₦airaland Forum

obimind:
Presently my solar charge controller is 20ah pwm and I have 4 pieces of 150 watts panel. My battery bank is 400 ah. My question is this: is my charge controller undersize?

Your 150w panels would provide a current of about 8.89A each,
if ur batteries are in series or parallels for either a 24v or 12v system, the charge controller would still be undersized.

In series (24v)
Then your panels would be connected in 2 strings, each having two panels.
8.89A(Isc) x 2 (strings) x 1.25 (safety factor) = 22.22A

In parallel (12v)
Then your panels would have to be connect in 4 strings,
8.89A(Isc) x 4 (strings) x 1.25 (safety factor) = 44.45A

you are definitely under utilizing your panels, either way so u need to upgrade your charge controller.

You can insult all you want but calculate the input power and output power from the picture u shared and compare then you'll see my point. Some of us are data based

JUO:
even after seeing the picture? getting facts across to 'sincerely ignorant' people is like baptizing a cat

My dear that's the point. Even premium brands like morningstar, midnight solar, xantrex etc don't lay claim to 100% efficiency cos energy is always lost right inside solar charge controller in the form of heat. Instead for our "supposedly enlightened" friend to face fact and acknowledge a flaw in the unit's measurement, he's attacking people (argumentum ad hominem).

DMerciful:
You can insult all you want but calculate the input power and output power from the picture u shared and compare then you'll see my point. Some of us are data based

mank1234:
My dear that's the point. Even premium brands like morningstar, midnight solar, xantrex etc don't lay claim to 100% efficiency cos energy is always lost right inside solar charge controller in the form of heat. Instead for our "supposedly enlightened" friend to face fact and acknowledge a flaw in the unit's measurement, he's attacking people (argumentum ad hominem).

Hello friends.
I hereby introduce this piece of a gadget to you.
I have been testing this small but mighty machine for over 3 weeks now.
The results turns out to be impressive.
I have a few number of them for sale to anyone interested.

It is 30 and 40amps mppt controller with additional features of equalization of flooded batteries every 28 days and inbuilt display .

New Epsolar Epever Tracer A series available. For small setup 12-24v. . Max pv input voltage 100v. 30a only 0000k for the first buyer
Features:
• Advanced MPPT technology
• High tracking efficiency no less than 99.5%
• Peak conversion efficiency of 98%
• Ultra-fast tracking speed
• Accurately recognizing and tracking of multiple power point
• Multi-function LCD displays system information intuitively
• User programmable for battery types, load control etc.
• 3-Stage charge with PWM output
• Common positive grounding design
• RS485 port with industrial standard MODBUS open architecture
• Fully programmable function via PC software or remote meter

Electronic protections:
• PV reverse polarity protection
• PV short circuit protection
• PV over current alarm protection
• Battery overcharge protection
• Battery over discharge protection
• Battery reverse polarity protection
• Load short circuit protection
• Load overload protection
• Overheating protection

N.B Remote not included
o8o-987-33709

48v also available

bigrovar:
first work before u even all of price is how to make your power consumption very efficient. Doing that can save u a lot of unnecessary cost. Hint. Your freezer don't have to run all the time, your AC don't have to run at all. Get rechargeable fans and even those run on demand. Get energy saver bulbs of not more than 11w. TV don't have to be on 24h. U need to itemise each load and hours it would run. Do that and cut down on the huge power consumption and watch ur bill go down.

My house is sooo Energy efficient that often time what we use in a day is replaced before noon the next day and in most cases we can run the house directly from solar while the battery stays in float. And yes my load include a 175L freezer. We barely scratched 40% dod of our 440ah battery bank.

Oga bigrovar can u tel us what ur setup consist of. Tx

JUO:
even after seeing the picture? getting facts across to 'sincerely ignorant' people is like baptizing a cat

@ Juo....you should have helped your friends by telling them the CC is mppt....

This is one of the reasons why some will advise the use of mppt controllers in solar setups...

I have seen these type of figures severally on my morning star CC although this happens before midday...because efficiency of solar panels dips with temperature...

