Would you do us a huge favor by sharing?

Routine equalization cycles are vital to the performance and life of a battery — particularly in a solar, wind or micro-hydro power system. During battery discharge, sulfuric acid is consumed and soft lead sulfate crystals form on the plates.

If the battery remains in a partially discharged condition, the soft crystals will turn into hard crystals over time. This process, called “lead sulfation”, causes the crystals to become harder over time and more difficult to convert back to soft active materials. Sulfation from chronic undercharging of the battery is the leading cause of battery failures in solar systems. In addition to reducing the battery capacity, sulfate build-up is the most common cause of buckling plates and cracked grids.

Deep cycle batteries are particularly susceptible to lead sulfation. Normal charging of the battery can convert the sulfate back to the soft active material if the battery is fully recharged. However, a solar battery is seldom completely recharged, so the soft lead sulfate crystals harden over a period of time.

WHAT ARE THE ADVANTAGES OF BATTERY CHARGER EQUALIZATION?

Slowing or preventing lead sulfation – Only a long controlled overcharge, or equalization, at a higher voltage can reverse the hardening sulfate crystals. Normal charging will reduce sulfation, but to remove it, the battery must be equalized.

Balance the individual cell voltages – Over time, individual cell voltages can drift apart due to slight differences in the cells. For example, in a 12 cell (24V) battery, one cell is less efficient in recharging to a final battery voltage of 28.8 volts (2.4 volts per cell). Over time, that cell only reaches 1.85 volts, while the other 11 cells charge to 2.45 volts per cell. The overall battery voltage is 28.8V, but the individual cells are higher or lower due to cell drift. Equalization cycles help make all the cells the same voltage.

Mix the electrolyte – In flooded batteries, especially tall cells, the heavier acid will fall to thebottom of the cell over time. This stratification of the electrolyte causes loss of capacity and corrosion of the lower portion of the plates. Gassing of the electrolyte from a controlled overcharging (equalization) will stir and remix theacid into the battery electrolyte.

HOW OFTEN SHOULD YOU EQUALIZE YOUR BATTERIES?

The ideal frequency of equalizations depends on the battery type (lead-calcium, lead-antimony, etc.), the depth of discharging, battery age, temperature, and other factors. One very broad guide is to equalize flooded batteries every 1 to 3 months or every 5 to 10 deep discharges. Some batteries, such as the large L-16 type, will need more frequent equalizations. The difference between the highest cell and lowest cell in a battery can also indicate the need for an equalization. Either the specific gravity or the cell voltage can be measured. The battery manufacturer can recommend the specific gravity or voltage values for your particular battery.

SHOULD YOU EVER EQUALIZE A SEALED BATTERY?

NO, NO, NO! Sealed batteries do not tolerate equalization cannot have distilled water replaced by the equalization charge, they are not able to gas (vent) and WILL be damaged if equalized.

{ 0 comments }

Would you do us a huge favor by sharing?

fm80 mppt controllerA charge controller is a piece of equipment designed to prevent the batteries in your system from overcharging.

It is similar to the voltage regulator in a car. However, unlike a voltage regulator in an automobile, charge controllers have advanced in ways never even imaginable to the hippies in Northern California, USA in the 1970s…

A typical 12 volt solar panel is capable of producing up to 17 to 22 volts. If the panel was left connected to a 12 volt battery, with no charge controller, the battery voltage would continue to rise until the battery/batteries become permanently damaged.

A charge controller can maintain healthy battery voltage by either:

  • short circuiting the solar panel
  • disconnecting the solar panel from the battery or by
  • diverting the excess electricity to a load such as an air heater, water heater or other electrical load.

Solar electricity can be either disconnected or diverted.

Wind and water turbines must remain connected to the batteries at all times so their electricity must be diverted or dumped in order to protect the batteries.


THE FOUR TYPES OF SOLAR, WIND AND MICRO-HYDRO CHARGE CONTROLLERS

Shunt type charge controllers- these are the first to be developed and most crude form of charge controller on the market today. They are only used as solar charge controllers (not for water or wind power). They shunt (or short circuit) the energy from a solar panel when the battery is full. These controllers have a set on and off voltage with a hysteresis (difference) sometimes adjustable by the user and sometimes factory preset. When the batteries hit the high voltage setting the entire electricity source is shunted (short circuited) until the voltage hits the low voltage setting. This keeps the batteries regulated but the voltage can vary between the on and off settings. They are the least accurate type of controller.

