Mi-Grid vs. the Powerwall

Mi-Grid vs. the Powerwall

We’ve had a lot of requests to layout the difference between a Mi-Grid system and a Powerwall. So, here goes!

First, let’s define a “Powerwall”. It is a Lithium-ion battery pack. It is not a complete power system. Implementing it requires a StorEdge inverter from Solar Edge. If you have solar, you also need a SolarEdge grid tied inverter and all of the required safety systems, breakers, disconnects, to properly implement. The “cost” most people associate with the Powerwall is only the price of the battery pack.

The SolarEdge+Powerwall system is a Grid-Tied solution. It cannot be used for off-grid. The Powerwall+SolarStor is designed to supply short term power from its battery pack for short (hours) service interruptions. If solar is present, it can store and disperse energy from the solar panels after sunset. However, the cost to store and retrieve the energy may be above the cost to sell to the network, even without net-metering.


Mi-Grid was originally designed as an Off-Grid system, specifically for the Off-Shore oil industry. It is designed to allow long term or permanent power with or without a utility connection. Mi-Grid’s Energy Management System (EMS) can take in multiple AC and DC sources, supply power and recharge batteries, all at the same time. It is also rugged and can be implemented outdoors.

Mi-Grid is “Agnostic” with respect to AC power, type of and manufacturer of solar panels, battery systems, as long as they meet the specified voltage ranges. Mi-Grid even has modules which can make use of “dirty” unstable utility power and turn it into “clean” pure sine-wave power.

Mi-Grid can be connected to a generator, allowing off-grid or utility down operation. The generator is only used off-grid or if the utility is down. The Generator recharges the batteries on cloudy or high power usage days, then shuts down. Even when operating with the generator, the solar array can assist recharging the batteries and supplying power. If the batteries become full, the EMS will modulate the array to match the power required,

The StorEdge-Powerwall system cannot implement a generator safely, unless the entire Solar/PowerWall/Stor-Edge system is bypassed. It uses a grid-tied inverter which cannot modulate the solar array output. Once the batteries are full, if the solar array output exceeds the user’s needs, it would send power to the generator, probably damaging it, potentially catastrophically.

Cost: It depends. Don’t you hate it when people say that? Mi-Grid comes with a generator and many more AC and DC inputs. If you eliminate the generator, you can compare the costs of the systems. The most fair comparison would be a Mi-Grid 1000 or Mi-Grid 2000 setup in essential circuits configuration. A Mi-Grid 1000 costs around $28,000 installed with 4.7kW solar and a 10kW generator. A Mi-Grid 2000 costs around $47,000 installed with 9.4kW solar and a 16kW Generator. Depending on location and codes, these prices can vary. For a “fair” comparison, you would need to implement 2 Powerwalls with any StorEdge System. You also need to include a SolarEdge 5 or 8kW grid-tied inverter and Optimizers at each panel.

Capability Comparison

Mi-Grid 1000 Mi-Grid 2000 SE5000+PW SE6000+PW
Max AC Power 4000 8000 5000 6000 Watts
Max AC Surge 8000 16000 7300 7300 Watts
Maximum Battery Output 4000 8000 1xPW=3300, 2xPW=6600 Watts
Energy Storage 19.2 38.4 1xPW=6.8, 2xPW=12.8 kWh
Energy Storage Usable 9.6-15.4 19.2-30.8 1xPW=6.8, 2xPW=12.8 kWh
Noise <30dB <30dB 1xPW=56dB, 2xPW=61dB  dB
Generator for contingencies Yes Yes No No
Grid-Tied Yes Yes Yes Yes
Off-Grid Yes Yes No No
Sell Excess Power Yes Yes Yes Yes
Run Whole House Air Conditioner No Yes No Maybe
Battery Life 3000 or 1800 Cycles,

50%/80% DOD respectively

1000@20% capacity loss

3000@60% capacity loss

Outdoor Rating NEMA 4/IP66 StorEdge IP65, PW IP10


Getting ready for a Hurricane – from Mi-Grid

Getting ready for a Hurricane – from Mi-Grid

I live in the Gulf Coast area and hurricane preparedness is extremely important. About every 10 years, my area is hit with a hurricane, tropical storm or other disasters. It is much more important to prepare ahead, than wait until the announcement by the weather forecasters.

