Would you buy if offered Battery Bank?

[einsvanian]

With daily cycling?
If so, I think it'll be far too expensive to be commercially viable.


$600/month on electricitly is quite a bit.
I don't see how it follows that people spending that amount would still pay the electric company $1k/year if installed solar.
Nor how you would build something with batteries that would reduce the amount paid to the POCO.

As others have pointed out, with net metering the POCO provides the "battery" for free.
They "store" the energy for months at no additional cost.
(Sure it's not actually a battery, nor is it stored energy - but from the homeowner's use model it acts the same way.)

If I were you, I wouldn't invest much into this endeavor.
You don't have a compelling reason for customers to buy it.

Why do people say POCO provides for free? Here in California I have a 5kw panel array and 3600w inverter and still pay $275 at end of year to local electric company. Not including the $5 to $10 monthly for taxes, emergency, and several other fees. The power company does not provide battery backup for free. Here in California Solar City is limited on production being 97% of consumption. I am still paying the power company 3% of my electricity.
Here in California some people even pay higher than $600 per month.

[SunEagle]

For those who don't know what impedance is: it is the total resistance in electronic circuits.



Your statements:
"All they do is match the impedance between a battery bank and a solar panel to maximize power transfer"
Electrical and electronic theory: Impedance matching minimizes on heat. Which is detrimental to chargers, batteries, cables, and connectors! Therefore, extending life of battery banks.

I recommend you Google: Impedance Matching

Impedance is resistance: resistance controls current in a circuit which creates heat. So when you match the resistance in one device to another you create less heat. batteries in battery banks maintain their temperatures during charging prolonging the life of the battery.

I rest my case.

BTW: I was using MPPT as an example: there are other types of chargers out there that used multiple types of charging techniques depending on the chemistry of the battery bank and other sorts.

In my honest opinion MPPT is the best type of charging system for any battery bank. In my opinion they have increased the left span of battery banks compared to 40 years ago. If you don't believe that then take a hike and get off my thread.

Your are correct that if you can control the heat buildup in a battery system while it is being charged or discharged you improve the reliability and possibly the life.

But as Tesla has shown that even with their very sophisticated cooling system their batteries still do not have the ability to have daily cycles with long life without spending a lot of money up front with the possibility it will last more than 5 years.

Sure having a battery system as a backup power source sounds great but again the cost to install a battery system is still much more expensive to installing a generator including the fuel and maintenance costs over the lifetime of the system. So what if the generator takes a little care and maintenance so does a battery system. The are not plug and play and definitely not something you install and forget about.

Maybe you have found the holy grail of energy storage but based on that $10k you plan to spend on your new design I would rather spend 1/3 of that and have a very reliable emergency generator for the very few times I lose power.

Oh. By the way you don't own the thread and since it is an open forum you should expect push back from people that do not have the same views are you do. So get a thicker skin or take a hike.

[einsvanian]

Daily cycling can be controlled if the battery bank is properly sized for load. Currently, the systems I work on have 6400ah battery banks and 7200w solar arrays and the load varies between 20a up to 100a with an average of 30a per hour. This gives weeks if not a month of run time before charging is required. The systems I work on are Solar Powered only and no other source is used.

[SunEagle]

Daily cycling can be controlled if the battery bank is properly sized for load. Currently, the systems I work on have 6400ah battery banks and 7200w solar arrays and the load varies between 20a up to 100a with an average of 30a per hour. This gives weeks if not a month of run time before charging is required. The systems I work on are Solar Powered only and no other source is used.

Then I would say your company may have found a useful product. But to come here and start asking open questions leads me to believe you are fishing for something that will financially benefit you or someone you know.

Since you are now stating that you work on very large solar / battery systems I believe my first assumption was correct. You may not be a salesperson but your company sells battery systems.

I would hope that whatever you build and sell meet all NEC and UL listing required for US usage.

[einsvanian]

Oh. By the way you don't own the thread and since it is an open forum you should expect push back from people that do not have the same views are you do. So get a thicker skin or take a hike.

I expect push backs and insults: I ask for the push backs so I can prepare myself for the unknown questions. The insults need to be kept at bay. I realize I was feeding the fire and I apologize for that. I delete most of my response on a few posts trying to put the fire out.

