Solar for Dummies.

10-10-20

https://www.boards.ie/discussion/comment/121922675#Comment_121922675

No way would I trust random power cable off Amazon - too much opportunity for problems. Like I got cable there recently - looks like copper - breaks like aluminium when screwed tight. Obtain cable from an electrical wholesaler here locally is my advice.

ColemanY2K

https://www.boards.ie/discussion/comment/121922847#Comment_121922847

Believe it or not there's a thread on boards explaining how to extend a CT cable.

I then went to Screwfix and bought a 10m long cat 5 cable for a tenner, a heat gun for 20 quid, solder sleeve connectors and sleeves from b&q for a few shekels and hey presto I have a 10m long CT cable.

graememk

https://www.boards.ie/discussion/comment/121923992#Comment_121923992

I just used wagos 😂

jasgrif11

Jelly connectors

slave1

https://www.boards.ie/discussion/comment/121922847#Comment_121922847

I was talking about buriable CAT cable, I’ve long runs under concrete and soil and zero issues, local Kellihers had none

Aph2016

Anyone know the recommended charge percentage for solar batteries, should the upper limit be 80%?

10-10-20

https://www.boards.ie/discussion/comment/121924409#Comment_121924409

Ok, fair enough. Didn't read back far enough.

https://www.boards.ie/discussion/comment/121925114#Comment_121925114

Depends on who you ask. Some would say to charge to 100% and right down to 10% or so.

graememk

https://www.boards.ie/discussion/comment/121925114#Comment_121925114

100%, No issue at all for solar batteries because its LFP, voltage of the cells dont rise until 99% full.

lower limit 10-20%.

bullit_dodger

https://www.boards.ie/discussion/comment/121926252#Comment_121926252

I'd also jump on that bandwagon. 100% as the upper limit for charging, and I'd go down to 10% no problem. The voltage curve drops (very quickly) under about 5% so 10% is a decent buffer. Even at that you won't wreck it if you did go lower. The 80% you've probably heard of is more traditional lithium batteries like the ones in your phone. Keeping them to 80-85% will indeed prolong the battery, but not here as Graeme mentions for LFP cells.

Only thing I wouldn't do is charge to 100% and then keep it at 100% for weeks/months. Unless you need it for a reason, I'd avoid charging and leaving it sit there at 100% indefinitely. I've not seen empirical evidence that it's really bad, but nevertheless I'd avoid it.

ColemanY2K

It's mornings like this I wish I had east facing panels.

If I was to add 2 panels facing east (on a vertical wall) and 2 panels facing west (@ an angle of 15 degrees) on a microinverter would the ESB know from my smart meter data that I've exceeded the 25 amp limit?

allinthehead

https://www.boards.ie/discussion/comment/121929607#Comment_121929607

Only if you export more than allowed.

ColemanY2K

https://www.boards.ie/discussion/comment/121929609#Comment_121929609

That's only ever likely to happen for a very brief period on very good days.

THE ALM

https://www.boards.ie/discussion/comment/121929636#Comment_121929636

Like you I have added 4x435w panels in an easterly direction to catch the morning sun, ours are all south currently. They are on a hoymiles micro inverter.

Ours were installed before the new 25amp limit so have a bit more leeway but have still hit 6823w export. They are in a temporary location before I move them to a permanent frame and am running a few options regards the angle of tilt to optimise them so expect to up the export further.

I plan on running the Eddi during this time or put a small steady charge into the car to keep the export down.

10-10-20

https://www.boards.ie/discussion/comment/121929607#Comment_121929607

Just looking at that. Due east (90 degrees) is very niche especially at a slope of 90 degrees; as would due West, but less-so than due East if the panels were at 15 deg slope (as you would get more indirect radiation). Around 130 deg azimuth would be a sweet spot, you'd get some very low sun in the Winter (little generating capacity due to the low irradiance), but it's better than zero.

The microinverter would only be generating on the shoulders of the main array (presume it's facing due-South), so would contribute well and not be a significant risk of pushing you past 25A, unless the main inverter goes full-export for some reason during a time that the microinverters are also at a max..?

Thinking about it, 4x 430w panels, two split 'east' and two 'west' might work better if the panels are paralleled into a dual-input (dual mppt) microinverter sized around 800w. I'm kind of thinking that a larger inverter would not be required as the panels aren't going to be in the optimal slope, plus the inverter should clip anyway if the input is too high...

https://www.hoymiles.com/product/microinverter/hms-600-700-800-900-1000-2t/

https://www.suncalc.org/#/52.1973,-7.0784,13/2024.06.20/11:31/1/3

bullit_dodger

https://www.boards.ie/discussion/comment/121930443#Comment_121930443

I'd be slow to go for vertical panels facing east/west especially if you have them flush to the wall. I've 2x panels myself (exactly south) vertically orientated on my shed, but have them on an extensible strut where i can vary the angle. The reason being in summer with the sun practically overhead at noon, the angle of incidence to the sun when they are flush kills production.

If you were to give it a lash, if you could get them 20 deg away from the wall that would help -a lot-. I'd probably go for 10-10-20 says above, but I'd have 2 x 2 panel micro-inverters. One microinverter for east and one for west. Need to be careful for wind loading though if you have these panels out in the exposed airflow. (Paralleling them would work, but it would probably be easier to avoid running the DC wires from one side of the house over to the other? Dunno depends on your layout I guess?)

