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All About Batteries

How do Batteries Work?

Grid-tied solar is wonderful technology, and the lower electric bills and environmental stewardship are meaningful. Adding batteries to your solar system changes the game and adds energy independence and resilience to that mix.

Batteries are chemical energy storage devices.  Most of us know a battery as an encased unit that can retain potential energy to be discharged as electricity. The differences in batteries arise from the materials used to create their component parts, namely the electrolyte and the two electrodes of different materials. When connected into a circuit, ions from one electrode move through the electrolyte (the conductive material around the electrodes and between them) into the other electrode, creating a flow of energy that manifests as electrical current. Many modern advanced technology batteries are fully sealed, with the electrodes connected to an external anode and cathode that conduct the electricity in and out of the battery. Other batteries require the addition of water to maintain the optimum levels of electrolyte concentration.

Each cell (a unit containing the two electrodes and the electrolyte) in a rechargeable battery (made up of one or more cells) uses the two electrodes to generate energy. The materials have been chosen because they can react and produce electricity that flows out of the battery (called discharge) as well as reverse the chemical reaction by receiving electricity from another energy source (called recharging). Over the years, people have discovered different combination of electrodes that meet a few important criteria.

Two Most Popular Types of Batteries

Lithium-Ion

Given their reputation for being smaller and lighter, as well as having long cycle lives, these batteries are becoming more common for residential battery storage. mtvSolar offers multiple types of lithium battery. They do need climate control to maintain peak operation, but overall these are perfect for running critical systems in a residential setting, such as refrigerator, electronics and other small appliances.

Lead-Acid

Highly consistent, Lead-Acid batteries can be applied to any size project as they can be scaled up infinitely for the largest applications. They do have a lower depth of discharge than Lithium, so they require a larger overall capacity for the same true energy output, and they can be a bit complicated and require specialized labor to install. Some versions are flooded and require watering and maintenance, but for safety reasons mtvSolar will only install sealed, maintenance free batteries, so there isn’t a chance of gasses or acid leaking from them.  Lead acid batteries are a very well-tested, established technology.  The DEKA Unigy II industrial grade batteries that we recommend and install were originally designed for backup in the Telecom industry, so they are very well suited for residential and commercial backup with extremely long stand-by lifespan.  Although lead is a toxic heavy metal, the lead in DEKA’s lead acid batteries is recycled from dead batteries; the recycling system for lead-acid batteries is well established.

With a properly engineered battery backup system, your refrigerator and freezer stay on, the well pump runs, and small appliances can be used. Harsh storms and utility problems can be gotten through much more comfortably. In addition, systems can be designed for long term preparedness to ensure that you have reliable uninterruptible power 24/7 for extended periods of time without utility power.

mtvSolar offers multiple types of battery systems:

Each has their own strengths and weaknesses and best applications.

Tesla PowerWall is a lithium-ion battery for your home. It allows you to store power that can then be used in the case of a power outage or, for solar owners, to store excess power produced by the panels. Although not specifically tied to solar as a technology, one can easily see how the PowerWall works very nicely with a solar installation.

The Tesla PowerWall builds on the expertise and technology of Tesla’s engineers to produce a lithium-ion battery that is small enough to reside neatly out of the way in your home, but powerful enough to provide meaningful electricity when you need it.  PowerWall is great for time of use shifting and backup, but not recommended for off-grid scenarios due to the AC coupling and lack of proper generator support.

EnergyHub is a combination of a SolarEdge EnergyHub inverter with SolarEdge lithium battery. These systems have the following major benefits.

EnPhase enCharge “The Enphase Encharge 10 all-in-one AC-coupled storage system is reliable, smart, simple, and safe. It is comprised of three base Encharge 3™ storage units, has a total usable energy capacity of 10.08 kWh and twelve embedded grid-forming microinverters with 3.84 kW power rating. It provides backup capability and installers can quickly design the right system size to meet the needs of both new and retrofit solar customers.” -enPhase Marketing

Ten-year limited warranty

Schneider Electric is a system comprising of a Schneider hybrid inverter and lead-acid or lithium batteries. These systems have the following major benefits:

The downside is they are labor intensive and more complicated.  These systems are especially great for off-grid applications.  Note that we do not install flooded batteries; therefore there is no danger of dangerous gasses or leaking acid.

