Elon Musk makes the Future Happen

Has the future finally arrived? I hope so:

Tesla's Elon Musk Unveils Solar Batteries for Homes and Small Businesses
The system could easily take a home off the power grid, especially with the use of many solar panels, Musk said

From a man who made his name and charted his career with lofty goals and often unexpected financial decisions, the news came with little surprise: Elon Musk, the CEO of Tesla Motors Inc., unveiled a product line of electric batteries late last night in Los Angeles.

Musk introduced the Tesla Powerwall, a wall-mounted lithium-ion electric battery for homes and small businesses, and the Tesla Powerpack, a heftier version of the same core product designed for utility-scale use.

He also announced a new wing of the company, Tesla Energy, which will begin shipping the Powerwall systems to domestic customers in three to four months. Deliveries will trickle out slowly, he said, then accelerate next year when the company begins shipping orders out from its so-called Gigafactory in Nevada.

Yet Musk spoke first about rising emissions and climate change solutions, not cars. He used a slide show of power plants and smoggy skies to introduce the problems. “It sucks, exactly,” he said. “I think we, collectively, should do something about this,” he added, “for us and a lot of other creatures.”

The Powerwall battery charging system, which can be stacked up to nine batteries high and mounted on an inner garage wall or outside, costs $3,000 for a 7-kilowatt-hour system and $3,500 for the 10 kWh option. The entire Powerwall system is roughly 3 feet wide and 4 feet long, and would stick out about 7 inches once mounted. It could easily take a home off the power grid, especially with the use of many solar panels, Musk said.

“Tesla is not just an automotive company, it's an energy innovation company,” the firm said in a statement. “Tesla Energy is a critical step in this mission to enable zero emission power generation.”

The utility version comes in 100 kWh blocks that can be grouped together. Musk said one utility company is already interested in a 250-gigawatt installation of Powerpack systems alone.

Shifting cities to 'stored sunlight'
“This entire night has been powered by batteries,” he told the audience in the warehouse in Hawthorne, Calif., pointing to gray, blocky Powerpack systems standing on end and powering the facility. “Everything you're experiencing is stored sunlight.”

Musk's solution is as audacious as it is simple. By harnessing energy from the sun—“this handy fusion reactor in the sky,” he called it last night—getting enough renewable energy on the power grid and smoothing out energy generation and use between peak and off-peak hours, the nation and planet can shift away from fossil fuels' dominance as a power source, he told the crowd.

The new batteries, he said, will help speed that transition worldwide. “These is going to be a great solution for people in remote parts of the world,” he said, noting that it allows homeowners to leave the power grid and ditch electric cables.

“It can scale globally,” he added, likening the battery systems' potential in emerging economies to mobile phones that penetrated markets faster than old technology and leapfrogged landline sales.

Tesla, the first American car company to go public since Ford Motor Co., has been a darling stock to many in recent years, climbing from trading in the $30 range in 2012 to above $200 a share for most of the past year.

In a research note about yesterday's announcement from Deutsche Bank AG, which was reported by Bloomberg, the authors struck a bullish tone, writing: “Based on the preliminary work on the economics of stationary storage, we believe that this has the potential to be more significant” than Wall Street analysts expect. The battery system, they wrote, could add up to $100 a share.

Karl Brauer, a senior analyst for Kelley Blue Book, said Tesla's new battery division could be even more successful than its car business. [...]

The German bankers recognize the potential. This is really exciting. I had posted previously about this new type of power grid that such batteries would create. Now it's actually starting to happen.

Hooray!
     

A new type of power grid

Why Tesla's battery for your home should terrify utilities
Elon Musk's electricity empire could mean a new type of power grid

[...] The prospect of cheap solar panels combined with powerful batteries has been a source of significant anxiety in the utility sector. In 2013, the Edison Electric Institute, the trade group for investor-owned electric companies, issued a report warning that disruption was coming. "One can imagine a day when battery storage technology or micro turbines could allow customers to be electric grid independent," the report said, likening the speed of the coming transition to the one from landlines to cellphones 10 years ago. Suddenly regulated monopolies are finding themselves in competition with their own customers.

They haven’t had to deal with this on the residential side yet, primarily because people can sell excess power back to the utilities at fairly high rates — a practice called net metering. But that’s hurting utilities, too, and some have tried to lower the price at which they buy back power, which has been met by furious protests from people leasing panels. If utilities lower the buyback rate too much, however, and batteries get cheap enough, people may just unplug from the grid altogether — or more likely, install systems that let them rely on it only rarely — prompting what those in the industry call "the utility death spiral." It’s quite a bind: by fighting net metering, utilities would help make battery storage more economically viable, driving the transition to a distributed grid.

Manghani believes utilities aren’t doomed, but they may undergo a radical transformation, becoming something closer to service providers and minders of an increasingly distributed grid rather than the centralized power producers they are today. Such a system would require lots of batteries to help balance the load and supply extra power during peak times, which is why GTM estimates the market will grow from $48 million today to about $1 billion in 2018. [...]

Excellent, I say bring it on! And Tesla seems perfectly poised to pounce and make it happen. Read the whole thing for the details that back it up, embedded links and more.
     

Charging and Maintaining Deep Cycle Batteries

I got a deep cycle battery to use with my Ham Radio, as back-up emergency power. I thought it would be easy to deal with, but there is so much to know:

Deep Cycle Battery FAQ

[...] Deep cycle batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates - not sponge. This gives less surface area, thus less "instant" power like starting batteries need. Although these an be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge.

Unfortunately, it is often impossible to tell what you are really buying in some of the discount stores or places that specialize in automotive batteries. The golf car battery is quite popular for small systems and RV's. The problem is that "golf car" refers to a size of battery (commonly called GC-2, or T-105), not the type or construction - so the quality and construction of a golf car battery can vary considerably - ranging from the cheap off brand with thin plates up the true deep cycle brands, such as Crown, Deka, Trojan, etc. In general, you get what you pay for.

