LFP OffGrid Price Point

	A	B	C	D	E	G	H	I	J	K	L
1	Utility Bills										Ver 1.6
2		Total Bill Amount	kWh/ month	Maximum kWh any one day	Maximum kWh any consecutive 2 days	Solar
3	January	$200				$/W installed	$1.00	Using	Using Summer Insolation
4	February	$200				% Oversized	10%	Array Size	17	kW
5	March	$200				Summer Insolation	6	Array Cost	$18,150.00
6	April	$200				Winter Insolation	3.5
7	May	$200				Conversion Eff	95%
8	June	$200				Note: If you already have sufficient solar offsetting your bill, set the $/W to zero
9	July	$200
10	August	$200
11	September	$200				Value
12	October	$200				Inflation Rate	2.00%
13	November	$200				Investment Rate	0.50%
14	December	$200			180
15	Yearly Total	$2,400		Avg max kWh/d	90	Value to replace	$59,480	$ paid to grid over 20 years
16						Cost to Replace	$90,788	$ to add battery, generator, solar PV, & inverter
17	Battery					Value if invested	$96,406	Going off grid doesn't look good
18	$/kWh Raw Cells	$156.00	1st Period	$80.00	2nd period
19	Days Reserve	2	Cycle life chart			Comments
20	Inverter Eff	92%				No idea how correct this might be, use at your own risk. It is what's under discussion on the DIY Solar forums at https://diysolarforum.com/threads/at-what-price-does-lfp-storage-make-it-possible-to-go-off-grid.34354 Just enter values into the Yellow cells on this worksheet, all other values are calculated. Any values in yellow boxes are just rough numbers, replace with your best estimates. Remember: if you have a good net-metering agreement there's no reason to go off-grid. This spreadsheet doesn't look at the net-metering case, oversizing PV to compensate for battery, altering life-styles to match daily consumption to generation amounts (e.g., charging the EV at solar noon), or using your EV for emergency backup. The spreadsheet picks the winter or summer insolation based on the janury/winter insolation > July/summer insolation, should be close in most cases. The array size is the average of the two highest consecutive days, obviously that's a matter of opinion. If your two consecutive days are outliers when you're okay running the generator you should adjust them as needed.
21	kWh Needed	245	Asssumes 80% efficient at End of Life
22	Years life	10	1st Period	10	2nd Period
23	Battery Costs	$47,072.44		$19,565.22
24	Total Battery Investment	$66,637.66	20 year costs
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26	Generator & Invertor
27	Minimum Generator Size		3.8	kW
28	Inverter Cost	$5,000	(20 yr costs)
29	Generator Cost	$1,000	(20 yr costs)
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