Best way to handle excess solar production

[Bluepr0]

Hello everyone!

I'm planning to set up a solar installation with the following equipment:

- Around 8kW peak solar panels
- 2x Victron Multiplus II 5kW
- 1x Victron Cerbo GX
- 1x Victron Smart Shunt
- 2x LifePO4 DIY batteries (16 cells in series, 13.4kWh each, both in parallel for a total of ~26.8kWh)
- Either Victron MPPTs or PV Inverter (this is the actual question)

My goal is to produce as much energy as possibleand not let the system throttle, meaning I will be producing all the energy the panels can offer and either be sending it to the batteries, some loads, or back to the grid.

My question is if I should use Victron's MPPTs or a PV Inverter like the Fronius Primo. (or the new Fronius Primo GEN24 that can actually directly charge the battery too)

I'm sure I'm missing some important information so please bear with me, really looking forward to your opinions and ideas! Thanks <3

 

[Zapper77]

Check out this thread.

Best way to manage excess power? MPPT or PV Inverter?

Hello everyone! I'm planning to set up a solar installation with the following equipment: - Around 8kW peak solar panels - 2x Victron Multiplus II 5kW - 1x Victron Cerbo GX - 1x Victron Smart Shunt - 2x LifePO4 DIY batteries (16 cells in series, 13.4kWh each, both in parallel for a total of...

diysolarforum.com

 

[Bluepr0]

Check out this thread.

Best way to manage excess power? MPPT or PV Inverter?

Hello everyone! I'm planning to set up a solar installation with the following equipment: - Around 8kW peak solar panels - 2x Victron Multiplus II 5kW - 1x Victron Cerbo GX - 1x Victron Smart Shunt - 2x LifePO4 DIY batteries (16 cells in series, 13.4kWh each, both in parallel for a total of...

diysolarforum.com

#sadtrombonesound

 

[740GLE]

I don’t know why people are so obsessed with harnessing each watt they can.


Size the system to handle 5 days without sun during the lowest solar production months and call it good, if not double it for 10 days storage ?

 

[efficientPV]

I do use every watt because I can, it is cheap and it is smart. I use power when it is available and send excess to heat water. Excess of the excess heats a tank for laundry. All cycles use hot water, clothes come out steaming and really clean. That alone is worth it. Don't need a monster battery to make it work. Batteries are money down the toilet. I can go 5 days with just ambient light.

 

[timselectric]

I don’t know why people are so obsessed with harnessing each watt they can.


Size the system to handle 5 days without sun during the lowest solar production months and call it good, if not double it for 10 days storage ?

I currently have 60 panels turned off. Because I don't need them right now.
I'm a bad , bad solar person. lol

 

[1201]

I don’t know why people are so obsessed with harnessing each watt they can.


Size the system to handle 5 days without sun during the lowest solar production months and call it good, if not double it for 10 days storage ?

We don't all have your money

 

[1201]

I do use every watt because I can, it is cheap and it is smart. I use power when it is available and send excess to heat water. Excess of the excess heats a tank for laundry. All cycles use hot water, clothes come out steaming and really clean. That alone is worth it. Don't need a monster battery to make it work. Batteries are money down the toilet. I can go 5 days with just ambient light.

What kind of washing machine do you have? It must be one of the good old school ones because I think hot water rinse has been extinct for at least 20 years now?

 

[Bluepr0]

Thanks all! So going to my main question... when should I use an MPPT vs a PV Inverter?

 

[Zapper77]

Thanks all! So going to my main question... when should I use an MPPT vs a PV Inverter?

When you exceed your AIO capacity.

 

[MrM1]

What kind of washing machine do you have? It just be over or the good old school ones because I think hot water rinse has been extinct for at least 20 years now?

Yes, without hot water rinse things do sink.

 

[MrM1]

Thanks all! So going to my main question... when should I use an MPPT vs a PV Inverter?

Our AIO is rated for 7000 watts in from 2 built in MPPTs. We overpaneled to 11,800 watts. Could the built in MPPTs have handled it? Maybe. But we added an external MPPT with 2 inputs so we could take advantage of all production.

Some MPPTs can handle overpaneling, some cannot.

In the resources section of the forum is an overpaneling guide for various MPPTs and AIOs

Overview of Over-paneling an MPPT controller

To get to the paper, click on the orange button at the top of the screen. There is a misconception that putting more panels on an MPPT controller than the controller is able to use will damage the controller. However, in almost all cases it is...

diysolarforum.com

 

[Bluepr0]

I’m not entirely sure if I understand what you guys mean with AIO (All in one?).

I do need either an MPPT or PV Inverter as the Victron Multiplus II doesn’t have PV input

 

[MrM1]

I do not know what you mean by a PV inverter? An AIO is an All in One.

Your multiplus is your DC to AC power inverter. Generally solar panels ate plugged into a Solar Charge Controller (aka SCC).

AIOs have SCCs built in

Whew ... That's a lot of acronyms

 

[timselectric]

A PV inverter is a grid-tie inverter. It needs to see a "grid" source to operate.

 

[MrM1]

A PV inverter is a grid-tie inverter. It needs to see a "grid" source to operate.

Check. Never heard it called that. Learn something new every day.

 

[Bluepr0]

I do not know what you mean by a PV inverter? An AIO is an All in One.

Your multiplus is your DC to AC power inverter. Generally solar panels ate plugged into a Solar Charge Controller (aka SCC).

AIOs have SCCs built in

Whew ... That's a lot of acronyms

Yep that’s why I need a mppt or PV inverter where to connect the solar panels!

 

[Bluepr0]

A PV inverter is a grid-tie inverter. It needs to see a "grid" source to operate.

Yep! The multiplus can provide that.

The main difference im seeing is that the PV inverter already takes solar and transforms it to AC while the MPPTs just adjust but still output DC to DC

 

[timselectric]

I would use a SCC, first.
If you get to a point that you have plenty of battery charging. Then you can AC couple with extra PV if needed.

 

[efficientPV]

What kind of washing machine do you have? It must be one of the good old school ones because I think hot water rinse has been extinct for at least 20 years now?

I have a LG front loader with direct drive. Hot water tank is connected to the cold water inlet. I use COLD TAP WATER setting so no heaters come on in the machine. Normally cold water is used for all the dispenser fills. I have same machine at home and there is always a soap film left. In fact I have to clean the fill tube every couple years to remove mold buildup. At camp you could eat out of the soap dispenser. I leave the camp washer for seven months and there is no mold.