Benefits of a second battery

I currently have a 14 panel 5.5kW (pk) solar PV system with GE 3.6kW hybrid inverter and GE 5.2kWh battery. I am considering adding an additional 5.2kWh battery to this installation.

Three questions:

• Does this solution increase the peak kW rate that can be stored in the batteries. [With a single battery, it is about 2.5kW]. Or does it simply increase the overall kWh capacity?
• Does this solution increase the peak kW rate that can be used from the batteries. [With a single battery, it is about 2.5kW]? Or does it simply increase the overall kWh capacity?
• Apart from the battery itself, is there any other equipment needed?

Thanks for any guidance

Robert

RobertSw as far as I know extra battery storage won’t increase your 2.5 kWh limit for a Gen 1 hybrid inverter. The Gen2 one has 3.6kwh. What is your daily house demand? If your first battery can’t match that then an extra one might be worth while but not sure about the payback economics. Bill G

RobertSw Unfortunately the extra battery on its own will only increase your storage capacity, it doesnt increase your throughput for discharging or charging. To do that you need to replace the inverter with a later generation model or add a second inverter for the new battery and move some of your panels onto the second inverter.

I have 2x Gen 1 hybrid 5kW inverters so can charge and discharge at up to 5.2kW. The multi inverter “plant” setup isn’t currently recommended by GivEnergy but mine works fine albeit with some screwy data sometimes in the portal reports.

Bear in mind that a second 5,2 battery will only give you about 4.2kW capacity with 80% depth of discharge.
Bang for your buck you are better off getting the larger batteries but even then I’ve struggled to make the economics work for adding in my case a 3rd battery

Many thanks both - that's really helpful. I can now look at the economics of the 2nd battery, but I'd be surprised if they it work out

Is it not the battery that limits the output? We have a 9.5 on ac3 inverter and get 3.6 out. The smaller batteries have lower output.

MarkyG82 The inverter limits the output as well - G1 hybrids can only draw 2.6kW from the 9.5kWh battery for example.

MarkyG82 How do you get 3.6 out. I just got a AC3 plus 9.5 battery and only discharges 3kw

john165 I dunno. It's been like that since I got it. we get regular peaks of 3.2/3.3. Most I've seen is 3.6XX.

There was talk of a 3.6kW AC inverter being available when the 9.5kW battery was first released, I was recommended to take the AC3 and 8.2kW which I did. Maybe GE are starting to release some of their promised developments, EMS next?

Depends what tariff your on I guess.
Weirdly on something like IO Flux it actually pays you to have the smallest battery possible attached to the biggest PV array you can get - to then use the national grid as your battery instead...

However - like the Tesla plan it is essentially based around, they can rug pull the tariff at short notice! (although I guess ultimately the same can be said about any of the other cheap overnight tariffs as well)