DIY Solar panel setup on a budget

may not even be that scammy. could just be a battery where, they 'typod' the capacity and it's really only 4.5kwh, or 45wh or some such.


but yeah you shop aliexpress knowing it's cheap. and you do get what you pay for. having said that I've not had any disastrous purchases, but my purchases are pretty hard to fake/exaggerate the claims. they worst they can do is supply something with cheap metallurgy or not well hardened or such.

 

How did you go getting the refund from paypal/your bank?
I've had to lodge requests before but only for small stuff and after some wrangling aliexpress played ball.

 

Paypal demanded I lodge a complaint with police or a government body & present a signed letterhead confirmation. I lodged with Fair trading NSW (useless in a dispute with a chinese company but at least not wasting Police time). Paypal closed the case anyway. I then tried the bank & because Paypal refused the refund, they did as well.
It was only $50 so not worth chasing further but I closed my Ali Express & Paypal accounts & will never again use either.

For what it's worth. I ordered a large number of servos & received a memory ram chip. The servos couldn't possibly fit in the bag sent which was all provided with photo evidence but because the sender stated they weighed the package before sending, no refund.

 

South west bris.
using existing 6.35 array.

 

I love itemised bills that aren't itemised - should be illegal.

 

It's a quote though so you still have the choice to not go with them if you feel like it.

 

quote or not. how do you know you're getting the $300 and $600 discounts, for all you know they're bullshit, completely absorbed by increases in the other items. or the total is just wrong.

I'd be asking for a proper itemisation before proceeding (or not).

 

My question is, how many KW are you using (Average) daily & how much do you pay per year for your electricity?

You not only have to justify your return on investment in terms of savings on energy bills, but you also have to factor the 19k that's not coming off your mortgage interest.

I really like the idea of being off grid with no reliance on corporations that get rich by charging you as much as they can legally, and not having to worry about price hikes & blackouts. But unless the numbers stack up, I don't see the point. Every time I've checked, the numbers don't go even close to stacking up.

 

oops, I just realised I posed in the wrong solar thread ha.
old man strikes again.

thinks we've considered so far -
the cost of install, the ROI period, the rising cost of electricity and how much higher it's likely to rise with incoming time of use tariffs for morning and evening coupled with feeding in during those peak time with providers like Alinta that pay the going rate to access batteries.
added in is blackout protection and being able to run aircon at night at near no cost.

feed in tarifs are VERY likely to fall to virtually nothing in peak times when solar is working in the very near future.

it's a large outlay indeed, but, given the way we're headed, that ROI time is going to shrink and shrink, and demand for batteries is only going to rise driving prices up. (especially with BYD and other major players having stopped their mining because the arse fell out of the lithium market)

 

it adds up quite quickly.
and as the market changes to time of use. it's going to get worse.

 

Not sure how much difference there is normally with BYD & Fronius to others, but seems expensive to me. I paid about $14.5k for all hardware for our system. 16kw Sungrow SBR, Sungrow 8kw Hybrid inverter. That was retail (eBay) for the Sungrow gear and some wire and ancillaries from local electrical wholesaler. Definitely wasn't $4.5k worth of labour involved.
That being said, it's been an amazing addition. We haven't touched power from the grid for general use since, we are only using grid for off-peak/hws atm. This bill would normally be around $1100 - $1200 for this period, and it's predicted to be $150 (the cost of either hw or daily service charge depending on how you look at it).

 

did you also pay for a switch board, cabinet and rewiring to have blackout protection for the house?

 

I've been doing some maths using my real solar production data from 2022 until now to work out how close we are getting to making battery make sense.

tl:dr - still too long.

I've calculated different sized batteries, assuming 100% efficiency. Putting all excess solar into the battery to its maximum capacity then using it overnight. For everything up to about 10kWh this is true most of the time, once I get above that the formulas don't quite reflect reality (and would lower the ROI and benefits)... but it's not worth fixing as the underlying point remains.
I've assumed $1,000 / kWh of battery and I'm also only using my existing 6.6kW on 5kW inverter solar system to feed it. More solar would help, especially in winter and would help drive up the ROI on the battery.

This table shows the relative values and ROI, using my existing solar install or doubling it (assuming $5K for that). My dirty number say that a 10kWh battery 20kWh battery is still about the sweet spot but needs more solar capacity to ensure I can fill the battery most of the time. Without extra solar, anything much more than 5 kWh in battery capacity isn't really used more than half the time.



Out of interest, my modelling says that against my real historical usage AND if I doubled my solar panels AND assuming my battery is fully charged at 7pm and has to make it to 7am ... you know how many nights I would actually cover that period...??? 11. My overnight usage would exceed my battery capacity 97% of the time.
At 20kWh of battery that number just dramatically to 221 days of full overnight coverage (the norm is 15 - 20 kWh / night), the ROI is only marginally increased to 13.6 Years, although the value per kWh of battery is technically lower. I really am cycling that battery every day and don't know how valuable it is at the end of its ROI period.

To make this work for my current thinking, I would want to get 20kWh of battery + double my solar capacity (by either adding another 6.6kW/5kW or installing a whole system) for under $17K total to get that ROI under 10 years. $12k would get me down to 7 years which is about my ideal "shut up and take my money" kind of level.

EDIT: I've updated the attached table as there was an error in the 10kWh battery line making it look like the sweet spot, for me it's more like 15 - 20kWh of battery capacity.

 

Ah, I missed that line in the quote. So, no I didn't get that (didn't need/want at this point for our use case) but that definitely brings it back to a more reasonable amount.

 

Out of curiosity, what are you using/doing overnight that draws so much power? Ducted air-con? Also, how have you measured your overnight consumption?

 

I download data from the energy provider which gives power data in 30 minute increments. Solar data is by the minute.

What do I do...

Between my comms rack full of network gear, IP Cameras and storage (which is about 275W while doing it's normal thing) plus an aquarium with a few hundred watts of heaters we idle at about 800W before you turn anything else on. In winter the gas heater actually pulls a bit of power to run its fans, in summer it's AC. Autumn and Spring are actually the best months! We do have five people in a large house including people who spend lots of nights gaming. It's crazy compared to many, but it's what we do. I do look for ways to reduce the draw, I think the aquarium is one of the big ones, but I haven't put the meter on that in a long time.

 

Yeh fair enough. We're not quite as high as you but our household runs a minimum of around ~300w before turning anything on as well. Same thing, server/network/cams. We've got an evap ac for summer, which seems to drawer around 800wh, so with us starting on the battery around 6pm or a bit later now, if we turn the ac off around midnight we don't run out of battery , lowest I've seen is around 8% remaining so far. Worst will be if we start getting our usual 40*C+ dry summer days, and the AC will stay on the whole night.

 

Thanks for doing this. I look at this every year-ish and draw basically the same conclusion. Not quite there yet.