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 > Your search for posts made by 'LScamper' found 46 matches.

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  Subject Author Date Posted Forum
Paralleling 3 batteries in a balanced setup

Would like to open a discussion on paralleling 3 batteries in a balanced method. There seems to be only one option that is mentioned on the forum. I have suggested a second method that may be easier in some applications. Seems that I'm the only one that thinks it will work. Would like comments from people that understand such things, not just repeating what they hear on the forum. Will it work? Is it the same as the other method? Is it a better method? Standard method: http://i.imgur.com/zp1DBE8l.jpg Other method: http://i.imgur.com/vl0rNA8l.jpg
LScamper 01/10/15 08:19pm Tech Issues
Picture test

This is a picture test. http://i.imgur.com/6MHkdF8l.jpg Test over.
LScamper 01/10/15 07:51pm Forum Technical Support
RE: Led lights

RV Buzz wrote: "I checked the voltage at the socket while the genny's running and it's 15.5 volts." Why do you have 15.5V at the socket, bad convertor? Way to high and may be doing damage to LEDs and other RV electronics!
LScamper 12/28/14 09:16am Tech Issues
RE: finding a outside beam on a trailer????

OK I'll take a stab at it. I had to do something like that on my travel trailer. The aluminum siding was bowing out as I was going down the road. I wanted to put some screws into the studs to hold the siding on. I removed the inside window trim from a window near where I needed to find the studs. After removing the window trim I could see the studs. I found the center of the studs and made a line up to the window. I put a mark on the inside of the window for the studs I could see. I was able to use a tape measure and slip it under the paneling to measure to the next stud that I could not see. From the outside I dropped a line from the mark on the window down to the bottom of the trailer. If things are square the line will be in the middle of the stud. I was able to hit five of five studs the first try! It can be done. If there is no window where you want to mount things try to use a stud finder on the inside paneling and measure to some reference point that you can get to from inside and outside. You may be able to remove a cover like the power cord cover or a water inlet cover and see a stud. It takes some careful measuring but possible. Good luck!
LScamper 12/02/14 10:27pm Tech Issues
RE: More MPPT Confusion and Question

The controller will look at the voltage at the controller input and the current at the controller input. The controller will multiply this current times this voltage to determine Watts. It will keep doing this at different volts and until it sees a maximum at the controller input. This is the voltage it will run at. It will keep checking this at what ever rate the designer programmed into it.
LScamper 12/01/14 07:17pm Tech Issues
RE: Paralleling Power Supply Units Made Easy ???

ken white "You do whatever you want, but my comments are for the general case and not a CV supply operating in current limit mode..." All convertors and power supplies talked about here have a constant voltage set point! A true constant current supply operating into an open will have infinite voltage!!
LScamper 12/01/14 07:09pm Tech Issues
RE: Astable 555 Timer (Recommended Resistors Are NUTS!)

Can not get there without more stuff with a 555 timer as others have said. If you want to use a 555 make sure it is a cmos version, they can use much higher value resistors in the timing circuit. Still can not do it with just a 555. Arduino is a very good choice for doing almost anything you can think of. If you get China knock off it is very cheap. The software is free open source. You can find a program on the WEB to do almost anything you want and down load it for free. Programming it yourself is easy if you know some basic programming, if not it will take some learning! It is worth learning. Another option might be this or something like it. http://smile.amazon.com/Intermatic-TN311-Heavy-Grounded-Timer/dp/B005MMSTNG/ref=sr_1_6?ie=UTF8&qid=1417482365&sr=8-6&keywords=timer+3+times
LScamper 12/01/14 06:20pm Tech Issues
RE: Where did you get your Electrical knowledge?

Started as hobby at around 12 years old. Nike Hercules missile radar, computer fire control operator. Side note. Nike computer was analog with servos turning big gears that turned large potentiometers. Potentiometers were wound with sin and cos tapers that did the calculations to steer a missile to a target. Repaired TV and stereo equipment while in school. Spent 35 years working in fusion energy research on multi megajoule pulse power systems. Mostly did control and instrumentation for one of a kind very large physics experiments. Part of a team that designed, built, installed and maintained 2.5 gigawatt feedback amplifier chain to stabilize a plasma for a fusion experiment (filament power 500 kW). Three years working on Star Wars particle beam accelerator RF feedback control system. Helped design high speed x ray camera for National Ignition Facility. About 100 pS resolution time. Retired 2004 and now playing with taking pictures of water drops using an Arduino micro for timing control. Some of the pictures are in my sig.
LScamper 11/22/14 02:20pm Tech Issues
RE: LED flicker

