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Author Topic: Workshop PV  (Read 13839 times)
Mostie
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« Reply #15 on: September 30, 2017, 03:28:10 PM »

Good stuff N2, I'm glad the Harlot from hell is gone, for some reason the Radiohead song "Burn the witch" entered my thoughts  Smiley
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2x Solis PV = 1.875 kW, Mitsubishi inverter heat pump. Yorkshire Boiler Stove.
Scruff
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« Reply #16 on: October 01, 2017, 12:25:06 PM »

Get a DC rated Switch-Disconnect for the PV.

Isolators are off-load switches. They don't have things like magnetic blowouts, anti-weld contacts, large arc gaps and fast (1ms) disconnect operation.



* Switch-Disconnect Symbol.png (15.36 KB, 76x108 - viewed 659 times.)
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Nickel2
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« Reply #17 on: October 01, 2017, 01:57:14 PM »

The big switch in the combiner box is a Craig and Derricot PV DC isolator from flea-buy. The individual panels are fused to 1.25 Isc (6.5A~ 7A microwave quick-blow), then switched with Carling 'A' series DC breakers rated at 5A continous, 6.2A break, the curves were checked before buying. The fuses are there to protect the system in the event of a panel-short, (e.g. neighbours throwing lumps of concrete/deliberate sabotage etc; probably not required now, as they have moved), the DC breakers are for isolation experiments to test panel performance under various conditions.
I'm only using 2 sections of the isolator switch, one in each leg. The spec allows a breaking capacity of 30A at 500V full load, DC21B rated, 3 poles one leg, 1 pole other leg, for the 4-pole switch.
I am using 2 poles with a Voc of 45.1V, Imp 4.2A per panel at STC. Although the isolator is quite capable of handling in excess of the break current, The maximum MPPT current will not exceed 28.4A. This is set and limited by the charge controller.
The system is still experimental and not fixed. The panels are brought in separately so that I have the option of coupling them in series, (combiner not used), for possible GTI use.




« Last Edit: October 01, 2017, 01:59:19 PM by Nickel2 » Logged

1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Nissan micra Spirita   (Short range)
kibi
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« Reply #18 on: October 02, 2017, 05:36:12 PM »

It's always a pleasure to see a neat, well thought out installation. It looks like you have enjoyed putting it all together.
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Scruff
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« Reply #19 on: October 02, 2017, 08:48:10 PM »

Sorry about the drive by pre-coffee comment N2. Aye your disconnect bares the brand of worthiness to the task. I found the C&D ABS plastic wanton and reinforced mine with bodge-o-car fiberglass. The disconnect is super fast though thanks to the preload. I much prefer turning off arrays with a blanket though.

..on the subjects of disconnects.. whistlie..maybe a not-ignition protected battery isolator next to the hydrogen vent deserves an upgrade?  surrender

Nice work, tidy.
Love the rails.
« Last Edit: October 02, 2017, 08:51:59 PM by Scruff » Logged
Nickel2
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« Reply #20 on: October 02, 2017, 11:12:56 PM »

Scruff, you're right about the C&D plastic. I dropped the poxy thing on the bench from less than 12" and a mounting-foot half-broke off. Short growlings followed by a visit from Mr Rapid-Araldite, stuck back together before anyone noticed. whistlie
The battery disconnect is only a "what can I do to temporary measure". The batts are sealed Hawker tank batteries 120Ah that I do not push anywhere near their specs, so hopefully any H2 will be re-combined before it causes a problem. Spec says charge at constant voltage of 14.25v + 0.25v, so I stick as close to 14.25 as the user-setting on the MPPT goes. Spec says float (where applicable) is 13.75, so I stick as close to that as possible.
The batts are from 2005, but still hold a reasonable charge considering they are ex-MOD. I'd have a stack of them if I could afford it! Everyone I know that has them say they last for ever. If the squaddies can't ruin them, I'd have to make a supreme effort to do so.
To you Sir 500-600 new. Second-hand 3-year old, 300. Thankyou, I'll have eight please!
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Nissan micra Spirita   (Short range)
Scruff
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« Reply #21 on: October 04, 2017, 01:12:28 PM »

in the case of morningstar the instructions dont say it, but after you ask they email a new page with it on!
even the new unit they sent from states has no mention of pv disconnect before batts.


MorningStar MPPT Operators manual page 29 "Power Up, Power Down"


Sad time of year for solar, I'm expecting my daily gain to drop off a cliff by the end of the month so I'm about to renew my accessory belt tensioner for improved diesel electron extraction. I'll be one month deep cyling from here to March.

If yer into smelly batteries you can get an awful lot more golf carts and not have to be gentle with them for less cost than ex-service AGM. Mine have never dissappointed me.

