Another Solar Quote Opinion

Lavabread

Hi All,
I'm slowly working my way toward a solar pv install but before I commit I thought I would seek the opinions of the pv'er experts here on the forum.
The installation will be 4.5KW/4KW in South Wales at 51 deg SW inclined at 30 deg and no shading
I've had a number of quotes but I am now focusing on a straightforward system as there is no shading, comprising of 18 off Seraphim 250W All Black Mono 54 Cell and a Solis Inverter at £5.9K or a 4KW system with 16 panels for £5.3K.
The questions I have is the 0.5KW allowable/worth it? Are the quotes competitive?
Anyone have an opinion about the inverter?
Is a solar cache a good investment? I was told there have been some reliability issues. If a solar cache is installed does it only 'utilise' the excess electricity after other appliances e.g. washing machine?
Is extra warranty advisable given that it will probably cover the hardware and not the labour etc?
Any views on an online monitoring product?

tunnel

Considering a friend of mine had near enough the same quoted hardware at £500 less for a 4kWp system I'd say its still a tad on the high pricey side.


I'm assuming solar cache is a diversion switch like the immersun or iboost. If you have a hot water tank then well worth having one and yes, it'll divert the excess "after" everything else is taken care of.


As for 4/4.5kWp...well it's a grey area, some will say 4.5 is ok with a capped inverter of 3.68kWp but you may need to get DNO approval. For the sake of 500Wp I'd be inclined to stick at 4kWp and save the hassle..unless you can squeeze even more up there, either same roof or maybe multiple rooves.


As for online monitoring, wattson solar plus is pretty impressive but there's plenty of choice, best do a bit of homework and maybe post on the renewables thread to speak to some of the other PV'ers, they'll probably give you a link to show you their own online monitoring.