+++++++++++++++++++++++++++++++ Date: Wed, 23 May 2001 12:06:45 -0400 From: "Bob Lewis \(AA4PB\)" Subject: Re: [Elecraft] Solar Charger "Can someone suggest a solar charger that would be an ideal match for a K2 with internal battery for Field Day?" http://www.seslogic.com/microm+.htm +++++++++++++++++++++++++++++++++ Date: Wed, 23 May 2001 12:11:35 -0500 From: "Jerry Ford" Subject: [Elecraft] Solar chargers Jeff: Go to www.harborfreight.com and use the word "solar" in the key word serch engine. See what you think. Several kinds of charges available here with a variety of $. 73 Jerry +++++++++++++++++++++++++++++++++ Date: Wed, 23 May 2001 17:59:31 -0400 From: "Bob Lewis \(AA4PB\)" Subject: Re: [Elecraft] Solar chargers > Go to www.harborfreight.com and use the word "solar" > in the key word serch engine. See what you think. Looks like some good stuff is there. One word of caution - be sure to use a charge controller with a small SLA like whats in the K2. You can hook a panel of a few watts through a diode to a car battery and it'll be okay (5 watts is small potatoes to a car battery). Do the same thing with the K2 battery and you'll cook it if you're not very careful about monitoring the charge level. ++++++++++++++++++++++++++++++++++++ Date: Sat, 9 Jun 2001 15:38:15 -0400 From: Ken Kaplan Subject: [Elecraft] solar power question I have a battery (gel cell) that I want to use to solar power my K2 for the needed extra points (my club won't go qrp). So, I hooked up the battery to the K2 and left it on, until the K2 went off, so I figure the battery is discharged. I now have the battery on a 5w solar panel with a charge controller. My question is: how do I know when the battery is fully charged? Please rely to wb2art at arrl.net, unless this may interest others 73 de, Ken Kaplan WB2ART K2 #769 1010#68484 FISTS#3456 QCWA (39 yrs) wb2art at arrl.net http://www.arkayengravers.com/wb2art/ ++++++++++++++++++++++++++++++++++++ Date: Sat, 09 Jun 2001 21:12:46 +0100 From: Larry Cahoon Subject: Re: [Elecraft] solar power question > >My question is: how do I know when the battery is fully charged? >Please rely to wb2art at arrl.net, unless this may interest others The table below is something I downloaded from one of the solar sites a year or so ago. Be aware that with an old battery you may not be able to get it up to a 100% charge. Also you should let it sit after charging for a few hours before you measure the voltage. So if you are using a solar charger, then check it a few hours after sunset. 100% 12.7 Volts 90% 12.5 80% 12.42 70% 12.32 60% 12.20 50% 12.06 40% 11.9 30% 11.75 20% 11.58 10% 11.31 0% 10.5 It is best not to discharge the batter below about the 20% level and it is preferred not to get below the 30% level. Solar charges with a low voltage disconnect usually cut of the load at 11.5 Volts. I would not recommend connecting a battery and letting it run until the item no longer works. You could seriously damage the battery. That is one of the reasons I don't let the kids use my rechargeable batteries - they leave too many things on until the battery is dead. 73 de Larry.............WD3P in MD http://www.qsl.net/wd3p/ ++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++ Date: Sat, 7 Jul 2001 08:05:22 -0400 From: "Bob Lewis \(AA4PB\)" Subject: Re: [Elecraft] Solar Panel and Battery question I'd suggest a voltage regulator IC so that if you don't have full sun and the panel output drops you can still get sufficient output to charge the battery. Not sure about NiMH batteries but I assume you would need to limit the maximum current in some manner - either by sizing the panel to produce no more than the rated maximum charge current for the battery or by adding a series current regulator. +++++++++++++++++++++++++++++++ Date: Tue, 2 Oct 2001 15:17:23 -0400 From: Subject: Re: [Elecraft] Solar panels The purpose of the Micro-M+ is to prevent overcharging of the SLA battery. It works in exactly the same way that the pulse charger does except that it depends on you to provide a solar panel that is not capable of supplying more than the maximum bulk charge rate for the battery (rather than using a current limiter circuit). The pulse charger would not be very efficient for solar panel use because of the power disipated in the current limiter. You would be carrying a larger solar panel to generate more power that would in turn be disipated as heat in the regulator. I highly recommend the Micro-M+ for use with a solar panel for the K2. It can even be fit inside the cover of the K2 next to the battery. For charging the K2 battery make sure that the