowing) then you could quiesce the system and open the contactors without interrupting any big current flow.

There is a way to do it remotely by setting the "charging disconnect" coil in the MODBUS control register from MSView. I use the "EQ triggered" coil quite a lot when testing, especially on the little SunSaver MPPT chargers as they have no buttons or anything on them but I can remote control them through the IP to EIA-485 bridge on the Tristar.

But it is a failing in the design that the controller could be damaged if running at power and the battery fuse or breaker to the charger trips unexpectedly (and I have had 60A fuses blow on me from age related thermal cycling stress). But so far I've not had a controller go pop.

I had to rebuild my Cotek 3kW inverter once as the entire bank of DC push-pull driver MOSFETs exploded (quite literally). The cause of that was an AC side IGBT going internally short circuit and generating a massive overload.



A quite complicated design as it has a brain board that does the control and then two 1.5kW power modules in parallel. A DC-DC converter steps 24V up to a couple hundred volts and then a H bridge (just like in grid tied solar inverters) makes the 230V AC.

The parts were about 30 but it took 2 days of de-soldering and re-soldering to get all the parts replaced. That's why the supplier said they were "uneconomic to repair" out of warranty. In warranty, they'd just bin the whole unit or replace a board/module and pass the cost to the manufacturer.
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3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
biff
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« Reply #309 on: October 13, 2016, 09:26:30 AM »

I would love to be able to fix such things,
                               I have a few controllers that need fixing but there will come the day that i will have the confidence to tackle them, meanwhile they wait patiently.
  Some weeks ago I got a visit from a friend who complained that his inverter was not strong enough to power his large cow byre lights,  a row of large twin florescence lights,60watt a time,
  The whole show is off grid and powerd by a Y/S 600watt W/T and 2 x 80watt pv panels,I gave him a very good 700watt sine wave inverter and that evening i got the call .He siad that it would
  light one light and then conk out when he tried to light the rest. So he tried different suggestions but the results stayed the same. I asked him to change the dc leads coming from the Bank,24v.
  And then he mentioned that he had a fuse on the line,a small thin wire fuse.. Grin I have heard nothing since.
                                                                                             Biff
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Tinbum
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« Reply #310 on: October 13, 2016, 10:01:31 AM »

Yes, that's the sequence recommended in the user guide. Disconnect the PV first (and I'd only do that when the power input is low or off at night).


That's been added to the  manual since I bought mine!!
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« Reply #311 on: October 20, 2016, 01:41:07 PM »

Energy efficiency matters when you're off grid (or trying to be).

I'd got an 8 port Ethernet hub a few years ago at a car boot sale to run the lounge network.

With an increase in gadgets and now two Morningstar charge controllers using Ethernet, I ran out of ports on the hub and it was getting a bit unreliable, sometimes losing connections.

So I bought a second hand 10/100 switch to replace it. This has 16 ports instead of 8 and should perform better as it is a switch rather than a hub. Pretty cheap at just 17 and no need for a gigabit speed switch.



But technology has advanced in power use as well. This 16 port switch uses much less power than the old hub (5.4W against 14.4W), saving 9 watts. That's 0.216kWh per day, 1.512kWh per week, 78.6kWh per year. Important, as the network switch is on 24x365.

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3.58kWp & 800Ah LiFeYPO4 off-grid(ish). See 'Cobbled together PV in W.Sussex' (in "Show Us Yours")
fourfootfarm
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« Reply #312 on: February 09, 2017, 08:33:30 PM »

Just read though this whole thread and its thought inspiring pioneering stuff.

Thanks for the contribution Outta
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Turkish Turnip
Scruff
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« Reply #313 on: February 22, 2019, 09:21:42 PM »



Clicky

 genuflect
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billi
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« Reply #314 on: February 22, 2019, 09:37:38 PM »

 true , Scruff , some  fab people here and have been , hope they   will revisit 
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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