Relay type charge controller – these were the second type of charge controller to be developed. They are similar in function to the shunt type except instead of short circuiting the panel output they open circuit between the solar module and the batteries. These controllers have a set on and off voltage with a hysteresis (difference) usually adjustable by the user. When the batteries hit the high voltage setting the entire electricity source is disconnected until the voltage hits the low voltage setting. This keeps the batteries regulated but the voltage can vary between the on and off settings and is not that consistent. These also can only be used as a solar charge controller (not for use with water power or wind power).

xantrex c40 pwn charge controllerPWM (Pulse Width Modulated) charge controller – This style of charge controller keeps the batteries regulated by disconnecting and reconnecting portions (or part) of the electricity available from the solar module several times per second keeping the battery voltage more constant.

With the development of these charge controllers came anew and improved way of charging batteries using a bulk, absorption, float and equalization charge.

These are a great improvement over relay charge controllers as they are able to keep the battery voltage much more stable. They do not increase the output of the solar array but are more efficient than the previous controllers. Aside from being a charge controller, these units can have many features including digital displays, remote displays, load control, lighting control, and dump/diversion control.

tristar 60 amp 600 volt mppt charge controllerMPPT (Maximum Power Point Tracking) charge controller – This style of charge controller uses pulse width modulated technology to keep the batteries regulated but is able to also increase the output of the solar array by finding the maximum power point of the array (which is a higher voltage than the battery bank) and reducing the voltage to charge the batteries. This can result in up to a 30% increase in output of the solar array. It also allows for a higher voltage transmission from the solar array to the controller keeping wire losses to a minimum.

Outback Power’ s FM60 MPPT charge controller is our favorite as it is useful over a wide range of voltages and super efficient. Aside from being an MPPT charge controller, these units can have many features including lighting control, diversion control and an extra programmable relay. Some of these charge controllers can accept voltages up to 150 volts DC to make long distance transmission possible and efficient. There are MPPT controllers being designed now that are capable of input voltages up to 200 volts DC.

MPPT (maximum power point tracking) technology is constantly being improved and is very exciting for our industry. Learn more about MPPT technology.

Today’s charge controllers do more than just maintain correct battery voltage…


EXTRA FEATURES BUILT INTO TODAY’S SOLAR CHARGE CONTROLLERS

Prostar 15m PWM controller with digital displayDigital Displays – Some charge controllers have an optional or included (built in) digital display on the front of the unit.

This display shows the user how many volts, amps and/or watts the system is generating as well as keeps track of total power production and other pertinent info as available.

To the right is an photo of an installed front mount display for a Morningstar Prostar PS-15 PWM charge controller.

Remote Displays – Some charge controllers include, or have as an option, a remote meter that can be installed in another room or building. They usually display the same info as the installed digital displays but can be more conveniently located for easy access.

Load Controls – To prevent a battery from becoming deeply discharged by a load (such as a light or motor), a load controller is used. The load controller monitors battery voltage and disconnects the load from the battery at the disconnect voltage and does not reconnect the load until the battery reaches the reconnect voltage. These on and off settings are usually user adjustable. Common settings would be to disconnect at 10.5 volts and reconnect at 12.5 volts. Many charge controllers have a load control feature but can only be used as a charge controller or a load controller, not both. Two controllers would be required to perform both functions. Two exceptions to this are Morningstar’s SunSaver SS-6 and SunSaver Duo dual function charge and load controllers.

Lighting Controls – A lighting controller is a charge controller used to control lighting. They have several lighting functions such as dusk to dawn lighting or other on and off settings. They are used for security lighting, home lighting and billboard lighting. They are microprocessor controlled, fully automatic and also act as a load controller to protect the battery from deep discharge. Morningstar’s SunLight charge controller is an example of a good quality lighting controller.

Diversion (Dump) Controls – When charging a battery with a solar panel the energy source (solar panel) can simply be disconnected to regulate the voltage. When charging the battery with a water turbine or wind turbine the energy source cannot be simply disconnected. This would over-speed the water turbine or wind turbine and destroy it. Instead…the turbine is connected directly to the battery and the excess power is now dumped (or diverted) from the battery to a water or air heater using a diversion controller. This type of controller monitors the battery voltage and diverts all or a portion of the produced energy as heat to the dump load. The dump load can either be a useful load (like a hot water heater) or not useful and be dumped into an outside air heater. Many charge controllers have a diversion control feature but can only be used as a charge controller or a diversion controller, not both. Two controllers would be required to perform both functions. The Morningstar TS-45 is an example of a good quality diversion controller.

xantrex-battery-temperature-sensorExtra Programmable Relays – Outback Power System’s FM60, OutBack Power System’s FM80, Apollo Solar’s T80 and Xantrex’s MPPT60-150 charge controllers have a user programmable relay that can be adjusted to perform many functions. The relay can be used manually as a switch for pretty much anything you want to control remotely or the relay can be used to dump/divert electricity to a dump/diversion load, a lighting controller, a load controller (with an optional solid state relay). Another option is to use it to control an exhaust fan for your battery enclosure or an alarm to tell the user the batteries have not been charged for a set amount of time.

