Battery size?

[hatienough]

I have 20 Mission Solar MSE320SR8T 320W, 60 cells, 40MM, Monocrystalline Silicon panels and Enphase IQ7-60-2-US 240W Microinverters. What size of battery is recommended for my system? Will my panels charge batteries over the 6.4 kw that the panels produce? In July of last year I used 1084 kwh- averaging 39.67, in August 1238 kwh with an average of 41.26, and in September 1050 kwh with the average at 23.68. The highest day usage for the year was 54 kwh. I have a 3/4 hp water well and a 4 ton central unit.
Thanks for any input,
hatienuff.

 

[Tecnodave]

NO........the microinverters output 240 volts AC at 60 hz......DO NOT connect a battery to high voltage AC....well it might be a quick suicide......SERIOUSLY DONT EVEN CONSIDER IT....

 

[hatienough]

Are you saying that I can't have battery storage with my setup?

 

[Tecnodave]

you can have battery backup but you will need to purchase additional equiptment to do that. The microinverters convert the low voltage DC from the panels into 240 volts AC right at the panel. You would need to purchase an inverter/charger to charge those batteries from the AC coming from the microinverters. And when you do that do be aware that when the grid goes down you will not be able to charge those batteries from the grid tie system. Only able to get AC from the microinverters when the grid is alive. There are all in one inverter/charger/battery units available. The Tesla Powerwall is one such unit......not cheep....others are available.....watch out for the cheep chinese clones that are sold on ebay and Amazon, many are not legal here and are 230 volts single phase and as such NOT compatable with American Style 240 volt.

 

[Bud Martin]

You will need additional equipment, for example:

Can I add batteries to a microinverter based solar system?

Yes you can easily add batteries with micro inverters such as Enphase! You simply use a technique called "AC Coupling" where the batteries are connected directly into the 240V AC in the switchboard...

support.solarquotes.com.au

 

[Tecnodave]

@Bud Martin

That is very misleading, the OP wanted to add batteries to microinverters to use excess power generated by the panels. Read the original post......Yes you can add a Tesla Powerwall or some such but you cannot add batteries to microinverters......there is a huge amount of equipment required to add battery backup, its not just plugging in a battery

 

[Bud Martin]

It is NOT direct hookup of batteries to the microinverter, as I said, he needs added equipment as shown in the block diagram.

 

[snoobler]

Are you saying that I can't have battery storage with my setup?

This is the universal reaction when an owner realizes they have no power when the grid goes down AND how expensive it is to get that feature.

You essentially need to have an off-grid system that becomes the grid for your grid tie system. Inverters that can AC couple will charge the batteries from the PV feeding the grid-tie inverters.

 

[Tecnodave]

go read the OP and reread my response

Of course if you throw ehough money at it you can add a battery backup system to any system but you cannot wire a battery to a microinverter

 

[Tecnodave]

@snoobler,

Yes, absolutely i get that......its all about planning in advance, its much harder to add stuff that was not forseen

 

[hatienough]

My solar panels produce 6.4kw. Do I need to get a 6.4kw battery or can I get one much larger?
Thanks again,
Hatienough

 

[HRTKD]

The battery bank is sized for your loads and how many days you need to satisfy those loads on battery should the grid not be available.