Power converter putting out too low of voltage

[Andonso]

I have a Class-C in a RV Park that pretty much stays in one spot for the last 10 years.

I replaced it's Parallax 35 amp power converter with a Progressive Dynamics 9280 which was sort of an overkill for a 23 foot RV.

I noticed when my Norcold refrig started to produce a Lo_Dc error futher testing showed dc voltage to be approx. 9.5.

Disconnecting the 3 house batteries it appears the 9280 stopped putting out 12 VDC. I'll further test sometime tommorrow but it appears the power converter is gone unless there's an internal fuse somewhere. The three external green 30 amp fuses appear to be ok.

I'm thinking it may be better to look for a new power converter rather than trying to have the 9280 repaired?

I probably don't need 80 amps as I only have 3 batteries which I really don't need as the RV rarely travels anymore and is lived in year around with utilities.

However the RV Norcold Refrigerator which I'm thinking of replacing with an electric does require 12 VDC and then there is the interior 12 volt lighting. I don't use it gas furnace anymore so I don't think 12 volts is really required other than for the refrigerator and lighting.


I've been looking around at new power converters but am not that familiar with their differences and quality.

So far have looked at Progressive Dynamics 45 - 60 amps, WFCO Ultra III 9800 45 amp, (WFCO replacement) WF-9835 - PowerMax 35 AMP, Powermax Pm3-45, Progressive Dynamics PD4560CSV 4500 series 60 amp,

and others.

I'm interested in this one from WFCO to replace my entire AC/DC control panel and board of which the 9280 was installed with very little room underneath. So I'm thinking with perhaps some modifications I can replace my entire existing AC/DC panel and the 9280 with this WFCO.

WFCO 55 amp RV power converter WF-8955PEC


I'm uncertain of the quality of some of the brands such as Powermax, WFCO, etc. when compared to Progressive Dynamics.


Should I stay with Progressive Dynamics?

[Andonso]

Yes, I think your correct I probably should have posted in Tech Issues forum instead of Class-C.

From what you and other have posted I've gathered enough information for installing the converter/charger.

I may create other posts in Tech Issues if installing an inverter.

I'm also going to be working restoring an older Class B camper, which odometer shows ~87,000 miles. It runs well and body is straight but has a few rusted areas on the exterior due from sitting outdoors somewhere up in Alaska.

It has everything but a toilet so I'll probably look around for a porta potty or perhaps a composting toilet.

There are composting toilets for RV's however there price is often over a grand for a new one.

Some RV's owners have created their own composting toilet, which isn't really a bad idea when traveling, off-grid, camping, etc.

[BFL13]

I recommend you shift questions about further electrical modifications to your 12v system set-up to the Tech Issues Forum, where solar, inverters, and battery charging discussions come up all the time. You get many points of view and lots of people who have already done whatever you might be thinking of doing, who share how it worked or not.

This Class C Forum seems to be more about the actual MH for RVing and not so much just for the electrical side of things.

[Andonso]

I'm uncertain as I've personaly haven't really have had a need to run an inverter while off-grid and don't really have much experience with inverters.

I have run a few power tools and electric motors using an inverter, which is one reason why I have the trip-lite 2000/4000 watt as it's designed for more heavy duty electronics with motors, etc.

However I did run across this discussion from solar-electric.com. Here's part of the discussion where a person was having problems with a trip-lite inverters.

The discussion also includes solar arrays so this problem may not directly pertain to an off-grid systems without renewable power.

I have thought about expanding my solar for off-grid use however because of the initial cost factor and my weather environment it would take years in my current environment for a solar system to pay off, and the solar array would need to be much larger than a typical solar systems installed in more arid environments. However since deserts and desert forest are exponentially expanding my area may soon have more sunlight and less rain. Essentially the forest around me approx. 100 years ago the average age was 750 years, today I believe most of the forests are under 100 years where much of the forest are around 20 to 40 years.

I believe there's a direct link to the disappearance of old growth forests and the annual increase of forest fires in the Western US and elsewhere on the planet. Old growth forest as actually worth much more than the actual use and profit derived from them.

