Consistent 12 volts for sensitive electronics.

ibdilbert01 · March 06, 2015, 08:11 AM

Seems like every time I open my truck on the Winnebago I get asked what the funny blue box does, so I made a video on what it does and how it works. The device is called a Buck Boost, it basically will deliver a nice clean 12 volts regardless of the input voltage.

https://www.youtube.com/watch?v=a3Ak2dA0894

eXodus · March 06, 2015, 01:59 PM

Or you could buy some IC L7812CV 10 pieces for $2 which do exactly the same thing.

Wire them in the line of the sensible device, and you are good to go.

ibdilbert01 · March 06, 2015, 06:11 PM

For sure an option, but you would loose the "boost" properties. It really wouldn't be that hard to build a buck boost, but your average DIYer needs a simpler solution.

eXodus · March 08, 2015, 07:36 PM

if you wire 3 wires to the ic7812 or 4 to the buck boost whats the differnce ?

ok its a litle smaller and you need a soldering gun.

dont get me wrong your device is cool, just wanted to display a cheaper option for people on a budget. In the near future we shouldn't have this problem anymore, the small electronics world is switching to 5V, USB powered.

then every 12v -5v converter must have a regulatur.

so far every 12v device i killed in a car, should have been built into a computer, like pc temperature gauges

ibdilbert01 · March 08, 2015, 09:55 PM

Sorry eXodus, I didn't realize the 7812 would boost the voltage up, just thought it was a regulator. I'll pull the specs up on it when I get to work in the morning.

Nice Find!

ibdilbert01 · July 22, 2015, 11:29 PM

Just to clarify, a LM7812 is just a regulator, it will not ramp the voltage up, aka boost. It will protect against voltage spikes, but will not protect against under voltage. Also its a very inefficient device.

https://www.youtube.com/watch?v=giGRrODKJSE

The device I have is pricy, if someone wanted to save some money just do a search on ebay for "buck boost". They range anywhere from $5 to 15$ and on upwards.

Here is a review of a decent model that works well for only $10 bucks.

https://www.youtube.com/watch?v=cUpJs6Z41YM

ebay - http://goo.gl/mXAnPZ

HamRad Mobile · November 13, 2015, 02:52 AM

Good morning, guys;

Yeah, the LM7812 really is a pretty good one active component (and two capacitor) voltage regulation system, and it does like to have at least about 1.5 VDC higher voltage applied to it up to about 35 VDC to regulate down to the standardized 12.0 VDC it is rated to put out. And you can actually use it for different voltages with some additional external components. But it is limited to no more than about 1.5 Amperes output current by itself. You can use its output to drive some additional regulating transistors to provide more current, but that function is probably better served by using the LM-723 Adjustable IC Regulator chip.

That output current limitation probably does mean that the LM7812 will have only limited application in a lot of the things we want to do with our motor home coach "12 VDC" power system.

The real problem is the motor home coach "12 VDC" power system itself. It is not what you might think, unless it is one of the very recently produced units that really is a true "12 VDC" power source. Most of the older systems are really just a remarkably simple unfiltered and unregulated nominal "12 VDC" full wave rectified pulsating direct current output waveform. The nominal voltage actually measured on it will probably be about 12.6 VDC measured with an "averaging" type DVM or an older analog D'arsonval meter movement voltmeter, or about 13.6 VDC when measured with an RMS reading DVM. The real problem is that the peak voltage of that full wave rectified pulsating direct current waveform will be right at about 18 Volts DC.

A lot of our modern electronics equipment and accessories designed for operation on a normal automotive 12 VDC electrical system are intended for about 13.8 VDC, and no more than about 15 VDC or 16 VDC. In my testing of the LED lights that I want to put into my motor home, I found that a lot of the lower cost LED lights without any onboard voltage regulation do not like that 18 VDC peak, and I have had a lot of them literally burn out.

I will say that I have had no problem so far in my LED testing with the more expensive LED brands such as Star Lights that are rated for use on a DC voltage supply of from 9 to 26 VDC. Those will be OK on the common "12 VDC RV power converter," and my Star Lights have been going for several months now, while many of the cheaper ones did not make it to even two (2) months.

