Energy storage is experiencing mad growth. Residential energy storage has grown 9X in Q1 and 10X in Q2, and 74% of customers say they’re interested in energy storage along with their solar power system. Now that we know the demand is clear, let’s talk about the products.
Sometime last year, SMA suggested exponential growth was coming in the storage application segment. Earlier in 2018, they announced their new SMA Sunny Boy Storage (still listed as coming soon on the website) – and now it is shipping.
The units are sized at 3.8, 5.0 and 6.0 kW sizes (SMA PDF specification page). The hardware is noted as accepting Li-ion batteries that are AC coupled with the unit. The spec pages suggest LG and BYD batteries, plus to check out SMA-Americas.com for additional units approved.
The inverter does not require that batteries are connected at the time of installation, and until the energy storage solution is integrated owners can still make use of instantaneous solar power availability via the 2,000W Secure Power System (SPS) feature long offered in SMA products.
And while the unit does note that it has “intelligent energy management solutions”, the marketing material notes that full backup functionality will be available with a backup unit from 3rd-party vendors.
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No where in the article is the battery voltage specification mentioned, so I used the provided link to the sunnyboy website.
I am pleasantly surprised at the functionality of this unit. It is remarkable flexible in several ways.
The input voltage may vary from 100 to 550 VDC, with the maximum DC voltage listed as 600 VDC. That’s quite impressive, if you have your druthers, you’d always want to be on the high side of 350 VDC to drive a 240 VAC inverter, but the lower limit of 100 VDC means you could conceivable drive this unit with lead-acid batteries. I understand that you can sometimes buy used golf cart batteries cheaply, which with a little bit of desulfating, and keeping the charge above 50% can last a long time. Anyway, the huge amount of voltage flexibility is wonderfully resistant to changes in battery technology over the decades. If the best, as in cheapest per kWh batteries end up being huge cells, sort of like lead acid batteries instead of the many small cell, high voltage batteries we envision today, you are ready for it.
The unit can operate at 50, or 60hz, meaning it will work in Japan, or Europe, as well as North, and South America. Presumably, the unit can also serve as a charger for the batteries, so that price arbitrage can be done with any spare battery capacity.
I noticed the unit has 2kW of what the specs call “secure power”, which I take to mean uninterruptible power. If I had one of these, my LED home lighting(but not lamps powered from outlets), my networking equipment, computers, and mobile charging would all be powered by this circuit. The “normal” circuitry of the home will be connected directly to the utility service, and even if you have automatic switch over in case of utility failure, you will see transients, and if there was some sort of failure of switch over, it would be nice to have lighting, and digital communication running no matter what.
The inverter, and battery unit are AC coupled, which makes using different types of batteries much simpler/cheaper, but results in a bit lower efficiency compared to DC coupling. For DC coupling, you’d have to have some sort of DC to DC converter to maintain the huge DC voltage range, which would lose any increase in efficiency.
On the other hand, the engineer in me likes the simplicity of having the input to the inverter, capacitors for high momentary demand, the output from the solar MPPT circuitry, the output from the rectifier connected to the utility service, and the batteries all sitting on one big DC buss. Of course, for this the batteries would need to be designed for the inverter/battery control
unit, at least as far as DC voltage range.
I can’t wait to see what these will sell for. Since one design works pretty much everywhere on the planet, and with any batteries, I would think mass production would let it be sold at a reasonable price.
I checked ebay, and found a 6kw unit for sale at $1499.00 about twice what a 6kW SMA grid compliant unit is going for. I’d say that is a very reasonable price for a unit this flexible, I’d expect prices relative to non battery capable units to come down, as production rates go up. Here’s the link
https://www.ebay.com/itm/NEW-SMA-SUNNY-BOY-6-0-US-40-6000-WATT-INVERTER-w-FREE-SHIPPING/192650573632?epid=579825770&hash=item2cdade7740:g:lWkAAOSw5WVbkEfg
Good, but I will want to make solar power plant 10Mbt and 5МWt in province Mongolian Gobi-Altai and Zabhan in 2020 year investment invited