1. Old growth allowed many areas in the US and around the world to recover from drought which they can no longer due to it's disappearance. 2. old growth forest was at one time comprised of diversified tress and undergrowth which had natural defenses against various diseases, insects, etc. Monolithic forest as seen today e.g. Canada, Alaska and the Northwest were replanted with a single species such as Douglas Fir which made the vulnerable. Much of the existing replanted forests are turning brown, the only defense is to spray them with chemicals which really doesn't work very well

Research and Resources on the Negative Effects of Pesticide and Aerial Spray

Toxic Forest Fire Retardant Threat to Wildlife

===== solar electric discussion

Re: Tripplite UPS Modified or Pure Sinewave

As an update the so called Electrical and Mechanical Engineer. He eventually withdrew the 36v MSW Tripplite Unit and replaced it with a Tripplite Pure sinewave 48v 6 kw Unit. At Tripplites expense according to the Installer. However the unit can only be configured by dip switches and the two charging options were approximately 27 amps or 95 amps. at 48v DC .Not much of an option .

To cut a long story short the new unit wouldn't sync with any generator for more than 15 minutes at a time the customers battery bank was down at 43/45 volts at best and they were already to sell up and go back to the Uk.

He was running his 4.5kva generator 9 to 12 hours a day. I went to see them at the request of his neighbor (My Friend) and found that although he replaced the 36v Triplite MSW with a 48v Pure Sine wave, he hadn't altered the 36v Nominal PV array to 48v. thus his 800w array was doing nothing. I loaned him an Xantrex C40 rewired his array to 60 volt to allow for a 75m wire run with substandard wire and put him on a strict recharge programed to get his batteries up.

He made enquiries with Tripplite and they confirmed my suspicions that they do not currently make an offgrid (generator based) inverter all there Inverters are for grid connection only. (UPS)

Again keeping it short. A summary of the next 4 weeks of nearly 12 hours /7 days a week genny run time he had with solar assistance got his batteries back to 52/53v when I installed a VFX3048E inverter and a MX60 CC. In 4 hours genny runtime his batteries hit 57.6 volts . He was gobsmacked. Over the last 2 weeks he has with genny assistance completed a full 90 min absorb cycle daily and has averaged about 2 hours runtime daily. He is now monitoring his saved batteries and reducing his genny runtime to get three full absorb cycles per week. He intends to increase his PV capacity by a further 40%.

This has been my first professional install and to not get any phone calls for problem shooting or hey my lights have just gone off in two weeks since commission and see smiling faces has been a joy . I turned up to day to pick my install fees. PS this was a complete new install with new outback gear and not related to my s/h VFX3048E teething problems from the other day. Im not posting this to blow my own trumpert because the original idiot installer (who has done a runner) and is the Villain of the post.

My purpose of this post is to thank all the great members of NAWS who have helped me over the last couple of years in developing a sound base of off grid installations I really enjoy my work. Thanks to every one. Nigel

------

[BFL13]

The existing 6300 to battery wiring is good enough to run the 12v systems from the battery. So when you run the systems from the converter across the battery, that same wire is still good enough to run the 12v systems from the converter.

Battery charging is only from the converter to the battery on the wires joining them (on the other side of the battery from the wires to the system) They need to have the ampacity to get your 75 amps to the battery bank.

Inverter wiring is also high ampacity to run a microwave or whatever, so short fat wire to the battery is needed. This means the high amp charger and the inverter can share the same wires to the battery (as with an inverter/charger) Just mount the inverter and the charger near each other and run short fat wires from one to the other's DC terminals and from there onwards have one set to the battery.

The neg and pos paths don't need to be equal. It is a circuit, so you add the resistance of each part of the circuit. It is the total R that counts. Often the RV frame is a big part of the neg path and the frame has fairly low R, so all you need is a good pos path to get total R low enough.

There are many factors with inverters to consider, but that is another story. You can run a microwave with a MSW inverter IF the inverter is rated for running "motors" (inductive loads) You only need PSW for a few things like electric blankets and certain battery charged power tools.

If you have a few of those things, often they can be run with a small watt inverter. So folks get say a 300W PSW inverter for that and a big MSW to run the big things which don't need PSW (MW, kettle, toaster, hairdryer, etc) this saves money where a big PSW inverter costs so much compared with a MSW one.

"Sine wave" often means the same thing as "PSW" or "True SW" as opposed to MSW depending on Brand, but you can check the specs for how close the wave form is to pure (by having more little steps)

I don't follow why you think having a PSW vs MSW inverter has anything to do with battery charging. The inverter has nothing to do with it. You might be thinking of inverter generators, which supply cleaner 120v to a battery charger so it runs better than with some ordinary generators.

[Andonso]

I was planning on tying into the Magnetex 6300's DC distribution which appears is lighter than #4 in and out to where it connects to 1/0 cables to the batteries.

