tag:blogger.com,1999:blog-4774014561040227748.post3693074791465999161..comments2024-03-22T10:42:05.161-06:00Comments on KA7OEI's blog: A "simple, effective, yet inefficient" solar charge controller.Unknownnoreply@blogger.comBlogger18125tag:blogger.com,1999:blog-4774014561040227748.post-87168317802523497912016-01-13T19:45:08.743-07:002016-01-13T19:45:08.743-07:00This project was never envisioned to include MPPT,...This project was never envisioned to include MPPT, but if I were to design an MPPT solar controller, it would be a completely separate project - 'dunno when I might get around to that.<br /><br />Thanks for asking.<br />KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-73444557265873285852016-01-10T23:30:55.666-07:002016-01-10T23:30:55.666-07:00Hi KA7OEI, would you be adding the MPPT feature to...Hi KA7OEI, would you be adding the MPPT feature to the solar charge controller in the near future ? M&Dhttps://www.blogger.com/profile/06584997619985554013noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-68228499427704273812015-12-08T23:24:37.279-07:002015-12-08T23:24:37.279-07:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/03309730104154118725noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-983945855182840962015-06-21T20:44:36.896-06:002015-06-21T20:44:36.896-06:00This circuit is known to handle the so-called &quo...This circuit is known to handle the so-called "29 volt" (at maximum power) panels, which have a nearly 40 volt open-circuit voltage. For charging 24 volt battery systems, I wouldn't use higher than the same "29 volt" panels as that would exceed the voltage rating of the specified transistors and the capability of the U1, the voltage regulator.<br />KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-53695941857893414402015-06-20T08:45:27.765-06:002015-06-20T08:45:27.765-06:00Hi KA7OEI,
What is the maximum wattage of PV in 12...Hi KA7OEI,<br />What is the maximum wattage of PV in 12v setup? And 24v setup?Anonymoushttps://www.blogger.com/profile/03275051278311610780noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-44669034062981746612015-02-26T08:15:45.720-07:002015-02-26T08:15:45.720-07:00The section of this article, "By the way, wha...The section of this article, "By the way, what's an 'MPPT' charge controller?" explains the problem in detail.KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-54899009928392807542015-02-25T22:11:25.421-07:002015-02-25T22:11:25.421-07:00Hi KA7OEI.
What do you mean by A simple, effectiv...Hi KA7OEI.<br /><br />What do you mean by A simple, effective, yet inefficient solar charge controller! Specially the word inefficient.Hennie Viljoenhttps://www.blogger.com/profile/11132847003888058194noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-82955016380626886122014-09-30T16:42:33.254-06:002014-09-30T16:42:33.254-06:00Hi Charlie,
If I rewrite the equation and substit...Hi Charlie,<br /><br />If I rewrite the equation and substitute 13.2 volts for Vbatt for a nominal battery voltage I get 23.684 volts for Voc when R11 = 68k and 16.229 volts when R11 = 33k.<br /><br />At least 23.7 volts should be expected if there is a reasonable amount of light falling on a "29 volt" solar panel when it is open circuit, so it is probably worth attempting to charge from it. Similarly, if you see at least 16.2 volts from an open-circuit "12-15 volt" solar panel then it will likely have at least some usable output.<br /><br />Remember that the idea here is that, when Q3 is open, will pull the bottom end of R11 down, the voltage across Q1 being the difference between the open circuit voltage and the battery voltage.<br /><br />When the junction of R10/R11 drops below 4 volts with Q3 open this will indicate that the open circuit voltage is adequate to attempt charging. Since we need only know "Voc" approximately to be able to determine if the panel is illuminated, we have a fair bit of latitude in this measurement and need only know Vbatt approximately as well.<br />KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-2901834714207981512014-09-18T08:33:36.436-06:002014-09-18T08:33:36.436-06:00Hi there! It's been almost a year after I ask...Hi there! It's been almost a year after I asked my first question about this circuit, and now I'm back! I'm determined to build this project soon, and as such I'm determined to understand it entirely. I think that I now have a basic understanding of why your method of measuring the Voc works, but I'm having difficulties with your calculation for R11. No matter what values I choose for Voc & Vbatt, I'm just not getting anywhere near the 33K (or "about 31K" as you noted) or 68K using the formula that's provided.<br /><br />Can you let me know what values specifically you're using for Voc & Vbatt to arrive at the R11 value? I'm sorry to seem so dense, but I want to understand it and I'm just not getting anything near the same values.<br /><br />Thanks!Anonymoushttps://www.blogger.com/profile/01370804939170569294noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-49813625491600607162014-06-05T16:28:35.085-06:002014-06-05T16:28:35.085-06:00thanks for a Excellent PIC based project, I was ab...thanks for a Excellent PIC based project, I was about to settle for NE555 based solar charge controller when I found this.<br />With PIC already available with me I am more keen in building this to charge my 12V 150Ah battery.<br />however I am in need to exactly know how many 12v 10W panel should I order to be able to charge the Heavy Home Inverter Battery.<br /><br />many thanks again for the excellent circuit and full explanation.<br /><br />Regards,<br />ghpkhttps://www.blogger.com/profile/09383462332893730189noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-62825201104842092602014-01-12T14:09:55.534-07:002014-01-12T14:09:55.534-07:00As you may noticed, .HEX files for both the PIC12F...As you may noticed, .HEX files for both the PIC12F675 and PIC12F683 have been made available.<br /><br />Good luck!KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-29175716034838168302014-01-09T10:58:18.066-07:002014-01-09T10:58:18.066-07:00For an N-channel FET that is turned off, current w...For an N-channel FET that is turned off, current will not flow if the source is more negative than the drain.