charge controler mppt bluesolar 150/70?

Cariboocoot wrote: »

The charge controller does just that: regulates the charging of the batteries from the solar panels. It will not allow the batteries to be overcharged, providing the settings match the batteries' requirements.

It does not have the ability to limit discharge of the batteries through the inverter (or other DC loads). The inverter should have a Low Voltage Disconnect setting to prevent that from happening. On many inverters this is a fixed value, and may be too low to be of practical use.

Nor will the charge controller prevent overcharging from any source other than the PV such as a charger built in to the inverter or other stand alone AC powered charger.

Fuses or circuit breakers should be used on both the circuit from the charge controller to the batteries and from the batteries to the inverter to prevent excess current in the wires from starting a fire.

BB. wrote: »

Yes, you are correct. The system you are looking at does allow you to make a stand alone off grid power system that can supply AC power (230 VAC at 50 Hz for Algiers, Algeria?).

I am not familiar with Victron equipment/systems. Their details for connecting of their shared data bus between charge controller, AC inverter (I am in the US, and not a solar power systems installer)--But the basics are as you think.

The solar panels connect to the solar charge controller which ensures the battery bank is not over charged. The charge controller "turns on" when the sun is shining on the solar panels and "turns off" when the battery bank is fully charged.

There are two major types of solar charge controllers. One is a "PWM" (Pulse Width Modulation). More or less, it controls battery charging current by turning "on and off" very quickly (ON for 1/10th second, OFF for 1/10th second is 50% average charging current. ON for 1/100 second, OFF for 99/100 second, then only 1% of available charging current).

The other major class is MPPT (Maximum Power Point Tracking). This is the type the Victron brand/model of charge controller you are looking at is. It contains a "switch mode digital power supply" inside. Basically, it can behave like a DC version of an AC Transformer. It can take "high voltage/low current" and "down convert" to "low current/high voltage" needed to charge the battery bank.

For example, this allows you to put three large solar panels in series (say 10 amps Imp (current maximum power) and 30 volts Vmp (voltage maximum power) example with a 300 Watt solar panel) and down convert to 58 volts needed to charge the battery bank:

3 panels in series * 30 volts Vmp = 90 Volts Vmp-array
90 volts Vmp * 10 amps Imp = 900 Watt solar array
900 Watt solar array / 58 volts battery charging = 15.5 Amps battery charging current

So, 10 amps in from the solar array becomes ~15.5 Amps at the battery bank. This is not "free energy". Power=Volts*Current (P=I*V). So with an MPPT controller, you can run the solar array at a high voltage and efficiently down convert to lower voltage/higher current needed by the battery bank. This allows you to use smaller diameter wire and/or longer wire runs from the solar array to the battery bank.

Note that Lead Acid flooded cell storage batteries are relatively good at storing electricity--They do have their requirements for charging current/voltage and time. You should read about the care of a lead acid battery bank (and you need to tell us what type of batteries you have--The major types used with solar power systems are flooded cell and AGM (Absorbed Glass Mat, Valve Regulated--"Sealed").

You need to read about the care and use of Storage Batteries to understand how best to maintain them. With batteries in automobiles and trucks, we tend to "forget about them". For Off Grid power systems, you need to understand and monitor them pretty closely. It is easy to over discharge them, over charge them, forget to add water, etc. and ruin your very expensive battery bank in days/weeks/months, instead of getting the 5-15 years of life you want.

Here are some links to Battery Information in English--And you can probably find similar in Arabic or other language(s) that you may be more familiar with (I only know English, poorly--So I am always impressed by people who visit this forum and hold very technical discussions not in their native language).

http://www.windsun.com/Batteries/Battery_FAQ.htm
http://www.batteryfaq.org/
http://batteryuniversity.com/

And, the other 1/2 of the system, connecting a battery bank to your AC inverter. Takes ~41-60 VDC power in and converts it to 230 VAC 50 Hz power out.

The battery bank is for storing energy (electrical power) gathered by the solar array and supplying it to the AC inverter when the sun has set, or if you need power during the day, it will take power from the solar array and/or battery bank as needed.

A basic solar power system is very much like your car's electrical system. The battery is the "heart" of the system. When the engine is stopped, the battery supplies energy to the lights/radio/etc.. When the engine is running, the alternator (or generator) will recharge the battery and supply other other loads.




Yes, that is all of is correct. Now we get into details of your "paper design" (don't buy any parts, batteries, etc. yet until you have a paper design--It is very difficult to buy "random" solar power parts and put them together in a cost effective/reliable power system.