« Last Edit: October 04, 2017, 01:30:56 PM by Scruff » Logged
eabadger
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« Reply #22 on: October 04, 2017, 06:16:52 PM »

i asked and this is what they said;

Hi Steve,

The proper power down procedure is on page 33 of the latest manual. The same process should be followed for any resets as well. However in your case simply saving an IP change should not have caused a reset as only the server portion of the controller would reset


when they sent a new one i checked manual and no page 33, so they emailed me it!
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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 #23 on: October 05, 2017, 10:01:06 AM »

Nice neat job N2,
                 I am involved in a similar kind of program at the moment but nothing as professional as your set-up.
  Taking the panels connections inside also gives you scope for comparing notes on their individual panel outputs.  Neat!
                                                       Biff
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An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Nickel2
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« Reply #24 on: October 05, 2017, 11:09:15 AM »

Cheers Biff. I have done equipment-wiring most of my life in a wide variety of areas, so my wiring is my signature. (but a lot tidier) As an experimental station, it will give me the opportunity to study the difference between panel voltages in sunshine and shade:
I want to find out if the MPPT unit gains or loses any power by forcing the shaded panels to work at the same voltage as the sunlit panels, away from their optimum operating point on their curves at a given irradiance.
It will also enable me to make a plot of power generated against power used on a day to night basis, and thence derive battery capacity empirically, rather than by rule of thumb or fag-packet calculation.
There is a very reliable grid source to my house, and like a lot of 'garden-shed inventors' I just like experimenting.  Smiley
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Nissan micra Spirita   (Short range)
Nickel2
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« Reply #25 on: October 15, 2017, 06:00:33 PM »

We were promised all-day sunshine today, but my area didn't get out of the mist until gone 2 pm. When it did clear, I plugged the PC into the inverter output and watched the watts adding up.
The first few days were between 300-700 Watt-hours, peaking at 840.  Tongue
Today was my first full kilowatt produced and used  extrahappy
The batteries are probably over ten years old and struggle to hold a decent charge, but are good enough to supply 24V DC to operate the MPPT.
Just got to find a suitable set of batteries now...




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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Nissan micra Spirita   (Short range)
biff
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« Reply #26 on: October 15, 2017, 06:52:39 PM »

The satisfaction is immense N2,
                      Maybe you will go for a set of 48v forflifts and parallel the 24s. Then later if you decide to go up the volatge, you can configure in series. There is some poke in a 48c x 800ah,
   You might get the liking for this electricity generating  Grin and save money at the same time.
  Then you might consider a small horizontal,gas driven Changfa,water cooled to drive a pmg,  Tres quiet, and Tres economical, built by yourself in your own workshop. To throw out 1kw +  for 10 cents an hour. Who knows, you might even decide to opt off grid Grin
                                                                   Biff
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Tiff
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« Reply #27 on: October 15, 2017, 07:10:33 PM »


Sorry Biff, I have to ask, what is a "gas driven Changfa" ?
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biff
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« Reply #28 on: October 15, 2017, 08:18:34 PM »

Well a changfa is normally a diesel powered Chinese horizontal engine,
                       It is a really old design and the engine is found all over the world, You get them small and large , They are a long stroke and have an open vented water tank on top, a bit like the early Blackstones but much lighter. They have been around for decades but are now enjoying a comeback being fitted to small tractors in eastern Europe and Russia. They are very common in the US and used for driving saw mills and generators.. The gas converted one runs very quiet. They have a slow rpm and would be ideal for driving a pmg Grin.
     I researched them years ago with the intention of getting one and almost succeeded but had to settle for a Yanmar clone.There are dozens and dozens of U dube sites dedicated to these engines. They are still produced with even newer models and the older one with a proper rad. The never seem to wear out. I got a strong suspicion that they had a lot to do with the Ho Che Minh Road. They also ran on wood gas. If you google "Chinese Changfa engine" You will see what I mean.
    I was getting carried away there. hysteria
                                              Biff
  There is one for sale on fleabay but under a different name, ( Kukie) It is stuck at 250.00 with one bid. Unused but sitting stored for 4 years.
                                                                                
 
« Last Edit: October 15, 2017, 09:53:10 PM by biff » Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Nickel2
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« Reply #29 on: October 27, 2017, 06:16:59 PM »

Sunshine all day, 1.17 kWh. It would have been more, but I went out in the afternoon, so when the battery got to 100%, it went into float and didn't use all of the power available. If I'd stayed in and used the power, I reckon it would easily have been double.
The morning had me sitting watching the power-level grow from zero to max, between early morning tree-shadows. It's an odd feeling; a frisson of excitement similar to watching your winning bid on flea-buy!
Peak was 455W, with not all panels out of shade.



 
I now have to learn how to manage my new-found power!
Batteries, hmmm...
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Nissan micra Spirita   (Short range)
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