Posts tagged with "generator"

Never Lose Power

Today I did a one year inspection on a Mi-Grid 4000. This is primarily a check on the batteries and to do the yearly maintenance on the generator. With the exception of a few dead bugs inside the generator enclosure (how did that cricket get into the air cleaner?!?), it looked as good as the day it started it up.

One anecdote from the Owner. Earlier in the year, there was a terrible storm. They thought nothing of it. There was one flicker of the lights, but that was it. The next day, he attended a local luncheon where the primary topic was the 5-6 hour electric outage. He looked dumbfounded and said: “What Outage?”.

EXACTLY!!!  With Mi-Grid, you never lose power.

If Mi-Grid is setup in UPS/Backup mode, and the utility goes out, it switches in less than a second to the inverter and batteries. If the batteries become depleted, the generator starts up and comes to full speed, THEN it switches over. You don’t lose power. And when the Generator finishes charging the batteries? It switches back to inverter BEFORE the generator shuts down.

With Mi-Grid, you simply never lose power!

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


El Nino means more Hurricanes

The La Nina weather pattern returns this year and with it, more Hurricanes


Get Prepared with a Mi-Grid Hybrid Solar Energy System or Mi-Grid Generator.

Get Ready For Hurricane Season: Investing In A Good Generator

Hurricane season is upon us again. It runs from June 1st to November 30th of every year, and that means it may be time to invest in a good generator. Along with hurricanes are dangerous tropical storms, and simple summer storms that cause damage as they make their way through our cities. The number 1 cause of power outages is mother nature. Fortunately, there powerful generators available that can help get you through hurricane season.

Investing in Backup Power

A generator can be a good investment for backup power. They typically only need small capital investments, but operating a generator is not inexpensive. Generators use fuel, and they also require maintenance. Generators also have a finite life.

Different Types of Generators

Generators come in a few flavors. Small portable, permanent backup and prime power.
Prime power means the generator is rated to run all the time. They are the most expensive. If you need permanent off-grid power, these are the generators. They also last the longest. It is not unusual for these to run for 90 days between shutdowns.

Portable generators are the least expensive, but they require liquid fuel, typically gasoline. You will need to place these units well away from your house but still have long extension cords. And you will need these extension cords to run any electric devices in your house. Portable units are usually loud and not designed to be run for long periods. They need maintenance about every 50 hours.
Permanent automatic backup generators usually are connected to your natural gas supply or propane tank. An automatic transfer switch is connected to the electric supply. When it senses a loss of utility power, it will disconnect the utility power and start the generator. Power is usually back on in 30 seconds to 2 minutes. Small units provide power to essential parts of your house. Large units can run your entire house including air conditioning.

Installing Your Generator

Tetra West Power sells and installs automatic backup generators. We also build hybrid solar energy systems. Every backup generator we sell can be the base for a future hybrid energy system. Don’t lose power this hurricane season and install a backup generator today.