So--First thing to do is to measure/estimate your power needs. 20 Lamps does not tell us much. We need to know their working voltage (230 VAC), their current (say 1 amp per Lamp * 20 lamps), and how many hours per day you will run those lamps (say 5 hours per night).

• 230 VAC * 1 amp = 230 Watts of lamp
• 20 lamps * 230 Watts = 4,600 Watts of lamps
• 4,600 Watts of lamps * 5 hours of run time per evening = 23,000 Watt*Hours of energy per night

The above is just an example, and for an off grid power system, that is a LOT OF POWER (Energy) used per night, and would be a very expensive system to build. A lot of solar panels, a very large battery bank, and relatively large AC inverter. It would be too expensive for almost anyone to build (other than very wealthy, for a business, etc.).

However, with solar power, we have many new devices that we can use instead of "old technology" to allow us to save energy/electricity. And for off grid solar power, doing anything we can to save electricity is usually worth the time/money. It is almost always cheaper to conserve power than to generate power.

For example, instead of using 230 Watt filament lamps (traditional light bulbs), you can get LED type bulbs (with reflectors, if needed) to direct light to where you need it at about 1/10th the amount of Watts (power) (LED lights are ~10x more expensive to purchase).

Now each bulb may use 0.1 amp, and the battery bank+solar array+AC inverter can all be 1/10 the size. Which now is a very reasonable size off grid power system (in my imaginary system design).

There are simple 'Watt*Hour' meters you can plug your appliances into and measure their power usage. Here is an example. You should be able to find WattHour meters locally (this is a United Kingdom/England version):

http://www.amazon.co.uk/Plug-In-Power-and-Energy-Monitor/dp/B000Q7PJGW

More or less, to give you an idea:

• 1,000 WH per day (1 kWH) is a "small" system that can give you lights, radio, laptop computer, small water pump
• 3,300 WH per day (3.3 kWH) is a "good size" system... Add refrigerator, larger well pump, clothes washing machine, etc. Pretty much would give a very energy efficient home a "modern" off grid electrical system experience (use propane, oil, petrol for heating/cooking)
• 10 kWH per day (300 kWH per month) is would power a reasonably efficient home with some electricity for cooking, some more fans/small amount of air conditioning, etc.
• 33 kWH per day (1,000 kWH per month) is the average power usage for a North American or European home (electric cooking, some electric hot water/heating, more computers, refrigerators, lights left on, etc.). Most people that have never worked at conservation could probably cut their electrical usage by 1/2 with conservation (new technology lighting, appliances, converting to propane for cooking/heating).
• 100 kWH per day (3,000 kWH per month) for homes in very hot/very cold climates that use lots of electrical heat and air conditioning.

More or less, only the 1-3.3 kWH per day systems are "comfortable" for most people. And small enough/"simple" enough for people to install the system their selves.

The 10 kWH per day system is possible and possibly cost effective for a full off grid home/business, but that is about the largest system we would be able to help with here. (of course, we want you to be educated about solar power so you can understand the basic elements when you have discussions with a solar power company).

Larger systems are usually too expensive for most people and most people would need to use a company/person with lots of experience with off grid power. The issues are too complex for a first time solar person with no electrical engineering experience.

End of Part 1

BB. wrote: »

Begin Part 2:




Note that we say "over charge" vs "surcharge" (surcharge is like a sales tax or extra fee for long distance shipping charges):



Your English is very good and readable--Just wanted to correct a term.

Solar panels are, sort of, variable output Solar Batteries (actually a variable current source based on the amount of sun hitting the panels--But save that for a different discussion).

The solar charge controller monitors the battery bank voltage to determine how much energy needs to be supplied to fully charge the battery bank. Basically we will talk about charging "stages". Note that solar charging terms are different vs (for example) terms used by industry for large "fork lift" battery banks):

• Bulk: All of the energy available from solar array is sent to battery bank (battery bank from ~41 to 58 VDC)
• Absorb: Once the battery hits ~58 VDC (charging set point), the charge controller will "turn off/off" rapidly for PWM controller (or reduce output current for MPPT charge controllers) to keep the battery bank at ~58 volts. This voltage will be held for ~2-6 hours (deeper discharged battery bank, longer "absorb" timer setting).
• Float: Once the charge controller has determined the battery bank is "full", the charge controller will drop the set point voltage to ~55 volts and hold that until the sun sets (and/or the loads exceed the available solar charging current).
• Discharging: Solar power no longer sufficient to hold the battery bank voltage at Absorb/Float, and when the battery bank voltage falls below ~51.2 volts, the battery is being discharged.