solar panel is rated at 600 mA or less and make sure you provide a separate charging connection direct to the battery (not thru the K2 power plug). By the way, circuit boards for the pulse charger are currently only available from FAR Circuits. +++++++++++++++++ From: "Ferguson, Kevin" To: elecraft at mailman.qth.net Date: Mon, 28 Jan 2002 14:33:23 -0700 Subject: [Elecraft] Solar charging regulators: Using a series pass regulator (e.g. 7815) is a poor idea in PV applications. These regulators will definatly prevent overcharging...in fact they may well prevent charging at all. Most of the panels don't have much voltage headroom, especially in the summer, and the 78XX series of regulators typically need to drop 2-3V or so, "wasting" 4-7 of the array's PV cells. Many low cost arrays only have enough cells to produce 14V under load, so a series regulator will seriously lengthen the charge time. The 17-18V input volts that the regulator wants to drop to 15V at the output can only be supplied by typical panels at near zero current. Even if a Low-dropout regulator were used, there is a basic mismatch with the application. A series regulator wastes the most power when the battery is flat, and wastes no power at all after the battery is fully charged. So when power is needed the most, the least is available. Since the array behaves more as a current source than a voltage source, shunt regulators are a much better solution. This will allow 100% of the panel power to flow to battery untill the voltage reaches the setpoint. In other words, the regulator starts out wasting no power, and wastes all the array power after the battery is fully charged. Sadly, there are essentially no off-the-shelf shunt regulators that are sutiable. They are pretty simple to design, however. Basic idea is that the circuit should behave as a perfect zener diode, with high dissipation rating, and temperature stable (actually, -26mV/C would better match lead acid chemistry) clamp voltage. National's LM10 combines a precision, buffered voltage reference and an op-amp. This chip combined with a power N-channel MOSFET or NPN power darlington would make a very low parts count shunt regulator. I think there are schematics for such in the application note for this part. Alternativly, most of the active circuits published for linear amplifier screen-grid bias would be suitabe if adjusted for 15V output. There are designs for switching regulators that will milk the last possible watt out of a PV array, though in clear violation of the KISS principal. These are known as tracking charge controllers. The cost of PV panels is so high, that a little extra care, complexity and cost in the charge controller is easy to justify...especially if it allows a lower cost array to meet the needs of the application. ++++++++++++++++++ From: DolfinDon at aol.com Date: Mon, 28 Jan 2002 18:59:06 EST Subject: Re: [Elecraft] Solar charging regulators: To: rlewis at staffnet.com, elecraft at mailman.qth.net In a message dated 1/28/2002 4:38:57 PM Central Standard Time, rlewis at staffnet.com writes: Take a look at http://www.seslogic.com/microm%2B.html for an efficient charge controller well suited to the K2 SLA battery. It's also described in detail in the Oct 2001 QST for those who want to build it themselves. ===================================== I have a much simpler design that functions the same as the above solar controller. It has a power fet, 1 IC, 2 diodes, 8 resistors and 3 caps. The circuit will handle up to 10 amps with the proper heatsink for the fet. If anyone is interested I will mail you the schematic. Just send a SASE to: Don Brown KD5NDB K2 #1808, #2174 K1 #542 K2 #2153-sold K2 #2468 SSB NB AF in work almost finished, for sale K1 #1000 ATU NB, for sale ++++++++++++++++++ From: "Don Brown" To: "Steve Lawrence" , "Elecraft" Subject: Re: [Elecraft] Solar battery charger Date: Wed, 27 Mar 2002 12:16:25 -0600 Hi The Pc board is 1 7/8" X 2 7/8" X ~1/2" It works the same as the Micro M+ but uses a different circuit that is mu= ch simpler. The circuit is made up of 8-resistors 1-8 pin IC 1-power FET = 1-Shottkey diode 1-led and 3-capacitors. A terminal block connects to th= e battery and solar panel. The design is for a 12 volt SLA gelcell or wet cell battery I have used t= he charger with a 2.8 amp battery and 5 watt charger and a 70 watt solar = panel with a 35 amp SLA battery. I haven't researched this but it may work with NiMH or NiCads with some r= esistor changes There are no rf generating circuits. The charger operates as a switch app= lying the full power from the solar panel to the