Commercial Battery Storage Applications

Demand charges are adders that utility companies charge commercial customers to ensure that they can deliver the maximum power ever needed by the client.

Demand charges are based on the highest 15-minute average usage recorded within a given month. If the facility tends to use a lot of power over short periods, the demand charges will comprise a larger part of the bill. If the facility uses power at a more consistent rate throughout the month, the demand charges will generally be a smaller part of the bill.

In our area we’ve seen bills where demand charges comprise 50% or more of the total. The good news is that mtvSolar can help you slash demand charges in three ways:

We believe the best way to charge a battery is with solar. mtvSolar can integrate a solar PV array with the battery storage. Even a small array can extend the battery autonomy by many days.

Ready to make the switch to solar energy?​

Book a call with a solar expert.

Choosing Appropriate Equipment

mtvSolar specializes in SolarEdge, Enphase, and Tesla inverter systems.  They are the three leading solar inverter manufacturers in the world. Each company offers a unique set of features and benefits, making it important to consider your specific needs when choosing an inverter.

SolarEdge

SolarEdge is known for its string inverter technology, which uses a centralized inverter to convert DC power from solar panels to AC power. This type of inverter is more efficient than traditional central inverters, and it also allows for individual panel optimization.

Pros

Cons

Enphase

Enphase is the pioneer in micro-inverter technology, which uses a separate inverter for each solar panel. This approach offers several advantages, including:

Pros

Cons

Tesla

Tesla is a relative newcomer to the solar inverter market, but the company has quickly made a name for itself with its innovative designs. Tesla inverters are known for their sleek appearance and their ability to integrate with Tesla’s Powerwall home energy storage system.

Pros

Cons

Feature
SolarEdge
Enphase
Tesla
Inverter type
String
Microinverter
String
Efficiency
Highest
Very high
High
Shading performance
Excellent
Excellent
Poor
Monitoring capabilities
Excellent
Excellent
Good
Safety
Excellent
Excellent
Excellent
Cost
Mid
High
Low
Reliability
High
High
Highest
Integration with energy storage
Excellent
Excellent
Excellent

The best solar inverter for you will depend on your specific needs and budget. If you are looking for the most efficient inverter possible, SolarEdge is a good option. If you are concerned about shading, SolarEdge or enPhase is also a good choice. If you are looking for a sleek inverter that integrates with Tesla PowerWall, Tesla is a good option. And if you are on a tight budget with zero shade, Tesla is a good choice.

Ultimately, the best way to decide which inverter is right for you is to talk to a mtvSolar consultant. They can help you assess your needs and recommend the best equipment for your system.

Ready to make the switch to solar energy?​

Book a call with a solar expert.

Frequently Asked Questions

Batteries are not required!  In a grid-tied system without batteries, the power coming from your solar panels will power your house. If there is not enough solar energy coming in, the excess comes from the grid. If you produce more power than you consume, you later get back that surplus electricity at no charge.  This is called net-metering.

Absolutely!  No matter how large or small your installation, you will directly offset your electricity bill by a certain percentage.  Every system pays for itself in electricity bill savings.  After you break even, you make money via avoided utility costs.

Chances are, yes!  mtvSolar is equipped to assist with various financing options, including zero down and low interest loans.

Typically in our service area of MD, WV, PA and VA, customers will realize a full ROI after 10-12 years.  In states with SRECs (Solar Renewable Energy Credits), your return may be closer to 10 years or even less.

This really is an investment – the good thing is, as the price of electricity goes up – you save more – every kWh of energy you produce is one you don’t pay for.  If you save 11¢ per kWh now and in a few years it winds up being 17¢ per kWh you will be saving 17¢. Since it adds value to your house, it’s an investment for your heirs as well.

The size of your system is based on how much electricity that you use, not the size of the house.  When we do an evaluation, we take into account your annual electricity consumption, the size of your roof or other location suitable for solar, and your budget.

If you have batteries, yes.  We specialize in custom battery backup systems which can keep the lights on when the grid fails.  If you do not have batteries, then the utility grid is equivalent to your “battery”.  Therefore, when the grid fails, the system must shut down as well.