You can also add other charging sources too... For large systems, you may need several solar arrays+charge controllers connected to one battery bank.

And, if you need solar power during bad weather, you may add a DC Generator or AC Generator + AC to DC battery charger (and many larger inverters can connect directly to a 230 VAC 50 Hz generator and both recharge the battery bank and power the 230 VAC loads at the same time).

Many of the new AC inverter+charger systems (and digitally interconnected charge controllers) are getting very complex. Before we go into any details--I would suggest understanding your loads and power needs first. We then do several "paper designs" and look at the size of battery bank and equipment you need--Then you can do a quick price check to see if the system is cost effective/capable for your needs.

After you have done the high level paper design, you can limit your research to charge controllers, AC inverters, Batteries that will work for your system.



Read more about lead acid batteries (there are other chemistries like, Sealed Lead Acid, LiFePO4--Various Lithium Ion chemistry type batteries, and others like NiCad, NiMH, etc.). Each has its own operational requirements.

And even for lead acid batteries, there are those designed for deep cycle (usually used for off grid power systems) and those designed for "float" or standby use (UPS, Uninterruptable Power Supplies, used for emergency computer backup power) that are only cycled a few times in emergencies.

You have to get the right battery for your needs.

In general, for standard deep cycle flooded cell batteries--They start "aging" as soon as they are built... So no matter how you treat them, they may have a 5-15 year life (depending on cost, design of battery). And any cycling you do on them ages them further.

Again, in general, you would want to cycle them down to ~75% state of charge (25% discharge) at least once per month. And 25% discharge per overnight (or daily use in bad weather) gives you ~2 days of storage with 50% maximum discharge (for longer battery life). A lead acid deep cycle battery that is cycled daily will normally last ~3-8 years or so. The deeper you cycle it, usually the less life it will have.

Also, temperature is very important too. Batteries are usually specified to operate at 25C nominal temperature. For every 10C over 25C, a battery will be expected to last 1/2 as long. Operate at 35C, the battery will last 1/4 as long.

Conversely, operating at 10C less than 25C, the battery will last ~2x as long. So keeping batteries from getting too hot is important (heating from charging, hot weather, etc.).

I will stop here--I hope I am being helpful here.

Energy usage is a highly personal set of choices--We want to help you understand the tradeoffs you will need to make for your power system.

-Bill

BB. wrote: »

The battery bank is what, more or less "regulates" the battery bus voltage. Somewhere between 41 volts (dead) and 59 volts (charging hard).

In between that range, the battery will source (discharge) or sink (charge) current based on its state of charge and the total current flow in the system.

• If you have a 20 amp load and no sun. The 20 amps will come from the battery bank to run the AC inverter.
• If you have 10 amp current from the solar array, then you will get a 10 amp draw from the battery (10+10=20 amp load).
• If you have 20 amp current from the solar array, then your battery will be at zero current (20+0=20 amp load).
• If you have 50 amps from the array, then 30 amps will go to the battery and 20 amps to loa
• If you have 50 amps from array, and no loads--Then all 50 amps will go to the battery bank.

In general, you want ~5% to 13% charging current going to the battery bank to fully/quickly recharge the battery bank. If you have a 200 AH battery bank, then you would want:

• 200 AH capacity * 5% = 10 amps minimum
• 200 AH * 10% = 20 amps nominal
• 200 AH * 13% = 26 amps "cost effective maximum

Or, if 10% rate of charge:

• 20 amps * 58 volts charging * 1/0.77 panel+controller derating = 1,507 Watt array (daytime charging and night-time loads)

Note that 5% is the minimum rate of charge we would recommend (weekend/seasonal power usage). 10%-13% would be recommended for full time off grid use (9+ months a year).

The above works well if you are charging during the day and running loads at night. However, if you also run loads during the day, you will want to have those "powered" by the solar array+the current needed to run the load.

For an AC system that draws 10 amps:

• 10 amps AC load + 20 amps nominal battery charging current (10% rate) = 30 Amp solar array

Or, a solar array sized:

• 30 amps * 58 volts charging * 1/0.77 panel+controller derating = 2,260 Watt array (daytime AC load + charging)

We are in the land of "made up numbers" -- It will make more sense when we design the system to meet your needs.



Yes... Nothing is for free. It is very much like having a water pump, a water storage bank on a hill, and an irrigation/home water system.

The goal is to keep the water level in the tank between 50% and 95%+ full. You are managing the water going out (house/irrigation use) against the water going in (solar panel and amount of available sun, backup generator).