The clearest and most obvious way to check the output waveform of the "12 VDC power converter" in your RV is with an oscilloscope, and that will clearly show it graphically. You can really see it. However, not everyone has an oscilloscope.

For most of us, you can use a "peak reading" DVM or Digital Volt Meter and measure the peak voltage coming from your "12 VDC RV power converter." Most of these that have that particular "peak reading" function probably will also be labeled as an "RMS" or "True RMS" reading DVM. Set the function to read the "peak" DC voltage, and see what you get on yours. It will probably be right around 18 VDC, and not the "12 VDC" that you are expecting to see. Sorry, but that seems to be what most of them have been for a long time, and most of them still are. This was not a problem with the old incandescent light bulbs, because they were quite happy with the "average" voltage being fed to them, but it sure is with the modern energy efficient lighting systems, such as the LED lights.

You may hear a lot of people saying that they have not had very good luck with trying to use LED lights in their motor homes or other recreational vehicle, especially when they are plugged into "shore power." This "pulsating DC waveform" output is the reason why. The standard coach battery power is fine. It is just the standard "12 VDC RV power converter" that has this problem.

Noting what I saw on the output of my "12 VDC RV power converter" when attached to "shore power," I thought that I would get a late model "slide-into-the-same-space upgrade" for my 1987 B-W Manufacturing Model 6345, with the C-01 Battery Charger Option, 12 VDC RV Power Converter, but when it arrived, I found that the contents of the new aluminum case for the "slide-in upgrade" looked almost like my 28 year old B-W. There is no real functional difference, and no difference in the output waveform. It is not really an "upgrade." I was surprised when I learned just how remarkably simple is the "technology" in the common "12 VDC RV Power Converter" today. We have had good ways since the 1960s to make good filtered and regulated power supplies, but it seems that not too many manufacturers are building them for our RVs.

To get something that will put out a true "direct current" smooth DC voltage output, you need to get something that states that it is filtered and regulated to provide a 13.4 to 13.8 VDC (or something very much like that) output, and it may also have a "Maximum Ripple and Noise" specification of something like " < 50 mv RMS" or something similar. That is a standard specification often seen with regulated power supplies. The development of power supplies for computer systems has brought down the price of these regulated power supplies in recent years. You can find them, but they will be a little more than the "replacement" RV power converters that you can also buy. Again, look for a Regulated Voltage specification, and a Ripple and Noise specification for a true clean smooth "12 VDC" regulated power supply for use with LED lights and all the other electronics, such as GPS navigation systems, satellite televisions, radios, computers, cell phones, monitoring systems, backup cameras, and all the other things that really do make our lives in a motor home very nice today.

I have also noticed that many of today's makers of "RV Power Converters" will say that schematics and other detailed information about their equipment design is proprietary and not available. I think that is mainly because they are embarrassed to provide proof and admit just how simple their equipment really is.

So what am I going to do with my old B-W 6345, AND the new "replacement upgrade" unit that I bought? I need to do something to stop burning out the LED lights and provide clean DC power to operate the electronics systems I want to use; my radios and things. I have concluded that the best way for me to do this is to design and install an outboard filtering and regulation system that will not require any change inside either of those units, but will filter the output to a quite reasonably smooth DC waveform and will work with the 120 VAC input to control the RV power converter voltage output with changes in the load on the RV coach "12 VDC" electrical system when I am plugged into "shore power." I can do it myself, and I will be using some of that technology that has been around since the 1960s. I do not yet know why they have not done that.

Enjoy;

Ralph
Latte Land, Washington

Rickf1985 · November 13, 2015, 09:33 AM

"If you build it they will buy"

Anyone with an older charging system should be interested in something like that, or a whole new system.

Bnova · November 13, 2015, 10:12 AM

Here's different idea, unless I misunderstand the intent. You could wire one or more of your 12vdc outlets directly to the coach battery so that it will not connect to the converter and get a clean 12vdc.

The battery is then maintained by the charger in the converter.

Rickf1985 · November 13, 2015, 10:19 AM

But that would be to easy. W% :)rotflmao

Bnova · November 13, 2015, 02:57 PM

If you're using LEDs through out the MH, you could probably wire the lights direct to the battery also to get clean power and not be too taxing on the battery and charger. Again, I'm not sure what the intent is, if it's to stop burning up LEDs or what accessories might need clean 12vdc.

