Good day

I don’t have much knowledge on functionality so will appreciate advise.

i have Kodak ~5kw 0G-10-0 with PV panels and grid connected to all loads except geyser and stove.

I want to connect the geyser. My options are to buy another Kodak inverter and connect in parallel and add more pv panels. Which will be the cheaper option as I can make use of my existing excess pv supply

However reading through this forum I see sunsynk has aux feature that I understand can protect my batteries from being used by the geyser.  Is this correct and will it therefore better to go with the sunsynk 8kw and get rid of the Kodak. Or is there a workaround with the 2 Kodaks in parallel.

any advise will be appreciated 

I don’t want to do solar geyser or vac tubes

On 2024/12/24 at 1:24 PM, Rivy said:

will it therefore better to go with the sunsynk 8kw and get rid of the Kodak.

Hi Rivy, welcome to the forum.

The answer is NO! 2 smaller inverters in parallel are better than one big. Because like any other electronic device inverter will fail one day. If you have 2 you will be able to have light with the remaining one until the failed is repaired.

However when buying the additional unit must be identical and with the same firmware with the first in order to be able to be paralleled. That might be difficult to find after a while from the first purchase.

On 2024/12/24 at 1:24 PM, Rivy said:

Good day

I don’t have much knowledge on functionality so will appreciate advise.

i have Kodak ~5kw 0G-10-0 with PV panels and grid connected to all loads except geyser and stove.

I want to connect the geyser. My options are to buy another Kodak inverter and connect in parallel and add more pv panels. Which will be the cheaper option as I can make use of my existing excess pv supply

However reading through this forum I see sunsynk has aux feature that I understand can protect my batteries from being used by the geyser.  Is this correct and will it therefore better to go with the sunsynk 8kw and get rid of the Kodak. Or is there a workaround with the 2 Kodaks in parallel.

any advise will be appreciated 

I don’t want to do solar geyser or vac tubes

How many are you in the house?

For us there are just two adults, fairly set in our routines. I have a heat pump. This is more efficient than a regular geyser (draws less current, heats faster) and it doesn't rely on the sun. I heat the water twice a day, on a timer, and so we can make sure that no other big loads run at the same time. 

I run it on the backed up circuits. I don't have a Deye/Sunsynk, I just have a choice between backed up or not. It draws about 1.2kW when the compressor is running. If I were to turn the kettle and the microwave and the toaster and etc etc on at the same time then something is going to trip, but with two of us this is easy to control.

Because I run it off the backed up circuits, it runs from batteries in the early morning, from PV at mid day (assuming sun). Either way it doesn't cost me much at all. And because I'm able to run it on the backed up side I had hot water and thus hot showers all the way through load shedding.

Also look at insulating the geyser. My geyser is at least 15 years old. New ones might be better insulated. But recently we had the ceiling insulated, and as part of that they insulate the geyser and the hot water pipes to the point at which they enter the wall. It has made a difference, the geyser retains heat for longer.

So there, to further confuse you 🙂, is another option.

Our heatpump is 13 years old now. We had the heatpump before we had solar, and there is no doubt that it saves money over a regular geyser.

I have 2x Kodak 7.2 OG. We went off-grid with 1, but added the second because we have one 3kW geyser, one 2kW geyser, one 1.5kW oven, and the one inverter often could not charge the batteries with all our solar (the solar clipped).

 

We spent an embarrassing amount of money converting our 3kW geyser to a solar geyser - adding a 20L thermal collector tubes system. It is horrible. If I could do it all again, I would just add a gas geyser to the loop (NO thermal collector). Something like:

 

On 2024/12/24 at 1:24 PM, Rivy said:

However reading through this forum I see sunsynk has aux feature that I understand can protect my batteries from being used by the geyser.

I am not sure I understand this. Unless your geyser is on its own circuit, and connected to its own output to the inverter, then I cannot understand how this would work. With the Kodak (Voltronic) inverters, you can set the output source priority to something where the battery is used as a last resort. So, theoretically, you could add something (e.g. microcontroller + switch + relay) to your loop which: when you want geyser, change output source priority to USB (or SUB), then turn on geyser.

 

Final advice about the units: Multiple smaller inverters is much nicer to have. Kodak's are less than half the price they were 1 year ago. Kodak firmware is finnicky - ENSURE the supplier (e.g. Segen) upload matching firmware if you are going to parallel two units.
I asked them to match the firmware, they said they would, and they still sent a unit with different firmware. It took 2 new control boards to get my parallel system up-and-running, and about 4 weeks of back-and-forth. So, ENSURE someone competent QAs your order.

 

Hope this helps

On 2024/12/24 at 1:24 PM, Rivy said:

Good day

I don’t have much knowledge on functionality so will appreciate advise.

i have Kodak ~5kw 0G-10-0 with PV panels and grid connected to all loads except geyser and stove.

I want to connect the geyser. My options are to buy another Kodak inverter and connect in parallel and add more pv panels. Which will be the cheaper option as I can make use of my existing excess pv supply

However reading through this forum I see sunsynk has aux feature that I understand can protect my batteries from being used by the geyser.  Is this correct and will it therefore better to go with the sunsynk 8kw and get rid of the Kodak. Or is there a workaround with the 2 Kodaks in parallel.

any advise will be appreciated 

I don’t want to do solar geyser or vac tubes

Are you fully off grid?

If not, then go with one larger inverter as apposed to two smaller inverters. 

You don't not need the redundency if you still have a utility supply. Should the inveter fail, all you need to do is switch over the change over switch and you are good to go.

Things to consider if you do decide on two smaller inverter as opposed to one larger one.

Paralelling inverters leads to additional complexities and ineffencies. Make very sure both are on the same firmware. Additional AC and DC wires causes additional ineffencies. Monitoring gets trickier, battery communication and set up is more complex.

By adding a 2nd inverter you are doubling you likelihood of having a failure.

An inveter can use anything between 75w to 100w to power itself. For 10 hours overnight that adds up to a lot. Multiply that but two if you want to paralell inverters. 

One larger inverter is usually more cost effecient (cheaper) compared to two smaller inverters. 

If you are offgrid with no utility supply it makes sense to go with 2 smaller inverters.

15 hours ago, I84RiS said:

You don't not need the redundency if you still have a utility supply. Should the inveter fail, all you need to do is switch over the change over switch and you are good to go.

Provided there is no load shedding. Otherwise you could sit in the dark. I'm preparing for the worst with 2 5kW parallel inverters. They run now for more than 4 Years with no problems. Another advantage is to have 2 MPPTs. That allows to connect sets of different type of PVs.