[...]

Cycles vs Life

A battery "cycle" is one complete discharge and recharge cycle. It is usually considered to be discharging from 100% to 20%, and then back to 100%. However, there are often ratings for other depth of discharge cycles, the most common ones are 10%, 20%, and 50%. You have to be careful when looking at ratings that list how many cycles a battery is rated for unless it also states how far down it is being discharged. For example, one of the widely advertised telephone type (float service) batteries have been advertised as having a 20-year life. If you look at the fine print, it has that rating only at 5% DOD - it is much less when used in an application where they are cycled deeper on a regular basis. Those same batteries are rated at less than 5 years if cycled to 50%. For example, most golf cart batteries are rated for about 550 cycles to 50% discharge - which equates to about 2 years.

Battery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%. Obviously, there are some practical limitations on this - you don't usually want to have a 5 ton pile of batteries sitting there just to reduce the DOD. The most practical number to use is 50% DOD on a regular basis. This does NOT mean you cannot go to 80% once in a while. It's just that when designing a system when you have some idea of the loads, you should figure on an average DOD of around 50% for the best storage vs cost factor. Also, there is an upper limit - a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the the positive plates rather in an even film. The graph above shows how lifespan is affected by depth of discharge. The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary.

[...]

Battery Charging
Battery charging takes place in 3 basic stages: Bulk, Absorption, and Float.

Bulk Charge - The first stage of 3-stage battery charging. Current is sent to batteries at the maximum safe rate they will accept until voltage rises to near (80-90%) full charge level. Voltages at this stage typically range from 10.5 volts to 15 volts. There is no "correct" voltage for bulk charging, but there may be limits on the maximum current that the battery and/or wiring can take.

Absorption Charge: The 2nd stage of 3-stage battery charging. Voltage remains constant and current gradually tapers off as internal resistance increases during charging. It is during this stage that the charger puts out maximum voltage. Voltages at this stage are typically around 14.2 to 15.5 volts.

Float Charge: The 3rd stage of 3-stage battery charging. After batteries reach full charge, charging voltage is reduced to a lower level (typically 12.8 to 13.2) to reduce gassing and prolong battery life. This is often referred to as a maintenance or trickle charge, since it's main purpose is to keep an already charged battery from discharging. PWM, or "pulse width modulation" accomplishes the same thing. In PWM, the controller or charger senses tiny voltage drops in the battery and sends very short charging cycles (pulses) to the battery. This may occur several hundred times per minute. It is called "pulse width" because the width of the pulses may vary from a few microseconds to several seconds. Note that for long term float service, such as backup power systems that are seldom discharged, the float voltage should be around 13.02 to 13.20 volts.

Chargers: Most garage and consumer (automotive) type battery chargers are bulk charge only, and have little (if any) voltage regulation. They are fine for a quick boost to low batteries, but not to leave on for long periods. Among the regulated chargers, there are the voltage regulated ones, such as Iota Engineering and Todd, which keep a constant regulated voltage on the batteries. If these are set to the correct voltages for your batteries, they will keep the batteries charged without damage. These are sometimes called "taper charge" - as if that is a selling point. What taper charge really means is that as the battery gets charged up, the voltage goes up, so the amps out of the charger goes down. They charge OK, but a charger rated at 20 amps may only be supplying 5 amps when the batteries are 80% charged. To get around this, Statpower (and maybe others?) have come out with "smart", or multi-stage chargers. These use a variable voltage to keep the charging amps much more constant for faster charging. [...]

And that's just a sample, there's LOTS more to know, regarding the age of the batteries, different battery types, charging voltages, charging regulators, temperatures, storage, etc.

And if all that isn't overwhelming enough, consider these:

Mini Factoids

Nearly all batteries will not reach full capacity until cycled 10-30 times. A brand new battery will have a capacity of about 5-10% less than the rated capacity.

Batteries should be watered after charging unless the plates are exposed, then add just enough water to cover the plates. After a full charge, the water level should be even in all cells and usually 1/4" to 1/2" below the bottom of the fill well in the cell (depends on battery size and type).

In situations where multiple batteries are connected in series, parallel or series/parallel, replacement batteries should be the same size, type and manufacturer (if possible). Age and usage level should be the same as the companion batteries. Do not put a new battery in a pack which is more than 6 months old or has more than 75 cycles. Either replace with all new or use a good used battery. For long life batteries, such as the Surrette and Crown, you can have up to a one year age difference.

The vent caps on flooded batteries should remain on the battery while charging. This prevents a lot of the water loss and splashing that may occur when they are bubbling.

When you first buy a new set of flooded (wet) batteries, you should fully charge and equalize them, and then take a hydrometer reading for future reference. Since not all batteries have exactly the same acid strength, this will give you a baseline for future readings.

When using a small solar panel to keep a float (maintenance) charge on a battery (without using a charge controller), choose a panel that will give a maximum output of about 1/300th to 1/1000th of the amp-hour capacity. For a pair of golf cart batteries, that would be about a 1 to 5 watt panel - the smaller panel if you get 5 or more hours of sun per day, the larger one for those long cloudy winter days in the Northeast.

Lead-Acid batteries do NOT have a memory, and the rumor that they should be fully discharged to avoid this "memory" is totally false and will lead to early battery failure.

Inactivity can be extremely harmful to a battery. It is a VERY poor idea to buy new batteries and "save" them for later. Either buy them when you need them, or keep them on a continual trickle charge. The best thing - if you buy them, use them.

There is so much to know, not just about deep cycle batteries, but the many kinds of batteries, and the different requirements they have. Gosh, who knew? Well I guess I do now.