I've got a couple LED lamps in mine and I just can get used to that kind of light so I've opted to stay with the old incandescent bulbs.

Rickf1985 · November 13, 2015, 04:35 PM

You can get whatever kelvin output color you want in LED lights. Incandescents are around 2500K-3000K. The really bright ones are in the 6000K range.

Bnova · November 13, 2015, 05:22 PM

I'll have to check into maybe getting some yellowish ones. Thanks

DRMousseau · November 13, 2015, 06:40 PM

I had converted the overhead lights to LEDs in the ol' Winnebago. The ceiling lights were simple LEDs, jus an on-off switch. But those above the sink and settee were hi-low-off touch controlled, and were troubled by other things on the circuit, like the furnace blower motor. No problem on battery supply, but when on shore power, even my "newer" converter/charger didn't prevent the flashing blinking problems with those lights, when the furnace fired up.

I'm considering LEDs in my current home, and will eventually be using those I have in the storage bunks till then. I too didn't much care for the clean white of those LEDs anyway, and be looking into "warmer" ones for the interior. No other problems with other electronics though, but I have wondered about such.

PwrWgnWalt · November 13, 2015, 11:54 PM

Bnova, glad you posted about running the converter/charger directly to the coach (house) batteries as a filter... I was thinking the same. Then all the 12VDC loads are taken from those coach batteries.
This is the way my Beach-Craft was and is wired, and I understood when re-doing all the electrical, including a new Boondocker, that this is the preferred way for steady DC coach power.

Bnova · November 14, 2015, 09:19 AM

I guess maybe my (so far) little use of the MH probably is clouding my vision on the subject, but I have no problems with the way mine operates, it is still wired the way it came from the factory.

It's the typical, all 12vdc comes from the converter with the exception of the fridge when running on DC goes directly to the battery. I haven't come across any of my accessories so far that are bothered by the converter 12vdc.

One thing I have noticed and I spoke to Parallax about it is the fact that when you've got more than just a few lights (incandescent) running, that the converter 12vdc won't be able to stay above 12 volts, would be more like 11.5 or something like that. And that is normal operation from the converter.

But all the while, the battery is getting charged at something like 13 volts or more.

I'm very pleased with the way the system works, but maybe if I were full timing or using it more, I might notice some deficiencies. Guess we'll see in the future.

I would try going directly to the battery as mentioned in the previous posts, just because it's simple and easy to do and no extra components that have the potential for break downs. Who knows, it may not work but I would start with that and find out. And I think I'd just start with the 12vdc outlets. And if the conv bothers the LED lights ops, then I would switch one of the lights circuits to the battery direct to see if setup can handle it that way.

HamRad Mobile · November 17, 2015, 12:35 AM

Good morning, Bnova;

There are some subtle distinctions in the way that each maker's RV DC power converter is made and wired. It is not possible to offer a simple one-way-fits-all suggestion to wire up an RV DC power converter that will work with all systems.

In the case of the original B-W Manufacturing Type 6345 with the C-01 Battery Charging Option, they are two separate circuits and the battery is connected to the coach "12 VDC" system through a relay when the shore power is NOT powering the primary winding of the transformer inside the RV DC power converter. In that case when the shore power is operating the RV DC power converter, there is quite a difference in the DC circuit voltage going to recharge the coach batteries through the separate small battery charging circuit, and the similar equivalent voltage available from the high current "12 VDC" power coming from the converter. Unfortunately, that higher DC voltage from the "12 VDC" power side of the converter will "boil the batteries dry" if connected straight to the coach batteries in an effort to use the batteries as a large filter capacitor to help smooth out the "DC power" coming from the RV DC power converter when there is only a light load on the coach "12 VDC" circuit.

For that reason, I cannot really recommend using the coach batteries as a "filter capacitor" for the coach "12 VDC" circuit.

Well, at least not in the case of the B-W Manufacturing type 6345 RV DC power converter. There may be another maker's 12 VDC RV power converter where you can do that, but I have not been able to identify one yet. And I will not hazard any guess about how much such a capable 12 VDC RV power converter would cost.

