Solar for Beginners [ask your questions here]

Markus Antonius · 27-09-2022 1:15am

https://www.boards.ie/discussion/comment/119669241#Comment_119669241

I'm planning a ground mounted system so if going up on the roof is the biggest problem then I won't be affected. Apparently microinverters last longer than standard ones too. I also like the thought of getting the most out of each panel.

The only thing turning me off is the high amperage - 1. for safety and 2. for the distance to the fusebox (which will be 23m and then another 10m to the meter)

With my limited knowledge of electricity, I assume there would be less of an energy loss over this distance with a higher voltage system in series.

bullit_dodger · 27-09-2022 1:21am

Don't forget that micro-inverters will be sending AC back to the fusebox at 220v. About 2% losses to the fusebox. Very manageable.

Voltage drop calculator (DC & AC) (photovoltaic-software.com)

If you have no shading, Microinverters won't get any more out of the panels than string inverters. I do have both a string and micro-inverter installation, but in my case the micro-inverters do have to deal with shading. That's not to put you off micro-inverters, only that if that's the reason your buying them, that might be misfounded.

graememk · 27-09-2022 9:19am

https://www.boards.ie/discussion/comment/119669311#Comment_119669311

it's the higher current that generates losses, not voltage.

I have panels about 50-60 m away from the inverter, on 2 strings.

Full power is 400 odd volts DC but only 8-9 amps. On 4 wires. On 6mm2 cable

If the inverter is beside the panels,

It's 230v, 25 amps on 2 wires. There would be more losses on the ac side.

Markus Antonius · 27-09-2022 11:42am

https://www.boards.ie/discussion/comment/119669319#Comment_119669319

Ah I didn't think about the AC being more efficient over longer distances, that's a great point.

I am slightly concerned about shading but have a greater desire for being able to add more panels, which may be more difficult with a series setup? I like the idea of putting in the wiring over the 23m to the fusebox and not having to touch it again.

https://www.boards.ie/discussion/comment/119669779#Comment_119669779

Yes, I said amperage not voltage. Do you have a battery setup? I don't plan on having batteries (as I plan to have an eddi installed and have a backwards running meter). Just wondering if having microinverters would be better or worse if not using batteries or if it matters at all.

micks_address · 27-09-2022 12:38pm

Hi folks,

Do the invertors and batteries make noise? I'm wondering if I should install in converted garage/office downstairs which would be warmer or we have a small space in the side of the house which originally had the oil boiler. It has a door but probably gets colder there especially at night etc.. apparently around 18 to 20 is optimum for battery performance?

Cheers,

Mick

unkel · 27-09-2022 1:02pm

Most inverters use convection cooling (heat sink plus fins but no fans), so are virtually silent. If you go for LiFePO4 batteries, they can be stored inside the house. Small benefit is that the bit of heat that comes from the batteries / inverter can be useful in your house. I wouldn't worry too much about the temps, except that you can not charge LiFePO4 below zero celcius (discharge is fine) as it will quickly kill the cells.

Interesting fact not too many people know is that the Tesla Power wall uses a lithium ion chemistry that is not safe to have inside your house. So these machines use an internal heater to prevent the above. The internal heater uses more energy than your solar system produces on many a winter's day. Not everything Tesla makes is brilliant 😂

micks_address · 27-09-2022 1:35pm

thanks Unkel - you wouldnt have any concern about putting in a inside/outside room/boiler house/shed?

graememk · 27-09-2022 1:38pm

https://www.boards.ie/discussion/comment/119670414#Comment_119670414

I plugged in some example numbers into that, basically it all comes out in the wash, there's practically no difference. For instance say panels are 25 m away and a 6kw inverter or a total of 6kw of micro inverters, 25 amps or so. Standard 3 core cable 6mm² out there

Or having a 6kw inverter at the house and running the DC cables back on 4mm² (but 2 pairs)

The losses on 6kw ac is about 3%,

The losses on the 3kw per pair of DC cables is about 1%. But 2 pairs together is about 2%

Basically it comes down to the amount of copper taking the electric. And the scales we are dealing with, it doesn't matter.

I have batteries but on a separate storage inverter nowhere near my solar.

bullit_dodger · 27-09-2022 2:34pm

I'd go the AC route purely on cost. Smaller cables are typically cheaper to buy. 25merter of 4mm2 (x2) probably wouldn't be cheap. It's also more of a "known quantity" as in is more familiar to people to run AC if someone (a spark) was coming looking down the road.