Output cannot be greater than input Oga.....mppt or zppt or whatever! Na perpetual motion machine? The controller may be solid but the reading ain't right!

bodejohn:
@ Juo....you should have helped your friends by telling them the CC is mppt....

This is one of the reasons why some will advise the use of mppt controllers in solar setups...

I have seen these type of figures severally on my morning star CC although this happens before midday...because efficiency of solar panels dips with temperature...

Morningstar Cc? Lol. May be yours is a Chinese copy, if you've seen such figure in yours before: instantaneous output power more than the input power.

Yes performance of solar panel dips during hot weather but that has nothing to do with cc. It's an inherent properties of solar panels.
Ignoratio elenchi.

bodejohn:
@ Juo....you should have helped your friends by telling them the CC is mppt....

This is one of the reasons why some will advise the use of mppt controllers in solar setups...

I have seen these type of figures severally on my morning star CC although this happens before midday...because efficiency of solar panels dips with temperature...

bodejohn:
@ Juo....you should have helped your friends by telling them the CC is mppt....

This is one of the reasons why some will advise the use of mppt controllers in solar setups...

I have seen these type of figures severally on my morning star CC although this happens before midday...because efficiency of solar panels dips with temperature...

Hello Mr Bode, Quite an age ! You are definitely right, likewise Juo . I have sold and installed several ep solar mppt cc and they perform real good till date. Apart from figures Juo posted via ep solar MT 50 remote display , I have actually clamped it whilst working and got exactly same readings with a mastech DC clamp meter.


*AUTHORISED DEALER PRAGMATIC TECHNOLOGIES*
All our prag / cyberpower products comes with reliable warranty

*AUTHORIZED DEALER SOLAR SHOP LTD PRODUCTS*
All our products come with 1 year Warranty

For best affordable prices,contact Smartcell Global Services,Lagos Nigeria. Simply call Sir Frankie "08135031951" for purchase,fast delivery and waybills .. Thanks !!

DMerciful:
Output cannot be greater than input Oga.....mppt or zppt or whatever! Na perpetual motion machine? The controller may be solid but the reading ain't right!

mank1234:
Morningstar Cc? Lol. May be yours is a Chinese copy, if you've seen such figure in yours before: instantaneous output power more than the input power.
Yes performance of solar panel dips during hot weather but that has nothing to do with cc. It's an inherent properties of solar panels.
Ignoratio elenchi.

I don't have words to argue with you both...
There is a reason why mppt is called maximum power tracking....

I'm a bit lazy tonight...I would have shared logs from my "Chinese" Morning Star CC...check the difference in the power....it's a few watts...

Guys....don't just argue....read about mppt controllers!

bodejohn:
I don't have words to argue with you both...
There is a reason why mppt is called maximum power tracking....

I'm a bit lazy tonight...I would have shared logs from my "Chinese" Morning Star CC...check the difference in the power....it's a few watts...

Guys....don't just argue....read about mppt controllers!

Check attached efficiency chat from the manufacturers themselves does it buttress your assertion. If yours function as you claimed it could be that measuring circuit is faulty. Efficiency of a cc can never be >100%. We are not arguing with you; we're enlightening you. Where we don't know we seek for advice, but on this one I think we are an authority on this subject.

mank1234:
Check attached efficiency chat from the manufacturers themselves does it buttress your assertion. If yours function as you claimed it could be that measuring circuit is faulty. Efficiency of a cc can never be >100%. We are not arguing with you; we're enlightening you. Where we don't know we seek for advice, but on this one I think we are an authority on this subject.

Looks like you have a Morning Star controller...when you have the time, log your daily harvest...make sure you select input / output voltage, input/output current and input / output power and temperature.

Before you do...check the graphs of the mppt algorithm, you will notice a slightly higher point on the maximum power current path as compared with the Isc of the panel...that point is always changing more reason the controller keeps tracking it...how should I explain the DC to DC converter in the controller that converters "excess" voltage to current to you?