Net-meter credits are kilowatt-hour (kWh) credits accumulated on your electricity bill.  At the end of each billing cycle, the utility will compare how many kWh you consumed, and how many kWh you produced in excess, difference those totals, and then bill accordingly.  It is possible to generate enough of a surplus in summer to zero out your bills all through winter, referred to as going “net-zero”.  In our service area, only Maryland utilities will pay you for an annual excess at the wholesale rate.  Other states roll-over to the next year.

The solar ITC can be spread over 10 years, however we are not financial advisors.  Please speak to your accountant for information as it pertains to your situation.

Absolutely!  Provided that you have an always-on Internet connection, we set up your monitoring free as part of our service package.  For locations without Internet, we have cellular options available.

The dial emulator is pointing to the left which means that our solar modules are pushing power back to the power company.

Code 01 = The “Net” kWh that you are billed for.

Code 04 = The kWh pulled from the utility.

Code 40 = The kWh that has pushed back to the utility.

Code 01 is really the only number used for determining how much you owe. If the value is greater than the prior month then you owe money. Likewise, if the number is smaller than the previous month you have gained credits and you only owe for the base charge.

It’s important to note that the kWh pushed back to the utility (Code 40) is not synonymous with the total power produced by our solar PV system. Some of the power produced is gobbled up immediately in the house – as soon as it is generated, before it even gets to the utility meter.. The leftover solar generation (the excess) is what gets pushed back to the utility.

Solar modules do not require any maintenance.  Battery systems, while largely maintenance free, should be checked for functionality annually to ensure that the batteries are healthy and the system is ready to operate during an outage.

Great question!  Many states in our service area have right-to-access laws, which forbid an HOA from preventing you from getting solar.  They may still have aesthetic requirements but we can always work with those.  We would be happy to speak with your HOA on your behalf.

Good news, it doesn’t.  Solar installations are not taxed, and do not count towards your property’s value for tax purposes.

Chances are, increase it!  We offer the Pearl Certification, which is a program to assist real estate appraisers in valuing property with solar installed.  Typically, homes with solar sell for 5% more than ones without.

It is a good idea to notify your homeowner’s insurance of the solar energy system.  Your premiums may see a small annual increase, but your system will be insured should anything happen to it.

All batteries that we install, whether lithium or lead, are sealed and maintenance free.

DEKA Lead: Our lead acid batteries are sealed GEL or AGM type that require no water or venting.

Tesla PowerWall: Completely Safe – Liquid thermal controls and touch safe technology maximize battery life and safety.

enPhase enCharge, Harris: Lithium-Iron Phosphate (LFP) batteries are the safest type of lithium battery available and are not known to combust.

SolarEdge Energy Bank: The residential energy system has a lithium-ion battery that contains an organic electrolyte that is sealed in a protective case. A built-in fire extinguisher is present.

Absolutely!  You can start with as few as six panels, and we will size the remaining components to support the maximum size desired.  The more panels that you install at any one time, the lower the price per panel.

The answer to this depends entirely on how much energy you are consuming.  If you’re sipping power for a refrigerator, Internet, some lights and not much more, you can likely go indefinitely if there is enough sun to recharge daily.  However, if you’re running large loads like space heaters, window units, or pool pumps, you can expect the batteries to be depleted much sooner.

Absolutely!  We also install on any other roof type capable of supporting the load, as well as the ground.  During an evaluation we can determine if your roof is suitable for solar.  For standing-seam metal roofs, there are absolutely zero penetrations.

Solar power systems for the home require either batteries or the grid to function, as solar inverters do not have the capability to start surge loads on their own.  For example, well pumps, refrigerators, small air conditioners, etc all require many times their normal operating wattage to start up (known as inrush), and if the grid or a battery were not present, the inverter would fault and stop operating.

By being grid tied, your house can be running entirely on solar energy.  When a large appliance turns on, that inrush power comes from the utility, or a battery during an outage.

This one is hard to answer.  It depends on how physically close the source of the EMP (electromagnetic pulse) is, and how much energy is induced in the electronics as to whether they would be damaged or not.  EMP protectors, or surge suppressors might help, but nothing can save electronics that are not inside a faraday cage if your system is at ground zero.

SRECs (Solar Renewable Energy Credits) are paid out by a broker (typically SRECTrade) for every MWh of energy produced by your system.  These are deposits made directly into your bank account, based on the going market rates.  Our office will initiate the setup process for you on SRECTrade.