That said, even if you don't angle them out, you will get decent production in the early morning/late evening and ...over the course of the lifetime of the panels, they'd pay for themselves. Plugging it into PVGIS.....800w of panels, 14% loss, 0 deg slope (it's flush to the wall) gives.

354 Kwhr per year. Apply a nominal FIT rate of €0.20, you'd "generate" €90/year with that. So you'd probably payback in 5-6 years depending on what you pay. (Roughly) After that your quids in. :-)

Aside: If you could angle it out 20 deg your production increases by 30% and goes to 450kwhr for 2x400w panels.

ColemanY2K

Cheers lads. Plenty of food for thought.

ColemanY2K

Is this a serious issue? I'm not at home at the moment.

10-10-20

https://www.boards.ie/discussion/comment/121932679#Comment_121932679

Leakage is when excessive current moves away from the live and neutral circuit and into the earth circuit or out through a metal component etc. It can cause a trip of the upstream RCD. Is it serious? Well, depends on the circumstance, but leakage on a kettle or washing machine for example is serious, but a solar install is less-so as it's not as accessible or frequently touched as an household appliance would be. Was it raining heavily when that event popped up by any chance?

ColemanY2K

https://www.boards.ie/discussion/comment/121933268#Comment_121933268

Ya we had a squall around that time. It was pretty intense. One of the strings is on the roof of a metal shed which is sort of concerning. That string is earthed back to the distribution board in the shed.

Perhaps I should contact the spark who commissioned the system to come back and add an earth rod.

graememk

https://www.boards.ie/discussion/comment/121935105#Comment_121935105

Earth rod wont change it, roof being earthed actually could affect it...

I cannot remember the name of it.. @allinthehead you had a thread on it.

10-10-20

Here it is:

https://www.boards.ie/discussion/2058326679/parasitic-capacitance

Parasitic Capacitive Currents in PV Systems Causing Nuisance Tripping

SouthWesterly

https://www.boards.ie/discussion/comment/121929732#Comment_121929732

Where did you buy the micro inverters?

ColemanY2K

https://www.boards.ie/discussion/comment/121935279#Comment_121935279

I can deal with nuisance tripping but is it dangerous is my question? Especially when you consider one of the strings is on a steel shed.

Aph2016

Should I disable charging the battery from the grid? Seems a waste as we don't use much at night, so prefer to wait until the following day for the PV to charge it up.

What do you all do?

NinjaTruncs

https://www.boards.ie/discussion/comment/121935355#Comment_121935355

It depends on how much your night rate is. For me, like many others here, I charge my battery at night and then sell most of what my panels produce back to the grid.

10-10-20

https://www.boards.ie/discussion/comment/121935312#Comment_121935312

Well, that's what I was explaining. I'm not an electrician but the way that I understand it is that it's a side-effect of the way that panels are assembled. It's generally undesirable to have leakage on any electrical system and can be an indication of other issues, except in this case it's DC leakage between the frame, cells and roof of the shed and it's all happening on the isolated side of the AC inverter. So my understanding is that it's not unsafe like having leakage from an AC powered household appliance where full 230v AC is present. At no time are you directly exposed to the DC string voltage nor the AC voltage - that is unless there is another more serious issue with the install - but the indication here is that it's rain-related capacitance.

One thing that I'd do is check with Solis to see what the trigger leakage current is for that specific error as there is a chance that it's set low as a warning - the actual leakage current in mA is not documented under the 1034 error:

https://solis-service.solisinverters.com/en/support/solutions/articles/44002492654-complete-list-of-alarm-display-messages

The thing to check is that all panels are bonded together as well as to the frame and then the shed-roof. That should take away some of the potential and then the 30mA RCD which feeds the inverter will protect the system as intended. If the nuisance trips continue to occur then you might need to look at installing that compensation cap.

allinthehead

https://www.boards.ie/discussion/comment/121935312#Comment_121935312

It's not dangerous, but unfortunately it's not easy to remedy either. Most installers are only now learning about the issue and awaiting updates to the regulations on how to deal with it.

Your spark won't install another earth rod either as it won't solve the issue and could cause other problems. Just be sure that the steel shed is bonded and has a low impedance measurement to the main earthing terminal. Panels and rails need to have the same low impedance measurement too.

Was this a semi diy install? How old is the house?

ColemanY2K

https://www.boards.ie/discussion/comment/121935473#Comment_121935473

Ya semi DIY in that we erected the panels and he came along and ran the cabling and fitted inverter, isolators etc.

This is the first time it has happened (the warning that is, it didn't trip) so was a bit unsure what the craic was. Will keep an eye out to see if it happens again.

GarlicBed

https://www.boards.ie/discussion/comment/121935473#Comment_121935473

100ma RCBOs are coming for solar. a

THE ALM

https://www.boards.ie/discussion/comment/121935307#Comment_121935307

This is where I got mine, took about a week to get here.

Make sure and select with VAT. You also want to order a BC05 connector for the AC out.

If going down the opendtu route make sure and order the correct RF module, unlike me🙄 The HMS series wants the CMT2300A module.