I have two 45amps morning star CCs...I have logged both CCs at different times...converting the logs to excel documents for analysis....it is not a one off thing... it happened every single time I did the logging...if you have not done this logging before...you are not yet a master on this topic not to talk of an authority...

bodejohn:
Looks like you have a Morning Star controller...when you have the time, log your daily harvest...make sure you select input / output voltage, input/output current and input / output power and temperature.

Before you do...check the graphs of the mppt algorithm, you will notice a slightly higher point on the maximum power current path as compared with the Isc of the panel...that point is always changing more reason the controller keeps tracking it...how should I explain the DC to DC converter in the controller that converters "excess" voltage to current to you?

I have two 45amps morning star CCs...I have logged both CCs at different times...converting the logs to excel documents for analysis....it is not a one off thing... it happened every single time I did the logging...if you have not done this logging before...you are not yet a master on this topic not to talk of an authority...

Those current spikes are caused by solar glare or sometimes by partial shadowing of the panel. At those times the voltage input is momentarily greater than Vmax of the Cc (ie >150V). The controller doesn't record the short pulse of voltage which is beyond its range but it however keep record of the current which is well within it's range. That doesn't mean that that's what you're harvesting.

It's been a topic of discussion in various forums where morningstar mppt cc is discussed. You're suppose to expung those spikes to get a true picture of your system's performance.

mank1234:
Those current spikes are caused by solar glare or sometimes by partial shadowing of the panel. At those times the voltage input is momentarily greater than Vmax of the Cc (ie >150V). The controller doesn't record the short pulse of voltage which is beyond its range but it however keep record of the current which is well within it's range. That doesn't mean that that's what you're harvesting.

It's been a topic of discussion in various forums where morningstar mppt cc is discussed. You're suppose to expung those spikes to get a true picture of your system's performance.

I am uploading a copy of my log for you to see...
I will also be attaching a screenshot later...
As i have said...log your controller and covert the logs to a csv file...

bodejohn:
@ Juo....you should have helped your friends by telling them the CC is mppt....

This is one of the reasons why some will advise the use of mppt controllers in solar setups...

I have seen these type of figures severally on my morning star CC although this happens before midday...because efficiency of solar panels dips with temperature...

bros longest time

JUO:
bros longest time

I'm good brother...

bodejohn:
I'm good brother...

your system is doing good according to the log. But your battery voltage, very critical. Enjoy sir

JUO:
your system is doing good according to the log. But your battery voltage, very critical. Enjoy sir

I'm on a 36v battery system...50% dod is 36.6V.

Imagine someone arguing fundamental physics...thanks for enlightening him....

mank1234:
Those current spikes are caused by solar glare or sometimes by partial shadowing of the panel. At those times the voltage input is momentarily greater than Vmax of the Cc (ie >150V). The controller doesn't record the short pulse of voltage which is beyond its range but it however keep record of the current which is well within it's range. That doesn't mean that that's what you're harvesting.

It's been a topic of discussion in various forums where morningstar mppt cc is discussed. You're suppose to expung those spikes to get a true picture of your system's performance.

You need to read about mppt, cloud dispersion as it affects power output above max rated power. What am saying is that the readings are not very accurate....doesn't mean d CC is not working well.

bodejohn:
I don't have words to argue with you both...
There is a reason why mppt is called maximum power tracking....

I'm a bit lazy tonight...I would have shared logs from my "Chinese" Morning Star CC...check the difference in the power....it's a few watts...

Guys....don't just argue....read about mppt controllers!

bodejohn:
I am uploading a copy of my log for you to see...
I will also be attaching a screenshot later...
As i have said...log your controller and covert the logs to a csv file...

A closer look at the log reveals something baffling, within 15min(item 15 to 19), the fluctuations in battery voltage suggest that the figures are inaccurate: up and down by as much as 10V. If it were accurate, there's no way output power will be more than input power. MPPT selects the the best power point (a point at which current * voltage of the array is maximum).

Hope you are using a battery volt sense wire and your ferrite core in place. Other than that morningstar specifically states that battery voltage reading will be inaccurate. Verify from your log that battery voltage sense wire is in place

bodejohn:
I am uploading a copy of my log for you to see...
I will also be attaching a screenshot later...
As i have said...log your controller and covert the logs to a csv file...