That is why I have stated that I need to make up and install a two part out-board accessory system that will both; (1.) filter and smooth the pulsating DC (rectified sine wave) waveform coming from the rectifiers following the secondary low voltage winding on the transformer, and (2.) also will sample and monitor the output voltage coming from the RV DC power converter which will then be fed to a voltage control feedback circuit that will "regulate" or constantly adjust the amount of power being allowed to go to the primary winding of the transformer and control the resulting voltage coming out of the RV DC power converter, even with changes in the output voltage as a function of the changing current drawn when things are turned on or off the coach "12 VDC" power circuit while the coach is plugged into "shore power."

Another way of saying this is that I want a basically "constant voltage source" with a voltage excursion of probably no more than from 13.2 VDC to 13.8 VDC, or is adjustable in that range, but it has a widely variable DC Ampere or current delivering capability up to the maximum rated output of the RV DC power converter.

What I really need is a DC power supply, and not just an "RV DC power converter" with its junk power output wave form that my electronic things do not like.

It is so much fun to watch what terms, words, or phrases that the marketing types will come up with to distract us from what they are actually doing, and then the company will declare that their circuit is "proprietary" and they will refuse to divulge the technical information that will show just how inadequate their products are in meeting the requirements of the equipment that we use in our motor home RVs today. What we were doing back in the 1960s and 1970s is not what we are trying to do today, but their technology has not yet caught up with the turn of the millennium. Yes, this one is a true "Y2K" problem.

Enjoy;

Ralph
Latte Land, Washington

DaveVA78Chieftain · November 17, 2015, 07:23 PM

QuoteThere may be another maker's 12 VDC RV power converter where you can do that, but I have not been able to identify one yet.

All the newer 3 or 4 stage converter/chargers like Powermax Boondocker, PD9100 Series, PD9200 Series, PD4600, Parallax, and IOTA are all designed to be connected directly to the battery so it acts as a filter. Their output varies depending on load and battery condition (boost charge to float).

Back in the 60's & 70's the only direct connect converter charger was the Triad ferro-resonant transformer based product (e.g. TRIAD TU-740).

Bnova · November 18, 2015, 11:24 AM

Ralph, I'm not sure we understood each other quite right. My thought, very simplistic, was not that you would wire the converter output to the battery, but wire your 12vdc outlet to the battery so that it does not use converter power but battery power.

Yes, when plugged into shore power with the B-W unit, the battery becomes disconnected from the coach circuits and gets connected to the charger. I was just assuming that the 12vdc components we use won't put a huge amp load on the battery and that the charger would keep the battery topped off or close to it.

Again as stated, very simplistic and maybe naive thinking but according to B-W charger adjustment procedure, it should put out roughly the voltages you're looking for.

HamRad Mobile · November 18, 2015, 12:35 PM

Good morning, Dave and Bnova;

Dave, thanks for the listing of a few makers and models of true DC power supplies for 12 VDC circuits. I am looking into those right now. Some of them look very promising with the inclusion of such words as "filtered output," Ripple and Noise figure of "< 50 mv RMS," voltage tolerance of 0.3 VDC, and some other specifications. There is hope yet, in spite of my having already purchased a "slide-in-replacement-upgrade" 12 VDC RV power converter for my old B-W 6345 C-01 Option power converter, both of which do exactly the same thing as far as the main 12 VDC coach electrical system is concerned. I do not consider it qualifying as an "upgrade" when all it does is add a temperature sensor to the battery charging circuit. That does nothing for an improvement in the output waveform and the cause of all the deaths with my LED lights.

And I am indeed familiar with the ferro-resonant transformer constant voltage regulating systems. The Sola people have been building them for years, and I especially like their CVS series. The only real criticism I have about them is that they are big and heavy, and sometimes the resonating capacitor on the tertiary winding may have a problem that requires attention to restore the system to normal operation. The main problem seen has been a shorted capacitor that shows up as a very low voltage on the output. Replacing the capacitor usually restores the system to full normal operation for a very long time period. There may have been some voltage spikes that prompted the problem with the capacitor failure mode.

Bnova, thank you also for the comments about the adjustment procedures and other things. Yes, I do agree that there are some things that sound nice, but in the actual analysis of what we are getting, there is no change in the real problem, and that is the unfiltered and unregulated rectified AC sine wave output going to the RV coach "12 VDC" electrical system, and putting an 18 VDC peak voltage on the circuit. That peak voltage is what has been causing the problems I have been seeing. And I get suspicious when they tell me to use a "true RMS reading DVM" when making that adjustment measurement.