battery until the termin= al voltage reaches the trip point then the current is switched off. Once = off there is a 4 second delay before the current can switch back on. When= the battery is fully charged a very short pulse of current is applied to= the battery every 4 seconds to keep the battery toped off as long as the= solar panel output is above the battery voltage. The power FET is rated at 64 amps so with the proper heat sink the contro= ller will handle just about any solar panel. The limiting component is th= e Shottky diode in series with the battery. The diode is rated at 8 amps = so the max power is about 75-85 watts. The power FET and a larger diode c= ould be mounted off board on a heat sink for a larger solar panel. The board is small enough to mount inside the K2 with KBT2 or it will fit= in an EC-1 enclosure with a 2.8 amp 12 volt SLA battery. You can also us= e a 1 amp 15-18 volt wall wart power supply with a 5-10 ohm 5 watt resist= or in series in place of the solar panel to keep the battery charged from= the mains. Don Brown KD5NDB K1 #542 K1 #1000 sold K2 #1808 K2 #2174 K2 #2468 For Sale ----- Original Message ----- From: Steve Lawrence Sent: Wednesday, March 27, 2002 10:27 AM To: Don Brown Subject: Re: [Elecraft] Solar battery charger Interesting... Don, How big is the charge controller? (what is the approximate cube size tha= t it would fit in?) How does it compare to the Micro M+? Can the controller charge NiMH or NiCads? Does the controller emit any hash noise? What is the range of battery capacities will it handle? Inquiring minds want to know... Thanks! Steve aa8af Hi All I have been working on a little project for the Elecraft EC-1 Project box that matches the K1. Powersonic has a gelcell battery (#PS-1228) that fits into the box with room for a small circuit board to control charging with a solar panel. I have come up with a design, a PC board and a kit of parts for the controller. The Powersonic battery is 12 volts at 2.8 amp hours so a K1 o= r K2 can run at full power from this battery for many hours. A small 12"X12= " solar panel rated a 5 watts will recharge the battery in a few hours or run the radio at the same time with reduced charging of the battery. The controller can handle up to a 90 watt panel so it is possible to run a K2-100 with a much larger battery and solar array. The EC-1 setup with a K1 or K2 would be great for portable or field day. You could also mount the controller inside a K2 to charge the internal SLA battery from a sola= r panel or a wall wart power supply. The PC board, instructions and kit of all parts on the board $25 shipped con US (check or money order) I still have plenty of the noise generator kits also used to align a K1/K= 2 $15 Don Brown KD5NDB 19132 Falls Creek Drive Flint, Texas 75762 +++++++++++++++ From: "Don Brown" To: "Elecraft" Date: Sun, 7 Apr 2002 09:42:08 -0500 Subject: [Elecraft] Re: solar charger Hi The kit includes: FR-4 type fiberglass circuit board with solder mask and= silkscreen similar to Elecraft boards (1.8"x2.9"). All parts that mount = to the board including all resistors and capacitors diodes, a 65 amp powe= r FET, 8 amp shottkey blocking diode, red LED, heat sink and mounting har= dware for FET and a 4 pin terminal block for connections to the battery a= nd panel. Assembly instructions and schematic drawings. Application note= s and possible modifications for more current or using with an external p= ower supply rather than a solar panel to charge the battery. =20 I am also including Speaker Grill cloth modification Kit at no extra char= ge Don Brown KD5NDB ----- Original Message ----- From: Clif Squires Sent: Saturday, April 06, 2002 4:44 PM To: DolfinDon at msn.com Subject: solar charger What comes w/ the above kit? 73 Clif W7ECS K2 #2010 ++++++++++++++++ Date: Sun, 07 Apr 2002 09:56:49 -0500 To: elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] KD5NDB solar charger Don Brown, KD5NDB, wrote: >The kit includes: FR-4 type fiberglass circuit board with solder mask and >silkscreen similar to Elecraft boards (1.8"x2.9"). All parts that mount to >the board including all resistors and capacitors diodes, a 65 amp power >FET, 8 amp shottkey blocking diode, red LED, heat sink and mounting >hardware for FET and a 4 pin terminal block for connections to the battery >and panel. Assembly instructions and schematic drawings. Application >notes and possible modifications for more current or using with an >external power supply rather than a solar panel to charge the battery. For what little it may be worth, I' have one of Don's Solar Charger kits and, although