Need a Solution: Increasing system capacity from 300w to 600w (Mismatch)

[robert55]

The problem is my original system is three 100W 12V panels in series, WHILE my addition is two 150W 12V Panels.

Panels are a mismatch (although at first thought it seemed like a good idea to get larger panels).

Running two series streams in parallel gives one 54V stream and one 36V stream which will combine to only 36V!

Running all five panels in series gives one 90V stream but the 150W panels are bottlenecked to only 100W each!

I have a 40A MPPT fused controller which can handle the five panels.

The other option is to boost the 36V stream up to 54V then combining. The step up converter costs $20 but adds concern.

The more advice, the better.

[littleharbor]

Drop one 100 watt panel and series wire the 2 100's and series the 2 150's. Then either get another 100 or 150 watt panel. If you're running 12 volt system 6 panels are going to over amp your controller.

[robert55]

Has anyone tried a step up booster? I can input up to 10A at 36V and get out 6A at 54V? 90% efficient

Could be a great solution to a common problem.

[Sunking]

You have 3 options. Take your pick.

1. Worse option is to wire than all in series for 500 out of 600 watts.
2. A better option is loose a 100 watt panel, wire the two 100 watt panels in series, and put them in parallel with the two 150 watt panels wired in series. Still 500 watts.
3. Best option is same as option 2 except buy another small MPPT controller for the queer 100 watt panel. That will give you the full 600 watts.

Learn three expensive lessons.

1.Never ever use 12 volt battery panels because they cost 2 to 4 times more than Grid Tied panels.
2. Do not use prime numbers of panels with the exception of 1 and 3. That only leave you two panel configurations. Either all in series or all in parallel.
3. Only use matched panels.

[robert55]

I am going to try the step up converter:

Input voltage: 8-60V

Input Current: 20A

Quiescent current: 15mA (12V liter 20V, the output voltage, the higher the current will increase too quiet)

Output voltage: 12-80V continuously adjustable
Output Current: 20A MAX Over 15A, please enhance heat dissipation (input, output pressure related, the greater the pressure the smaller the output current)

Constant Range: 0.5-20A

Output Power:
Input voltage * 20A, such as: input 12V * 20A = 240W, input 24V * 20A = 480W,

Enter 36V * 20A = 720W, input 48V * 20A = 960W, input 60V * 20A = 1200W

If you need more power, you can use two modules in parallel, such as the output to 30A, two modules can be used in parallel,
The current per module can be adjusted to 15A.

Working temperature: -40 to + 85 degrees (ambient temperature is too high, please enhance heat dissipation)

Operating frequency: 150KHz

Conversion efficiency: up to 95% (efficiency and input and output voltage, current, pressure related)

Overcurrent protection: Yes (with reduced flow adjustment, adjustable output current limit, current exceeds the current limit, the output current is automatically reduced to a minimum 5A, vary according to the nature of the load current will be.)

Short circuit protection: Yes (input 20A fuse) double short circuit protection, the use of more security.

Input reverse polarity protection: None, (if necessary, please enter the string into the diode)

Output Counter filling: Yes, for charging plus blocking diode is not required.

Installation: four 3mm screws

Connection: solderless terminals output

Module dimensions:116x52x15mm

Weight: 300 g



If that fails, I have a 30A charge controller coming from windy nation with an LCD display for $30

This is a portable off grid system used primarily for camping with a large battery bank for evening use.

[Mike90250]

I am going to try the step up converter.........

Only if it is a MPPT converter rated for use with solar panels. Otherwise, it's not going to work,

[PNPmacnab]

Do you have more technical experience than just ordering? I use buck and boost converters on solar panels and it is quite effective. The caveat is that the input voltage to the converter has to be controlled as well as the output. This can be done with a fixed voltage comparator that shuts off the converter by faking the output voltage is too high. That input voltage can be changed seasonally or br made to track a little with temperature. That gets you 80% of MPPT. Otherwise the converter will just keep drawing more current to supply output demand.

