Am I oversizing my system?

[Ampster]

Im in Southern California. Sounds like DIY isnt going to pan out so well haha

It depends on your local jurisdiction and whether they have adopted NEC 2020 yet. Last year I did a permitted GT install and then self installed a UL listed hybrid inverter in compliance with the code at the time. I am not advocating doing anything that is illegal but there is some grey area and the line is not always perfectly defined. It would be better to discuss the details off line.

[jplee3]

Are you in Australia? I read in some other forums that some are having luck with LFP cells from China that are selling for about USD 150 per kWh. The DIY battery market in the US is complicated by NEC 2020 which requires UL listing for batteries installed under a building permit. Tesla, Generac, BYD, LG Chem, Outback and some others have product for that niche.
I have a 42 kWh DIY pack I installed a year ago using EVE LF280 cells that I purchased two years ago for USD 125 per kWh delivered to my door.

Im in Southern California. Sounds like DIY isnt going to pan out so well haha

[Ampster]

BTW: anyone have specific recommendations on batteries? Brand? Size? I was looking at the sizing guide here and it seems to indicate for the system size we're considering and our average # of kwhs used, the suggestion falls around 16kwh for the battery size

Are you in Australia? I read in some other forums that some are having luck with LFP cells from China that are selling for about USD 150 per kWh. The DIY battery market in the US is complicated by NEC 2020 which requires UL listing for batteries installed under a building permit. Tesla, Generac, BYD, LG Chem, Outback and some others have product for that niche.
I have a 42 kWh DIY pack I installed a year ago using EVE LF280 cells that I purchased two years ago for USD 125 per kWh delivered to my door.

[ktran1]

Battery install need electrician, the cost per kwH should be under 800

[jplee3]

BTW: anyone have specific recommendations on batteries? Brand? Size? I was looking at the sizing guide here and it seems to indicate for the system size we're considering and our average # of kwhs used, the suggestion falls around 16kwh for the battery size - https://www.solarchoice.net.au/blog/...g-quick-guide/

[jplee3]

Yes, that is where battery come into play. Just observe your usage, and NEM charge. If your NEM charge go up, then do battery/

Makes sense. Yea, I think we may wait on the battery. Someone mentioned there's a shortage of them too right now so pricing may actually behigher due to supply. So if we can wait (for supply to normalize and pricing to come down) then all the better.

Sorry for the unit laziness 16 KWh The battery pack is actually larger but the rest of it is reserved for hybrid operation.

I'm curious as to what a "good price" is per kw/kwh for a battery. I was looking around online and saw that the Enphase Encharge 3 that my solar installer wanted to charge $7k for sells for $3k~ - I haven't delved into solar battery pricing so I have no clue but I assume $7k is overpaying (even with install) and at least $3k ($1k per kw~) is the standard price point?

Is this something that most/all electricians can just install for you or do you *have* to get a solar installer to install and connect the battery?

[peakbagger]

Thanks. How big is your battery pack btw?

Sorry for the unit laziness 16 KWh The battery pack is actually larger but the rest of it is reserved for hybrid operation.

[ktran1]

Yes, that is where battery come into play. Just observe your usage, and NEM charge. If your NEM charge go up, then do battery/

[jplee3]

currently NEM2.0 in CA, peak time will be 4pm-9pm where solar does not generate enough power. If you have EV, need about 3500KWH to drive 12000 miles. You should oversize it, otherwise you will pay big time at true up, especially if you use AC during peak hours, the cost about 1.5 time off peak

Sounds like this is where a battery would also come into play no?

Thanks for confirming tho... 19 panels it is!

[ktran1]

currently NEM2.0 in CA, peak time will be 4pm-9pm where solar does not generate enough power. If you have EV, need about 3500KWH to drive 12000 miles. You should oversize it, otherwise you will pay big time at true up, especially if you use AC during peak hours, the cost about 1.5 time off peak

[RichardCullip]

Hey Richard one other question I forgot to ask but what do you get paid per KWH that goes back onto the grid? Per the current NEM it seems to indicate 2-3 cents per KWH?

