ojeysky:


Documentations that I have read[1] suggests that combiner boxes are for high PVs with over 500kw. How is it going so far with your new tool?

Regards
1. https://www.quora.com/What-is-the-purpose-of-a-combiner-box-in-solar

NiyiOmoIyunade:
My Oga,

For surge protection, a device like the MNSPD 600 will do very well provided you already have a low resistance earth connection installed for your site - see product link below;

https://www.amazon.com/dp/B00BSYSZP4/ref=cm_sw_r_wa_apa_i_-jGwCbDTNSWRN

If you are a risk taker, you could even deploy an MNSPD 300 for finer/more precise surge protection given that your target operating voltage is within the MNSPD 300's MCOV range - pertinent to note, an 'ungrounded PV array' does not mean or imply that the installation is not surge protected and grounded/earthed at the DC side.

For combiner boxes you can either buy any of Midnite's boxes (premium priced) or improvise one by yourself using a suitable enclosure and properly rated DC breakers and/or busbars.

duwdu:


OK, thanks a lot for steering me on the right things as usual; makes my choices very clear.

With the part of your statement I have put in bold characters, and assuming I provide proper surge protection, will grounding the array to the ground connection provided on the inverter itself be sufficient or even desirable? (My apologies if I've made little sense here, as the instructions say grounded arrays may provide a path for current leakage to the inverter and are therefore not called for? I have attached some extracts from the Instructions that made me interpret it to be so, for further help.)

........
P34c3
.....
...

NiyiOmoIyunade:
My Oga,

I believe that a surge arrestor cannot work effectively if it is not connected to a earth/ground point so that any fault current (surge) can be diverted safely to earth/ground. In fact having a surge arrestor in place with no earth/ground reference increases the risk of catastrophic equipment damage in the event of a surge.

To satisfy the requirements of item 11) "Grounding Instructions" and item 15) "Caution" per the screenshot below, you should simply connect the PV+ and PV- of Solar Panels from your Combiner box to the Inverter PV+ and PV- receptacles and connect the inverter's earth receptacle to your installation's permanent earth/ground point with suitably rated cables.

Install the surge protection device at the PV combiner box - connect positive of SPD to main trunk PV+ of combiner box..........

So in summary leave the actual solar panels ungrounded but ground the inverter, ground the combiner box, connect the SPD to combiner box main PV+ and PV- and definitely ground the SPD - if possible all devices should connect directly to central earth/ground but you may share thesame earth connection between combiner box and SPD.

If panels are more than 50 feet from the combiner box, you could also ground the panel mount frame/rack.

The ideal earth/ground point is a low resistance earth implemented with......

Trueigbo:
I have a solar system of 2 panels, 100ah battery and 1kva inverter.

I have changed the inverter twice as the inverter gets damaged and stop giving output.

What should i do because i want to get another one.

Trueigbo:
I have a solar system of 2 panels, 100ah battery and 1kva inverter.

I have changed the inverter twice as the inverter gets damaged and stop giving output.

What should i do because i want to get another one.

NiyiOmoIyunade:
My Oga,

I believe that a surge arrestor cannot work effectively if it is not connected to a earth/ground point so that any fault current (surge) can be diverted safely to earth/ground. In fact having a surge arrestor in place with no earth/ground reference increases the risk of catastrophic equipment damage in the event of a surge.

To satisfy the requirements of item 11) "Grounding Instructions" and item 15) "Caution" per the screenshot below, you should simply connect the PV+ and PV- of Solar Panels from your Combiner box to the Inverter PV+ and PV- receptacles and connect the inverter's earth receptacle to your installation's permanent earth/ground point with suitably rated cables.

Install the surge protection device at the PV combiner box - connect positive of SPD to main trunk PV+ of combiner box and negative of SPD to the main trunk PV- of combiner box - it may help to use busbars in the combiner box and crimp heavy duty cable lugs (like the type used for battery cable connections) onto the Surge Protection Device's wires so this way you can torque everything down tightly onto the positive and negative busbars - the combiner box should have a 3rd busbar or wire terminal which is dedicated/already connected to central earth/ground for the installation. You must connect the 3rd wire (green earth wire) of the SPD to the combiner box earth bus bar or splice on suitable cable (crimp, do not twist wire together) so you can connect SPD directly to the central earth/ground point.

So in summary leave the actual solar panels ungrounded but ground the inverter, ground the combiner box, connect the SPD to combiner box main PV+ and PV- and definitely ground the SPD - if possible all devices should connect directly to central earth/ground but you may share thesame earth connection between combiner box and SPD.