as yet un-built, the quality of the PC board, and parts appears to be great. -- snip -- 73, Tom N0SS +++++++++++++++++ From: "Carter Craigie N3AO" To: "Elecraft List Members" , "Ronald A Pfeiffer" Date: Mon, 15 Apr 2002 17:27:13 -0400 Subject: [Elecraft] Re: K2 Solar Charging??? Hi Ron, Sure! My solar panel is a Model MSX10L, made by a company called Solarex. The panel is stiff, metal-backed, and its size is 10.5" X 17.5." It is supposed to put out 7.2 watts at 480 mA. I use a Sunlight Energy Systems charge controller on the wires between the panel and the K2. On the rig side of the wires leading from the charge controller is an RCA male plug. On the K2 I placed an RCA-type female socket in one of the holes provided for the XVTR (since I won't be building the XVTR circuit). I ran black and red wires directly to the minus and plus terminals of the internal K2 battery. I put the solar panel on the top of my tent's rain fly in the morning, connected to the K2. When I return from hiking the SLA in the K2 is all charged up for an evening's operation! Pretty simple and straightforward... Hope this helps, and thanks for asking! 73, Carter Craigie N3AO EPA QRP Nr. 13 K2 Nr. 678 K1 Nr. 159 Subject: K2 Solar Charging??? > Saw your post and womdered if you could share how > you are charging the battery for the K2 with a Solar Panel. > > Ron - N1ZSW ++++++++++++++++ From: "Mike McCoy" To: Date: Mon, 29 Apr 2002 08:32:13 -0500 Subject: [Elecraft] (Solar) charging the K2 battery I came across a deal on a solar panel I couldn't resist. It's the Uni-Pac 15 and according to the tech sheet it puts out 17.6v. 15.8w (max). Pretty cool panel. See it here: http://www.unlimited-power.co.uk/Uni-solar_Portable_Solar_Electric_Panels.ht ml I plan on using Don Browns Solar panel controller to charge the 'stock' KBT2 battery using this panel. I've read the KBT2 manual & the tech article 'care and feeding of a K2 battery' and I have a couple question for those with experience using the K2 battery & solar chargers: According to the manual, the KBT2 provides current limiting ("typically 250ma eliminating the need for a current limited PS for charging"). Thus when using a controller I don't need to worry this panel can put out close to an amp in full sunlight and overcharge/overheat the battery? According to 'Care and feeding of the K2 battery' under no circumstances should I connect the panel (and controller) directly to the normal K2 power input. If this panel/controller is regulated to provide 14-14.2v, why couldn't/shouldn't I use the panel to charge the K2 from the normal power input? Aside from the solar panel, I have a Yaesu FP-4 (13.8 vdc. 4A) PS I plan to use with the K2. (Assuming I can) 'Care & feeding' suggests I should adjust the voltage of the PS to 14-14.2v so as not to undercharge the battery. Otherwise I should turn the batt switch off when using this PS and only connect the PS to an additional 'charger jack' (and removing the 6.2 ohm current limiting resistor, add a fuse, etc.) to charge the battery per the 'Care & feeding' article? Ya? Sorry if these are dumb questions... Solar panels/controllers & charging gel cells (in general) is a brand new area I know nothing about and I don't want to do something dumb and/or fry something. Thanks & 73 Mike - AD5IU +++++++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] (Solar) charging the K2 battery Date: Mon, 29 Apr 2002 10:00:03 -0500 Hi If you are using my solar controller you must connect it directly to the = battery terminals with reasonably short wires between the controller and = the battery. The wire length is not critical between the controller and t= he panel. The reason for this is the controller must sense the battery vo= ltage to know when to disconnect the panel. If the K2 blocking diode is i= n the circuit the controller will not work properly. The controller has a= blocking diode on board but the voltage sense is before this diode so th= e controller can accurately read the battery voltage. =20 If you are building the controller into the K2 then connect the battery t= erminals directly to the controller and install a connector on the back p= anel to plug in the panel (use one of the transverter connector holes if = you don't want to drill any new holes). =20 If you are using the controller externally then install a fused power jac= k connected directly to the battery terminals on the back of the K2. Conn= ect the controller to this jack with less than a couple of feet of wire t= o keep the voltage drop down. =20 With this arrangement you can use the normal power input jack to power th= e