  • Our Premium solar modules carry a 25 year limited warranty.  They will provide meaningful power for decades longer.
  • SolarEdge Inverters carry a standard 12 year warranty, optionally extendable to 25 years.
  • SolarEdge optimizers carry a standard 25 year warranty.
  • EnPhase IQ micro-inverters carry a standard 25 year warranty.
  • The Tesla PowerWall carries a 10 year limited warranty.
  • The DEKA Unigy battery carries a 10 year limited warranty.
  • The Harris Lithium battery carries a 10 Year Warranty (5 full/5 prorated).

Yes!  For grid tied systems, we will tie the solar in at the utility connection point, so as to avoid back-feeding your generator and causing damage.  Certain types of solar battery systems can also utilize a generator for battery charging.  Our most advanced DC coupled systems are grid/battery/generator interactive and can utilize energy from all sources simultaneously.

Every system that we install is completely custom.  Contact us for a free estimate today.  Our zero pressure consultants will get you the answers you need to make an informed decision.  We also have financing options available.

Standard grid-tied solar works by offsetting a portion of your utility bill, which results in monthly savings.  During the day, your meter “spins backwards”, and at night it “spins forward”.  This is called net-metering.  Think of the utility as a bank account.  You deposit and withdraw energy from it each day, and only get billed for what you use in excess of your solar production.

If your solar panels are covered in a couple inches of snow, they aren’t going to work as efficiently. This does not mean that solar does not work in a snowstorm. In addition to being warmer than the ambient outdoor temperature, solar panels are slippery when wet and positioned to catch the most sunlight. Both of these factors help them resist snowfall or eliminate it quickly. Solar panels are also usually installed at a steep enough angle that helps persuade the snow to slide off. Of course, a lengthy snowstorm will eventually get the best of your panels and diminish their crucial power making ability. That said, they will attract enough sun to clear themselves off relatively quickly after the storm ends.

Generally speaking, no.  Rain and snow sliding off does the job.  In fact, we did an experiment and found that the gains from cleaning what appeared to be a dirty panel resulted in very little output gain.  If your array is near railroad tracks or interstate highway, your panels may benefit from the occasional scrubbing due to diesel soot buildup.  There is no risk of being shocked while cleaning your panels.

Generally, no.  If your inverter goes down under warranty, it will be replaced by the manufacturer.  Also, inverters are continually improving.  Having one sit around as a backup would result in you replacing what you have without being able to take advantage of improvements to the product.

Unlike a generator, which requires time to come online and power loads, mtvSolar’s battery systems supply power immediately and silently, eliminating possible interruptions in critical infrastructure operation. They are also maintenance free.

We believe the best way to charge a battery is with solar. mtvSolar can integrate a solar PV array with the battery storage.  Even a small array can extend the battery autonomy by many days.

At mtvSolar, we will choose the battery type that makes the most sense from a technical standpoint for a given application. We consider space, power requirements, operating temperature, cost and equipment availability among a few important design considerations.

Demand charges are adders that utility companies charge commercial customers to ensure that they can deliver the maximum power ever needed by the client.

Demand charges are based on the highest 15-minute average usage recorded within a given month. If the facility tends to use a lot of power over short periods, the demand charges will comprise a larger part of the bill. If the facility uses power at a more consistent rate throughout the month, the demand charges will generally be a smaller part of the bill.

Demand charge mitigation

The good news is that mtvSolar can help you slash demand charges in three ways:

  1. Install a solar PV array which will lower overall power usage, including demand charge during the day.
  2. Install battery storage to store power and release it as needed during periods of peak load, therefore reducing demand charges from the utility. This implementation is called “peak load shaving”.
  3. Analyze power usage to help further reduce demand charges by changing how equipment is turned on, or adding controls to reduce surge loads.

For demand charge mitigation, we implement Tesla’s lithium solutions.

  • We guide you through the entire process, making getting solar EASY
  • We handle the permitting, inspection, and net-metering process for you
  • Our customers love us and often come back for expansion (see testimonials)
  • Your system will be wired by licensed electricians, not temporary labor
  • Our panels and batteries are top of the line quality
  • We use name brand equipment with full warranties
  • We are fully licensed and insured
  • Local customer service you can depend on!
Ready to make the switch to solar energy?​

Book a call with a solar expert.