Portable Solar Generator In A Battery Box

Portable Solar Generator In A Battery Box

Nothing makes it more clear that you need an off the grid type of system than when a hurricane hits and knocks your electricity out for a week. Even up here in Ohio, hurricane Ike hit us with winds that left us without power. But, I have also lived in Michigan, where we lost power more often than we lose it here in Ohio. And a portable system lets you use that power in other situations, such as camping or boating. More than that though, it's just fun to generate your own free electricity without feeling dependent upon your local power company.

I have read a number of newspaper stories about seniors who have died in extreme heat or extreme cold, so living without power even for a short time can be life threatening for some.

This post is intended to help you build your own portable solar generator. For this prototype, a battery box was used.

Meter Layout

Portable Solar Generator In A Battery Box - Meter Layout - The Krell Lab

Wiring Schematic

A general schematic of the wiring:

 

Portable Solar Generator In A Battery Box - Wiring Schematic - The Krell Lab

Videos

  Portable Solar Generator In A Battery Box Part 1    - The Layout
        
 Portable Solar Generator In A Battery Box Part 2  - Getting beyond the layout:
  
 Portable Solar Generator in a Battery Box Part 3 - Wiring the layout:

 Portable Solar Generator in a Battery Box Part 4 - Meters & Switches

 Portable Solar Generator in a Battery Box Part 5 - Final Layout & Solar Tracker

 Portable Solar Generator in a Battery Box Part 6 - The Solar Tracker Problem & Trouble-Shooting It
    
 Portable Solar Generator in a Battery Box Part 7 - Solar Tracking Problem Resolved
 
Wagan Wattage Guide

 Wagan includes this handy wattage guide with the 400 watt pure sine wave inverter:

Wagan Wattage Guide

Parts List

NOCO HM318BKS Group 24-31 Snap-Top Battery Box .......$  51.88

  I was able to get the box on sale for $9.00, so shop around.

   

  Wagan EL2601 Elite 400W Pro Pure Sine Wave.................$199.95
  
 I was able to get the inverter on sale for $119, so it may help to shop around.

 

RENOGY® 30 Amp PWM Charge Controller with LCD Display ......$56.00

 This controller would be for my sealed lead acid batteries. You can get one cheaper without the display.

  Batteries

   PowerStream HR22-12 ...........................................................$ 67.10

   However, a LiPO4 batteries twice as powerful could be used in this space.
   If you use a lithium battery, be sure to also use a lithium controller.
   Also, be careful to insulate the battery from the heat of inverter.

   I have used the Lithium Battery and Lithium Charge Controller in my portable solar generator in a File Folder box.


Blue Sea Systems Dual USB Charger Socket ...........................$ 25.98

  I was able to get this USB socket on sale for $ 16.77

Cigarette lighter fuse/circuit breaker.............................................. $  4.87

Waterproof LED Rocker Toggle Switch SPST Marine .......... $9.99 + $4.49 shipping

Battery Cut-off Switch ....................................................................$ 20.00

   I was able to get the cut-off switch on sale for $8.00

  

 Lighted power switch Cherry SWITCH ROCKER SPST 20A 125V ..............$1.30

 35 Amp Circuit Breaker Digi-Key Part NumberPB1049-ND ..........................$4.55

 Circuit Breaker 15 Amp 1/4" Terminals .........................................................$4.89

 

 Circuit Breaker Switch 20A 125VAC 50VDC .................................................$3.54

Links:
 

Portable Solar Tracking Mount

How To Calculate Battery Run Time by Powerstream  

Homemade Modified Sine Wave Power Inverter(350/500w) on a Breadboard

I am very excited to have finally gotten this hefty little circuit working on a breadboard today. 

I first saw this on a You Tube video called Homemade Modified Sine Wave Power Inverter(350/500w) by electronicsNmore.

 
O.K.,  first I have to admit that I was not able to get it working the first time through. I had let it sit on the back burner while I worked on some other things. But, today, I gave it another shot, and am happy to see it working from a breadboard.

 The circuit was designed by John Parfrey, as is indicated in the schematic.

Homemade Modified Sine Wave Power Inverter(350/500w) by John Parfrey

Second time through, I wanted to test that it was functioning by leaving out the 7808 voltage regulator, just to make sure that it worked. After confirming that it did work, then I add the 7808 voltage regulator, upside down on the breadboard, simply because the schematic shows the input to pin #1 was to the right, and I wanted to visualize that. The remaining parts are laid out pretty much as the schematic has it.