Run or Hide?

The saying is run from the water, hide from the wind. It means if your area will flood, get out of there! If your area won’t flood, you can “hunker down”, protect yourself and generally stay in your area.

Run from the water. Flooding is no joke. There isn’t anything you can do except evacuate. If you are in a flood-prone area, your preparedness is to have an inland location in mind, and your irreplaceable items “ready” to go. Know your evacuation route. Consider side roads and county roads which the rest of the public are not familiar. Keep extra fuel handy since there is usually a run on fuel just before the storm. Be prepared with a few days of food and water, since it may take time to evacuate. Remember, there will be LOTS of other people, so it will take much more time to get out of your area than normal.

Hide from the wind. Most people should stay where they are. First, the roads will be clogged with the people who need to evacuate. People in areas which won’t flood do not need to leave. If they do, they make the evacuation routes worse. So stay if you are not in a flood-prone area.

What do you need if you will be in a place to stay?

Food, water, and shelter. Your house is generally enough for shelter. If you are inland, the winds may be strong, but they generally not high enough to destroy your house. Most serious damage is storm surge and flooding. You may consider boarding up windows. Focus on the south and east windows, as this is usually where the wind comes from. Also look around your yard and remove anything which the wind can move. If you have a pool, tables and chairs can go in the water.

Food and water. Most people think they need bottled water. The water that comes out of your tap is EXCELLENT. But the power may be out and the water pumps off. So store water. How? Trash cans. Buy new ones!!! And you might want to put line them with trash bags. You also want to fill bathtubs and have a small bucket for pouring into toilets for flushing. Just buy the trash cans early and store them away unused.

Food you have a lot of choices if you prepare ahead. You can buy survival food. Not super tasty, but it is better than nothing. You can buy canned food. If anything needs heat to prepare, make sure you have a portable stove and fuel. Have a minimum of 2 weeks of food for every person in the house. That is about how long it will take to get emergency systems in place!

One real issue is post hurricane. In many places, the power may be out for weeks. Many people use generators to help them through. Portable generators need fuel and long-term storage of enough liquid fuel for 2 weeks can be a problem. They are loud!

Permanently installed natural gas or propane generators are much better. They have a big fuel source and they are not as noisy as portable units. They do require maintenance, so be prepared to change oil and spark plugs every 100 hours or every 4 days!

The best solution is a hybrid solar system combining solar panels, energy storage and a generator. It provides the power you need with minimal use of the generator. And the solar panels will save you money the rest of the time!

For help with hurricane preparedness, contact Tetra West Technology and ask about a Mi-Grid!

Solar Power System: How To Convert RV To Solar Power

Solar Power System: How To Convert RV To Solar Power

There has never been a better time to convert your RV to solar power. Going mobile into remote places, there are no hook ups for easy power. Solar Can provide your basic needs. And the price of solar has dropped to the point that it is easy to afford.

First things first

The most important thing to consider before self-powering your RV is energy efficiency. Every light bulb should be replaced with LEDs. All appliances should be selected for low power consumption. Anything that heats should be propane. It will cost less to replace energy efficient items than to power them with a bigger energy system

The Generator

Most boon-dockers use battery systems to power their essential needs. But they need to run a generator for the recharge the batteries. And to run larger appliances, the generator has to run all the time. This takes fuel and usually requires multiple fill-ups per day. And generators are noisy, possibly spoiling the whole reason for going remote.

Going Solar

A couple of solar panels, either hard mounted or setup when stopped, can recharge these basic battery systems. The typical system uses a charge controller between the battery and the panels. The charge controller disconnects the solar panels from the battery when they are full and at night. You are still limited to powering DC items.

