Batteries and inverters basic

[Alexphd1]

Thinking about upgrading the system (will be applying for g99).  Just trying to get my head around the basics. Can the battery manufacturer be different from the inverter manufacturer (was aware of high/low voltage batteries and inverters) or best to keep the whole system from one manufacturer Ie solex.

[sharpener]

Two basic options.

1. Buy a Chinese hybrid setup from Solxxx where xxx are more or less letters of your choice. You get whatever they are capable of. May not be fully compliant with anti-islanding regs and so forth. Difficult to integrate with existing or extend/expand later.
    
2. Buy Western-designed separate components e.g. Victron charger/inverter, Fronius grid inverter, 3rd party batteries (probably from China) e.g. Pylontech, BYD. Very flexible. May avoid you having to scrap your existing stuff.

I see your existing setup is described in this post. Tell us also what there is scope for in the way of more panels. Also size of house, lifestyle etc inc HP, EV and cooking preferences.

[Alexphd1]

@sharpener thank you for a prompt reply.

 

420m2 new build with good level air tightness and insulation (passive level but no accreditation). Mvhr,  ASHP still to be connected up. Pv diverter. 8m2 solar thermal. 20kw log boiler. (heating system overkill) Probably end up with a electric van being eyeing up the vw id buzz. 

 

Current PV set up  in roof approx 4.2kw with a 3.68kw inverter. Very basic sma inverter. Would like to at least double PV size with battery storage and be able to add more battery capacity at a later date. Would be adding different orientation of panels to existing so get a but more output in the evening. 

Was originally thinking of ditching inverter and using a hybrid inverter.

[JohnMo]

Or just get AC coupled battery. But really need to decide what you want the battery to do and then size.to suit.

[Dillsue]

22 hours ago, Alexphd1 said:

Would be adding different orientation of panels to existing so get a but more output in the evening. 

If you've got/getting batteries then orientating panels for evening generation may not be necessary if you can orientate them for daytime generation where total generation will be higher, assuming your batteries can soak up all thats generated. Obviously if you've not got the spare space for optimum daytime orientation then put them where you can

[sharpener]

On 23/05/2024 at 20:35, Alexphd1 said:

Current PV set up  in roof approx 4.2kw with a 3.68kw inverter. Very basic sma inverter. Would like to at least double PV size with battery storage and be able to add more battery capacity at a later date. Would be adding different orientation of panels to existing so get a but more output in the evening. 

Was originally thinking of ditching inverter and using a hybrid inverter.

 

Based on our experience with a 5kVA Victron charger/inverter in a 200 m^2 house you would probably want to build a system around this 8kVA model with at least 14kWh of e.g. these Pylontech batteries (which look a lot neater than their more industrial products).

 

System schematic here. They have a matching EVCS though the myenergi zappi integrates well also.

 

You would then get a very versatile expandable setup and not need to scrap your existing sma inverter. Connected to the output of the Victron it would keep going during grid failure, and indeed the transition to running the entire house in a blackout would be seamless and almost imperceptible.

 

Expanding the battery and solar panels then becomes easy when funds and inclination permit.

 

 

Edited May 25, 2024 by sharpener

[frankmcs65]

Hi there, I'm running a DIY 17s Lifepo4 34kw storage happily without directly comunication with the inverter.The two banks are secured by the means of the two seperate bms's,a smart shunt which can shut of,in case of overload,two sepersate fuses which further provide some  peace of mind and then the inverter itself,which regulates the power towards the lifepo4 banks.In this case I've got seperate mechanisms to jump in,if something goes wrong.....I decided on this because firstly my inverter doesn't seem to want to comunicate with any chineese bms- and unfortunately most of them are, and I've seen a lot of problems once you've got banks in parallel....In my setup everything is kept seperate and protects for itself...I'm happy with this🧐cheers frank