[Mike90250]

Do you have more technical experience than just ordering? I use buck and boost converters on solar panels and it is quite effective. The caveat is that the input voltage to the converter has to be controlled as well as the output. This can be done with a fixed voltage comparator that shuts off the converter by faking the output voltage is too high. That input voltage can be changed seasonally or br made to track a little with temperature. That gets you 80% of MPPT. Otherwise the converter will just keep drawing more current to supply output demand.

If you have a reliable way to trick the DC-DC so that it does not collapse the PV voltage, then you have it all set. But plain DC-DC converters will fail to harvest much of the panel capacity,

[Sunking]

I am going to try the step up converter

Go ahead, it will not work and you will wished you had listened. Have fun loosing money.

Look you have made mistakes from the start, and keep making more bad mistakes. Now you want to make another mistake.

A 40 Amp Controller operating at 12 volts is MAXED out at 500 watts. You made 3 mistakes right there from the start.

1. You used Battery Panels
2. You chose 12 volt battery
3. You used a Prime Number of Panels.

Now you compounded your problem with another big mistake.

1. You chose mismatched battery panels again.
2. You still have a Prime Number of Panels that you cannot use.
3. You have exceeded your Controller 500 watt input limit at 12 volts.

Now you want to make more mistakes.

Use option 3 in my last post. I can even make it easier. Use the Queer 3rd 100 watt panel connected directly to the battery without a controller until you understand what is going on and finally decide to fix it correctly. Stop running around like a chicken with its head cut off.

Hint: Buy a second controller is how you fix all your mistakes. Then get smart and move up to 24 volts if you plan to grow anymore.

[robert55]

Go ahead, it will not work and you will wished you had listened. Have fun loosing money.

Look you have made mistakes from the start, and keep making more bad mistakes. Now you want to make another mistake.

A 40 Amp Controller operating at 12 volts is MAXED out at 500 watts. You made 3 mistakes right there from the start.

1. You used Battery Panels
2. You chose 12 volt battery
3. You used a Prime Number of Panels.

Now you compounded your problem with another big mistake.

1. You chose mismatched battery panels again.
2. You still have a Prime Number of Panels that you cannot use.
3. You have exceeded your Controller 500 watt input limit at 12 volts.

Now you want to make more mistakes.

Use option 3 in my last post. I can even make it easier. Use the Queer 3rd 100 watt panel connected directly to the battery without a controller until you understand what is going on and finally decide to fix it correctly. Stop running around like a chicken with its head cut off.

Hint: Buy a second controller is how you fix all your mistakes. Then get smart and move up to 24 volts if you plan to grow anymore.

Honestly, this is the most unfriendly forum I have ever visited. Your attitude is beyond confrontational to abusive.

PhD ChE PE MS EE

[Sunking]

Robert I have given you the best advice you will ever receive. You own your mistakes. Now face them. You wil waste your time and money trying to use a converter. What do you think a MPPT controller is?

A MPPT controller is made to converter a current source to a voltage source with unknown power. A boost converter your way is not designed to do what you want and will fail as everyone is trying to tell you.

Please go ahead and try it your way. In the meantime please go to the Northern AZ Wind and Sun forum where they coddle and lie to members telling you exactly what you want to hear so you feel warm and fuzzy. You get hard facts here. You do not like facts and intend want to shoot the messenger.

Last time I am going to tell you. Get another controller or throw a 100 watt panel away. Take your pick. Or your way. waste your money and leave. Your mind was made up before you came here.

[anaslater]

Hello, I'm a student from the University of Reading currently studying BSc Human and Physical Geography.

I am writing my dissertation on microgeneration with particular focus on what motivates as well as puts people off installing a microgeneration system in their home. I am also interested on whether those who have have invested into microgeneration feel like their investment has been worthwhile and for what reasons. The questionnaire should only take a few minutes.

https://goo.gl/forms/kCbc6U1Poy2vpfPx1

[PNPmacnab]

Your survey didn't work past page 2. These surveys are meaningless as they never ask the right questions. I was just curious, I never finally submit these anyway.

[littleharbor]

Maybe one of the other 2 strings the op inappropriately inserted his survey into will work.

[Logan5]

Honestly, this is the most unfriendly forum I have ever visited. Your attitude is beyond confrontational to abusive.

PhD ChE PE MS EE

cognitive dissonance