MPPT does not increase power, it only ensures that your panel operates at the optimum voltage/current that will ensure maximum power. In reality the output power is always less by a few Watts due to heat generated in the scaling down of the voltage (increase in current)

DMerciful:
Imagine someone arguing fundamental physics...thanks for enlightening him....

Now...I see what JUO was saying...

How can a glare happen every 5 minutes from 8am to 12 everyday on two different controllers?

A bit of more clarity...the panels have points on their curves where voltage and current is producing maximum power...this is what your mppt controller is tracking...some CCs will show you what you would have been receiving if the mppt algorithm was not there.

Unfortunately, you guys think that's the maximum the panel is producing...

Why don't you take the challenge...upload the CSV files from your own controller if it produces any...

mank1234:
A closer look at the log reveals something baffling, within 15min(item 15 to 19), the fluctuations in battery voltage suggest that the figures are inaccurate: up and down by as much as 10V. If it were accurate, there's no way output power will be more than input power. MPPT selects the the best power point (a point at which current * voltage of the array is maximum).

Hope you are using a battery volt sense wire and your ferrite core in place. Other than that morningstar specifically states that battery voltage reading will be inaccurate. Verify from your log that battery voltage sense wire is in place

You should also have noticed the corresponding increase in the power generated within that same period.

The down trend on the voltage indicates when my power guzzlers...two fridges and a freezer, came into the party...

I have at no time said the controller increases the amount of power generated....but it ensures you are getting the best from your panels...

I have had voltage sense cables from day one the controllers were installed.

Since you all are experts with TriStar...how about you uploading your CSV files?

bodejohn:
Now...I see what JUO was saying...

How can a glare happen every 5 minutes from 8am to 12 everyday on two different controllers?

A bit of more clarity...the panels have points on their curves where voltage and current is producing maximum power...this is what your mppt controller is tracking...some CCs will show you what you would have been receiving if the mppt algorithm was not there.

Unfortunately, you guys think that's the maximum the panel is producing...

Why don't you take the challenge...upload the CSV files from your own controller if it produces any...

My dear, your battery voltage reading is inaccurate and that's what is making you believe efficiency can be > 100%. Get whoever installed the gaddam stuff to connect battery sense voltage.

Having uploaded your log, it's clear that your distorted figure isn't due to glare or shading but rather due inaccurate reading.

36V system cannot charge by 10V under 5minutes.

Give me kudos when you get it sorted out.

bodejohn:
You should also have noticed the corresponding increase in the power generated within that same period.

The down trend on the voltage indicates when my power guzzlers...two fridges and a freezer, came into the party...

I have at no time said the controller increases the amount of power generated....but it ensures you are getting the best from your panels...

I have had voltage sense cables from day one the controllers were installed.

Since you all are experts with TriStar...how about you uploading your CSV files?

You said so, dear friend when you supported wrong reading ab-initio. We only pointed out that output figure is not possible cos of efficiency limitations. Your log also suggests that, power is increased. Welcome to our side, though.

As regards, your challenge: the web server in my charge controller crashed in 2014, my laptop doesnt have serial port.

mank1234:
My dear, your battery voltage reading is inaccurate and that's what is making you believe efficiency can be > 100%. Get whoever installed the gaddam stuff to connect battery sense voltage.

Having uploaded your log, it's clear that your distorted figure isn't due to glare or shading but rather due inaccurate reading.

36V system cannot charge by 10V under 5minutes.

Give me kudos when you get it sorted out.

First...there wasn't any 10v battery difference...what you are referring to is the period the controller was doing a sweep of the power curve to determine the maximum power point...you can set the frequency of this sweep with some controllers. You should that the corresponding input and output power at that instance were zero.

I did the installation of the controllers myself using the recormended sense wire gauge.

One fundamental point you guys are missing is that the input power you see on the controller is not the maximum the panels can deliver...solar panels are dummies and batteries are even dummier, the more reason why a controller is needed to match the batteries to the panels.