Remote Temperature Sensors – An RTS or remote battery temperature sensor is used for temperature compensated battery charging. As a battery gets warmer gassing increases. As a battery gets colder it becomes more resistant to charging (requires a higher voltage to charge). The more the temperature changes, the more important a battery temperature sensor is. The image on the right is an Xantrex RTS used for the C40, and C60 charge controllers.


THE FOUR STAGES OF PROPER SOLAR AND BACKUP BATTERY CHARGING:

Bulk Charge – The bulk charge is the beginning of the three step process of most advanced charge controllers on the market today. During the bulk stage all current available from the solar panel is applied to the battery until the battery reaches the preset absorb voltage as specified by the charge controller or user. At this point the charge controller enters absorbing mode. For a 12 volt nominal lead acid battery this voltage might be anywhere from 14.0 – 15.0 volts.

Absorption Charge – During the absorb stage just enough current is applied to the battery to hold a preset absorb voltage for a set period of time. This stage is designed to prevent overheating and over-gassing of the battery. The current is tapered down to maintain battery voltage. The voltage for this mode in a 12 volt system is 14.0 – 15.0 volts. If the voltage is able to be maintained for the preset period of time the charge controller will enter float mode.

Float Charge – During float mode, a maintenance charge is applied to the batteries until there is no more excess energy available (the end of a sunny day) The voltage for this mode in a 12 volt nominal lead acid battery will be approximately 13.4 volts.

Equalization Charge – An equalization charge is a periodic boost charge applied to stir the electrolyte, level the cell voltages and complete the chemical reactions within the battery. It is usually done at a set period of time from every month to every three months depending on battery manufacturer recommendations. The higher quality charge controllers will perform this stage automatically. The voltage for this mode in a 12 volt nominal lead acid battery will be above 15.0 volts and up to 16.0 volts. For more information on battery equalization read our equalization page.


DO I NEED A CHARGE CONTROLLER FOR MY SOLAR ELECTRIC SYSTEM?

Most systems require a charge controller. However, very tiny systems do not.

As a general rule you need a charge controller if your solar modules are making more than 2 WATTS PER 50 AMP HOURS (AHs) of battery/batteries (at the same voltage).

The formula… BATTERY BANK AMP HOURS / 50 AH X 2 WATTS

For example: if you have a 12 volt, 120 amp hour battery (a typical large RV battery), any module 5 watts or less will not require a charge controller.

BATTERY BANK AMP HOURS / 50 X 2 WATTS

(120 amp hours divided by 50 amp hours) X (2 watts)=4.8 watts.

If your solar module is larger than 5 watts …you need a charge controller.


HOW TO CHOOSE A SOLAR CHARGE CONTROLLER?

First you need to decide what type of controller is suitable for your application.

Things to consider include:

  • the distance from your solar array to the batteries. The more distance, the higher you might want the voltage to keep wire losses to a minimum. In this case consider an MPPT charge controller.
  • the open circuit voltage of your panels
  • is the voltage of your solar panel the same as the battery voltage? If not you are going to need an MPPT charge controller.
  • do you need to get every watt possible out of your array? If yes then you are going to need an MPPT charge controller.
  • is cost the most important factor to you? If yes, you might consider a PWM or relay type charge controller.
  • is this just a very small one panel system? If so the Morningstar SunKeeper SK-12 might be a good solution.
  • is your single panel system 40 watts or less? If so the Morningstar SunGuard SG-4 would be a good solution.

Battery Voltage – Charge controllers come in various sizes (current and voltage). To choose the correct controller you need to know your system’s battery voltage (12, 24, 36, 48 or 60) Most controllers are designed for either 12, 24, and 48 volt systems or a combination of two or three of these voltages. Some are designed for only one voltage. Morningstar’s Tristar TS-45 and Tristar TS-60 are user programmable using a serial cable, to any battery voltage between 12 and 48, making them suitable for even 32 and 36 volts systems.

Amperage – All controllers have a maximum current limit. They can be as small as 4.5 amps and as large as 100 amps. Please note this is the amperage between the charge controller and the battery and not the input amperage of the solar panel(s). Generally you should size your charge controller at least 25% larger than what is required. This allows the charge controller to operate cool and can also increase the lifetime of the unit.

Options – Many charge controllers contain different options as listed above. Be sure to check to check the specification sheet of your controller before making a purchase. It should give you a good idea of the options available for the specific charge controller and whether on not it will work for you.

{ 0 comments }

Would you do us a huge favor by sharing?

The maximum power point tracking… MPPT charge controller … has got to be one of the most innovative, game changing and misunderstood components in the solar industry.

solar mppt charge controllers

There is so much misinformation, it is time to clear up the myths of the MPPT charge controllers, explain what they do and explore what they cannot do.