You have to remember Tesla is working with a battery bank that has physical limits: size, weight, higher discharge rates, and so forth. Battery Banks for homes have very little limiting. They still have some but are a lot less than what Tesla is facing!

The batteries I am using are considered one the best types of batteries used for many applications. They just never been thought of when it comes to battery banks. Their battery composition is the best I found so far. The charge controllers I found are great and have many features than most other competitors. I've tested them for over 4 years now and I feel they are market ready.

My plans are to make them proprietary by locking them inside a specially designed storage to keep others out for safety reasons, as well as, to protect the 15 year warranty on them. These battery banks will be built with quality and durability in mind. I don't want to go into details without discussing this with an attorney of what type of information I should provide without damaging my proprietary design.

[foo1bar]

Why do people say POCO provides for free?

Because they do - it isn't any additional charge.
That's what net metering does - and why it's such a good deal for solar system owners.
I'll give the POCO >10kwh during the day today, and use them tonight or in a few months.
I'll get credited full retail price for the kwh I give them.
then pay the retail price back when I use them.
Often with TOU the retail price credited is peak price (and higher) and the price at night when they're used is off-peak and therefore lower.
Personally I'm not on TOU - so it's the same price all day. (My TOU isn't as beneficial for solar as those that PG&E or other companies have)

Here in California I have a 5kw panel array and 3600w inverter and still pay $275 at end of year to local electric company.

What are you paying?
is it for additional kwh beyond what you produced?
My guess is that's a good part of it.
I'm guessing you're Southern CA - and IIRC they have a $15/month minimum - which would be $180/year.
And that's the same minimum whether you "store" 0 kwh with them or 10000 kwh.

The power company does not provide battery backup for free.

Not battery backup - power "storage" for free - ie. net metering.

Here in California Solar City is limited on production being 97% of consumption. I am still paying the power company 3% of my electricity.
Here in California some people even pay higher than $600 per month.

I live here in California.
Solar City is not limited to 97% by any statewide law.
That is probably their own limit that they use, since they should be trying to keep you right at using enough kwh that you use up the minimum charge in those places that have it.
(I'd think 90% or less of usage on a kwh basis would usually be closer to the right size once you go TOU tariff)


So - are you saying you want to pay POCO even less money?
There's 3 scenarios here I think.
1> you add more modules (panels) so that you are sure to get to the minimum charge.
2> you add batteries and modules and go off-grid (no more POCO bill at all - BUT - batteries alone will now be >$5K, and last only 10 years at best - meaning you avoided paying SCE/SDG&E $2750 by paying $5000 to the battery manuf.
3> you add batteries and modules, but stay on-grid - your bill goes from $275 to $180/year - can get by with smaller battery, so maybe only spend $2k to avoid $950 over 10 years.

All of those are not great financial scenarios - #1 is probably the best option of the 3, but even it probably is around a 10 year payback because you're mostly in the lower tier for the extra kwh you are using.

[einsvanian]

I pay about $80 /month to Solar City and I pay about $5 to $10 per month to Edison and then I pay another $275 per year to Edison for consumption.

My inverter is undersized: 3600watts total. My panels produce 5kw per hour. I get about 7 hours of production for a total of 35kwh but my inverter handles only 25.2kwh. If I took the 9.8kwh produced over what my inverter can handle and store them in a battery bank I could use that during the night time when I am using Edison's grid. When I signed up for Solar City I asked for a 5kw system but I got the 3.6kw inverter with a 5kw solar panel. Doesn't make sense and SC is currently looking into it.

Another thing, SC didn't take into account that I was using a battery bank and 1kw solar array when they used my electric bill to design their system. I tried to explain to them but that got lost when the order was placed on the engineer's desk.

[einsvanian]

Then I would say your company may have found a useful product. But to come here and start asking open questions leads me to believe you are fishing for something that will financially benefit you or someone you know.

Since you are now stating that you work on very large solar / battery systems I believe my first assumption was correct. You may not be a salesperson but your company sells battery systems.

I would hope that whatever you build and sell meet all NEC and UL listing required for US usage.