I'll give this example....I came home one day and saw about 300watts max generation on my CC, I went in and then switched on one of the fridges...the power jumped to about 500watts...where did the extra power come from? Of course from the same panels.

When the load, that is, the batteries are not optimised or matched with the panels, the power will be will be generated by the panels but will not be transmitted to the batteries.

mank1234:
You said so, dear friend when you supported wrong reading ab-initio. We only pointed out that output figure is not possible cos of efficiency limitations. Your log also suggests that, power is increased. Welcome to our side, though.

As regards, your challenge: the web server in my charge controller crashed in 2014, my laptop doesnt have serial port.

Your CC can deliver more power than it 'says' it has received from the panels.

This is because what you see on the input of the controller is not the maximum the panel is producing at that moment especially in the morning at cold temperatures and because your batteries are at a lower voltage in the morning.

bigrovar:
Happy new year all the Pro and DIY gurus in the house. I have been following this thread from the sidelines for a very long time now while I put together my first renewable energy system.

I have very little electrical background coming mostly from IT. The idea is to have a very small offgrid system which will power essential appliances in my house. Basically Home Entertainment system and Lights. I knew for a long time that my future would be renewable and to prepare for this, I gradually installed energy efficient 8w philips bulbs in my house. I also have a 43inch LED tv, a 1100watt 5.1 sound system, a laptop acting as a media center, and a dstv satellite reciever. From my estimate my total load for this system would be Max 600w. I have 90% of the component I require for this project which I intend to DIY with an electrician friend who will assist with grounding and other areas. I would appreciate if all the gurus can looking into my plan and point out areas I can makde improvements etc

Design:

PV
I have 2 240w polycrystalline panels with the following specs
VMP=30.1
IMP=7.78

I intend to have the panels mounted on the ground. Reason for ground mounting are as follow:
* South facing part of my roof is completely shaded by 15:00 till sun set. (This is pretty much the main reason)
* Since it is a rented apartment, not comfortable with tempering with the roof
*Easy access to panels to carry out cleaning (Abuja can be very dusty) and ease of removal in case I leave the premise
* Phobia for height

Wiring, Distance and Losses
The estimated length of wire which would be required to the power from PV to CC should be about 60feet. Hence I intend to connect the panels in series to reduce resistance and allow me use a 6mm cable with estimated loss of 3-5% (depending on the weather, position of the sun etc). I plan to use 10mm between the controllers and the batteries and batteries and inverter.

Charge controller
3215RN Epsolar MPPT rated at 30A

Batteries:
2 200AH SMF Sukam (I know I know - But it is what I could afford) Deep cycle batteries, connected in parallel

Inverter
12v Sukam 1050v falcon plus inverter: would of loved to use something more industry standard but had to keep the setup within my budget. The falcon plus seem to be the best option availble to me (from all the low end inverter models out there) and here is why. It has built in temperature sensor for ATC and a SMPS for power factor correction and does the "6 stage charge" at least according to this review http://upsinverterinfo.com/su-kam-falcon-plus-inverter-unbiased-indepth-review.html It also could work in low current between 90v -240v. Anyway based on my budget it was what I could afford.

Charge current = 14A

Protection and Safety:

I put a 10A Cbi vdc breaker between PV and CC, a 40A Cbi vdc breaker between CC and Battery, and a 63 vdc Cbi Breaker between Inverter and Battery.

I also intend to put a 15A AC breaker between Grid and Inverter and a 20A AC breaker between Inverter and Load.

I also intend to ground all the equipment from the panel frames to the panel, cc and inverter.

Infuture and close to raining season I hope to get a thunder arrestor

I intend to have all the load the inverter would be powering to terminate to a separate DB from the main house DB. This is meant to reduce issues of overloading the Inverter since only the load to be powered by the Inverter will be terminated to the inverter nothing more.

Run time: I intend for the backup time for the system to be 6 hours. My max load is 450w.. lets say less than 500w * 6 = 3000 / 12 = 250ah.
Because I have a battery bank of 400ah. I hope to ensure I don't pass the 62.7 state of discharge.

considering that I will not be running all the loads at the same time. I expect the state of discharge threshold to be close to the 50% mark.