-Bill

BB. wrote: »

You really really need to define your power needs... If you can not run your power when the weather is bad (say an A/C system that only needs to run on sunny/hot days), then the battery bank can be relatively small.

However, if you need to run equipment sun or rain (run your business, kids need to use the computer for homework, lights at night, etc.), then the battery bank will need to power your system even if the sun is not running--So the bank would, for example, power your loads for 2 days and 50% maximum battery discharge--Or roughly 4x your daily power needs.

Also, you need to size the solar array based on the amount of sun light you get... For example, using the solar electricity handbook for Algiers (fixed array titled to average best angle entire year harvest):

http://solarelectricityhandbook.com/solar-irradiance.
Algiers
Average Solar Insolation figures

Measured in kWh/m²/day onto a solar panel set at a 53° angle (from vertical):
(For best year-round performance)

Jan
Feb
Mar
Apr
May
Jun


4.24

4.88
5.83
6.30
6.25
6.59


Jul
Aug
Sep
Oct
Nov
Dec


6.72

6.67
6.13
5.34
4.10
3.84


So, if your power needs are for AC during the summer, and lights during the winter (as an example). If you wanted 3.3 kWHs of AC power (24 hours per day, even through bad weather/no sun):

Battery bank sizing:

• 3,300 Watt*Hours * 1/48 volt battery bank * 1/0.85 AC inverter eff * 2 days of storage * 1/0.50 max discharge = 324 AH @ 48 volt battery bank

To charge the battery bank, we want 5% to 13% typical rate of charge:

• 324 AH * 58 volts charging * 1/0.77 panel+controller deratings * 0.05 rate of charge = 1,220 Watt array minimum
• 324 AH * 58 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 2,441 Watt array nominal
• 324 AH * 58 volts charging * 1/0.77 panel+controller deratings * 0.13 rate of charge = 3,173 Watt array "cost effective" maximum

And then we also need to look at when you need the power... If this was relatively constant power usage throughout the year--Then I would suggest sizing the system to run ~9 months of the year from solar, and for bad weather in winter, you use a genset (and/or reduce power use), and February works out as the poorest 9 months at 4.88 hours of (average) noon time equivalent sun per day:

• 3,300 WH * 1/0.52 overall system efficiency * 1/4.88 hours of sun = 1,300 Watt array minimum (February "break even" month)

So, for a "generic" system (use much of the power in the evening, and provide 2 days of "no sun" power), your array would be a minimum of 1,300 Watts. And for a full time off grid home, you could use a 2,441 to 3,173 Watt array system.

If you choose, a 10% array, then it would produce on an average February day:

• 2,441 Watt array * 0.52 system efficiency * 4.88 hours of sun = 6,194 WH of available power in February

So--Such a system could supply around 3.3 kWH per day (good weather or bad), and for ~9 months of the year, it will produce an (average) minimum power (during sunny weather) of ~6.2 kWH per day.

For the average day, you could use ~3.3 kWH overnight, and an additional (6.2-3.3=) 2.9 kWH or more for daytime loads (Air Conditioning, Fans, Water Pumping, etc.).

Does this all make sense? It really is easier to understand if we design a system to meet your needs first, then talk about other general issues once you see how the basics apply to your needs.

Once we "define" the paper system, then you can look at the hardware to implement your specific needs.

-Bill

BB. wrote: »

It all depends on your loads... If you can turn your 1,000 watt load off when the sun is not shining--Then you do not need to store much power.

If you need 1,000 watts * 5 hours every day, rain or sun, then you need to have the battery bank sized to produce the power during bad weather (during dark cloudy conditions, it is not uncommon to have 5% or less power generation by solar array--virtually zero useful power during bad weather).

And, the array needs to recharge the battery bank plus support the loads once the sun returns.

In general, it is difficult to justify storing more than ~2 days of energy (a very large lead acid battery bank is expensive and has its own issues). Usually, your best bet is to plan on using a generator if you have >2 days of bad weather in a row (and/or reduce or turn off loads until sun returns).

Power usage is a highly personal set of choices. You have to make the cost/benefit decisions on what will work best for you (and what you can afford).

We try to help you understand the basis for those decisions and what configurations/designs will work best for you.

You have not discussed any details about your loads--Can you give us some information? Sometimes, there are better solutions out there that can reduce your needs for off grid solar power. Pumping water, as an example, there are lots of options that can work out much cheaper than a full off grid AC + battery bank power system.

-Bill

BB. wrote: »

In general, if the sun is not up, the battery will supply all current (energy) needed to run the AC inverter and any DC loads. The battery will hold ~24 volts and the current will be what the loads demand.