Here is the MPPT solar controller in the shortest description…don’t worry…this will all be explained later.

#1   MPPT charge controllers attempt to connect to the solar module at its MPPV (maximum power point voltage or  “sweet spot” voltage (which is the voltage when the solar module’s voltage multiplied by the solar module’s current will produce the most electricity).

They constantly adjust the solar module’s voltage up and down as:

  • the position of the sun changes
  • the solar module gets shaded by clouds or other obstacles
  • the solar module’s temperature changes

#2   Maximum Power Point Tracking charge controllers then connect to the battery at the battery’s voltage (while increasing the amperage) to collect as much electricity as possible.

#3   MPPT controllers also act as charge controllers that make sure your battery bank is never overcharged by performing BULK, ABSORPTION, FLOAT and EQUALIZATION charges to make your batteries last as long as possible.

THIS CAN BE VERY DIFFICULT TO UNDERSTAND SO WE WILL DO OUR BEST TO EXPLAIN IT!


CLICK ON IMAGE BELOW TO ENLARGE…(or open PDF)

mppt charge controller diagram


The first things we must learn are:

canadian solar moduleSOLAR MODULES NEVER PRODUCE THEIR RATED POWER !!!!!!!

They just CAN’T and DON’T!

Not even with MPPT!

But MPPT (Maximum Power Point Tracking) will make a huge difference in some situations.

OTHER REALITIES ABOUT SOLAR MODULES AND MPPT

  • Solar modules are rated at standard test conditions (STC)
  • STC assume the available energy from the sun is 1000 watts per square meter (1000w/m2)
  • STC assume the solar module is held at 25 degrees C.
  • Solar modules are current limited
  • STC assume the solar module’s and battery’s voltage are perfectly matched

Morningstar's TS-45 MPPTSOLAR MODULES ARE RATED AT STANDARD TEST CONDITIONS (STC)

Let’s look at this. First we have to realize there has to be some way of comparing solar module’s that is not an apples to oranges comparison. If not, any manufacturer could say anything about their solar modules and there would be no way to prove or disprove their claims. That is why Standard Test Conditions (STC) were established.

STC assume the available energy from the sun is 1000 watts per square meter (1000w/m2)

All solar modules are tested and rated according to this hypothetical situation that the sun is beaming 1000 watts per square meter of ground in your location. That means that in a perfect world, 1000 watts of heat (energy) is being absorbed (for every square meter of earth) where and while the sun is shining. This rarely (if ever) is true. Even if it is true, the solar module would have to point exactly at the sun horizontally and vertically for STC to be accurate.

Interesting Fact: If solar modules were 100% efficient, a 1000 watt solar module would only be one square meter in size. However as solar modules are roughly 10-20% efficient, it requires 5-10 square meters of physical space to make a 1000 watt solar module (if 1000 watt solar panels actually existed).

STC assume the solar module is held at  constant 25 degrees Celsius

It doesn’t take a rocket science to see how rarely this would happen. Solar modules are in the sun. The sun heats the solar module. Unfortunately, the hotter the solar module is, the less power it produces because the voltage decreases. Just a fact.

Nothing we can change other than making sure your modules/solar array have ventilation (air gaps and spacing) to help keep them as cool as possible.

The upside of the temperature conundrum is:

“the colder the solar module is, the more power it will produce as the voltage increases”.

This can be a good thing for those in very cold locations. I have seen solar panels exceed their manufacturer’s voltage rating (and output) by as much as 15% in -30 degrees Celsius but your tongue will stick to the aluminum frame of the solar panel at that temperature. Try to resist.

ALL SOLAR MODULES ARE CURRENT LIMITED!

Solar modules are current limited. They can only make a certain amount of current no matter how bright the sun is. This is usually referred to as the short circuit current, Isc (I for current, sc for short circuit), Is.c., maximum current and a few other terms depending on the manufacturer.

Think about it: Let’s pretend we have a 200 watt solar module that is rated to produce 10 amps @ 20 volts (10A X 20V=200W).

Now let’s take the same module and connect it to a 12 volt battery that is full at 14.4 volts. (10A X 14.4V = 144W)

Now let’s take the same module and connect it to a 12 volt battery that is dead at 10.5 volts. (10A X 10.5V = 105W)

Now let’s take the same module and connect it to a 6 volt battery that is full at 7.2 volts. (10A X 7.2V = 72W)

EVEN THOUGH THE BATTERY VOLTAGE MAY BE SIGNIFICANTLY LOWER THAN THE SOLAR MODULE’S “MPP” or “SWEET SPOT” VOLTAGE, THE CURRENT COMING FROM THE MODULE WILL NOT INCREASE !!!