There are at least two things that do not match to specifications (on my breadboard), the transformer and the 0.1uF electrolytic capacitor (to the left of the schematic). The design calls for a 10-0-10 center tapped transformer, and I am using a 12-0-12, 4 Amp transformer. Also, I do not have the 0.1uF electrolytic capacitor, and am currently using a 1uF electrolytic capacitor (until I can order the correct capacitor).


Otherwise, I am using the STP55NF06L mosfets, for the 500 watt version (as is shown in the schematic).

I did observe that the waveform is indeed a modified sine wave (using a 4 watt light bulb):

Modified Sine Wave from John Parfrey's Power Inverter design

You might also notice that the frequency is nowhere near the 60 Hz that I want it to be, indicating that the change to a 12-0-12 transformer may require less resistance than indicated in the schematic. You might note that ElectronicNMore YouTube video indicates that he is using an old microwave oven transformer, so the design can be modified successfully. Other factors that can affect frequency would be that I am using the 'cheap' version of the 4017, which does not operate as effectively as more expensive versions, and my battery amperage on this breadboard is minimal. (You can see from the breadboard photos that my power source is AA batteries. I also test with a 7 Amp Hour battery, and a 22 Amp Hour battery). A more powerful battery under a larger load would be more likely to deliver a different frequency.


Being relatively new at this, I think one of my initial problems was that I had not seen the breadboard on this one. So, I will add breadboard pics for others who may want to try it out.

Homemade Modified Sine Wave Power Inverter(350/500w) on a Breadboard

 
 Here is a close up view with the positive rail at the top:

Homemade Modified Sine Wave Power Inverter(350/500w) on a Breadboard02

Here is a view from the other side, which shows that after the 7808 was added (upside down), I used the inner rail for the positive side downstream of the 7808:


 

Homemade Modified Sine Wave Power Inverter(350/500w) on a Breadboar03

Finally, I am including a link to the You Tube video that shows the inverter in action.

You will want to read the text following the video, as ElectronicsNMore also added circuit inrush protection, a fan, and a low battery indicator. You can search the ElectronicNMore video channel for the design (and video) regarding circuit inrush protection.

Also in the video, he demonstrates his finalized project, using a both a hand held sander and high power garage light. You may notice in the video, he is using the 350 watt version of the schematic (by using IRF3205 mosfets). Nice to see a video of the inverter in action.

You Tube Video "Homemade Modified Sine Wave Power Inverter":

Schematic Reference

   Modified Sine Wave Mosfet Inverter Schematic by John Parfrey
 
Videos from electronicNmore:
 
   Homemade Modified Sine Wave Power Inverter(350/500w)
    
   Simple/Effective Solution To Inrush Current Problems

   Simple 120/240 VAC LED Power Indicator

   12V Lead Acid Battery Low Voltage Alarm Circuit 

   12V Lead Acid Battery Overdischarge Cutoff Circuit

  Super Simple Temperature(Heat) Activated LED/Cooling Fan Circuit

   Under Voltage/Over Voltage Cut Off Circuit (12vdc/120v/240v) (Video)

His temperature activated cooling fan (above) uses the bimetal sensor normally used with NiMH battery packs, available on Amazon and Ebay. Here's a link to an Amazon listing:

Amazon (Normally Closed??) "High Quality KSD9700 250V Bimetal 45 Celsius NC Temperature Control Switch Pack Of 10." 

Amazon (Normally Open??) "10 Pcs Bimetal Temperature Control Switch Thermostat 40C N.O TLRS9700" 


YouTube video link: 
Electronic Projects Circuits Blog Article:

   Battery voltage monitor circuit by LM339

Homemade Circuit Designs Just For You Blog:

   Under Voltage/Over Voltage Cut Off Circuit (12vdc/120v/240v) (Blog)

  

100 Watt Inverter Circuit Schematic using Pulse Width Modulator IC SG3525 (my review)

100 Watt Inverter Circuit Schematic using Pulse Width Modulator IC SG3525

                                  (my review)

 Here's a nice little gem that I found on the circuitsgallery.com web site, designed by Khaleel.

 

 

12v to 230v Inverter Circuit Schematic using Pulse Width Modulator IC SG3525 by Khaleel

Fairly straightforward, and fairly easy to build. You have to watch for a few resistors that are 1/2 watt, some capacitors have strange terminology, and some of the symbols are explained in the text portion. So, be sure to review the article if you want to build this one.

 

I currently have this one running on the breadboard.

 

The design calls for a 12-0-12, 5 Amp transformer, but I only have a 4 Amp transformer, so mine is not quite to specifications. However, it still works. The Rt is adjustable if it is replaced with a preset or potentiometer. That adjustment was necessary (for me), due to my 4 Amp transformer. At any rate, the final result was that I was able to adjust to the 60 Hz frequency using a 4 Amp transformer and adjusting Rt as a potentiometer. (The 4 Amp transformer requires less resistance at Rt.)