You've a good few options though and as Graeme mentions you could have a seperate storage inverter inside the house totally distanced from the production side. (I like that idea myself too - although I don't have it)

unkel · 27-09-2022 2:43pm

https://www.boards.ie/discussion/comment/119670954#Comment_119670954

No I wouldn't as long as you are certain the battery is LiFePO4. That said, all my inverters and batteries are outside of my house in steel cabinets or mounted to stone walls 😂

Markus Antonius · 27-09-2022 3:28pm

https://www.boards.ie/discussion/comment/119670972#Comment_119670972

https://www.boards.ie/discussion/comment/119671292#Comment_119671292

Some great wisdom here, thanks a lot. I'll do a bit more research and get a plan/costings together.

Seeing as we're heading into a very solar unfriendly period - do we tend to see any reduction in prices from DIY providers? I'll have to keep an eye on the prices. Might be best to wait until Nov or Jan before I start purchasing.

AckwelFoley · 27-09-2022 4:22pm

Not sure what to do with batteries, and conflicting opinions I'm sure.. but..

I have a 5kw battery due to me but I'm tempted to get a second one

Store of excess in the summer to balance out use during day night without having to use grid but main motivation would be for winter. When we are on the smart meter, if ingo with the "super night rate" tariff at the 12c per kw between 2 and 4 am I could charge / topup batteries rather than use the grid at the 40c+ per kw they will be charging..

10kw stored night rate plus any pittance from the solar I can get in the winter should cover us.

Extra 5kw battery is 2500k

Thoughts?

DC999 · 27-09-2022 5:03pm

https://www.boards.ie/discussion/comment/119671591#Comment_119671591

I think we're heading for a very unfriendly energy pricing period that's multi year. Not spooking people, but I don't see energy products getting 'cheap'.

I don't personally believe that with the worldwide drive for solar (thanks, Putin!!) that costs for kit will come down. Nor labour from installers (sellers market now). Panels are not really getting more efficient (nothing of note anyway). So that only means the producers making more of them to satisfy global demand. And some of them compete with other raw materials that are in demand elsewhere outside solar land (certainly batteries). So that will keep costs higher.

Others have a different view, but I think we're going to see long term energy price rises (so more demand for renewables of course). It's not just Ukraine, more the climate crisis and need to get off fossil fuels. Even a small example is the targets for EV ownership even in Ireland. Majority of cars are supposed to move to EV. Which doubles the energy use for a small-usage house. That juice has to come from somewhere that's not petrol.

slave1 · 27-09-2022 7:56pm

https://www.boards.ie/discussion/comment/119671898#Comment_119671898

Wait and see how you get on, I know you will likely baulk at the idea but the optimal decision is to sell your current 5kWh and do a DIY battery from China (check out the relevant threads), you will get a 10kWh from China for the cost of a 5kWh one here

Fantana2 · 27-09-2022 8:17pm

https://www.boards.ie/discussion/comment/119671898#Comment_119671898

Sell the batteries and buy more panels.

AckwelFoley · 27-09-2022 8:19pm

https://www.boards.ie/discussion/comment/119672818#Comment_119672818

No, wouldn't necessarily baulk at it at all. I haven't got the Puredrive yet as they didn't have it in stock so I can draw a line under it of necessary. I'd need to look into the relevant threads mentioned

kevin101 · 27-09-2022 10:32pm

Hi. Can anyone tell me when is the optimal time to fill my 5 kw battery on night rate. Have a 5kw ( east / west) system installed two months and have €▪︎08 night rate with energia. After only generating 6 kw today and only getting battery up to 60% I'm thinking soon. Or am I better waiting another month or so. Thanks

Jonathan · 27-09-2022 10:37pm

https://www.boards.ie/discussion/comment/119673789#Comment_119673789

No hard and fast rule. You need to be able to get through until night rate starts because the EV day rate is high. The E/W arrays will start to suffer quicker than south arrays as the sun gets lower in the sky.

DC999 · 27-09-2022 11:25pm

Crap. I have an E/W setup for last 2 months too. Didn't know it would suffer more than S with low sun. Ah well, all we could get roof wise. And still delighted to have solar.

yankinlk · 28-09-2022 12:00am

https://www.boards.ie/discussion/comment/119673789#Comment_119673789

I charged up last night amd it rained all day. Tomorrow looks better so I canceled the charge.... maybe wait for clocks to go back if you want to set it and forget it.