 

module label to explain mppt charge controller

STC ASSUME THE SOLAR MODULE’S AND BATTERY’S VOLTAGE ARE PERFECTLY MATCHED

This is where MPPT charge controllers change everything. In the SCHUCO solar module label shown we have the following specifications at standard test conditions:

  • Pmax (maximum power) 180.3 watts
  • Vmp (maximum power voltage) 24.0 volts DC
  • Imp (maximum power current) 7.50 amps

If we multiply the Vmp X Imp we get the following:

24.0 volts X 7.50 amps = 180 watts.

If, and only if, the voltage being produced by the solar module is 24.0 VDC, will the SCHUCO solar module produce 180 watts. If the output voltage is any less, so will be the output in watts.


schneider 60 amp mppt controllerUsing what we have learned, let’s look at a few different solar modules in a few different installation configurations to see how the MPPT solar charge controllers work…

Under STC, solar modules are rated at their maximum output level which only occurs when the electricity is being harvested at:

  1. a specific current called the “maximum power point current”
  2. a specific voltage called the “maximum power point voltage”.

As stated earlier…

“In the real world, this never happens!”

Let’s look at the specs of a common solar module…the Canadian Solar CS6P:

How MPPT solar controllers work

All solar modules have a specification sheet and a sticker on the rear of the module telling the maximum output (in watts) and how the company attained (and proved) that wattage output.

What we need to look at is the Vmp (maximum power point voltage) and the Imp (maximum power point current). Those numbers are essentially the “sweet spot” of the solar (or the voltage and current when the module produces the maximum or rated output).

We know that VOLTS X AMPS = WATTS, so when when we look at the Canadian Solar 260P we see its maximum (or rated) power is attained when the voltage is 30.4 and the current (amperage) is 8.56.

30.4 VOLTS X 8.56 AMPS = 260 WATTS (exactly the rated output)


BUT WHAT IF THE BATTERY VOLTAGE IS ONLY 24.6 VOLTS?

Now we need to change things up a bit and use the Isc or short circuit current because that is the maximum current (amperage) the solar panel will produce when the voltage is lower than the panel’s MPPV (maximum power point voltage) no matter how low the voltage is.

If we look at the specs for the same solar panel (Canadian Solar’s CS6P 260P) we can see the

Canadian Solar's CS6P short circuit current

Isc (maximum current/short circuit current) is 9.12 amps.

Now our output looks like this:
24.6 VOLTS X 9.12 AMPS = 224 WATTS


BUT WHAT IF THE BATTERY VOLTAGE IS ONLY 21.0 VOLTS?

First of all, that is one seriously dead battery bank. Don’t do this to your batteries!

If we look at the specs for the same solar panel (Canadian Solar’s CS6P 260P) we can see the

Canadian Solar's CS6P short circuit current

Isc (maximum current/short circuit current) is 9.12 amps.

Now our output looks like this:
21.0 VOLTS X 9.12 AMPS = 192 WATTS (NOT GOOD)


For a moment, let’s pretend we are incompetent and we used Canadian Solar’s CS6P 260P on a 12 volt battery bank with a standard charge controller.

BATTERY VOLTAGE = 13.4
SHORT CIRCUIT CURRENT = 9.12

13.4 VOLTS X 9.12 AMPS = 122 WATTS (OUCH!)


Those above numbers are not exactly what we hoped for when we paid good money for every watt a solar module is supposed to produce.

The problem is STILL this:

solar modules are current limited…

meaning they can only put out a certain amount of current (and no more)…

no matter what (or how low) the voltage is.

It would make sense for us to keep the voltage as high as possible to get the maximum amount of electricity out of each solar module as one of the factors in watts out is the voltage. (VOLTAGE x CURRENT = WATTAGE)

This is the where the MPPT solar charge controller rises above all the others!


It is hard to explain the maximum power point tracking charge controller (MPPT solar charge controller) without mentioning the first attempts at solar charge controllers or battery voltage regulators.

In the beginning there was the battery and the solar module. Solar modules were connected to a battery directly or with a non MPPT controller (with or without over-current protection) and the results were less than impressive.

The main problems were:

  • at night, the electricity would go back into the modules and slowly discharge the battery (without a controller)
  • the solar module was never able to operate at its maximum power point voltage
  • the solar module was never able to operate at its maximum power point current
  • the battery would overcharge if you didn’t constantly monitor the battery voltage (without a controller)
  • only a 12 volt module could be used to charge a 12 volt battery bank
  • only a 24 volt module could be used to charge a 24 volt battery bank (or two 12 volt modules in series)
  • large 12 and 24 volt arrays required huge wiring as the current could be huge

With these issues, we were lucky to get 50-60% of the solar module’s rated wattage into our battery without a charge controller and 60-70% of the solar module’s rated wattage with a standard solar charge controller.


outback power systems mppt fm60 controllerTHE MPPT CHARGE CONTROLLERS APPEAR IN THE SOLAR INDUSTRY

This was a VERY exciting time for solar energy professionals.