Making AC power

The next step up is adding an inverter. Inverters take DC power, say from batteries, and convert it to AC power. This AC power, if the inverter is large enough, can power most of your AC needs, for example air conditioning. The issue with powering everything is the limit of the number of solar panels and the size of the batteries.

Getting it all together

What would be best is something that combines the best of each of the above. Solar to power DC and recharge batteries. An inverter to cover AC needs. And a generator for the times you need full power.

Tetra West Technology make Mi-Grid, a hybrid energy system. It combines solar panels, battery storage, inverter systems and a generator, all controlled by their patent pending energy management system. Solar panels supply DC power and recharge batteries during the day. The energy management system contains an inverter to power most of your AC appliances. And the automatically controlled generator starts up for large appliances and to re-charge the batteries if they get low.

And Mi-Grid is more affordable than you might think! Systems start at $4495 and include inverter / energy management system, high quality/long life deep cycle batteries and the automatic start generator. Solar panels are selected based on the configuration of your RV. Many models are available to match your needs.

Saves Time

When you’re out with your RV, playing with the generator is not top of the priority list. Mi-Grid allows you have full power, without the inconvenience of daily filling and weekly oil changes. Besides being messy and time consuming, the environmentally minded have to store the debris for proper disposal.

Saves money

Compared to running a generator alone, a typical Mi-Grid system reduces run-time and fuel consumption up to 90% or more. Generator refills become weekly events instead of multiple times per day. Reduced run reduces oil change, sparkplug and other maintenance activities, letting you enjoy your RV more. Finally, reduced run time extend the life of the generator. A Mi-Grid system can pay for itself in a little as 90 RV days!

For more details on how to convert RV to solar energy, please contact Tetra West Technology.

Solar Power System: Everything you need to know to add solar to your Food Truck

Solar Power System: Everything you need to know to add solar to your Food Truck

People living in the city are most likely to be familiar with the new trend of food trucks and their tasty fare, even though they have actually been around for years. With increasingly more people turning to the food truck industry for a cheap, quick meal and even at times a gourmet meal, patrons want a gourmet atmosphere. Emissions and noise from these gas guzzling generators can ruin that impression.

How can we now keep the power on our food trucks, while cutting the environmental impact?

The simple answer is to go solar. A lot of food truck vendors have discovered this, and are presently taking their local, sustainable and organic food job to the next level by using solar power. They aim to bring tasty, fresh, healthy and affordable food to the masses, and they are a more eco-friendly choice compared to several other fast food options.

Food trucks with solar power are presently taking a lead for several different reasons. A few include:

They are Cost-Saving

For many food truck operators solar is a cost-effective source of power. An average food truck owner operating on a traditional generator spends a minimum of $5 to $10 daily on fuel. There is also cost, labor and hassle in maintaining a generator. And the cost of replacement or repairing generators down the line can be costlier than installing solar panels. For a food truck operating 50 hours a week, the time for pay back can be as short as 9 months!

Traditional Food Trucks pollute the environment

The majority of food trucks operate on a diesel or gasoline generator that is specifically designed to run only a few hours. Operators tend to run them at a stretch for up to 14 hours, resulting in a high output of greenhouse-gas emissions, particulate matter, nitrous oxide and carbon monoxide. And the worst pollutant, is NOISE!

Considering the harmful effects, and the way solar power can offset operating costs, it is not difficult to see why solar food trucks are trending to solar. For more details on adding solar to food truck, contact [company name]

Off-Grid Solar Power System: Can I run my Air Conditioning too?

Off-Grid Solar Power System: Can I run my Air Conditioning too?

Several individuals have always considered off the grid and air conditioning never to belong in the same sentence, suggesting that you cannot have air conditioning off the grid.

The general response has been NO. Reasonably priced Off- grid solar power cannot run Air Conditioning. They are not powerful enough or the cost of a system is too great.

Mi-Grid is different. Mi-Grid is a hybrid solar energy system, combining battery storage PV solar with a backup generator. Even the smallest Mi-Grid can operate an Air Conditioner. The inverters and generators are sized to be able to start and run appropriately sized units. A tiny Mi-250 can run any 15 amp 110VAC window unit or even a 15,000 BTU/hr RV air conditioner. A Mi-Grid 4000, can run two 5-ton Air Conditioners with properly installed soft-starters.