When am out during the day, I might consider running the freezer with a timer based plug and set it to run between 12-14:00 depending on the weather.

What I have:
CC, Breakers, Panels,Inverter, Cables.

What am expecting:

Ordered 10 mc4 connectors from Aliexpress, a Killawatt meter, an MC4 Crimping tool and MC4 disconnect wrench.

I hope to start the setup and installation once the tools arrive.

There is pretty much my solar plan. I would appreciate if all the gurus look through and point out mistakes and suggestions.

I have attached a schematics of the project.

I think it is just apt to show guys here the update. This project is now live and has been a resounding success. Of cause some adjustments were made mainly increasing the size of the inverter and making the whole system 24v. 24v is more efficient across the board. On inverter side easier to convert 24 - 220v than 12 - 220v, on cc less work on the cc and I can use it optimally, it is also more efficient has mppt work best when battery voltage is about twice the total voltage from the PV.

On the consumption side. I have done a lot to trim down my load considerably. Use of Led >=5w goes a long way. My average current load is about 120w (Including 43inch led, laptop powered home theater PC, 1200w 5.1 Home theater sound system, ceiling fan and couple of light bulb 8-5w which come on demand) this when u include an inverter efficiency of 85% puts my current draw from the battery system at 6amps/h putting me very close to achieving a C40 discharge rate from my 220ah battery. (this reading was done with a watt meter)

My daily consumption stands at 1600w (Including the Freezer running for 4 hours daily) which is about 30% dod. the whole 1600w is put back into the battery the next day. By noon my batteries are in float. On afternoons on weekends, generate enough from the 480w panels to run the house while keeping the batteries at float. (TV-Home theater, Fan or Just powering the freezer - not both at once)

Gen has been totally and resoundingly deprecated.

Here is the mandatory Video
https://www.youtube.com/watch?v=DlkYU02g-HE

mank1234:
You said so, dear friend when you supported wrong reading ab-initio. We only pointed out that output figure is not possible cos of efficiency limitations. Your log also suggests that, power is increased. Welcome to our side, though.

As regards, your challenge: the web server in my charge controller crashed in 2014, my laptop doesnt have serial port.

is not your fault. For challenging my bros after seeing his log, I will blame your lecturer, the University/ the school you attended, Nigeria system and especially you for refusing to learn. I suspect this is what you are referring to?

bodejohn:
I'm on a 36v battery system...50% dod is 36.6V.

noted sir

bigrovar:
I think it is just apt to show guys here the update. This project is now live and has been a resounding success. Of cause some adjustments were made mainly increasing the size of the inverter and making the whole system 24v. 24v is more efficient across the board. On inverter side easier to convert 24 - 220v than 12 - 220v, on cc less work on the cc and I can use it optimally, it is also more efficient has mppt work best when battery voltage is about twice the total voltage from the PV.
On the consumption side. I have done a lot to trim down my load considerably. Use of Led >=5w goes a long way. My average current load is about 120w (Including 43inch led, laptop powered home theater PC, 1200w 5.1 Home theater sound system, ceiling fan and couple of light bulb 8-5w which come on demand) this when u include an inverter efficiency of 85% puts my current draw from the battery system at 6amps/h putting me very close to achieving a C40 discharge rate from my 220ah battery. (this reading was done with a watt meter)
My daily consumption stands at 1600w (Including the Freezer running for 4 hours daily) which is about 30% dod. the whole 1600w is put back into the battery the next day. By noon my batteries are in float. On afternoons on weekends, generate enough from the 480w panels to run the house while keeping the batteries at float. (TV-Home theater, Fan or Just powering the freezer - not both at once)
Gen has been totally and resoundingly deprecated.
Here is the mandatory Video
https://www.youtube.com/watch?v=DlkYU02g-HE

Very nice setup. I have 1200watts of solar panels ( 4x 300 watts mono) plus 24v 1.5kv inverter, and 2 200 battery, does it mean i will be able to use freezer?