The first “REAL” high quality MPPT solar controller was designed by the “old TRACE ENGINEERING” boys when they left Trace to found OUTBACK POWER SYSTEMS.

They introduced the Outback M60 and it changed everything! More about that later…

The MAXIMUM POWER POINT TRACKING charge controllers can do the following:

  • increase a solar module’s or solar array’s output by 30-40%
  • connect to the solar module/array at its “sweet spot” and reduce the voltage to the system’s battery voltage
  • charge a 12, 24 or 48 volt battery bank from solar arrays with voltages as high as 600 volts
  • allow high voltage DC transmission from the array to the controller
  • allow much smaller wire sizes and breakers/fuses
  • provide bulk, absorption, float and equalization charges
  • prevent electricity from discharging batteries into the solar modules
  • protect batteries and battery banks from overcharge
  • include relay drivers for dump loads
  • prevent electricity from discharging batteries into the solar modules at night

INCREASE A SOLAR MODULE’S OUTPUT BY UP TO 30-40%

As discussed earlier, the higher the temperature of a solar module the less output (in watts) it will produce. Do your best to keep them cool by having an air space under the modules especially on a roof mounted solar array.

But imagine you have a 12VDC battery bank and a solar module with an output of 17 volts. The battery voltage is 13.8 volts and temperature is a mere 40 degrees C. The solar module’s voltage will drop significantly as the module is likely closer to 50 degrees C as it is dark colored and hot. Now you have a solar module that is nothing but a pretty ornament. The solution? Install two modules in series for 34 volts and use an MPPT controller to reduce the voltage to 12VDC.

Lower temperatures actually produce more wattage than standard test conditions. This is because the voltage actually increases as the temperature goes down. This may sound awesome for those of us who live in cold climates, but MPPT charge controller can…

BLOW UP IF THEIR MAXIMUM INPUT VOLTAGE IS EXCEEDED!

Let’s imagine we purchased a maximum power point charge controller with a maximum voltage input of 150VDC like the FM60, FM80, Apollo T80 or otherwise.

Let’s suppose you build a solar array that has a MPV of 145 volts at 25 degrees C (STC) and you live in an area that can go down to -40 degrees C.

The voltage

Either the battery voltage is too low, or the temperature is too high or there is fog, clouds or a number of other problems.

As we know that the watts out of a given solar module can be found by multiplying the volts x amps, we must try to keep those factors as high as possible to get the most out of the solar module.

raises and lowers voltage on the module side constantly to try and extract the most power available at any given time

Connect to the solar module/array at its “sweet spot” and reduce the voltage to the system’s battery voltage

makes the most difference when batteries are low

Charge a 12, 24 or 48 volt battery bank from solar arrays with voltages as high as 600 volts

ability to charge lower voltage battery banks from higher voltage solar arrays

large solar modules are 24 volt nominal or higher

suitable for using grid tie solar modules to charge 12, 24 or 48 volt battery banks

Allow high voltage DC transmission from the array to the controller

Allow much smaller wire sizes and breakers/fuses

Provide bulk, absorption, float and equalization charges

Prevent electricity from discharging batteries into the solar modules

Protect batteries and battery banks from overcharge

Include relay drivers for dump loads

some models can be used with hydro and even wind turbines using a dump load when the battery bank is full

Prevent electricity from discharging batteries into the solar modules at night

 

 


At what point does it make sense to spend the extra for an MPPT controller?

When you should not use an mppt controller

 

Outback MX60

Outback FM60

Outback FM80

Morningstar MPPT Tristar 45

Morningstar MPPT Tristar 60

TS-MPPT-60-600V-48
(Standard)

TS-MPPT-60-600V-48-DB
(With Disconnect Box)

TS-MPPT-60-600V-48-DB-TR
(With DC Transfer Switch)

TS-MPPT-60-600V-48-DB-TR-GFPD
(Pre-wired with Ground Fault Protection Device)

Morningstar SunSaver MPPT

Midnite Solar Classic 150

Midnite Solar Classic 200

Midnite Solar Classic 250

Schneider Conext XW 80-600 MPPT Charge Controller

 

{ 6 comments }

Would you do us a huge favor by sharing?

Off grid water systemThe best possible scenario when designing your “off the grid water system” is to not need a pump at all!

This can be accomplished in many ways:

  • a natural spring fed well that is up the hill from your home or cottage
  • a dug well on a hill above your dwelling
  • create a well with a driven point above your dwelling
  • lugging water in buckets from a lake, river, stream or shallow (not something my wife would not do)
  • a drilled artesian well (a well that is under natural pressure; rare but does happen)
  • a roof (or other clean surface) water collection system

In order for water to flow through your plumbing system, it needs pressure or head.

