Mixing Gen 3 Hybrid 8kw inverter and Gen 1 battery

Can I couple a new Hybrid 8kw Gen 3 inverter with an existing 5kwh Gen 1 battery plus additional Gen 3 batteries?

I have an old Gen 1 3.6kw Hybrid which is just too small. Whereas a Hybrid 8kwh Gen 3 would give me plenty of capacity to charge at night as well as during the day plus miss the evening peak. It would allow me to realistically run a heat pump (in future) - most of the time too.

What I can't get a handle on is how many batteries I need (and of what gens) I need to support the 8Kw discharge rate that the inverter is rated at. I might not go that far, but I might consider (if its viable) having a 8Kw Gen 3 Hybrid inverter + my old Gen 1 5kwh Battery + a new 8.2 kwh Gen 3 battery. (I've got a 4.5kw solar string).

Any advice please!

No, i Believe the new 8 and 10kW hybrids are needing high voltage battery stacks

you could keep your old gen 1 with its battery and add a new 8kw gen 3 with its own battery stack. As @wrighar says the new inverters take new high voltage battery stacks. Good news is that they are much easier to upgrade now - video on the giv youtube channel

but you will experience cross charging between the two as they operate independently of each other and so one can discharge and the other charge on what it perceives is exported energy.

you would need to carefully schedule the two devices charging and discharging to minimise the cross charging, or use something like home assistant

Thank you both. I have home assistant and should be able to control this. I'm currently evaluating the relative merits of adding a little more storage to my current Gen 1 stack. Or a significantly larger Gen 3 stack (as you both describe). The 'HV' concept had been lost on me (I've not been browsing the new kit for a few months and its now appeared) - now I can see that it all makes sense. I saw an "Artisan Electrics" video on installing the GivEnergy HV kit - interesting.

My main concern now is planning for two things (a) Long-term movement to Time of Use tariffs and likely decrease in Export rates, except at Peak evening hours (See 'Garry Does Solar' recent video - which I agree with) (b) Heat Pump, which I need to model; which will need power all night, and in the evenings.

Obviously cheapest is to increase the storage linked to my Gen 1 Hybrid. But I'm trying to decide if its worth it.

JimBow (b) Heat Pump, which I need to model; which will need power all night, and in the evenings.

You probably won’t need a lot of power for the heat pump overnight because most people set a setback temperature overnight. eg I have my home temp at 19 during the day & evening and 17 overnight.
All depends on how well your house holds heat in, but I find the heat pump doesn’t come on unless it is really cold overnight.

Since I moved to Cosy in January I did change the heating profile, setting the house thermostat to 19 degrees at 5am to 7am so it did some pre-heating in the cheaper Cosy rate.

geoffreycoan Thanks got that. I think mine would drop to 16 or 15 overnight from 19. But likely it would come on intermittently or run at low output as a consequence. Interesting comments. I'll consider them. Thanks