Solar PV battery options

Currently planning on expanding my system to take me up to nearly 8kwp and getting close to pulling the trigger on an Ali order. Debating whether to just stick with the 10kw or go mad and get the 20. I think the 10kw will make a big impact but wondering if adding the extra 10 is worth it and would appreciate some recommendation from those who know better. It’s a busy house and our usage averages about 20kwh/day.

Loadshifting the extra 10kWh for 200 days per year saves about €130-€140, to give you an idea of the financials. That's based on a 9c difference between day and night rate (like on the better plans available today), but this difference could of course become much bigger in future. It already is on some plans, like the Energia EV plan.

Not all about money though, loadshifting is better for the environment too as already over 50% of all electricity generation in Ireland during night rate hours is from wind.

LiFePo4 should be 90% usable. I did take that into account in my calculation and the about 20% losses of battery cycling too.

Hi all,

I joined the DIY battery club commisioning last night...finally. Thanks to @championc for the advice last year where the stuff gathered dust in my garage for too long. It has been an extremely rewarding experience and to see myself 93 percent self-sufficient today is beyond my expectations already. Thanks for all the great info here.

Sorry if i'm going over old ground, but I have 2 questions:

1. I have a powerdiverter(same thing as eddi) that doesn't seem to be kicking in now when i have excess going to the grid. Maybe it's a CT clamp positioning issue, but just wondering did anyone have this issue
2. Even though i might be generating 1.5/2kw the battery only appears to be charging at about 300watts... Before i go messing with settings, also, any pointers here?

Thanks again

Excellent info here. Just on the BMS I have mine sitting here from Ali. Search:

"SEPLOS BMS Smart BMS Compatible Inverter 8S-16S 150A 200A Li-ion LiFePo4 Solar BMS Supports Inverter Cell Balance PCM" and look for seller "Minerals Official Store". Cost me € 200.20 with VAT taken off and was charged less than €5 by customs as the vlaue was declared low.

My batteries should be here in the next week or so and my invertor has been sourced too. Excited to get going and planning to document everything. I already have a fair shopping list from this thread for cabling, isolation switches etc etc. I will post the full inventory before purchasing to see if I'm missing anything. One thing I've not seen mentioned (I think) is a fuse between the batteries or BMS and the invertor. Shouldn't I be fitting a midi fuse as well as the isolators and rcbo?

In case anyone needs a seplos bms 150a, I have a brand new one here, with lcd and usb adapter, PM me for details.

I have been running from sun for 7 days now. Still managed to export some as even with 20kWh battery and water diverted I was not able to use everything.

that is class :) hopefully, I'll have similar by end of April.

is that Grafana?

I don't believe its possible to add anything other that AlphaESS own brand battery packs to the AlphaESS inverter. The inverter knows what battery is connected to it when you look at the advanced settings, there is no option to change this or set custom parameters to suit any other battery.

At present I just have solar and would love to build a diy battery however dont have a steal or concrete shed. What are peoples opinion about storing a diy battery in an attic? The shear weight would have me concerned if I wanted to build 20kwh battery, 179.2 kg sitting across roof rafters. Is there anyone storing them in an attic and somehow mounting on a wall so weight is not being placed on the roof structure?

Haven't tried Failte, will wait to see how the China option plays out.

Confirmation today my batteries should be here in about 3 weeks. Excellent communication from oye store but nothing whatsoever from pwod with my other cells but just assuming they are enroute too.

Seplos and extra copper busbars arrived today. Excellent price on the seplos through AliExpress and only 4.74 vat due on them so saved about €100+ on if had bought from UK. Thanks again to buzzfish for the Ali recommendation.

Just one question for those who have got the extra busbars from AliExpress. Are yours also several thin copper bars held together with the shrink tubing in centre as expected mine to arrive as one solid copper bar or at least that is how they appeared when ordered with their photo.