————————————————————————————

spring fed or dug wellNATURAL SPRING OR DUG WELL ABOVE YOUR DWELLING:

In the first two above examples,  head pressure is created as the water source is above the area it is needed. For every 2.2 feet (0.67 meters) of drop, 1 psi (pounds per square inch) or 6.89 kilopascals of pressure is created.

2.2 FEET = 1 PSI (POUNDS PER SQUARE INCH)

0.67 METERS = 6.89 KPA (KILOPASCALS)

A toilet for example requires very little pressure. As long as there is enough pressure for water to enter the toilet tank, it will work. That usually amounts to 1 to 2 psi (6.89-13.78 kPa) as most toilet tanks are 2-4 feet (0.61-1.22 meters) tall. The lower the pressure, the longer it will take to be ready for its next flush but “What’s the rush?”.

A shower requires much more. While a shower could operate with as little as 3 or 4  psi (20-28 kPa), it will barely create a trickle and won’t satisfy most people. Many people enjoy showers that feel like they could peel the skin off.

A typical home operates somewhere between 30-50 psi or (206.-344 kPa) although this is entirely dependent on preference. That would mean your natural spring or dug well would have to be 66-110 feet (20.-34 meters) above the highest tap or shower nozzle in your home or cottage.

It is easy to see how difficult this would be. The pipe run (distance) would likely be very long, adding cost to the system.

However, gravity fed systems use no energy and require no maintenance once they are installed properly!

————————————————————————————

DRIVE A WELL POINT TO CREATE A WELL ABOVE YOUR HOME:

 

————————————————————————————

bucketCARRYING BUCKETS OF WATER FROM A DUG WELL OR OTHER WATER SOURCE:

Lugging buckets of water from a river, stream or shallow well doesn’t really need much explanation…primitive but how the majority of the world gets their water.

————————————————————————————

ARTESIAN (OVERFLOWING OR “UNDER PRESSURE”) DUG OR DRILLED WELLS:

Artesian wells cannot be planned. They just happen or don’t. Don’t should be bolded as it is quite rare to drill or dig a well that is under pressure. A well can also be considered artesian if it overflows over the well casing (or whatever material is used to hold water) however just overflowing is not that  useful unless your well is many vertical feet (meters) above your home or cottage AND there is adequate flow.

There must be both head pressure (vertical drop) and adequate flow (a few gallons per minute/10-15 liters per minute) for an artesian well to help you in your quest for electricity free household potable water.

————————————————————————————

ROOFTOP OR OTHER CLEAN SURFACE WATER COLLECTION:

{ 0 comments }

Choosing the Best Well Pumps for Off Grid Homes

July 13, 2016
Thumbnail image for Choosing the Best Well Pumps for Off Grid Homes

Would you do us a huge favor by sharing? If you are not careful when designing your off grid water pumping system, your pump can be the single largest load on your solar, wind or micro hydro power system.   The best way to provide water to your off grid home is to not use […]

10 comments Read the full article →

Commercial Free Run or Free Range Chickens

November 18, 2015

Would you do us a huge favor by sharing? COMMERCIAL FREE RANGE / FREE RUN This has got to be the most misleading statement you will ever read on an egg carton. It is a joke. When most people envision “free range” or “free run” they imagine a bunch of cute little chickens frolicking in […]

0 comments Read the full article →

Making a Dump Load with a Hot Water Tank Heater

September 18, 2015
Thumbnail image for Making a Dump Load with a Hot Water Tank Heater

Would you do us a huge favor by sharing? Can a standard off-the-shelf tank style electric hot water heater can make a dump load? Electric tank water heaters are an excellent choice to make a dump load for your solar, wind or micro hydro power system as they are easy to get, cheap, already insulated […]

10 comments Read the full article →

The Difference Between AC and DC Fuses

August 17, 2015
Thumbnail image for The Difference Between AC and DC Fuses

Would you do us a huge favor by sharing? It saddens me that folks are risking their lives, family member’s lives and personal property by trying to save a dollar by using off-the-shelf AC (alternating current) fuses (or circuit breakers and switches) in their 12, 24 or even 48 volt battery systems, not to mention […]

4 comments Read the full article →

What Voltage Should My Battery Bank Be? 12, 24, or 48.

August 14, 2015
Thumbnail image for What Voltage Should My Battery Bank Be? 12, 24, or 48.

Would you do us a huge favor by sharing? The most common question I get as a solar consultant is… What voltage should I use for my battery bank? And Why? Almost everyone who is new to solar, wind or micro-hydro assumes that 12 volts is the way to go. It seems obvious. You can […]

20 comments Read the full article →

Why Renewable Energy Isn’t For Everyone | In Fact Almost No One!

August 13, 2015
Thumbnail image for Why Renewable Energy Isn’t For Everyone | In Fact Almost No One!