If they sun is shining, the charge controller will take all available current from the solar array (more current as the sun rises towards noon)--And the when the battery bus voltage hits ~27.6 volts (float charging) or ~29 volts (absorb charging)--The solar charge controller will reduce its average charging current if the battery voltage exceeds the set-point, or it will attempt to output more current when the battery voltage falls below the set-point.

Don't get too concerned about the details--It does work pretty well...

Where you can get into issues is if you use a lot of current during the day (say irrigation)--Then the high average load does subtract available charging current from the battery bank. So--You may need to add more solar panels for the situation where you have have higher average daily loads plus night time loads.

Given that, on average, solar panels are at a historic low price--Adding solar panels to an off grid power system is not nearly as painful as it used to be even 5-10 years ago.

-Bill

BB. wrote: »

Lead Acid Batteries "age" in two ways... One is pure age. They are chemical devices that slowly "die" over time from the day they are manufactured.

The second is cycling (the following is a very great simplification--And, like many engineering issues, the devil is in the details). For Lead Acid deep cycle storage, there are ones designed for "standby use" (only a few deep cycles and they would be dead--Such as computer uninterruptible power supplies).

Others, like for cars and trucks Starting, Lighting, and Ignition (SLI). These are designed for short/heavy current (cranking the engine, running accessories, glow plug heating on diesels, etc.). If you cycle these deeper than 10-15%, they will not last very long.

And then the "true" deep cycle battery. More or less, they are designed to be discharge from 75% state of charge to less than 50% state of charge, and back up again to ~100%. And with Lead Acid Batteries, they may last 2,000 cycles with 25% (shallow discharge) and only 500 cycles with 80% discharge (very deep cycling). Interestingly--To a first approximation--If you get 2,000 cycles with 25% discharge, you will get ~1,000 cycles with 50% discharge. The battery will supply about the same amount of energy over its life--Either divided with a lot of "small cycles" or fewer deep cycles.

We use a lot of rules of thumb to help us "size" a system to quickly and easily give us a system that will (or at least should) give the owner a reliable system that meets their needs (cost effectively).



There are different schemes for operating an off grid power system. But, the basic one is that the Solar Charge controller will recharge the battery bank back full every day. And if the battery is discharged for 2 days, it may take several days to fully recharge the battery bank.

If you over discharge the battery bank, and/or do other things wrong (forget to keep the electrolyte over the plates, etc.)--Lead acid batteries can be killed pretty quickly.

That is why we tell people to get "inexpensive" batteries the first time--Most people "murder" their first battery bank or two as they learn how to run their system.

If you are interested, perhaps you can build a "small" system. Perhaps 1,000 WH per day 12 VDC with a small 300 Watt AC inverter and experiment with it (around 500 watts of panels and a 400 AH @ 12 volt battery bank).



Victron, as I understand, makes equipment. For a 1,000 Watt array on a 24 volt system, you would only need ~30 amp charge controller--The 70 Amp Victron is on the "large" side (70 amp controller).

Perhaps one of our European members can tell you about Victron and other vendors that may be good choices for your needs.

For the AC inverter, with a 321 AH @ 24 volt battery bank, a ~1,500 Watt AC inverter would be a good fit (for that size battery bank). The battery bank would have difficulties supplying more Wattage (you would take more current than the battery bank could supply).


This is assuming a ~52% efficient system from Solar panel derating through charge controller to battery bank to AC inverter losses:

• Total efficiency = 0.81 solar panel derating * 0.95 charge controller efficiency * 0.80 flooded cell battery eff * 0.85 inverter eff = 0.52 = 52% end to end efficiency

The calculations are "rough" numbers... For solar power, anything within +/-10% is pretty much "the same" (that is the level of "accuracy" for most solar calculations).

We are sizing the battery bank based on expected daily power draw. The solar array is calculated two ways--The first is based on the needs of the battery bank itself (5-13% or so charging current). The second is based on the amount of sun for the location it will be installed (I usually use ~9 months worst case, or ~4.0 hours of sun for planning).

It is sort of minimum set of calculations. For places/seasons with lots of sun, the array will produce "More Power" than the battery should store daily (over paneled). But you still need to meet the minimum charging current for the battery bank (5% minimum rate of charge for weekend/summer usage, 10%+ for daily usage for full time living).

In general, during summer you will have "more power" than the battery can "supply" (2 days of autonomy and 50% maximum discharge).

During winter, the array cannot supply all the power--And you either don't use power (or don't use very much power), or you use a generator to make up for poor solar power production.



Yes, that the above is the basic idea of how the system is connected together.

-Bill