Would you buy if offered Battery Bank?

[einsvanian]

If and when your system hits the market you might see a nice income. But be careful that someone doesn't come along and hit you up with stealing someone's else's design.

I'm using different equipment and batteries to include a slight difference in design.

[einsvanian]

The larger the battery bank the less damage you will do to the plates in each battery.

Using the 72kwh battery bank:
(If I could get your total night time use I can get better calculations.)
Throughout the day your consumption varies hour to hour; lets just use the average of 1.9kwh (45kwh/24hours)
You consume 1.9kwh per night which totals to 34.2kwh.
You just drained your battery bank by 47.5% of its capacity
Leaving about 52.5% capacity left in the bank.
I would recommend the 114kwh battery bank.

Using the same numbers as above with the 114kwh bank:
34.2kwh drains the bank by 30% leaving 70% capacity left in the bank: less damage to the plates.
I would even recommend larger: a 171kwh bank will drain down by 20% leaving 80% capacity left in the batteries. With this I can provide a 15 year warranty.

Rule of thumb: they say do not drain your batteries below 80% of capacity.

Anything smaller than 72kwh bank would drain down by over 50%. This will definitely damage your batteries.

Lets use the 16kwh system from Sonnen:
You wouldn't even get through the whole night before your batteries shut off. You would get about 2 hours of run time. This is a battery back up system.

My 600ah bank provided 10.8kwh which gave me 6 hours of run time at 1.8kwh. On a 24vdc bank I was discharging by 75amps per hour which drained my bank down to 20% capacity which I had set the LVD (Low Voltage Disconnect for those who don't know).

With that said you can get by with a 45kwh bank but would need replacing within 5 years.

[SunEagle]

People are paying $7k for Tesla and $5.9k for Sonnen and their systems are under 10kwh. Their base unit is under 7kwh; their expansion packs run about $1k up to $3k.

You would have to buy 10 of their expansion packs to reach 72kWh I know for a fact you will be paying more than $10k to Tesla or Sonnen.

If and when your system hits the market you might see a nice income. But be careful that someone doesn't come along and hit you up with stealing someone's else's design.

[SunEagle]

Yeah. But why would I purchase a 72kWh system when I average about 45kWh a day. Seems like leaving a lot of money on the table to me.

Even if the battery price comes down a solar pv system is not in the cards for me until I build my retirement home in a couple of years.

[einsvanian]

People are paying $7k for Tesla and $5.9k for Sonnen and their systems are under 10kwh. Their base unit is under 7kwh; their expansion packs run about $1k up to $3k.

You would have to buy 10 of their expansion packs to reach 72kWh I know for a fact you will be paying more than $10k to Tesla or Sonnen.

[foo1bar]

I just did the math: with the 72kWh for 15 years @ $10k comes to $0.03/kWh: if you go just for 5 years it is: $0.08/kWh.

$.03/kwh?
Wow.
Who would actually pay that much? I know I wouldn't. And $.08/kwh? Holy <*****>.

I suppose it's cheap if you're off-grid and you're normally paying over $.50/kwh for batteries and it can do the same job and do it at that price. (I'm skeptical that it can - because if it could why isn't it already being done?)
But for those of us with grid tie, that's a really expensive proposition.

[einsvanian]

My mother is dead and 6 ft under, no need to bring her into this. She died when I was 19. I am not going to play your games.

[einsvanian]

I just did the math: with the 72kWh for 15 years @ $10k comes to $0.03/kWh: if you go just for 5 years it is: $0.08/kWh.

[einsvanian]

Based on a quick calculation a 4kWh battery with a daily cycle of 100% for 3 years would generate ~ 4300kWh. At $2k that comes to ~ $0.46/kWh. More than likely you would only get about 80% DOD per cycle so that comes to ~ 3500kWh or ~$0.57/kWh.

Since I only pay about $0.11/kWh it would be very hard to financially justify an energy storage system.

Maybe in a few years when the price of that energy system comes down to $0.15/kWh over its lifetime people might jump to purchase one. But that is much lower then what you are quoting now and I would guess the price will stay high if you get to a 15 year lifespan..

$2k was just an estimate actual costs are around the $900 just like Sonnen which is $0.20/kwh. I can probably get the cost down to maybe $700 with a 3 year warranty @ $0.16/kWh.

[Sunking]

I already know how MPPT works; I use it on the 6400ah battery banks at work. It is just one way to charge batteries. I use a much smarter way.