Would you do us a huge favor by sharing? In the developed world we have become accustomed to having unlimited electricity. We turn on a light switch and a light turns on. We leave the light on for two weeks straight and the light stays on for two weeks straight. Even if we do leave […]

2 comments Read the full article →

How to Choose a Clothes Washer for Your Off Grid Home

August 11, 2015
Thumbnail image for How to Choose a Clothes Washer for Your Off Grid Home

Would you do us a huge favor by sharing? We just purchased a new MAYTAG MAXIMA X Front Loader 4.7 cubic foot unit that is rated to consume 108 kWhs of electricity per year assuming you do eight (8) loads of laundry a week (Canadian Energuide Rating) and use the “NORMAL” setting. Our own testing […]

2 comments Read the full article →

Please Do Not Raise Chickens in Cages

May 12, 2015
Thumbnail image for Please Do Not Raise Chickens in Cages

Would you do us a huge favor by sharing? CHICKEN / HEN CAGES (AKA. BATTERY CAGES, BARREN BATTERY CAGES, ENRICHED BATTERY CAGES) Perhaps the most disgusting and sinister method of raising poultry has got to be the cage also referred to as the battery cage or the barren battery cage or the new type enriched […]

5 comments Read the full article →

Raising Chickens for Beginners

May 5, 2015
Thumbnail image for Raising Chickens for Beginners

Would you do us a huge favor by sharing? Keeping Chickens / Hens for the First Time * This article is just the first of at least ten that will show the different ways to raise chickens for beginners (with tips and tricks) to compare the options and hopefully make your decisions easier. Look for […]

5 comments Read the full article →

Why use HE Laundry Detergent?

May 5, 2015
Thumbnail image for Why use HE  Laundry Detergent?

Would you do us a huge favor by sharing? For years we have been told that our front loader washing machines must use special HE (High Efficiency) laundry detergent. No…not just any liquid or powder soap will do. It must be approved for HE (high-efficiency) washing machines. Blah, Blah Blah! Here is the reasoning: High […]

2 comments Read the full article →

Homemade Liquid Laundry Detergent Recipe

May 5, 2015
Thumbnail image for Homemade Liquid Laundry Detergent Recipe

Would you do us a huge favor by sharing? How to Make Liquid Laundry Detergent (HE) You can easily make liquid laundry detergent for HE washing machines but it is a little more tricky to make than our powered recipe, although the powered recipe cost more than double per load. If you want a quick […]

4 comments Read the full article →

Making a Solar Electric Water Heater | Can it Be Done?

April 1, 2015
Thumbnail image for Making a Solar Electric Water Heater | Can it Be Done?

Would you do us a huge favor by sharing? As the price of photovoltaic modules (solar modules, solar panels) continues to drop there are many discussions about using solar electric modules to heat water. No more leaks, messy and complicated plumbing, heat exchangers, controllers to fail, pumps to maintain and fluids to freeze. Solar hot […]

23 comments Read the full article →

The Best Choices for Heating Your Solar Home | And The Worst!

March 17, 2015
Thumbnail image for The Best Choices for Heating Your Solar Home | And The Worst!

Would you do us a huge favor by sharing? The largest energy consumer of any home-built in the northern hemisphere is the heating system. Designing the correct heating system is critical in the success of the off grid home. Build it wrong and nothing else will matter. Almost all heating systems require some form of […]

28 comments Read the full article →

The Best Off Grid Heating System

March 14, 2015
Thumbnail image for The Best Off Grid Heating System

Would you do us a huge favor by sharing? The greatest advance in home heating in the past few decades has to be the Open Direct System invented by Radiantec. The Open Direct System uses a highly efficient condensing tank-style water heater that provides both radiant space heating and domestic hot water all in one […]

16 comments Read the full article →

Why 120/240 Volt 60hz (or 230 Volt 50hz) Generators Are Not Great Battery Chargers

January 13, 2015
Thumbnail image for Why 120/240 Volt 60hz (or 230 Volt 50hz) Generators Are Not Great Battery Chargers

Would you do us a huge favor by sharing? Using a 120 volt or 120/240 volt (or 230 volt) single phase generator to charge your batteries is very common, inexpensive to purchase and horribly expensive to operate. BUT you must expect to pay anywhere from $2.50 to $5.00 per kWh when using a single generator […]

9 comments Read the full article →

Our Steam Engine Videos | Steam Power is Awesome!

December 9, 2014

Would you do us a huge favor by sharing? Below are some videos of our 8 horsepower (HP) at 500-600 RPM steam engine running for the first time in over 40 years. Since 2007, we had been looking for some type/brand/size/make/model? of steam engine to make into a serious battery charger in case of TEOTWAWKI […]

0 comments Read the full article →