So to achieve a maximum of 75 amps a #4 pos+ cable wound need to be run from the converter/charger to the battery banks 1/0 cable or directly the battery bank?

Either way, appears it would require approx. 8 to 10 feet of #4 wire.

My experience with wiring vehicles for batteries is the neg- ground wire usually doesn't require to be the same gauge as the pos+. While wiring my Jeep for a second battery I used a smaller gauge neg- cable and a frame ground.

Some high amp devices such as inverters, winches, etc. it benefits to use the same aught for pos+ and neg- ground.

I have a couple of inverters in storage I haven't really used in the past. One is a Trip-Lite PV2000FC 2000/4000 watt that has 2/0 cables. Some inverters and combo inverter/converters it's recommended to use 4/0 pos+/neg- cables. Trip-lite recommmends to use 2/0 or higher for the PV200FC.

2000W PowerVerter Plus Industrial-Strength Inverter with 2 Outlets

The PV2000FC uses a PWM sine wave which I've gathered is a step above a modified sine wave but not as good as true sine wave. Considered a mid-level waveform by most, desirable for all but the most sensitive of critical of computing applications.

I also picked up a used Xantrex 1750 Plus which is probably good for up to to around 1200 watts.

Both are not true sign wave but should be good enough for my current needs.

However for better efficiency with the entire installation battery bank, converter, geny, etc. a true sign wave inverter is a better choice as it effects battery charging when using a geny.

The problem here is not all inverters are designed for off-grid systems using a geny . Some inverters even though true sign wave can make a battery charging system to have lower efficiency similar to using a modified sign wave inverter.

So when looking for an inverter to use with an off-grid system you may want to look for one that's been certified for off-grid as some are only certified for a grid connection only.

[BFL13]

Good thinking. Note the air flow in the unit is at both ends and you want to be able to get at the holes in that one side, so your cupboard venting should be more on the sides too, but a vent on the door can't hurt. The more venting the better. And keep the dustballs from gathering at the converter's end vents.

You will need good light to see to operate the screwdriver in the holes. The switch on the left is quite small and not very robust so don't poke at it real hard. You don't want to be on your hands and knees twisted around in a small space trying to do all this, so another location might be better.

You need two lengths not much more than five feet each
of #4AWG copper (not cu-al) to the battery to ever see the 75amps, but just to run the RV 12v at 13.6v, you can go longer with thinner wire, so another location might be easier.

[time2roll]

Very little heat dissipation is needed except for charging batteries that are low on charge.

[Andonso]

I thought of going for a smaller amp converter/psu such as a PM3 - 35 to 60 amp. However the price for a new PM3-35 is at least ~$100.00.

I suppose I went with the PM4-75 amp because of the price and wanted some veratility and leeway in case I need to install into another RV with a larger battery bank and to go off-grid with a geny.

In the past I have gone off-grid with the Class-C for up to several months. Mostly up in the mountains where there are zero utilities. Trying maintain batteries becomes an issue. Without DC the refrigerator stops working, no pumps for water, no fans, etc. and the RV basiclly becomes a shelter.

I also have an older Class-B I'm planning upgrading for off-grid use so perhaps I'll find another smaller converter for the Class-C and install the 75 amp into the Class-B camper van.

The other thing is I'm thinking of instead of cutting the cord of the PM4-75LK is to install a fused 120 VAC recepticle into the cupboard for the converter. Which is what I probably should have done for the PD9280.

I'm also thinking of installing a vent into the door of the cupboard where the converter will be installed, but am uncertain how much air space for heat disapation the converter actually requires?

The cupboard is a little smaller than ~21" x ~15" x ~12" as there's a small part of the wheel well protruding from the cupboard's floor.

[BFL13]

No idea about the fuses. Normally they would be ok sitting there. I suggest you save my post on how to operate it, as the owner's manual is kind of vague IMO.

Meanwhile I never got it clear on whether your 12v system is ok except for the converter. I suppose it must be since that is what you are doing. Hope it all works out for you.

BTW, those LKs (which came out in 2016) were something of an experiment for PowerMax to combine all those features into one converter. Apparently, they were not a big seller because it is so "complicated". Most RVers and other folks want just simple automatic ones they don't have to think about. So you can get them on Amazon from BoatandRV at a low price for what it does, but not featured much elsewhere, even on BoatandRv's own site. The market rules! "The customer is always right."

If you get into battery charging in a big way, you will appreciate what that unit can do. If not, it will still do the job you need it for.