 

The Pulse Width Modulation (PWM) automatically adjusts for powering devices with various power needs. I currently have it running from the breadboard, but I suspect I may build it with two outlets, or otherwise I would suspect that I should be able to use an extension cord with lights of various voltages.

 

Let me see, the only drawback of a circuit this straightforward is that the waveform is not a sine wave form, nor a modified sine wave form. Which means, it may be a bit harsh to use on sensitive electronic devices. I would only use it for lights.

 

Still, I am short on emergency lighting, and need some practice adding things like a fan and some circuit protection. So, I intend to build a finished version of this little one, simply for those reasons. 

 

Nicely done, Khaleel. I suspect this would be a quick build for most folks. This could be useful for emergency lighting, or for lighting the workshop. Thanks.

   

Reference:  

12v to 230v Inverter Circuit Schematic using Pulse Width Modulator IC SG3525

 

 

300 Watts PWM Controlled, Pure Sine Wave Inverter (my review)

  300 Watts PWM Controlled, Pure Sine Wave Inverter

There are so few pure sine wave inverter designs available, I just had to put this one together on a breadboard:
 
  http://homemadecircuitsandschematics.blogspot.in/2013/10/modified-sine-wave-inverter-circuit.html

This one appears on the pages of Homemade Circuits Just For You, but is designed by an avid reader of that blog, Mr. Theofanakis.

It certainly is a sign wave form, as you can see on the graph on the web page.

This one is put together using the 4017 integrated circuit.

I have not run this one through it's paces yet, and have not tested under heavy load.

However, I have tested on the breadboard with a 4 watt bulb. Unfortunately, the frequency is my concern. I found it hard to hold the frequency at a constant rate, so I have put further testing and completion of this on my waiting to do list.

300 Watts PWM Controlled, Pure Sine Wave Inverter Homemade Circuits Just For You

Here, I have the inverter with no load:

300 Watts PWM Controlled, Pure Sine Wave Inverter with no load

Here, I have the inverter running a 4 watt light bulb:

300 Watts PWM Controlled, Pure Sine Wave Inverter with 4W load

You can click on the images to enlarge, where you might notice that the frequency is getting away from me.

I still have the need to review my parts, and ensure that they are to specifications, etc.

For the moment, the Pure Sine Wave Inverter Using the 4047 (100 Watts, designed by Mr. Swagatam Majumdar) is the one I would like to concentrate on. The initial performance (of the frequency and sine wave) from the 4047 appears to be much better than this one, including after modifications to 250 Watts (or more by using 4 mosfets / 2 in parallel,etc.).

Pure Sine Wave Inverter with IC 4047

              Pure Sine Wave Inverter with IC 4047

Here's a screen capture of the pure sine wave output using 4 mosfets (two mosfets in parallel) from the pure sine wave inverter with the IC 4047 circuit, designed by Mr. Swagatam Majumdar:

Pure Sine Wave Inverter with the IC 4047 designed by Mr. Swagatam Majumdar

I've been working on the design for a while now, and this is my first attempt at adding mosfets in parallel. As you can see, I have been trying to figure out on my own (unsuccessfully) why there would be spikes on the output. I have tried a flying diode configuration on pins 10 and 11 of the 4047 (which seems to help diminish the spikes), but the spikes are still with me. Currently using a blue toroid with 5.46µH inductance factor and a permeability of 4300 with 32 turns of 22 guage wire. It looks like I may have to ask for an answer to that one (from Mr. Majumdar).

Currently I am using a 10K potentiometer at P1, the C1 capacitor at 0.1uF, and about 200K at R1 (as opposed to 180K off of pins 2, 6, and 7 of the middle 555 IC1).
From my initial testing, these are the values that I have found useful for tuning the inverter (prior to the addition of additional mosfets):

 For R1 (off of pin2 of the 4047) and C1 (between pins 1 and 3 of the 4047), with only two mosfets from the original design, these values were useful in frequency adjustments:

R1 ~=  100 with C1 = 1.0 uF
R1 ~=  470 with C1 = 0.22 uF
R1 ~=  15K with C1 = 0.1 uF
R1 ~=  37K with C1 = 0.047 uF
R1 ~= 202K with C1 = 0.01uF

This was for the 100 watt, two mosfet configuration using a 10k potentiometer at pins 1 and 3 of the 4047. That is, I only tested this one up to 100 watts.

However, after adding mosfets in parallel, the frequency does not appear to be as stable under light loads. I have not tested heavier loads enough yet, but the frequency appears to be more stable under heavier loads from what I have seen thus far.


