How to select a second hybrid inverter

[Moxi]

Well for the present we manage really well on the 3.6kW, peak load for us is alway tea time when it’s a combination of any of the following; the hob, oven, air fryer x2, micro wave and kettle.

After a few hiccups the first week my better half has now grasped the concept of spreading the load by switching the various items on at a few minutes intervals and now it all works smoothly.

No doubt this will change when we eventually opt for the ASHP but even then it looks like a 5kW unit would be plenty for us so with some scheduling we could conceivably manage with 3.6kW inverter even then.

Heating at tea time generally comes from the cooking any how.

Because I incorrectly thought dc meant additional hybrid it was a case of well 2kW extra might be useful at some point but having been dragged back to reality I can now revert to type and see how much I can squeeze the house load to meet the available inverter power - not essential but helps me to try and limit my power needs and drive reductions.

Really kicking myself because I have two dc chargers sat in a box in the shed and another cheapo unit running a 20 watt dc panel, battery and bunker lights / phone charger.

I even have some copper earthing strip pieces that are 20mm wide 4mm thick and about 260 mm long to make bus bars for multiple inputs from different charge controllers and panels that will eventually be dotted around the garden.

Moxi

[Joeboy]

Good on ye Moxi. Nothing better than multiple smaller feeds of generation adding up to a net increase in soc. We had it today with 0.75kW incoming. I was grateful.

[Stinsy]

Well for the present we manage really well on the 3.6kW, peak load for us is alway tea time when it’s a combination of any of the following; the hob, oven, air fryer x2, micro wave and kettle.

After a few hiccups the first week my better half has now grasped the concept of spreading the load by switching the various items on at a few minutes intervals and now it all works smoothly.

No doubt this will change when we eventually opt for the ASHP but even then it looks like a 5kW unit would be plenty for us so with some scheduling we could conceivably manage with 3.6kW inverter even then.

Heating at tea time generally comes from the cooking any how.

Because I incorrectly thought dc meant additional hybrid it was a case of well 2kW extra might be useful at some point but having been dragged back to reality I can now revert to type and see how much I can squeeze the house load to meet the available inverter power - not essential but helps me to try and limit my power needs and drive reductions.

Really kicking myself because I have two dc chargers sat in a box in the shed and another cheapo unit running a 20 watt dc panel, battery and bunker lights / phone charger.

I even have some copper earthing strip pieces that are 20mm wide 4mm thick and about 260 mm long to make bus bars for multiple inputs from different charge controllers and panels that will eventually be dotted around the garden.

Moxi

I have a 3.6kW inverter and a "7kW" HP and I get by just fine. It doesn't take much for "one thing at a time" to become natural when cooking. Wait 'till the oven is up to temp before using the hob, if I'm boiling veggies I turn them on earlier to "6" rather than cranking to 9, etc.

A smidge of peak electric here and there makes no difference to anything and most of your big loads (kettle/toaster/etc) only pull power for a very short period. I typically use 30-40kWh of peak electric a month. Sure I could reduce this significantly by running a stricter regime but frankly it isn't worth the effort.

[resybaby]

Only a 3.6kw invertor here too, and agree that the limits such impose can be fairly well 'worked around'. To us as lower users its all about the battery replenishment rate.

MrsResy is occasionally frivilous with the power sucking to the extent that a gentle reminder that the import meter is spending her money is required.

So for those of a similar vintage to myself ive made her this little reminder for Christmas to hang in the kitchen.

Regretably, the singer was 0.6 out with his title, and yes my humour is a little odd.

[Moxi]

spot on !

Moxi

[wookey]

Is there any secret to selecting a second hybrid inverter to run in parallel to your main hybrid inverter ? What do you need to look out for in terms of compatibility?

Some inverters will specifically allow you to pair up another in parallel on the same phase and it will work. e.g. Victron. That doesn't help you if you existing inverter is not Victron (which it isn't). I don't know if any of the other brands have the same feature when you can just add a second when you want to expand.

Also if you have a (recent-enough?) Fronius PV inverter then you can specifically add a Victron inverter and the two will co-operate to respect output limits.

And almost any inverter will work together with a Victron one on AC if you are off-grid (the frequency is shifted to make the other inverters reduce output - i.e using the standard grid mechansim). But that doesn't help here.

As others have pointed out, getting a DC/DC MPPT controller to just DC-connect your extra panels straight to a battery is the simplest way to make this work, and may well be more efficient if you self-consume a reasonable amount via the battery because the DC/DC conversion is 98%+ efficient, which will be better than going through your existing hybrid. But if it's mostly exported then it'll be worse. So overall efficiency very much depends on usage patterns. That doesn't help if you don't have a battery and don't want to get one.

[Moxi]

Hi Wookey, we tend to use all that we can make through the year, it’s only in the last few weeks that I’ve finally bitten the billet and got a smart meter to help us with a cheap tariff through the winter months.

I am just waiting for a break in the Christmas spend then I can buy two kWp of panels and build a lean to shed using them as a pv roof due south at 35 degrees to maximise insolation for my location. That should allow us to be significantly more self reliant than we already are and in the summer we should be able to keep the EV charged up on pure solar - we are low mileage most of the time barring some trips south for work now and again.

Moxi