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A Little Solar Charge Controller that may be able to do more! (Read 3518 times)
electron
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Re: A Little Solar Charge Controller that may be able to do more!
Reply #5 - May 8th, 2012 at 9:52am
 
I ran a test with this charge controller and a 300W Grid Tie Inverter connected to the same solar panel and the results are good.

I hooked the GTI up as usual, direct to the solar panel. The grid tie is the 14V to 28V input type.

I also hooked the charge controller to the same two wires from the solar panel, it was now in parallel with the GTI.

The 12V battery was hooked up to the two terminals for the battery. ALWAYS hook up the battery first!

When you do this what happens is the battery will go to about 14.7V (or where you adjusted it with the little POT inside the controller) and any leftover energy will now go to the grid!

Some energy is always required to keep a battery charged so this is a good way to keep a battery charged for emergencies. The rest can lower your power bill.

If you run down that battery, the solar power goes to charge it up first, because the GTI won't kick in till it sees 14V.

SOME IMPORTANT POINTS:

The battery (-) is switched on and off by the solar controller, so the battery can NOT be connected to your whole system if the solar panel is also part of that system.

So if you do this that battery and any loads you want to drive with it should be separate, or your panel has to be separate. I hope that makes sense.

Second thing, depending on how you set up your earth grounds, you want to check and make sure the GTI's ground and (-) are separate and floating, they generally are but just check that and make sure if you going to have the solar panels separate from the ground on the battery.

Third thing, you should use a 50W or better solar panel so the voltage can come up enough even with the GTI running that there is some voltage left to put a little into the battery to keep it topped up.

If it's confusing, just draw it all out.
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electron
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Re: A Little Solar Charge Controller that may be able to do more!
Reply #4 - May 8th, 2012 at 9:36am
 
Paul wrote on Jan 4th, 2012 at 7:03pm:
Bought one of these circuits to regulate the battery charge for a old diesel AC generator with a 24volt control panel, the rectified "DC" supply voltage was to high and blow the two controlling IC, so I reversed engineer it by drawning a schematic of this PCB to find out how it work, I replaced the IC U2 (Cmos schmitt trigger NOT gate x 6) and U3 (Oprational Amplifier x 4) to get it working again. I found that the U2 component was a high-voltage gate that only Texas Instruments make, its rated up to 20volt and the U3 rated to 32volt max, the way they get round this is to use 15volt breakdown diodes "zener diodes" to adjust Q2 base a NPN transistor which supply the IC with there power.

The pot W2 adjust the supply isolation voltage turning the charging N-Channel mosfet Q6 off by turning on NPN transistor Q1 on via an optical coupled isolator transistor U1..

This forum I found when I when looking for a schematic without success, so desided to share my finding for anybody else that may be having problems, in short make sure your supply doesn't go above 28 volts otherwise may get some problems.. if it does you could try adjusting the the supply mosfet to isolate at lower potential from 28volts its mean't to isolate at, the charge LED will pulse then go out when it is fully isolated..
It would be great if you could post / attach your schematic, even a scribbled down one would be good to have.

U2 is a HEF40106 Hex Inverting Schmitt Trigger
U3 is a LM324 Op Amp

The datasheet I got on the Hex inverter was from Phillips.

One of the things I noticed is that the "load" output will flip on and off very rapidly when it gets near the voltage it should turn off. They could have done a better job on that, but most people won't use it anyway.


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Paul
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Re: A Little Solar Charge Controller that may be able to do more!
Reply #3 - Jan 4th, 2012 at 7:03pm
 
Bought one of these circuits to regulate the battery charge for a old diesel AC generator with a 24volt control panel, the rectified "DC" supply voltage was to high and blow the two controlling IC, so I reversed engineer it by drawning a schematic of this PCB to find out how it work, I replaced the IC U2 (Cmos schmitt trigger NOT gate x 6) and U3 (Oprational Amplifier x 4) to get it working again. I found that the U2 component was a high-voltage gate that only Texas Instruments make, its rated up to 20volt and the U3 rated to 32volt max, the way they get round this is to use 15volt breakdown diodes "zener diodes" to adjust Q2 base a NPN transistor which supply the IC with there power.

The pot W2 adjust the supply isolation voltage turning the charging N-Channel mosfet Q6 off by turning on NPN transistor Q1 on via an optical coupled isolator transistor U1..

This forum I found when I when looking for a schematic without success, so desided to share my finding for anybody else that may be having problems, in short make sure your supply doesn't go above 28 volts otherwise may get some problems.. if it does you could try adjusting the the supply mosfet to isolate at lower potential from 28volts its mean't to isolate at, the charge LED will pulse then go out when it is fully isolated..
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« Last Edit: Jan 4th, 2012 at 7:09pm by Paul »  
SinurnowRonCZ
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A Little Solar Charge Controller that may be able to do more
Reply #2 - Dec 4th, 2011 at 6:25am
 
Isnt Nevada Solar One a 64 MW facility?

And isnt the proposed Ivanpah facility 392 MW?

I guess these are not solar arrays, but solar-thermal. Still its the same in principle, no?
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Katty
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Re: A Little Solar Charge Controller that may be able to do more!
Reply #1 - Nov 5th, 2011 at 3:14am
 
wow its really nice. thanks for the post.
tell me how far is it feasible?
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electron
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A Little Solar Charge Controller that may be able to do more!
Aug 11th, 2011 at 6:02pm
 
This is one of those 12V / 24V 10A Solar Charge Controllers you see on Ebay for around $15. Model "CMP12" or "CMP12/24".

Taking it apart you find that it's a really simple circuit, just a couple of ICs and some mosfets. This is NOT a PWM charge controller, just simple on/off.

The surprise is that there are three RU6099R mosfets. They are rated at 90A !

The TO-220 package limits them to 75A though, which is still pretty high. 60V max. .006 ohms typical on resistance.

And there is room for 3 more on the board!

One of the mosfets is for switching on and off the load, "light bulb". If you were not using the load, you could use that mosfet as a replacement spare.

I am thinking that with a little beefing up of the circuit traces on the bottom side by adding some bus wire and more solder, and maybe adding more metal to the heat sink, you could make this into a nice 20A to 40A controller!

You couldn't build something like this for $15.

It's possible that not all of these have a overrated mosfet in them, but this one did so if you get one you will need to check the mosfet part numbers before you make any further mods.

But the circuit board does have places for more mosfets connected in parallel, and better mosfets are available online.

The two regulating mosfets are connected in series so that one acts like a diode but is turned on during operation so that you don't have a diode voltage drop during the day! Very nice. Pics of the insides, with the solder side of the board follow.

Other parts of interest:
Varistor -Voltage Dependent Resistor MYG 14D 471K
A pot for adjusting something?

The specs (from ads):
1. over-load protection
2. short circuit protection
3. protection from the lightning strike.
4. under-voltage protection
5. over-charging protection 
6. Dimensions: 10 x 9.5 x 3.7cm ( 4 x 3.7 x 1.5 " )
7. Temperature Compensation: -20�C ~ +60�C
8. This product has been certified by CE
Rated voltage: 12V or 24V Voltage of stop power supply *10.8V or 21.6V
Rated charging current: 10A Voltage of resume power supply *11.8V or 23.6V
Rated load current: 10A Voltage of *14V or 28V
Full Charge Cut : 13.7V/27.4V
Low Voltage Cut : 10.5V/21V
Working temperature: -20 ~ +60�C Temperature coefficient of voltage stop charge -3mV/�C/cell

Thanks to "brownbrve" for the pics!

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