[Andonso]

Ok, thanks I appreciate the info, the manuals don't really get into much details of operation.

I entered an offer for $86.00 with free shipping and the offer was accepted.

The converter / psu from it's pics didn't appear to be terribly used, with dust, etc. From the seller desciption the converter has been sitting around.

One thing I thought was odd is part of the sellers description

“Item is used. Item is in good condition. Item may have minor cosmetic imperfections such as scratches/scuffs. Item has a small dent in the grates (please see last picture).

Due to sitting item may need fuses change by the time the item arrives"

I'm uncertain why the seller describes the item as the fuses may need to be changed from sitting?

For anyone interested I found this spec sheet for PM4's

PM4 Spec Sheet

[BFL13]

That 75 amper is the "LK" model, which is both a fixed voltage 4-stager and an adjustable voltage. The two holes in the side are for operating that choice. A small screwdriver is required.

The left hole has a switch behind it that snaps back and forth sideways. To the left, you get a normal four stage operation, that is automatic so you don't have to do anything, same as any converter. To the right it becomes an adjustable voltage single stage, which you then turn the pot behind the right hand hole.

If you want 14.8 for your Trojans or whatever, just set that and do the recharge, and when they are full, dial it back to 13.6 and leave it there. If it is 35F out, 14.8 is now 15.2 so set that. (the 14.8 is for 77F)

You should not twiddle the pot on the right when you have chosen normal four stage operation or it will skew all the set stage voltages. But you can put it back where it belongs if you mess up.

You have to set the pot to 13.6 before you switch back to normal four stage.

You need a voltmeter where you can see it when adjusting the voltage, and the converter should be disconnected from the battery bank when you do that. Once the battery is connected, the voltage you see will be somewhere between what the battery was and what the converter is set at. As the battery recharges the voltage you see comes up to eventually be what you set the charger at.

The PowerMax ads say that their 75 ampers are power factor corrected, but they are not, so ignore that. Their 100 ampers are PF corrected.
Your PD 9280 is not PF corrected (PF is 0.7) so expect that 75 to draw almost as much VA from a generator --but the 75 does not require a 20 amp (120v)circuit-- it runs on 15a ok.

The LK has an internal fan so it doesn't have the usual fan sticking out, but you need to mount it where you can get at those two holes in the side.

[Andonso]

I'm looking at a used PM4-75 amp on ebay for approx. $100.00 or best offer.

I think I'm going to make an offer on it. The PM4-75 appears to have variable voltage control.

https://postimg.cc/gallery/2w515er4c/

Also the efficiency is higher than the 60 and lower amp version @ >93%.

[Andonso]

Ok so you're saying I don't really need a PM4 which is approx. ~$25.00 more than the same ampherage PM3?

Perhaps your correct if a battery or battery bank is going to be near it's normal voltage most of it's life and the charger in float or normal mode most of the time.

Progressive Dynamic 9200 series also has a boost mode and doesn't require a battery to be connected for clean DC as it's well regulated.

I suspect the Powermax is similar, works as a well regulated DC PSU without a battery?

PD9200 series

14.4 boost mode
13.6 normal mode
13.2 storage mode

Boost mode rapidly brings up batteries up to 90 percent of a full charge.

Has variable speed cooling fan and other features.

One thing that lowers the life expectancy of a battery is using them at 50 percent charge and less. I think the boost mode may help to extend the life of a battery. It's not quite the same as battery chargers with a desulfation mode, however a boost mode stage may help to prevent sulfation.

RV batteries are fairly cheap compared to solar banks. e.g.

Crown 430 AH 12VDC 5,160 Wh (2) Battery Bank Price: $772.00

Actual deep cycle batteries may require a charger that's better than your average RV charger / converter.

[BFL13]

The enclosed one is a "deck mount" you can put anywhere. The open one is to go in the "lower portion" where the original one was. They are the same converter for how they work. You want the deck mount.

Make sure that cupboard gets air to cool the converter

The 4 means it has an extra stage trick to do a shot of 14.x every so often after it drops to the 13.2 storage stage. You will never see that doing 13.6 all the time using the RV on shore power, so a PM3 is the same for you. Besides that, the value of that shot of 14.x every so often is dubious. More of a sales gimmick IMO.

I have PowerMax converters and like them. I mostly like the ADJ version with the adjustable voltage so I can meet different battery specs that call for various voltages. In your situation, the basic PM3 would be fine.