My test configuration for mosfets in parallel:

Pure Sine Wave Inverter with the IC 4047 (proposed mosfets in parallel)
.

Update: 10/27/2014 - 

After having melted some wire insulation and breadboard fittings, it looks like I will need to figure out how to get this off the breadboard for further testing. The point being that I am seeing the need to bump up the amperage level, and in turn, bump up the resistor an potentiometer (P1 and R1 on pins 1 and 3 of the 4047). I ended up the day today with R1 set at 100K, P1 at 100K, and testing the various capacitors for best response to frequency adjustments. 

Adding the mosfets in parallel is changing what I need to get the targeted frequency (which I believe, for the U.S. should be 120 Hz). I can get to 60 Hz, but with 4 mosfets in place, I am having difficulty getting to 120 Hz. I am thinking Mr. Swagatam Majumdar intended the frequency to be for phased power, but keep forgetting to ask him about that.


Yet another update:   10/29/2014 -


I just wanted to post this image of the sine wave this morning.

Pure Sine Wave Inverter with the IC 4047 - 60 Hz no load

This is with two IRF 3205 mosfets in parallel (4 fets total) and 0.047uf for capacitor C1, although the image is similar for C1=0.22uF, etc.

Main thing there is that the spikes are gone. I believe the two main items that I changed there were:

a) The resistance at R1 and P1 on pins 1 and 3 of the 4047. 
     I bumped both up to 100k Ohms in an effort to control the frequency more easily.
     Of course, bumping up these means I need to work with more battery amps.

b) The 1F capacitor linked to the 557 transistor between IC2 and IC2 (555's).
    I am now using a Metalized film capacitor 250 WVDC max that I picked up from Radio Shack.

c) I am now testing with batteries with more amperage. I don't have a variable power supply.

Not sure which one made the difference in the presence of spikes, but if I were to guess, I would say it was the 1uF capacitor or the increase in amperage. Or, it could simply be that I have no appreciable load for that screen capture. I don't know, this is new territory for me.

Without bumping up the resistance, the frequency began running away from me. The increased resistance helped me to keep the frequency around 50-60 Hz. I still have not figured out the exact resistor values needed to get that to around 120 Hz

Increasing the amperage power of the battery is still giving heartburn with melting wire insulation and breadboard fittings, but I hope to figure something out so that I can determine how much power in watts is being delivered by mosfets in parallel (4 and 6 count).


Which means, I may simply build the prototype, just to get it off the breadboard, and enable me to test the mosfets. That would mean I would be crossing my fingers that I have the resistance in the required range. 

Currently, the following settings appear to provide 60 Hz frequency (with the 4 mosfets and the 0.1uF capacitor at pins 1 and 3 of the 4047):  

R1 ~=  44K with C1 = 0.1 uF using 4 mosfets and a 100k Ohm 1/4 watt potentiometer at pins 2 & 3 of the 4047

However, my 4 amp transformer is getting hot easily, which I presume tells me I need a transformer with more amps with the 4 mosfet configuration. 

Finally got a wiring arrangement that permitted me to run from the breadboard with the wires being slow to heat up. Here, I am running a 250 watt flood light at 120 Hz using 4 mosfets, C1 = 0.047uF, R1 = 15K, with P1 = 100K 1/4 watt from a 4 Amp 12-0-12 transformer:

Pure Sine Wave Inverter Using the IC 4047 at 120 Hz, 250 Watts using 4 mosfets

Problems not yet addressed:

In the current configuration, I have the mosfets isolated on a separate breadboard, so they are yet to be hard wired separately. I still have a wire heating problem, although I am now using heavier wire on the high current areas. And, the 4 Amp 12-0-12 transformer still gets fairly hot very quickly. 

I have ordered a few specialty light bulbs so that I can do a reality check on the measurement of the watts. I believe that I will need to get a transformer with more Amps, and use still better insulated wire for the high current areas. Alternatively, I could try increasing the number of mosfets in order to see if the transformer holds up under more power. I suspect not, but I do not know that yet.

As you can see, I have not yet gotten rid of the spikes under a heavier load. My current thoughts on addressing that is to use yet heavier wire on the toroids that I have added off of pins 10 and 11 of the 4047.


Update: 10/27/2014 - 

Well, in my review of Mr. Swagatam Majumdar's notes about the 4047, it turns out that he has probably already suggested a remedy for the spike problem that I am having.

In his comments regarding the Mr. Daniel Adusie after connecting a 0.22uF/400V capacitor and a suitable load, Mr. Majumdar suggests an inductor on pins 1 and 3 (of the 4047), along with the capacitor.