A few terms. http://en.wikipedia.org/wiki/Ripple_%28electrical%29 Ripple is a periodic variation of DC at a the fundamental or multiple of the fundamental. In a full wave rectifier it is 120Hz. In a switcher it could be 10kHz to maybe 1MHz. http://www.tvss.net/trans/trans-x.htm Transient voltages are random and often caused be switching inductive loads. A capacitor of the correct value and type placed in the correct place will help to eliminate both ripple and transient voltages. LED flicker may be caused by a random fluctuating voltage, bad connection, bad LED, bad convertor, or other things that are slowly fluctuating. Ripple on a LED at 120Hz can not be seen with your eyes even though the light is varying. A slow fluctuating voltage may not be filtered out with a capacitor depending on the amount of current drawn and the length of time between fluctuations. The battery is a good filter at low frequencies, not so much at high frequencies. Putting the LED across the battery with the power on may tell you that the converter is bad ( a volt meter may help also). It may tell you that the LED flickers with the higher voltage at the battery from the converter. If it does not flicker then wiring to the filtered output of the converter may fix the problem. Anyway it is just another test to help narrow down the problem.
LScamper 11/20/14 10:29pm Tech Issues
RE: LED flicker

Unlikely that it will stop the flicker. Try the LED connected directly to the battery and see if it works there. The battery acts as a very large capacitor so there should be little ripple there.
LScamper 11/20/14 10:07am Tech Issues
RE: LED flicker

Schematic for Parallax 6300. http://12078.net/rv-stuff/Parallax_6300_Schematic.PDF You are correct in that there is a relay that connects the battery to the unfiltered loads, that is mostly lights, when power is off. When power is on the converter supplies about 5A to charge the battery and about 45A for other things. The problem comes when the power is on. The voltage regulator uses an SCR (40A, 200V on schematic) in a form of pulse width modulation to charge the battery. For higher charge rates the SCR conducts for a long time, maybe many cycles. As the battery charges the SCR conducts less time as called for by the voltage comparator (SCR T106A1 on schematic). The T106A1 turns on when the battery voltage reaches the regulator set point and keeps the 40 A SCR from turning back on. The 40A SCR relies on the CURRENT in it going to about ZERO to turn off. This happens when the full wave rectified DC from the four diodes goes to zero at the zero crossing 120 times per second. If you put a capacitor on the output of the diodes the voltage will NOT go to ZERO. If it does not go to zero the SCR will not shut off and the battery will try to charge to the sine wave peak value, around 18V! This may not be exactly how it works but very close. I know this will happen because I installed a fan with speed control one time in parallel with a light in the ceiling. The lights got really bright and measured 18V. I had to get out my scope to find out what was happening. I rewired the fan to the filtered output and all was well.
LScamper 11/19/14 07:19pm Tech Issues
RE: LED flicker

CAUTION!!!!! Do not put any capacitor anywhere on the unfiltered converter output line (Blue wire on converter). That is the output that most likely is driving the lights. The capacitor can be connected to the filtered battery output lead (Red battery lead on the converter).
LScamper 11/19/14 05:30pm Tech Issues
RE: Drilling P.C. Boards (tips solicited)

More tips! Soldering station I have. Not a Weller but seems to work fine. Would not use in industrial setting. http://smile.amazon.com/X-TRONIC-6040-Soldering-SOLDERING-MAGNIFYING/dp/B0052M8SZA/ref=sr_1_1?ie=UTF8&qid=1416156860&sr=8-1&keywords=x-tronic+6000&pebp=1416156864766 They have models without the hot air. Radioshack has some of the best solder I have ever used. http://www.radioshack.com/high-tech-rosin-core-silver-bearing-solder-1-5-oz-/6400013.html http://www.radioshack.com/rosin-core-solder-2-5-oz-/6400005.html Radioshack desolding braid is also about the best I have used. http://www.radioshack.com/desoldering-braid/6402090.html And for seeing small things on a circuit board you can not go without this. http://www.amazon.com/Donegan-Optical-Binocular-Magnifier-Lensplate/dp/B000YZCSBU/ref=sr_1_2?ie=UTF8&qid=1416155615&sr=8-2&keywords=optivisor+lensplate+%237 The #7 lens plate works for me but there are others to look at. Then this light works perfect with the magnifier. http://www.amazon.com/Led-Light-Attachment-For-Optivisor/dp/B0058ECQ46/ref=sr_1_3?ie=UTF8&qid=1416155227&sr=8-3&keywords=optivisor
LScamper 11/16/14 09:53am Tech Issues
RE: Drilling P.C. Boards (tips solicited)