The BEST choice for Air Conditioning is always a Mini-Split or inverter drive air conditioner. They require little startup power and are extremely efficient, reducing the amount of energy used for cooling. For the smaller Mi-Grid units, choose a 110VAC unit. For the Mi-Grid 1000 and up, 220VAC units can used.

Standard window air conditioning units can also be a good choice for the smaller Mi-Grid systems since they are 110VAC. Usually these are installed in bedrooms or small areas. 110VAC units work great with an essential circuits Mi-Grid. Get the most efficient one you can afford. Again, a mini-split is always best for your “essential” room.

Large whole house type Air Conditioning units can work with larger Mi-Grid units, especially with the addition of a small A/C soft start unit. The normal problem with running Air Conditioners is the power needed for startup. It can be as much as 5 times the operating power. A properly installed soft starter limits the starting power to only 50% over running power. This means a smaller inverter or generator can startup a larger air conditioner. And as always, get the most efficient one as possible.

One type of air conditioner/heat pump works extremely well with whole house Mi-Grid systems. Geothermal heat-pumps circulate coolant into the earth where year-round temperatures are far more moderate. This allows the heat pump to work much more efficiently and use much less power. Some of them have SEER’s between 40 and 50!!!

Mi-Grid can also be setup to provide power to all your essential circuits and outlets. High power circuits, for example air conditioners, are setup to only run with the generator. This allows the comfort of air conditioning while minimizing generator operation.

One final note: Insulation and shade. The cheapest way to keep cool is to not get hot in the first place. A shaded home/RV will use much less power. The more insulation, and the higher R-value insulation, the less heating or cooling you will need. And finally, cook outside in the summer. The less heat you add, the less air conditioning you need. Solar doesn’t work in the shade, but potable solar panels or ground mount arrays, can be placed in the sun with your house or RV in the shade.

You don’t have to give up comfort off-grid. Mi-Grid provides the power for everything.

Off-Grid Solar Power System: What can you power?

Off-Grid Solar Power System: What can you power?

Solar panel systems are powering virtually anything you can imagine and most likely a number of other systems you were not even aware existed.

Presently, solar powered lighting systems are utilized for illuminating Streets, secured storage areas, Parking lots, pathways, business roadside signs and traffic control lights.

Offering both decorative accent lighting and functionality, solar lighting can now be used with motion sensors so that the light source switch on itself whenever they are triggered by intruder’s movement or visitors. And now, stairways and pathways that use to be dark in the evening can be lighted with solar lighting systems. Furthermore, a number of communication firms are making use of solar-powered systems with battery backups to power their communication towers in remote locations. In addition, solar powered systems that are coupled with battery backup systems enable homeowners to power their remote locations that are off-grid. Clinics and hospitals as well utilize them for emergency power backup systems, security alarm systems and medical refrigeration systems. Solar powers are also used for water well pumps in remote locations where power is not considered for grid supplied, businesses and homes. As a matter of fact, the use of solar power systems can only be limited by your resourcefulness and imagination.

Some cities across the globe are even making use of solar powered trash bins which compact the trash on scheduled time periods making better use of the capacity of these trash bins and reducing the frequency with which they need to be emptied again thereby saving thousands of dollars yearly in hourly personnel wage costs. Solar power can likewise be used to recharge gadgets from your mobile phones to laptops and it comes in a wide range of packages from handheld devices to backpacks with solar modules built into their clothing.

It is no longer news that solar energy manufacturers are making more modern devices that can be used daily and by so doing, enabling us to tremendously lower our reliance on the conventional carbon fuel produced electricity. Although these newly-developed devices and systems will come with a higher rate to cater for their R&D expenses, with the prices for solar modules already falling, it is not different from buying that new LCD TV set when it first enter the marketplace with the exception that these systems will save you money in the long run and ought to be taking seriously into consideration for your use and purchase.