I've been running a flyback diode on pin 11, with a balancing toroid on pin 10. I had done that in response to the power problem with my substitute mosfet, IRFP150. Just too much power there for me, which was one of the reasons that I had decided to switch to the IRF3205 style mosfet. I was getting a good sine waveform from the 3205 and the toroids, and the frequency was responding to the R1 and P1 settings.

Therefore, my understanding would suggest a trial of an inductor off of pins 1 and 3 of the 4047.

Now, I don't have a collection of inductors, but I do have a few toroids. That should enable me to test the number of windings, the wire thickness, whether or not I need the toroids off pins 10 and 11, and whatever variance in resistance that might involve.

Finally, I only have one 22 Amp hour battery that enables me to run at 250 watts in my test mode. One day of testing should run down the charge on that battery. Therefore, my game plan this weekend is to test the inductor configuration on pins 1 and 3, checking for number of windings, thickness of coil, and whether or not the toroids on pins 10 and 11 are really needed for the waveform. Since I have limited battery power, I will test from the 2 mosfet, 100 watt configuration on with batteries that are not as powerful.  That should help me get an approximation of what inductor (toroid) structure is needed for the 4 mosfet configuration.

Of course, not to forget that another option for me is to see how the configuration works with the IRFP150 (as opposed to the IRF150 in Mr. Majumdar's schematic).


Additionally, I will be looking at heavier insulated wires, and perhaps shopping for a new transformer (with more amps) if the transformer heat problem does not improve. I am also looking at overload protection, adding a fan, and adding a voltage regulator. It would be nice to add some sort of battery monitor as well. The design has an ammeter area, and I am currently using a BeesClover amperage and voltage meter at that location (between pins 2 and 3 of IC1 and IC2). That little BeesClover ammeter has been helpful here.


Very nice to see this design has a number of options, and that it holds so well up to my abusive testing. The design has been fairly durable thus far.

Lots of options there for me to explore this weekend.

update 11/03 - Corrected number of windings on toroid to about 32 turns. Now checking to see if a different number of turns will correct the spikes.

Update  11/12/2014:

This one appears to be responding to what I believe is called "passive" filtering, with respect to the 'spike' problem. I have removed the toroids inductor(s), and removed the flyback diode, and have placed 10 Ohm resistors and 0.1uF capacitors (630 volt poly metal film) between the mosfets and the transformer. I have a schematic of what that looks like:

Pure Sine Wave Inverter Circuit Using IC 4047 With Passive_Filter

I plan to use four levels of this resistor/capacitor filter, but just so that you can see the difference, here is a view of a level 3 passive filter example from a 4 watt light bulb, using just the two mosfets, as in the original 100 watt version of the inverter:

 

Pure Sine Wave Inverter Circuit Using IC 4047_W_0.1uF_75Hz_2FETS_55K_P1_Level3_filter

Needless to say, the spikes are really no longer a problem at level 3 filtering, but I do hope to eliminate the spikes altogether by taking the filter to a fourth capacitor/resistor configuration. In the image above, I am using IRFP150 mosfets.


P1 = 10K, R1 ~=  55K with C1 = 0.1 uF, no toroids, using passive filtering

 I am having problems locking in on the frequency, as I have not experimented with this configuration much yet. Currently using C1 = 0.1uF, R1 = 55k at pins 1, 2, and 3 of the 4047. For the filter configuration and voltage less than 5, the frequency wants to hover at about 1.5 KHz, which is something I would like to improve. The frequency for higher voltages looks O.K. for the moment, but I don't want to show that until I have tested these low voltages sufficiently.

As for the filter, I have already looked at using 1 uF for the capacitor, but that appears to decrease the efficiency, requiring more Amps from the battery. I have also looked at using a 0.01 uF filter capacitor, but that is making it a bit difficult to get a handle on the frequency. 

This also appears to have relieved some stress on the transformer. At the moment, I am still using a 4 Amp, 12-0-12 center tapped transformer.

Perhaps with some combination of C1 on pins 1 & 3 of the 4047, and the right selection of the filter capacitor, it might be possible to come up with a trade off between a stable frequency and battery efficiency.

Videos:
  
Pure Sine Wave Inverter with IC 4047 Schematic 

Pure Sine Wave Inverter with IC 4047 on a Breadboard

  

In the video, I should note that I added a voltage regulator (LM7808) and a silicone controlled rectifier (SCR, 2N6507).
The multimeter was not connected to the power outlet, as demonstrated when I shorted out the connection (and the light went out at about 9 minutes into the video). So, there was a little wireless power going from the outlet to the multimeter probes.