<br /><br />In the case of this circuit, an open-circuit solar panel will produce more voltage than the battery being charged: With the positive lead of the solar panel being permanently connected to the battery positive lead, the panel's negative lead would therefore be more negative than the battery's negative post.<br /><br />I could have designed this circuit with a FET in the positive lead - and this is admittedly a bit more intuitive at first glance. To make this work, however, I would have had to do one of the following:<br /><br />- Use a P-Channel FET. This would be wired with the source connected to the panel V+ and the charge controller would drag the FET's gate toward ground. The caution here is that one must put protection on the FET's gate - as was done in the above circuit - to keep the gate within 20 volts of the source lead or the FET would likely be damaged due to excess gate-source potential. I chose not use a P-Channel FET because N-channel FETs are far more common and generally less expensive.<br /><br />- Use an N-channel FET in the positive lead - the drain connected to the solar panel positive lead. The problem with doing this is that in order to turn on the FET, one must make the gate more positive by 10 volts or so than its source so this would require that one generate a voltage source that is always!<br /><br />It is mentioned in the post that current will flow backwards through the FET's intrinsic diode if there are not blocking diodes in an unilluminated solar panel, but most panels intended for charging batteries, those designed to be paralleled or those referred to as "shadow tolerant" typically have diodes already wired in. If your panel doesn't have a diode, or you are not sure if it does, then it's a fairly simple matter of covering the panel to prevent it from producing any current and connect it to the same voltage of battery as you intend to charge with a means of measuring current connected in series with one of its leads.<br /><br /><br /><br />Thanks for asking!<br /><br />KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-27435467959639445182014-01-09T08:37:40.240-07:002014-01-09T08:37:40.240-07:00Hi,
I want to know what happens to N-Channel Mosf...Hi,<br /><br />I want to know what happens to N-Channel Mosfet Q3's internal body diode, when the Mosfet is turned OFF, Panel current will continue flow into to Battery thru this body diode, Isn't it ? Or am i wrong ?nurahttps://www.blogger.com/profile/03605318427721745597noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-12007485233690253412013-12-16T03:06:56.053-07:002013-12-16T03:06:56.053-07:00dear sir,
Iam sudhindra vu3pwt from i...dear sir,<br /> Iam sudhindra vu3pwt from india. Kindly send the hex file and charge controller circuit.vu3pwthttps://www.blogger.com/profile/15953445079806232920noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-53280224478616873542013-11-21T10:16:25.865-07:002013-11-21T10:16:25.865-07:00You are right that the 7805 is used as the main vo...You are right that the 7805 is used as the main voltage reference. The R10/R11 divider will measure the panel voltage *only* if Q3 is turned off and because that voltage goes negative with respect to the "ground" on the PIC, the R10/R11 voltage divider is configured so that the voltage is always positive and the precise open circuit voltage of the panel could, in theory, be calculated as an increasingly-negative voltage from the panel will drag the voltage down toward ground. You would have to take into account the battery voltage in making the calculation (e.g. the battery voltage plus the voltage difference between ground and the panel's V-) - but this is a computer, so that's easy to do!<br /><br />When the battery is fully charged, Q3 is open most of the time so measuring the open circuit panel voltage is pretty easy. When charging, however, it is necessary to occasionally (and briefly) turn off Q3 so that the open circuit panel voltage can be measured - a hundred milliseconds or so is all that is needed.<br /><br />Another function of pin 4 is the source of Vpp - the 13 volt (or so) programming pulse used when downloading code to this processor, so it must *never* go above Vdd or else the processor will do strange things.<br /><br />Perhaps because it must tolerate the Vpp pulses, this pin cannot be used as an output and it does not have a pull-up resistor, therefore it must be tied to either Vdd or Vss if it is not used. In addition to a general-purpose digital input, it could also be configured as !MCLR - a master reset, but I didn't configure it that way in this case.<br /><br />I chose to tie it to Vdd in the event that I might, in the future, enable !MCLR, but since the PIC has some built-in start-up circuitry of its own to assure that it will run - even if the voltage source is slow-rising, I probably don't need to use !MCLR.KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-88430401305338011582013-11-21T10:12:43.307-07:002013-11-21T10:12:43.307-07:00This comment has been removed by the author.KA7OEIhttps://www.blogger.com/profile/01153508130273704727noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-7590221914281899032013-11-21T09:54:18.710-07:002013-11-21T09:54:18.710-07:00First of all, thanks for the info that you've ...First of all, thanks for the info that you've posted! It will certainly be a help to me as I attempt to build a solar charge controller of my own.<br /><br />Secondly I have a question that I hope answer. I'm just a beginning electronics hobbyist so it's probably just a misunderstanding on my part. I'm having trouble understanding how the R10 & R11 voltage divider helps you to measure the solar panel voltage. I can see that R10 is connected to the output from the 7805 so I would guess that the PIC pin 6 (GP1) would always measure some fraction of +5VDC and wouldn't necessarily have any correlation to the solar panel voltage. Or maybe that's your voltage reference? If so what is PIC pin 4 (GP3) used for?<br /><br />Thanks in advance!Anonymoushttps://www.blogger.com/profile/01370804939170569294noreply@blogger.comtag:blogger.com,1999:blog-4774014561040227748.post-12755156898228141922013-10-09T06:31:47.085-06:002013-10-09T06:31:47.085-06:00hello..if it is not a problem for you..i would lik...hello..if it is not a problem for you..i would like to ask for the hex file..because im keen to do this project as it is interesting and is challenging to constructFinal Year Project Ikhwan Fadzlihttps://www.blogger.com/profile/08015237027960242148noreply@blogger.com