SF Bay Area solar system planning: help me avoid making dumb mistakes

[Naptown]

Around here pool
Pumps are required to be on GFI breakers. They are made for 240 service.

[inetdog]

Well, after investigating by flicking off circuit breakers, it appears my pool equipment is the main offender, drawing 1.7kw 24 hours/day, and 3kw part of the day. I can only see a single 1.1kw motor, so I have no idea where the rest of the power is going. And the control panel doesn't have any obvious time-based control.

I know I specified a low-power motor for the pool gear, and asked that the motor not run all of the time. I'll be having a talk with my pool guy this week to find out what changed.

Ignoring the pool, my power use is much closer to ~1kw (except when the A/C or dryer kicks in.)

Well, for what it is worth, a line to ground fault that does not draw enough power to trip a breaker can go undiscovered for years, and will end up costing a lot on your electric bill. Does the motor run 24/7? If defective or with a binding pump mechanism it might be pulling 1.7kW instead of 1.1kW. There is also the possibility that some of the power from the pool circuits is going somewhere else in your house, or to a neighbor's yard via an extension card.
If there are no visible time-based controls, that leaves pumps filling pressure tanks, and heaters as obvious part-time loads.

[Naptown]

Sounds like you are filtering 24/7 and going to high speed for the pool vac a portion of the day.
Set your filter pump so you get 1-1.5 turn over's a day in water gallons.
Unless you are dropping a bunch of debris into the pool you can cut back on the pool sweep also. Perhaps go to manual operation on the pool sweep.
You aren't heating that pool by chance are you?

[Blammar]

Well, after investigating by flicking off circuit breakers, it appears my pool equipment is the main offender, drawing 1.7kw 24 hours/day, and 3kw part of the day. I can only see a single 1.1kw motor, so I have no idea where the rest of the power is going. And the control panel doesn't have any obvious time-based control.

I know I specified a low-power motor for the pool gear, and asked that the motor not run all of the time. I'll be having a talk with my pool guy this week to find out what changed.

Ignoring the pool, my power use is much closer to ~1kw (except when the A/C or dryer kicks in.)

[KRenn]

Well, as it turns out, due to setback restrictions and a requirement for access to the tank by the fueling truck, there appears to be no place we can install a tank on our property (which is fully landscaped.)

So Plan C is AC-coupled grid-tied using Sunpower AC panels.

This is just my thoughts on the matter, mind you I'm in Arizona and not California, but I did live in Tiburon for quite awhile and I'm well-versed with what a PITA PG&E is.


Based on the numbers you've provided, your usage is pretty high, meaning you're getting dinged pretty hard due to being in a high tier. I would look at a system that provides enough solar offset to get you into the lower tiers, whatever the minimum size is to get you there, I would look at that and not worry about batteries or backup systems....etc. Financially, by far, it would be your best option over the long-term.

[mm01]

Well, as it turns out, due to setback restrictions and a requirement for access to the tank by the fueling truck, there appears to be no place we can install a tank on our property (which is fully landscaped.)

So Plan C is AC-coupled grid-tied using Sunpower AC panels.

The new SMA Sunnyboy TL-US 3000,4000 and 5000 inverters offer an "off grid" emergency backup outlet. If the grid goes down there is a dedicated outlet you can pull power from. It won't feed into your house system but you'll have some power available to keep the fridge etc running. You could hook up a small battery generator to that if you want more flexibility. A Goal Zero Yeti is a nice package (albeit expensive $/Whr) or you can DIY for a LOT less. Again, it won't run your house but you'll have SOME emergency power.

[Blammar]

Well, as it turns out, due to setback restrictions and a requirement for access to the tank by the fueling truck, there appears to be no place we can install a tank on our property (which is fully landscaped.)

So Plan C is AC-coupled grid-tied using Sunpower AC panels.

[Sunking]

If you go propane do yourself a favor and purchase and own your tank(s).
I have had houses with propane and if you own the tank you get to shop for the best deal. If they own it you are at their mercy price wise.

You got that right. Their selling point is they provide the tank and installation for FREE.

[Naptown]

If you go propane do yourself a favor and purchase and own your tank(s).
I have had houses with propane and if you own the tank you get to shop for the best deal. If they own it you are at their mercy price wise.

[inetdog]

Some places give you the tank as long as you purchase an amount of fuel each year.

I think what you mean is that the do not itemize a separate monthly lease charge for the tank as long as you purchase a minimum amount of fuel each year.

I have seen properties with three propane tanks, each from a different vendor, with two sitting unused because they do not bother to pick up their old tank when you change companies.

[SunEagle]

The 20kw Generac is only around $4500, which surprised me. Is it true that if you draw say 5kw from a 10kw generator, it's able to consume less gas? I.e., it's more efficient to buy a larger generator than you need, correct?

I assume you need to hire a propane truck to come and refuel your tank. Just say no to sparks when that's happening.

I know that most generators have fuel consumption rating based on the % load that is being used. I don't think it is linear. There has to be a certain % of waste depending on how lightly it is loaded. The smaller the load the lower the efficiency and the higher the waste. I would check out what the manufacture rates their equipment.

And yes you would need a fuel truck to come by every so often. They should have all of the proper tools (usually brass) when they make the fuel transfer.

Before you purchase the gen set check out what the cost is to refuel as well as the tank sizes. Some places give you the tank as long as you purchase an amount of fuel each year. You don't want one too small but too big has other issues. Hopefully you can get more than one quote on that.

[Sunking]

The 20kw Generac is only around $4500, which surprised me. Is it true that if you draw say 5kw from a 10kw generator, it's able to consume less gas? I.e., it's more efficient to buy a larger generator than you need, correct?

I assume you need to hire a propane truck to come and refuel your tank. Just say no to sparks when that's happening.

Optimum is 75% at full load like the HVAC running with a few lights. But in SF I doubt yu really need AC. Coldest place I ever went was SF to Candle Stick Park for a baseball game in summer.

[Blammar]

I can recommend Generac as a very good propane generator. I have one of their 3250w cont - 3750w peak portable units and it does a real nice job. If you want to have a true back up go with a whole house type with a large anchored propane tank.

You may also want to add a second generator using a different fuel type (gas or diesel). That way you will not be depended on just one fuel source for long duration outages.

The 20kw Generac is only around $4500, which surprised me. Is it true that if you draw say 5kw from a 10kw generator, it's able to consume less gas? I.e., it's more efficient to buy a larger generator than you need, correct?

I assume you need to hire a propane truck to come and refuel your tank. Just say no to sparks when that's happening.

[SunEagle]

On the other hand, I have been seeing comments on other forums (like MH) that if you want to do your own generator maintenance or do not buy through a local dealer Generac's customer support really sucks.

I hadn't heard that. Generac seems to be a pretty big supplier with distributors at HomeDep. I would think they would yank some chains if there was a customer service issue or stop distributing them. Don't want to make a bad name for themselves.

Since i have a portable I didn't really worry about a service call. I would just take it to someone that works on generators although I don't expect issues anytime soon.

[inetdog]

I can recommend Generac as a very good propane generator. I have one of their 3250w cont - 3750w peak portable units and it does a real nice job. If you want to have a true back up go with a whole house type with a large anchored propane tank.

You may also want to add a second generator using a different fuel type (gas or diesel). That way you will not be depended on just one fuel source for long duration outages.

On the other hand, I have been seeing comments on other forums (like MH) that if you want to do your own generator maintenance or do not buy through a local dealer Generac's customer support really sucks.