radio and/or charge the battery from an external power supply or use th= e solar power jack to plug in the solar setup and power the radio and/or = charge the battery. Because a solar panel is a constant current source the cable length doesn= 't matter from the controller to the panel. You can use a 50 or 100 foot = extension cord if needed to get the panel out in the sun. If you are goin= g to use an extension cord you may want to use different plugs than the s= tandard AC plugs so someone doesn't plug your solar setup into 120 volts = by mistake :-( =20 Do not remove or modify any of the K2 internal battery circuitry or you w= ill defeat the K2's protection features. Do not try to plug the solar pan= el directly into the K2 power jack. A solar panel can output over 20 volt= s and depending on the load and the size of the panel you may apply too m= uch voltage to the K2. If you have a very small solar panel less than 2 or 3 watts you can conne= ct it directly to the battery terminals through a separate power jack and= fuse without a controller. The risk of overcharging the battery is low w= ith such a small panel and you can check the battery voltage with the K2 = display function from time to time to make sure. Only 2 or 3 watts going = in would limit your operation time but may work in some applications if y= ou only wanted to work a few hours a day. A small setup like this will st= ill benefit from the controller by making it all automatic. Any panel lar= ger than this will require a controller or you will overcharge and ruin y= our battery. Please fuse any direct connections to the battery that have external conn= ectors. Even though the battery is small it can supply a very large curre= nt melting wires, destroying parts or causing burns if a short occurs. Be= careful when working around SLA batteries. Don Brown KD5NDB ----- Original Message ----- From: Mike McCoy Sent: Monday, April 29, 2002 8:36 AM To: elecraft at mailman.qth.net Subject: [Elecraft] (Solar) charging the K2 battery I came across a deal on a solar panel I couldn't resist. It's the Uni-Pac= 15 and according to the tech sheet it puts out 17.6v. 15.8w (max). Pretty c= ool panel. See it here: http://www.unlimited-power.co.uk/Uni-solar_Portable_Solar_Electric_Panels= .html -- snip -- ++++++++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] The Thoughts of Young Men Date: Fri, 17 Jan 2003 08:23:38 -0600 Hi If you are speaking of a QRP K2 then a panel in the 5 to 10 watt range will keep you on the air using the 2.9 amp hour internal battery or even better a 7 amp hour external battery. These batteries are used in small computer backups and can be found surplus at reasonable prices. I have used a 5 watt panel from Northern Tool (also Harbor Freight) with my controller and it will do a nice job of keeping the battery charged. This panel sells for $69 sometimes on sale for $59 If you are talking about a K2/100 then you will need a little larger setup. I used two 35 watt solarex panels charging a 35 amp hour gel cell battery with my controller at field day this year. We were running the K2/100 at 100 watts most of the time on CW and SSB powered by this system and had no problems keeping the battery charged during the day. We operated until around midnight when I switched to a power supply to run the rig. The battery was still ok but I did not want to take it down too far. The next mourning the panels had the battery recharged in a few hours even though we were operating the K2/100 from the solar setup at the same time. I did not use the AC power supply to charge the battery at any time. If you were willing to operate only a few hours per day and lower the power to 50 to 75 watts a 35 watt panel and a large 90-110 amp hour deep cycle battery could power a K2/100 KAT100 rig totally from solar power. If you are wanting a backup in case of power failure this would work also if you tie in your station power supply to keep the battery charged and would automatically switch to solar if the power failed. My solar controller 2 Will handle up to 16 amps or about 200 watts max, way more than you will need to run a K2/100. The solar panels get very expensive when they are larger than 70-100 watts. Figure about $7-$9 per watt. The controller kit is $35 and can be ordered from: Don Brown 19132 Falls Creek Drive Flint, Texas 75762 Includes the circuit board and all parts on the board instructions and application notes on how to use with a K2 or K2/100 I also still have the noise generator kits for $15 Don Brown KD5NDB ----- Original Message ----- From: To: Sent: Thursday, January 