I did state I am looking into selling battery banks, I do not sell them currently. I work for the Government on their solar array systems and radio communications. I do not sell any solar products at this time. I am completely a solar customer; Government buys and I am buying my system from Solar City.

My intentions was to see if there is a demand for battery banks/backups; which I am taking by all the push back here on this forum nation wide there is no demand. Only in California, there is a demand due to limitations on our systems. Correction: Only a few areas have demands for battery banks not just California.

I am certified and have to fall under the NEC; UL is not required but are just like BBB good to have because most people use them as standards.

[DanKegel]

My intentions was to see if there is a demand for battery banks/backups; which I am taking by all the push back here on this forum nation wide there is no demand. Only in California, there is a demand due to limitations on our systems. Correction: Only a few areas have demands for battery banks not just California.

Well, there's a large "you've got to be cruel to be kind" contingent on this bulletin board, and they feel morally justified in using insults. You just have to ignore that part of it, and pay attention to their substantive comments.

Demand will come when there's a product worth buying. The few areas that have already stopped offering net metering and/or have instituted demand charges are your likely target markets.

Tesla, Sonnen, Adara, Sunverge, and LG are testing the market now. If you want to compete with them, knock yourself out, but I'd suggest getting started some other way. Sell some kind of system that is already practical, and add storage to it when that becomes available. Or maybe be one of their installers. Good luck!

[foo1bar]

I pay about $80 /month to Solar City and I pay about $5 to $10 per month to Edison and then I pay another $275 per year to Edison for consumption.

Ok - so you have a system that doesn't meet 100% of your demands now.
I don't think batteries will help that much with it.

My inverter is undersized: 3600watts total. My panels produce 5kw per hour. I get about 7 hours of production for a total of 35kwh but my inverter handles only 25.2kwh. If I took the 9.8kwh produced over what my inverter can handle and store them in a battery bank I could use that during the night time when I am using Edison's grid.

Do you have 5000W of modules? Are they fixed position (roof mounted or in a fixed/non-tracking ground mount)?
If so, then it's only for a fraction of the time are you producing more than the 3.6kW that the inverter can handle.
It's not 7 hours worth like you are calculating.
You can get a guesstimate by looking at your production curve over the day and seeing when (or if) it reaches 3.6kW and how long it stays at that level.

You should do some reading on results from search of "undersized inverter clipping".
I think you'll find that you *may* be getting some clipping with a 5000/3600 ratio.
But it's probably only a few percent.

BTW - If you're paying Solar City per kwh that you get from them, then it doesn't matter too much to you (other than you might have been better off with 5.5 or 6kW system instead of 5kW - and that would probably be worth arguing with them to increase the size of the system, both more modules and larger inverter)

Also - since it's a lease / power-purchase-agreement, if you change their equipment (by adding in batteries in between the modules and the inverter) that's going to cause you all sorts of problems. If there's ANY issue with the equipment (even if it's not because of your changes) they'll blame you.

Only in California, there is a demand due to limitations on our systems. Correction: Only a few areas have demands for battery banks not just California.

Even in CA there isn't a demand.
All 3 major POCOs have net metering.
And I think all 3 have a solar-friendly TOU tarriff. (so storing from peak times to be used at off-peak is even less of a benefit)
Because of net metering, the solar install can be sized to match the annual usage.
And the end bill will be the monthly minimum charge.
That your install was apparently undersized is not something that generalizes to all (or even most) of CA. It's a problem with your installer and/or your specific situation. Your neighbor could go buy a properly sized install that would be just ~$180/year for the monthly minimums.

[Mike90250]

........
My intentions was to see if there is a demand for battery banks/backups; which I am taking by all the push back here on this forum nation wide there is no demand.
......
I am certified and have to fall under the NEC; UL is not required but .......

So, I'm off grid, have daily consumption of about 12KWh summer and 9KWh in winter. Currently using a 800Ah 48V bank with thousands of $$ in 48V gear.
I have 5KW of PV, and usually have been in float for a hour or more if it's a sunny day. Do you know of another battery bank I should be using ?

And I question your statement that UL is not required. AFIK, electrical gear connected to household electric system needs UL cert to meet homeowners insurance requirements, and most city codes also require UL cert. How do you comply with that ?