For small hand held hole enlarging the Dremel bit set that Gdetrailer points to is fine. The carbide bits used for mass PC board drilling are much sharper but are brittle and may break if not careful. If you are coating the boards remember that will make it very hard to repair! If using wire wrap don't try to make it neat. Short straight routing, called rats nest, is best to keep cross talk down.
LScamper 11/15/14 09:32am Tech Issues
RE: Drilling P.C. Boards (tips solicited)

Don't need any fancy stuff to enlarge perf board holes unless you have many to do. Try a search for pin vise. Something like this. Not saying this one is good. http://www.amazon.com/Empire-Level-2715-Precision-Drill/dp/B001DZE5BQ/ref=sr_1_4?ie=UTF8&qid=1416009599&sr=8-4&keywords=pin+vise I have used a pin vise and small bits to enlarge hundreds if not thousands of holes in perf board in the last 40 years.
LScamper 11/14/14 05:03pm Tech Issues
RE: Unknown Brand AC/DC Inductive Ammeter?

This is a review of the meter. Clicky
LScamper 11/09/14 10:05am Tech Issues
RE: Cannot connect to public WiFi

Had the same problem with a new Dell Windows 8.1 desktop out of the box. Would connect but no internet access. Called Dell, after many things to try no luck. It was new and nothing had been installed. They said try to do refresh to new condition using windows recovery. After doing that it worked perfectly and I never had a problem with it again. All so have an HP laptop. I could not get some programs to run sometimes on it. Tried for several weeks. Gave up and did a refresh to new condition. Never had a problem with it after that. Strange that two new Windows 8.1 computers had bad Windows installed from factory. Just luck I guess, but strange. Both have been working perfectly for months now.
LScamper 11/07/14 10:22am Technology Corner
RE: Paralleling Power Supply Units Made Easy ???

Yet another stability paper. About the same as the one Salvo noted. It shows how to measure stability in a CLOSED LOOP system. You do not have to open the loop. It injects a stimulus into the loop. Is this the same as injecting a stimulus as in connecting another power supply in parallel? I think so. As long as the stimulus is not so big that it causes the loop to saturate it seems it should work. http://www.edn.com/design/power-management/4412230/Testing-a-power-supply---Stability--Part-three-
LScamper 11/04/14 12:12am Tech Issues
RE: Paralleling Power Supply Units Made Easy ???

From this EDN note "Multiple PSUs share load" Using diodes to isolate power supplies. http://www.edn.com/design/power-management/4419835/Multiple-PSUs-share-load The results were disappointing, since they show that in the case of ±1% voltage deviation, 90% of the power is supplied by a single supply. Basically, this circuit is not a good solution for power supplies with more than a few tens of millivolts difference. The problem is that not all off-the-shelf power supplies have output voltage adjustments – especially not the sealed ones. To solve this issue, a circuit was developed to ensure load sharing using off-the-shelf power supplies and components (Figure 2).
LScamper 10/27/14 10:26am Tech Issues
RE: Paralleling Power Supply Units Made Easy ???

Salvo wrote: “That's not quite right. The supply that sees higher voltage than it's setpoint will just shut off. The pwm duty cycle will go to zero percent. This is a very safe condition for the supply.” Correct, this is one of the condition that I think could happen. “When the first supply reaches its setpoint it goes into constant voltage mode. When the other supply charges the battery voltage above that set point the first supply's control loop tries to lower the voltage to its setpoint, it can not do that. It will keep trying and will saturate. At that point the first supply is operating open loop. Depending on the supply design it may just shut the output off, a good thing.” Condition 2: “It is possible that the error amp, being over driven, will saturate and reverse its output if it is not designed well. This would turn on the output to full voltage, a bad thing!” Salvo wrote: “ You're not going to overstress the error amp either. The amp is probably powered by 12V. The reference voltage to the error amp is usually around 5V. If the first supply is at 15V then the second supply needs to go up to 15V * 12/5 = 36V. That's highly unlikely that the two setpoints are that far apart.” It has been many years and my memory is not what it use to be! My terminology may be wrong when I said error amp is over driven. What I am trying to say is that at the point that the control loop, while trying to lower the output voltage, will at some point saturate. At this point I agree with what you say. “The pwm duty cycle will go to zero percent.” At this point the control loop is now open loop. When it is open loop there is no feedback to drive the + and – inputs to the error amp to the same voltage. A long time ago operational amplifiers had a nasty habit of reversing or latching their outputs in the opposite direction than it should when this happened. This would turn the converter output full on, a bad thing. Maybe this condition can no longer happen, I don't know. With parts being made in China I would not bet on anything. From MEXICOWANDERER's last post it seems as if something bad happens when paralleled! Maybe what I just said?
LScamper 10/19/14 05:29pm Tech Issues
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