16, 2003 6:47 PM Subject: [Elecraft] The Thoughts of Young Men > In wintertime, the thoughts of young men (and women, > maybe) turn to... > > SOLAR PANELS! (Yeah, right) > > Well, I'm not young anymore, but it is winter, and hard as it may be > to believe, my thoughts have once again turned to solar panels. > This past summer, I bought the "Dolphin Don" solar charge controller, > the most affordable component in the chain of what was to be my > ideal of a completely solar-powered HF/VHF station. Regrettably, > budget constraints have mandated a more modest goal. > > With that in mind, I ask: Based on your own personal experiences, > what is the "best" solar panel out there that can keep the K2 > battery charged? I'm looking for something of high quality and not > necessarily portable that won't send me to Ham Heaven after hearing > the price quote. I'm obviously not looking for a panel or set of panels > to sustain a large metropolitan city, just my K2. > > Thanks in advance for your input. > > 73, > > Bob WA4FOM > > K2 # 2537 "B-upgraded and loving it" ++++++++++++++++++++ From: BobDobson at aol.com Date: Sat, 15 Feb 2003 16:30:14 EST To: elecraft at mailman.qth.net Subject: [Elecraft] K2 # 2537 now exclusively solar-powered Yeah, this is just a chest-beating "lookie here what I did" post. It contains virtually no technical information; I'm just dancing the Snoopy dance now that my K2 can run independently of the power mains now. Thanks to the $30 "DolfinDon" solar charge controller from KD5NDB, I just set a BP Solar SX-20 and a little Concorde PVX-340T AGM battery. It works great! The only change I made to Don's basic design was to substitute a Radio Shack 5mm blue LED (part # 276-316) for the LED he supplies. It's really, really bright, so there'll be no doubt as to when the battery is charging. The controller, as Don claims, produces no RFI that I am able to detect, and costs one helluva lot less than most of the other controllers out there. Plus, you get to build it. More Mojo! Field Day is going to be extra fun this year, I think... 73, Bob WA4FOM +++++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] Solar panel question Date: Sun, 23 Feb 2003 12:06:52 -0600 Hi You can connect the panels in parallel although it may be a good idea to use a blocking diode so if one panel is in the shade the panel in the sun does not try to force reverse current into the panel. Most panels already have this protection diode so it is usually not necessary to add one. Dan Kolean sent me some very nice solar panels used to trickle charge the batteries on Volkswagens while in shipping. The panels are 3.2 watts and have suction cups so they can be stuck to the inside of the windshield of a car and then plugged into the cigarette lighter socket to keep the battery topped off. The panels are about 12X9 inches and housed in a very rugged looking plastic case. The panels do not have a controller and output about 18-20 volts open circuit or 170 ma at 13 volts. I believe these panels are available on Ebay I have one of these panels charging a 2.8 amp hour Powersonic SLA battery now through one of my controllers and it looks good. One or two of these panels could power a K1 and maybe even a K2. These panels work great with my controller and you could parallel as many as you like for more power. The controller can handle 200 watts This battery (PS-1228) will fit into a EC-1 box with room for the controller. This would make a nice portable solar powered rig that matches the K1. With the 12 volt battery you could run 5 or more watts with the K1 as opposed to the internal battery option limit of 3 watts. This battery is only .1 amp hour less than the K2 internal battery but is more square so it will fit into the EC-1 I ran a completely solar rig at field day for the last 2 years. I even had a picture and write up in the local paper about the solar setup last year. I used two 35 watt solar panels and a 35 amp hour SLA battery with one of my controllers. This powered my K2/100 at 100 watts out or a TenTec 6n2 meter radio with a 160 watt amplifier running about 150 watts. The solar power setup worked with no problems for the entire weekend. Don Brown KD5NDB +++++++++++++++++++ Reply-To: "Bob Lewis (AA4PB)" From: "Bob Lewis (AA4PB)" To: Subject: Re: [Elecraft] re: solar power Date: Fri, 21 Mar 2003 06:42:20 -0500 > Look at the heat sink on this controller! This is a shunt mode controller. During the times that the charge is not needed by the battery, the power generated by the solar panel is dissipated as heat in the controller. This does not really equate to wasted