Markus Antonius · 28-09-2022 1:14am

https://www.boards.ie/discussion/comment/119669311#Comment_119669311

One downside to the microinverter option I didn't think of is if they are the Grid-tie type they need to "sense" the grid in order to work. In the offchance we head into an era of blackouts and/or I opt to install a battery array - the PV panels would be useless if the grid is down...

Also there is quite a poor choice of microinverters out there.

AckwelFoley · 28-09-2022 5:45am

Just received my first ESB bill since I got the solar in.

Bless them, they estimated it. 😄

idc · 28-09-2022 9:09am

https://www.boards.ie/discussion/comment/119673789#Comment_119673789

I've 11kWh and have started filling 55% about 2-3 weeks back - if days turns out good put on wash/charge the car, bad day like yesterday battery empty by 11.45! It can depend on your system too, if the only way to setup it up is to go to the attic you might not want to adjusting it every day! With mine I can enable/disable from phone so even in the summer i can enable it in the morning if day looks terrible!

unkel · 28-09-2022 9:57am

I'm filling my 20kWh battery fully every night since last week. I use it to heat the house during the day / in the evening. This is slightly more expensive than using gas, (as the round trip cycle through the battery loses about 20%) but better for the environment.

I just ordered a couple of infrared panels, which should provide more efficient heat from electricity than the convection electric heating I use now

The only thing I will have to be very wary of is that I don't want to use day rate electricity for heating (almost 30c / kWh), not quite sure how to handle this, some automation required as I don't want to micro manage / manually monitor it all day.

DC999 · 28-09-2022 10:17am

https://www.boards.ie/discussion/comment/119674958#Comment_119674958

Will you let us know how you find the infrared panels? I'm going to get one to try too and might then get more. What brand did you go for? Cheers

slave1 · 28-09-2022 10:46am

https://www.boards.ie/discussion/comment/119674958#Comment_119674958

A storage heater or two (avoiding day rates for heating), I have one in converted garage and it works well, haven't started heating the house yet, ye townies must feel the cold before us hardened outside the pale

unkel · 28-09-2022 11:36am

https://www.boards.ie/discussion/comment/119675048#Comment_119675048

Got a couple of cheapies in Amazon. A few left with a further 10% discount so I paid GBP116 (€130) incl. Irish VAT and shipping each. It's a dumb 600W panel, so without smarts or thermostat. I will likely use one in my large shed / workshop / work from home office, which has no heating system. Could put it on a smart plug or something

https://www.amazon.co.uk/gp/product/B07RXQ6VXX/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

cobham · 28-09-2022 1:22pm

I refer to previous discussion about used old outhouse for battery/inverter. I had hoped to do same but electrician now says that it is located too far from the fusebox. ( he mentioned max of 5 m?). Also I did not realise there was an optimum temp for battery and the outhouse with simple wooden door would fall below freezing in winter. I have seen mention of inverters being located externally. So both will do in downstairs room ( original garage) and under the fusebox and alarm system box. I asked about noise as room could be used for bedroom or office and he said no noise. He suggested boxing in all the apparatus and to put a vent in same.

bullit_dodger · 28-09-2022 4:49pm

Yeah, the lithium batteries chemistry don't like the cold, especially below freezing when you charge them as that can damage them. So locating them outside in a drafty shed is probably to be discouraged. Not sure where the 5m distance though from the fusebox, that's not really "a thing" other than perhaps he wants to save himself a bit of work and not be laying a long expensive cable.

No noise from these things. You could sleep in the room with one as they are passively (no fan) cooled. You do however want to make sure that you have adequate airing for them. The inverter shouldn't be installed in a closed closet as they can get hot and while they are not fan cooled, they do have to have an adequate amount of air to circulate around them.

unkel · 28-09-2022 5:23pm

I wouldn't rule out a draughty shed because the one or two days we have in Ireland where the temp would be below zero inside that shed. If I think back of last winter, it was mild, we might not have had a single day like that. Remember discharging below zero is fine, just not charging. If you have a cheap BMS, it shouldn't let you anyway. And if you have a high quality BMS (the one residing between your ears) then it would just be aware not to charge when it's that cold.

Solar for Beginners [ask your questions here]

Comments