Why even have batteries?

[bevo]

As I showed with my bill, I constantly pay $10-$15 per month with prime. I switched from the 4-9 and my monthly bill is less. I don’t know where people are getting the $20+ per month info.

The bill that was shown to be -$10.77 is really $18.23 if the $29 California credit is taken out.
But yes, generally your bill may be lower since you have Powerwall and your NBC will be lower. And I'm not doubting that Prime is a better plan for you because as you stated, there are many factors.

 

[Silicon Desert]

I wish the Time of Use thing was better advertised... although it is a confusing topic since the Power Company makes their rates so damn complicated.

Yea, I used to live in that area so I now what you mean. But now I am in an area of inexpensive power that is a constant rate all hours of the day. I sure like that a lot better, and I have no need for batteries to help offset a TOU rate as in some places of good ole USA.

 

[Silicon Desert]

You have fuel costs and oil change etc. even if you do it yourself. If you pay a service you pay more (most would pay a service).

Hmmmm, If H20fun has a system similar to mine, then there isn't any service cost, oil, etc. so not sure what you mean. I've had my generator for 5 years now and it has come on twice during short power outages. If it needs service, it tells me, but none yet. I guess it is pretty clear from the posts in the threads that some people are better off with powerwalls for their situation and some are better with generators (or both if they desire). I'm glad we went the route we did for our situation.

 

[skepticcyclist]

The bill that was shown to be -$10.77 is really $18.23 if the $29 California credit is taken out.
But yes, generally your bill may be lower since you have Powerwall and your NBC will be lower. And I'm not doubting that Prime is a better plan for you because as you stated, there are many factors.

Yes. This is an exception because of the large amount of grid power due to not seeing the sun in 2 weeks (damn marine layer.) The basic charge was $13 (we had $4.80 in NBC's because of a lot of grid use.) The previous months bill was $15 total.

Yes, it is the NBCs that give the 4-9 plan a better deal for most people in most situations.

 

[h2ofun]

Hmmmm, If H20fun has a system similar to mine, then there isn't any service cost, oil, etc. so not sure what you mean. I've had my generator for 5 years now and it has come on twice during short power outages. If it needs service, it tells me, but none yet. I guess it is pretty clear from the posts in the threads that some people are better off with powerwalls for their situation and some are better with generators (or both if they desire). I'm glad we went the route we did for our situation.

Yep, we seem to be the same on the generator

 

[darhall993]

Yep, we seem to be the same on the generator

I also have a Generac 22kW and Honeywell Branded 20kW Generac units and the recommended service intervals are below. I live in an area with frequent power outages because of Tornadoes, post Hurricane Tropical Storms etc, so my systems have runtimes of anywhere from 70-125 hrs/yr so I tend to have run in exercise mode twice a month and have them serviced and tested per the recommended schedule. I suppose if the units aren’t running much you extend the time between servicing.

 

[h2ofun]

I also have a Generac 22kW and Honeywell Branded 20kW Generac units and the recommended service intervals are below. I live in an area with frequent power outages because of Tornadoes, post Hurricane Tropical Storms etc, so my systems have runtimes of anywhere from 70-125 hrs/yr so I tend to have run in exercise mode twice a month and have them serviced and tested per the recommended schedule. I suppose if the units aren’t running much you extend the time between servicing.

View attachment 663289

Yep, depends on how much use. In 1.5 years, only have 19 hours, most which is from the exercise process. Luckily have not had to use much, and now with the batteries, who knows, may never need again.

 

[Silicon Desert]

Yep, depends on how much use. In 1.5 years, only have 19 hours, most which is from the exercise process. Luckily have not had to use much, and now with the batteries, who knows, may never need again.

Seems like a fair amount of use for 1.5 years. Is it safe to assume that much of that use was due to PG&E fire outages and precautions?

 

[Electrph]

Seems like a fair amount of use for 1.5 years. Is it safe to assume that much of that use was due to PG&E fire outages and precautions?

much of that may be the "excercise schedule" .. monthly or whatever when they start up / run for certain amount of time on their own (per a schedule )
was at a hospital hiding / eating my dinner when one of the two very large (diesel?) generators kicked on i assume exercise since no outage .. scared crap out of me

 

[Silicon Desert]

much of that may be the "excercise schedule" .. monthly or whatever when they start up / run for certain amount of time on their own (per a schedule )
was at a hospital hiding / eating my dinner when one of the two very large (diesel?) generators kicked on i assume exercise since no outage .. scared crap out of me

Maybe so, but in the 5 years of my system, it has only run about 2 1/2 hours due to regular testing. Yea, if one of those hospital systems were to fire up around me, I'd jump too. Fortunately our system is quiet and not close, so I don't hear it if it comes on.

 

[darhall993]

My newest 22k system has really been put to the test, we had a three day outage with temps in 90’s and a 2 day outage, all with 3 adults at home, too bad the local fiber was down for the entire time. Might have to get Starlink as a backup!

 

[h2ofun]

Seems like a fair amount of use for 1.5 years. Is it safe to assume that much of that use was due to PG&E fire outages and precautions?

I used for having some poles replaced for 3 different days. Maybe ran 3 hours each. No PGE outages yet.

 

[h2ofun]

much of that may be the "excercise schedule" .. monthly or whatever when they start up / run for certain amount of time on their own (per a schedule )
was at a hospital hiding / eating my dinner when one of the two very large (diesel?) generators kicked on i assume exercise since no outage .. scared crap out of me

Mine cycle on fridays at like 3, like twice a month, for like 5 minutes each time

 

[tomuo]

It could be. The 4-9 plan may be better for some over the Prime. It depends on how much you use, when you use it, and many other variables. The best thing to do is look at your history of usage and compare it to your solar production.