Yes, SDG&E pays a small pittance for excess kWh at true-up. I was paid $0.4365/kWh for a grand total of $99.04 which rolled over as a credit . The price paid varies each month and is based on the true-up month. I'm on NEM2.0 as my system was install in early 2019.

[jplee3]

I also have a plug in Rav 4 Prime. It takes about 16KW to fully charge. I have a 2300 Kw array with a battery pack that takes about a sunny day to recharge.after charging the Prime overnight.

Thanks. How big is your battery pack btw?

[peakbagger]

I also have a plug in Rav 4 Prime. It takes about 16KW to fully charge. I have a 2300 Kw array with a battery pack that takes about a sunny day to recharge.after charging the Prime overnight.

[jplee3]

I have a modest system and modest electrical usage. My 4kW system has averaged ~7,700kWh per year and our usage has averaged 5,500kWh per year. This leaves use with a 2,200kWh per year buffer for future use. Now that I've added a Rav4 Prime I've been averaging 100kWh of charging each month. We don't drive much, less than 5,000miles per year. So far the 42mile range on a full charge in the Rav4 has covered about 90% of my driving. In the 3.5 months I've owned it I driven 1,150 miles and used a quarter of a tank of gas (say 3.5 gals). I've used 370kWh for charging. I'm happy with the results.so far.

Hey Richard one other question I forgot to ask but what do you get paid per KWH that goes back onto the grid? Per the current NEM it seems to indicate 2-3 cents per KWH?

"Net Surplus Compensation and Renewable Energy Credits (RECs)


At the end of a customer's 12-month billing period, any balance of surplus electricity is trued-up at a separate fair market value, known as net surplus compensation (NSC). The NSC rate is based on a 12-month rolling average of the market rate for energy. That rate is currently approximately $0.02 to $0.03 per kWh (for up-to-date NSC data, follow these links: PG&E, SCE, SDG&E). This rate structure was established in Commission Decision (D).11-06-016 pursuant to Assembly Bill (AB) 920 (Huffman, 2009). More information on the Commission's implementation of AB 920 can be found here.

Customer-generators may also receive compensation for the renewable energy credits (RECs) associated with this excess generation. To receive compensation, a customer-generator must register their generation facility with the Western Renewable Energy Generation Information System (WREGIS) and follow the eligibility guidelines contained in the latest version of the Overall Renewable Energy Program Guidebook from the California Energy Commission."


Unless you got into an earlier NEM?

[jplee3]

I have a modest system and modest electrical usage. My 4kW system has averaged ~7,700kWh per year and our usage has averaged 5,500kWh per year. This leaves use with a 2,200kWh per year buffer for future use. Now that I've added a Rav4 Prime I've been averaging 100kWh of charging each month. We don't drive much, less than 5,000miles per year. So far the 42mile range on a full charge in the Rav4 has covered about 90% of my driving. In the 3.5 months I've owned it I driven 1,150 miles and used a quarter of a tank of gas (say 3.5 gals). I've used 370kWh for charging. I'm happy with the results.so far.

Thanks Richard. What is your sq footage? I'm just wondering how much of a correlation there is in that sense, if any. Also, are you running your HVAC pretty regularly and if so what size HVAC system do you have??

I was just googling the "average" # of kwhs an electric oven/stove, heat pump water heater and electric dryer all end up using on an annual basis. Between the three of those it all adds up to around 2500kwh annually. If we got say a Tesla, and we put 5000miles on it (which is what we put on our Rav4) per year, I believe that translates to somewhere between 2500-3000kwh annually. So in total, we're looking at probably 5000-5500kwh of annual load usage that could be [gradually] added if/when/as we convert to electric appliances and a single EV. Right now we're at 7500kwh annually but when we get the new heat pump in that number will probably drop a good amount. Let's say it drops to 6500kwh, another 5500kwh puts us at 12000kwh. The 7.6kw system is slated to generate just over 12000kwh. So I think we may be roughly 'on target' here...