If panels are more than 50 feet from the combiner box, you could also ground the panel mount frame/rack.

The ideal earth/ground point is a low resistance earth implemented with suitable rating, number and length of ground rods and suitably thick cables - use proper earthing chemicals where required and avoid the use of earths implemented with charcoal lumps and salt unless the charcoal has been grounded into fine powder and mixed thoroughly with suitable base materials to form a slurry.

NiyiOmoIyunade:
I thought again that if budget is a constraint you could dispense with a combiner box and use a set of busbars to simulate a combiner box especially since your array is simply a set of panels in series and no parallel connections.

You would connect your panels in series as usual then run suitable gauge wire from PV + to DC Breaker (make sure breaker is rated for your high PV voltage) then from DC breaker to positive bus bar. The DC breaker allows you to isolate the array for inspection and maintenance - I would be very careful here that the breaker actually disconnects the PV as you definitely don't want to be zapped by 360vdc while attempting maintenance

But I digress....

You would connect the main PV- to a suitable gauge cable and run directly to the negative busbar. You should have free ports on the busbar to which you can now torque down your surge protection devices positive and negative cables (I still advise to crimp on cable lugs). The idea here is that you don't want to fit two cables (PV+ and SPD+) into your Inverter's PV+ terminal so that you have a firm mechanical and electrical connection (very key for lightning/surge diversion) and also to decommission the installation with minimal damage to cables.

The SPD's 3rd wire (green/earth) would then go to the installations central earth/ground point.

The busbars must be properly covered/isolated since they will be carrying dangerous DC voltages.

Namzy:
Is their anyone selling used 16mm2 cable for cheap? I'm asking for a friend. Thanks

nonoski:
Finally finished my connections and powered the Outback Flexmax 80 Charge Controller and joined the club.

Thou I'm still confused about some of the readings

My set up for now is 12 nr 300watts panels (3600kw) in 3S4P connection and battery bank is 48v 200amps.

(I intent to add 3xtra panels to make it 15 panels and increase the battery bank size to 48v 400amps in the next few weeks)

earthrealm:


Any cons of this CC?..180 usd price diff btw it n my beloved morning star....sorely tempted

GeorgeD1:


i have some meters of red and black 16mm cables used in my last installation.
if interested you can pm me. but note however that it's not multi-strand and
the insulation has been scrapped in a few places (will require you applying the
usual black electrical insulation tape to make it good)

Peterjosh:
Hi...

I need a very cheap and durable solar device to just power my laptop consistently.

I live in a village with no electricity..

Where can I get one and what's ur advice??

kiekie1:
Pretty dull weather today! Seeing less than 55-63a as usual. Ran heavy load overnight , doubt if Batteries wld float today ....

Saipro:
The DC calibration on my 3kW 48V MustPower inverter has finally gone haywire. Showing 63.2V at a factual 57.0V absorb. It forces it to power down with an error 9. Over the years, it's been swinging between correct calibration to it's current absurd one.

I can lower absorb to 56.6V to make it usable but I've cracked out the spare Victron until I'm sure the MustPower won't burn down the house.

Any help?

kiekie1:
A unit of fairly used Emerson 24v 60a bulk charger module up for sale ...#20k

Contact,
Smartcellglobal
081-350-31951

Saipro:

1.2kW instantaneous and you're complaining? My 3kW array hardly fares better understand the harmattan haze here; same array which generates 2.5kW during the monsoons

Jiteshell:
Hey guys..

So I'm not a DIY person when it comes to stuff like this.
What I'm concerned about is powering a freezer (see pics attached for wattage info and stuff) for about 10 hours everyday with solar.

I would also like if it can power my laptop for that same amount of time.

For those into stuff like this, can I get an estimated cost for without the laptop and with it? I know laptops don't need lots of power...but just saying.

So solar + inverter...hybrid system preferably...

earthrealm:


120w x 10hrs = 1200w
,min batt config i wud recommend is 2 units of 12v 200ah,
min panels i wud recommend is 1000w/900w 4 x 250w, 3 x 300w, 3 x 330w etc
laptop takes 40 to 80w depending on size, and once that batt is fully charged, its consumption drops to below 40w, so its negligible

250w cost = 35k to 65k..depending on type/make
12v 200ah cost btw 90k to 140k depending

a good 1.5kva inverter can power your load, but if the your budget is a lil freer, go for a 2,4kva
check the prices from our vendors here....that shud give you an idea of budget.
you can also keep 30k to 80k for logistics/labour/other ancillary items you might need