No you don't, you already proved that and makes it very easy to see you are a FRAUD.

BUSTED

MODS you need to ban this guy, he has proved he is a Liar and a Fraud. Not to mention a SPAMMER. What are you waiting for?

Only one who believes him is DAN

[Sunking]

Sunking, I am sorry you feel that way. News flash your MSEE, PE are pieces of paper as well..

You forgot to add a STAMP as well and is recognized by Authority Having Jurisdiction.

Your so called Certification is completely WORTHLESS not even recognized by your Mother.

[SunEagle]

Based on a quick calculation a 4kWh battery with a daily cycle of 100% for 3 years would generate ~ 4300kWh. At $2k that comes to ~ $0.46/kWh. More than likely you would only get about 80% DOD per cycle so that comes to ~ 3500kWh or ~$0.57/kWh.

Since I only pay about $0.11/kWh it would be very hard to financially justify an energy storage system.

Maybe in a few years when the price of that energy system comes down to $0.15/kWh over its lifetime people might jump to purchase one. But that is much lower then what you are quoting now and I would guess the price will stay high if you get to a 15 year lifespan..

[einsvanian]

Thank you, my goal is to make large banks affordable for instance: just read that Tesla and Sonnen banks are only 7kwh and 4kwh. The ones I have been talking about are 72kwh and 144kwh at $10k starting price. If you all want a 4kwh bank for $2k we can provide it but we will not offer a 15 year warranty maybe a 3 year at most; I might be able to push 5 years using smaller banks but cycling will definitely be involved into the calculations.

Keep in mind: turning on your clothes dryer will cycle Telsa's and Sonnen's bank once in one hour and then some.

[SunEagle]

Well, the way he posts makes me think he is some wet-behind-the-ear 20 year old graduate or a stuck up engineer who needs to retire his degree.

If he does have the knowledge and experience as you say then he is being senile and picking fights for amusement; then he got the best of me.

If I provided the plans to any engineer I guarantee they would stamp it. I guarantee both of you would sign off on it as well. You both would also agree that the batteries I use would go at least 15 years if not 20 once you look into the design and chemistry make up.

You would also agree: climate-controlled storage box with a "Void Warranty if Broken" would help prolong battery banks and equipment. You would also agree that discharging each battery in the bank at less than 1amp each would also prolong them and discharging them by only 20% of capacity would do the same. Though the batteries I am using can be drained down to 20% capacity and have no effect on performance and in all reality doing this actually prolongs the batteries.

Interesting that you and that battery manufacturer have come across something that very large companies and research departments have missed or forgotten.

What ever the history of your "battery" I wish you luck getting it to market. I do look forward for an energy storage system that most joe blows can afford and justify.

[einsvanian]

If you have any mismatched impedance what happens is that the voltage hits either a higher or lower resistance in the battery; when this occurs if high it has some of the charge reflected back to the charge controller and heat is created (bad for chargers); if low the batteries get high current which creates heat inside the battery (bad for batteries). Matching the resistance inside the battery the charge controller can provide a more smoother current with no reflection to itself and doesn't over flood the batteries with high current. No matter what there will always be heat. MPPT minimizes heat and distortion between solar array, controller, and battery (bank).

Batteries are not all the same: some will be higher in resistance and others will be lower. Manufacturers try to get them identical but that is only in a perfect world. MPPT takes the whole impedance and matches that. You will get different currents still going to each battery and that is where you get the miss matched resistance and heat is generated.

What MPPT does is it provides a defined current matched at the overall impedance of the battery bank. Each battery in the bank will take a portion of that charge according to their resistance; so in all reality each battery is provided with the exact amount of current it needs to charge without burning it up.

Also, MPPT acts as a DC to DC converter. It doesn't use dummy loads to reduce voltage it does it even smarter. It kind of transforms the voltage or steps down the voltage allowing a higher current on the 2nd winding and lower amperage on the primary winding. Dummy loads drop voltage and current and creates heat which is wasted. Either it transforms using maybe an isolation transformer or it uses solid state devices to reduce voltage; haven't really Google'd any schematics but it lowers the DC voltage with minimal loss to maximize power output. There is still loss but a lot less than PWM chargers.

So with that said: MPPT doesn't force the panels to drop voltage which creates heat; the MPPT does it for the panels. I can go on longer but I think this will give others plenty to nit pick and misunderstand. I'll be making updates.

In other words: It Isolates the Solar Array from the Battery Bank with minimal loss in current and heat.