What I really need to do is to get the photographs I have taken shrunk down in file size so that I can attach or imbed them into a message that can be posted here so that the actual waveform can be seen for both the pulsating DC output and a normal true smooth 13.8 VDC straight line waveform can be compared. Then I think that the difference and the problem I have seen will be apparent.

I will work on that also.

Again, thanks, guys.

Enjoy;

Ralph
Latte Land, Washington

Bnova · November 18, 2015, 01:41 PM

Quote from: Bnova on November 18, 2015, 11:24 AM
I was just assuming that the 12vdc components we use won't put a huge amp load on the battery and that the charger would keep the battery topped off or close to it.

Again as stated, very simplistic and maybe naive thinking but according to B-W charger adjustment procedure, it should put out roughly the voltages you're looking for.

Okay, maybe I'm getting it now, I suppose this (the battery charger in the conv) still being from an A/C source will still give you the unwanted ripple even if you tapped directly from the coach battery as long as the charger was in use? Pumping unfiltered D/C into the battery?

sasktrini · November 18, 2015, 02:46 PM

I am observing the same things, and thankfully have not finalized my rebuild.

I am typically running my generator through my converter/charger (shore cable plugged into generator receptacle). I installed one LED bulb, and notice it flicker sporadically.

I have tapped my coach lighting off of one of the 12VDC fuse connections in the converter unit. Because the circuit is being directly fed off the converter while I'm on "generator shore" power, it's subject to dirty voltage peaks, causing the flicker.

If I'm correct in understanding this, if I ran my lighting circuit from my battery, fuse it, the battery would filter the voltage?

BUT

I am having second thoughts. I'm imagining that my coach batt+ would now have the converter/charger batt+ and a light batt+ wire attached (and solar in my case). If the charger was pushing voltage back to the battery, unfiltered, that unfiltered power would now just continue into my lighting circuit anyway, wouldn't it? How would we really get filtered electricity while the charger is operating without adding an actual filter or capacitor to the light circuit?

Bnova · November 18, 2015, 04:11 PM

Sasktrini,

I think you are correct on both accounts, the battery alone should cause no flicker in your lighting, but put the charger from the converter onto the battery and it will most likely be getting unfiltered charge current from the converters battery charger. Back to flickering lights.

I'm going to have try this on mine, I've only got a couple LEDs installed, but I've never noticed them flickering. Unless I just didn't catch it. Next time I go to my storage unit, I'll give it a try on shore power and see what happens.

DaveVA78Chieftain · November 18, 2015, 07:49 PM

Ralph,
You did purchase the 6345RU kit that includes the new DC board correct? I only ask that because you need the new DC board to account for the single converter output of the replacement converter. From what little I can see of the new board, the battery connection appears to only be isolated by fuses intended to provide reverse polarity protection. So, in essence, the new converter output is directly connected to the battery (acts as an additional filter. The converter documentation says it is supposed to be regulated with battery connected or disconnected however I see nothing about AC ripple voltage specs. I will say I am not partial to the Parallax converter products.

You want a 3 stage converter charger like one of these which replace the old 6345 (B-W, Parrallax, Magnetec) converter sections

Progressive Dynamics http://www.progressivedyn.com/pd4600_converter_replacement.html

WFCO 8945 based http://www.bestconverter.com/45-Amp-Converter-Replacement-Kit_p_46.html#.Vk0ZtOJjQT4

FYI - The old 6345 converter section was nothing more than a unfiltered full wave rectifier.

DRMousseau · November 19, 2015, 10:31 AM

I have the PowerMax Boondocker,... I like it. But I did experience problems with a particular LED light setup. This only showed up when the furnace motor fired up and was annoying. I "assumed" it was jus the old blower motor causing interference which I knew would soon need replacing. Never went any further.

NOW, I still have those lights in a box around here, I did reinstall the Boondocker in my new home,.... but I'm thinkin' I might temporarily hook up one of those lights to check out in the new home, and better assess my CURRENT setup before I think about hi-tech upgrades again.