[SunEagle]

I expect push backs and insults: I ask for the push backs so I can prepare myself for the unknown questions. The insults need to be kept at bay. I realize I was feeding the fire and I apologize for that. I delete most of my response on a few posts trying to put the fire out.

You have to remember Tesla is working with a battery bank that has physical limits: size, weight, higher discharge rates, and so forth. Battery Banks for homes have very little limiting. They still have some but are a lot less than what Tesla is facing!

The batteries I am using are considered one the best types of batteries used for many applications. They just never been thought of when it comes to battery banks. Their battery composition is the best I found so far. The charge controllers I found are great and have many features than most other competitors. I've tested them for over 4 years now and I feel they are market ready.

My plans are to make them proprietary by locking them inside a specially designed storage to keep others out for safety reasons, as well as, to protect the 15 year warranty on them. These battery banks will be built with quality and durability in mind. I don't want to go into details without discussing this with an attorney of what type of information I should provide without damaging my proprietary design.

I understand. I would hope that once your design has been proven in more than a few beta tests, you go the route of getting it UL listed so there isn't any doubt concerning safety or IEEE compliant.

[DanKegel]

Even in CA there isn't a demand.
All 3 major POCOs have net metering.

Well, SDG&E just hit their cap, so they're transitioning to NEM 2.0. That makes storage slightly more attractive (I think NEM 2.0 charges two cents or so per kWh stored in the grid, so that's a cost you could avoid by storing those kWh in a real battery).

California has incentives for energy storage, I think; the SGIP handbook says it's $1.31/watt. That might help a bit, too (though you have to get an energy audit to qualify, and who knows what else).

And I think the federal solar investment tax credit also applies, in a somewhat limited way.

So, there might be room. You need to really get your ducks in a row to make that case, though.

BUT: you probably have to match Sonnen's features, and that might be hard to do... their system is smart, you'd probably end up having to write a bunch of software. How are your C skills?

[jflorey2]

Electrical and electronic theory: Impedance matching minimizes on heat. Which is detrimental to chargers, batteries, cables, and connectors! Therefore, extending life of battery banks.

No. It does not MINIMIZE impedance It MATCHES impedance. That means that it changes the apparent resistance of the battery system to get the most possible energy out of the solar panel. In general, it increases apparent resistance, so that the panel operates at a higher voltage than it ordinarily would. (A PWM charger forces the panels to operate either at battery voltage or open circuit.)

Impedance is resistance: resistance controls current in a circuit which creates heat. So when you match the resistance in one device to another you create less heat. batteries in battery banks maintain their temperatures during charging prolonging the life of the battery.

By using an MPPT device to match impedances, more current can be delivered to the battery compared to a PWM charger. Since the internal resistance of the battery does not change depending on the charging system, and heating is proportional to I^2R, internal heating INCREASES with an MPPT charger (with a given solar panel array.)

A good example of something you could stand to learn a bit more about.

In my honest opinion MPPT is the best type of charging system for any battery bank. In my opinion they have increased the left span of battery banks compared to 40 years ago. If you don't believe that then take a hike and get off my thread.

No thanks. You are still pretty clueless when it comes to this, and I'll continue to post corrections to your mistakes.

But rather than telling you to take a hike, I'd invite you to stick around and learn a bit more about renewable energy.

[jflorey2]

Why do people say POCO provides for free?

That's how net metering works.

Here in California I have a 5kw panel array and 3600w inverter and still pay $275 at end of year to local electric company.

Right. And I have a 10kW array and pay about $8 a month. Net metering does not mean you are guaranteed to have a zero bill - it just means you can send power back to the grid, then use power from the grid later, and use the power you sent to the grid to offset your later usage. If you want to get your bill close to zero, then install more solar or (much smarter) reduce your usage.

Not including the $5 to $10 monthly for taxes, emergency, and several other fees. The power company does not provide battery backup for free. Here in California Solar City is limited on production being 97% of consumption. I am still paying the power company 3% of my electricity.
Here in California some people even pay higher than $600 per month.

Yep. And if they had battery systems, they'd be paying even more.

[DanKegel]

And if they had battery systems, they'd be paying even more.

Truth. With net metering 1.0, batteries are a definite minus. The grid is your battery.