power because that power is not needed by the battery during the time it is being dissipated anyway and its essentially free from the sun. The biggest problem is simply getting rid of the heat. Series mode controllers "open" the circuit to the battery when charging is not needed therefore the series mode controllers don't generate so much heat. The problem with series mode controllers is that many designs require some sort of switching regulator to generate the higher voltages needed for the control circuit and this can generate RFI. Take a look at http://www.seslogic.com/microm+.html for a series mode charge controller that does not use a switching circuit and so does not generate RFI. ++++++++++++++++++++ From: "Don Brown" To: "Bob Lewis (AA4PB)" , Subject: Re: [Elecraft] re: solar power Date: Fri, 21 Mar 2003 07:29:39 -0600 Hi Bob is right on this. The controller kit I sell is a series mode controller but uses a 45 amp P channel FET so it is turned on by pulling the gate to ground. A switching supply is not required for this circuit so there is no RF generated that may get into the receiver. The heat sink on my controller is a small TO220 type and is really only needed if the panel is over 100 watts. The real limiting part in the design is the reverse current diodes and I use 2 8 amp shottkey's in parallel. The controller IC has a precision band gap reference and 2 precision comparators and I provide 1% metal film resistors in the measuring circuit so there are no adjustments required. There is also a LED that indicates when the panel is charging the battery and when the battery is fully charged. The controller operates by connecting the panel to the battery and monitoring the voltage. When the battery voltage reaches 14.0 volts the panel is disconnected and a wait period starts of about 4 seconds. At the end of the wait period the battery voltage is checked again and if it is below about 13.8 volts the panel is reconnected to the battery. The controller will maintain a 13.8 volt level on the battery. Don Brown KD5NDB ----- Original Message ----- From: "Bob Lewis (AA4PB)" To: Sent: Friday, March 21, 2003 5:42 AM Subject: Re: [Elecraft] re: solar power > > Look at the heat sink on this controller! > > This is a shunt mode controller. During the times that the charge is > not needed by the battery, the power generated by the solar panel is > dissipated as heat in the controller. This does not really equate to > wasted power because that power is not needed by the battery during > the time it is being dissipated anyway and its essentially free from > the sun. The biggest problem is simply getting rid of the heat. -- snip -- ++++++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] re: solar power Date: Fri, 21 Mar 2003 07:52:49 -0600 Hi I should mention that my controller operates the same as the MicroM+ but I use a different circuit and different IC. The circuit is much simpler and more accurate because of the precision band gap reference and precision comparators in the IC. Also the LED on my controller will not light if the panel is not providing enough voltage to charge the battery. The kit is $30 and includes all parts and fiberglass circuit board. Don Brown KD5NDB +++++++++++++++++++++ From: "John" To: "Don Brown" , "Elecraft" Subject: Re: [Elecraft] re: solar power Date: Fri, 21 Mar 2003 09:47:26 -0700 I am a happy user of Don's controller. As I speak it is merrily charging my 15ah SLA. John K7SVV ++++++++++++++++++++++ From: "Don Brown" To: "Elecraft" Date: Mon, 24 Mar 2003 09:34:05 -0600 Subject: [Elecraft] Solar controller and Noise generator kits Hi I have had several requests for more info on my solar controller. I do not have a web site set up but I will describe them here. The solar controller is designed to charge a gel cell or wet cell 12 volt battery with a solar panel. Panels from 1 to 200 watts can be used and I have used one with 3 panels equaling 150 watts total with no problems as well as a small 3.5 watt panel charging a small 2.8 amp battery. The kit comes with a 2x3 fiberglass silk screened and solder masked circuit board. All parts for the board and instructions and app notes. The price is $30 The Noise Generator is a wide band noise source for use in aligning the K2 or K1. The kit comes with a 1 1/4x2 fiberglass silk screened and solder masked circuit board. All parts for the board and instructions and app notes. The price is $15 To Order please send check or money order to: Don Brown 19132 Falls Creek Drive Flint Texas 75762 Sorry I do not have credit card of paypal accounts. Thanks Don ++++++++++++++++++++