I was on the 4-9 plan originally. But because of the morning marine layer and when we run our pool pump, the prime ended up saving me money in the long run. For you the 4-9 may be better.

I was just clarifying that the 4-9 is not always the best for all people, as well as the misconception that higher rate plans pays you higher rate for production (which it doesn't.) Net metering is only 1:1 for production matching usage. Any net over production is wholesale and is paid at the same wholesale rates for all plans. The baseline credit does give you additional production money based on what your allocation is.

For anyone new to this, they should try to the 4-9 plan first since that is what they automatically sent you up with anyway. Monitor you usage and see what it would be if you went to the Prime. Then determine which is better

Agreed, it's a complicated set of factors to calculate the best plan, it would probably change if you only look at partial year usage.

As soon as my PW was turned on, I switched to D-Prime. I was on the grandfathered 2pm-8pm plan before that, and looking back I could have stayed on that for longer.
But in my case, since I also switched to heatpump central heat, I'm going to be net using quite of lot of energy during the winter months when PV production is low, and I don't yet know if I'll be net positive for the year to be able to save enough credit to cover it all.
I have a smallish set of panels, so I should have enough to charge the PW to avoid peak usage in the winter, but I still need the cheapest power from the grid in the morning.
All the other plans have a mid level cost from 8am, so I'd have to fully heat the house before that for best cost performance.

Going partially back to the main question of this thread though:
Once you have a battery and manage your daily usage and electric plan to benefit from it the most, what happens if part of the system goes down?
I had this problem back in March - one of my inverters broke, leaving 5kW of panels offline for over 3 weeks.
That was leaving me pulling power at peak times, so my careful plans of aiming for a zero usage power bill were blown up.
I had to do some zen breathing to get through that - "it'll all be worth it when it's fixed".

 

[skepticcyclist]

The bill that was shown to be -$10.77 is really $18.23 if the $29 California credit is taken out.
But yes, generally your bill may be lower since you have Powerwall and your NBC will be lower. And I'm not doubting that Prime is a better plan for you because as you stated, there are many factors.

Just posting this to show my bill continues to be under $10/month. This month is $7.19 and last month was $5.67 with Prime

 

[bevo]

Just posting this to show my bill continues to be under $10/month. This month is $7.19 and last month was $5.67 with Prime

Are you on NEM instead of NEM2? The basic charge for TOU-D-Prime on NEM2 is 0.40 per day. In a 30 day month, that would be $12. If your bill is less than $12 for a 30 day month, then you must not be on NEM2 or you have credits somewhere that reduces your bill below $12.

 

[h2ofun]

Are you on NEM instead of NEM2? The basic charge for TOU-D-Prime on NEM2 is 0.40 per day. In a 30 day month, that would be $12. If your bill is less than $12 for a 30 day month, then you must not be on NEM2 or you have credits somewhere that reduces your bill below $12.

I know folks on NEM1, and myself on NEM2, and we both pay 10 bucks a month for interconnection fee. Everything else goes into true up. Now with that said, because of the credit PGE gave everyone, it moved around the last 2 months. I thought the credit was like 17 bucks, so was negative for about 2 months

 

[skepticcyclist]

Are you on NEM instead of NEM2? The basic charge for TOU-D-Prime on NEM2 is 0.40 per day. In a 30 day month, that would be $12. If your bill is less than $12 for a 30 day month, then you must not be on NEM2 or you have credits somewhere that reduces your bill below $12.

I'm on NEM 2.0

 

[evmusic]

It seems this type of question often turn into a generator vs battery comparison. It's a false one to me. I see generator as a required component of a practical on-demand backup power solution even if you have batteries. Solar is not a reliable power source despite what the home battery peddlers say.
The simple fact is that batteries won't get charged enough on cloudy, smoky or just winter days. So, I see batteries as an add-on component in a practical on-demand backup power solution to minimize but not eliminate the use of generator in general.

Also, I think it's not very productive to try to justify home batteries strictly on financial ROI. I doubt most ROI focused solar owners would accept even a 10-year ROI for home batteries. It's just not the main factor used by people who buy home batteries so far. It's more about convenience and comfort which is why I am still considering home battery despite the lack of ROI. However, I really don't like the hassle of a major construction project and I don't like huge ugly looking boxes and conduits permanently attached to the house. Lately, I am starting to think perhaps a community (e.g. city/county level) battery-as-a-service option (if one exists) would be a better fit for people like me.

Your though process is not incorrect just missing one angle. I agree with you the properly sized solar system -which as average provides 100% coverage- have issues to cover on those day when solar production is not great. However, you can attack this problem differently rather than having a generator. You can also have an oversized solar system from the cost you would spend for the additional generator. You can have 30-50% bigger solar system what you need. In this case it WILL provide sufficient energy during those low production day. I am just saying. Different angle.

 

[holeydonut]

Your though process is not incorrect just missing one angle. I agree with you the properly sized solar system -which as average provides 100% coverage- have issues to cover on those day when solar production is not great. However, you can attack this problem differently rather than having a generator. You can also have an oversized solar system from the cost you would spend for the additional generator. You can have 30-50% bigger solar system what you need. In this case it WILL provide sufficient energy during those low production day. I am just saying. Different angle.

Man you lucky bastards being allowed to oversize your arrays. PG&E nit-pick me on one single solitary panel because it would push me over 110% previous year consumption. That one extra panel is all I can fit on my roof that still faces in a useful direction.