Going Off-Grid

[SolarBen]

Hello Everyone,

We are considering going off-grid due to the difficulties in getting power to our proposed house location. I have estimated our daily power consumption to be 5700 watt-hours and come up with the following equipment needs:

6000w Solar Panel Array
Schneider Electric Conext XW MPPT 60 Amp Solar Charge Controller
Schneider Electric Conext SW 4048 3,400 Watts, 48VDC Inverter/Charger for Split-phase 120/240 VAC
Schneider Electric Conext XW+ & SW Automatic Generator Start (Xanbus)
Schneider Electric Conext XW+/SW System Control Panel (SCP)
LiFePO4 Prismatic Battery 48V, 100Ah

The house will be near Lexington, KY.

We will install a generator as a backup to the system.

Any Thoughts/Suggestions?

Sincerely,

Ben

[Naptown]

Where will this be located

[SolarBen]

Where will this be located

Near Lexington, KY

[Naptown]

That would require a 1200A battery bank at least 2 of those charge controllers
Is the property on a well?
Start amps on a traditional well could trip out the inverter depending on how much is running.
You will need another charger as IIRC
The internal charger is limited to 50 amps in that inverter. ( stacking two inverters may solve the well and charger issue and offer some redundancy.)

[SolarBen]

What is a 1200A battery bank? 1200 Amps?

IIRC?

No well, the property has water.

[inetdog]

What is a 1200A battery bank? 1200 Amps?

IIRC?

No well, the property has water.

1200A would probably be 1200AH (amp-hour), which is the right dimensions for battery bank capacity. But I do not see 1200AH at 48V as being the right number at first glance, so let's do the explicit calculation:

5700Wh, assuming 100% efficiency, would be 118Ah at 48V.
You do not want to draw your lead-acid battery bank below 80% SOC on a typical day, so that means that you would need 118 x 5 = 590AH battery bank.
To avoid paralleling batteries you would have to build that out of perhaps 4V or more likely 2V batteries to get that high an AH number.
For Lithium, on the other hand, you can get away with running the battery up and down between 20% and 80% IF you have a generator to take you through cloudy weather. In that case, you would need 118 divided by .6 or 200AH of battery, not 100AH. Fortunately lithium batteries take somewhat better to being paralleled that lead acid.

It will be expensive and you will be paying for battery bank replacement very 4-5 years.
That will pay for a pretty high price of bringing grid power in, when you amortize the latter over 20 years or so.
Even if you are not planning to hold onto the property that long, grid power can add a good amount to the sale price of a property.

[Sunking]

Hello Everyone,

We are considering going off-grid due to the difficulties in getting power to our proposed house location. I have estimated our daily power consumption to be 5700 watt-hours and come up with the following equipment needs:

6000w Solar Panel Array
Schneider Electric Conext XW MPPT 60 Amp Solar Charge Controller
Schneider Electric Conext SW 4048 3,400 Watts, 48VDC Inverter/Charger for Split-phase 120/240 VAC
Schneider Electric Conext XW+ & SW Automatic Generator Start (Xanbus)
Schneider Electric Conext XW+/SW System Control Panel (SCP)
LiFePO4 Prismatic Battery 48V, 100Ah

The house will be near Lexington, KY.

We will install a generator as a backup to the system.

Any Thoughts/Suggestions?

Sincerely,

Ben

Not near enough battery, not near enough controller.

Why do you want to pay 6 to 10 times more for power the rest of your life? Once you find out what it really takes you will change your mind.

[Sunking]

It will be expensive and you will be paying for battery bank replacement very 4-5 years.

Wait until he finds out what that battery cost $13,000 and weighs 3400 pounds.

[inetdog]

Wait until he finds out what that battery cost $13,000 and weighs 3400 pounds.

Even for Li?
The original proposal was for LiFePO4 Prismatic Battery 48V, 100Ah. I just threw in Lead Acid for comparison.

SolarBen,
Going that large in Li for a first system at a new site is risky as the knowledge about Li for RE is still evolving.
Of the members here PNJunction may have the widest familiarity with LiFePO4 and other Li alteratives with Sunking coming in ahead of most members based on theory and experience with Li in the electric vehicle arena

[Sunking]

Even for Li?
The original proposal was for LiFePO4 Prismatic Battery 48V, 100Ah. I just threw in Lead Acid for comparison.

6000 watt panel on a 48 volt 100 AH system? The OP has not answered the very first and most important question of all. How Many Watt Hours in a Day? . Until that question is answered he is just pissing in the wind. Once that is known, he will not like what it really takes. But one thing I can tell you he is not putting a 6000 watt panel on a 48 volt 100 AH battery of any type. That just scares the heck out of me.

[inetdog]

6000 watt panel on a 48 volt 100 AH system? The OP has not answered the very first and most important question of all. How Many Watt Hours in a Day? . Until that question is answered he is just pissing in the wind. Once that is known, he will not like what it really takes. But one thing I can tell you he is not putting a 6000 watt panel on a 48 volt 100 AH battery of any type. That just scares the heck out of me.

I have estimated our daily power consumption to be 5700 watt-hours

How's that?

[Naptown]

Sorry i miscalculated battery size for FLA.
About half is correct

[SolarBen]

Thank you all for your insights.

I am looking at Lithium Iron because it has very little degradation over time. They seem to cost around $3k per 100 amp hours but if they will last indefinitely it seems worth it.

[inetdog]

Thank you all for your insights.

I am looking at Lithium Iron because it has very little degradation over time. They seem to cost around $3k per 100 amp hours but if they will last indefinitely it seems worth it.

The biggest problem (beyond the risk of destroying your very expensive battery bank while learning your way around) seems to be that all of the cycle life specifications are the result of accelerated testing, rather than actual experience under RE conditions.

As for the risk, not all folks starting out with Li realize that:

1. Going for that last 20% or so of charge puts the battery into a state where it ages many times faster just sitting there than it would at a lower SOC. You can easily cut your battery life in half just by regularly charging it fully (not just by overcharging, which is harder to do.)
2. Even if you do not go down the 0% SOC based on the starting point of irreversible reactions inside cell, there is a higher voltage threshold (somewhere above 10% SOC I believe) at which the cells will not safely accept the normal C/2 or even C/10 charging rate and will be damaged unless trickle charged back to a safe point.

Read the various threads on LiFe and other Li chemistries from PNJunction for more details.

[LETitROLL]

Hello Everyone,

We are considering going off-grid due to the difficulties in getting power to our proposed house location. I have estimated our daily power consumption to be 5700 watt-hours and come up with the following equipment needs:

6000w Solar Panel Array
Schneider Electric Conext XW MPPT 60 Amp Solar Charge Controller
Schneider Electric Conext SW 4048 3,400 Watts, 48VDC Inverter/Charger for Split-phase 120/240 VAC
Schneider Electric Conext XW+ & SW Automatic Generator Start (Xanbus)
Schneider Electric Conext XW+/SW System Control Panel (SCP)
LiFePO4 Prismatic Battery 48V, 100Ah

The house will be near Lexington, KY.

We will install a generator as a backup to the system.

Any Thoughts/Suggestions?

Sincerely,

Ben

Any chance of getting grid power to the location for $50,000 ?