Power Converter/Charger Replacement

[WineStream]

I've seen a lot of talk in a few different threads lately about Univolt replacement. I am wondering if there's really a reason to replace if there's no indication of a problem or is it good $150 insurance policy against spending $500 later for a new battery and a new converter later on?

My trailer had an IOTA 45A in it when I bought it. So far, it's been flawless. The Argosy motorhome that we just bought last May has the original Univolt. It seems to work just fine. It hums, but honestly it's not very noticeable...never kept any of the family awake at night. The house battery on the moho is a "Group 27" placed by 2 PO's ago. It is hard to tell the condition as it's been relocated to under the step area and I don't feel like laying on my back to remove it without good reason. We like to stay overnight in parking lots while travelling (boondocking) and we also go to one or two rallies per year where we boondock the entire time. I don't ever plan on adding additional batteries for more boondock capacity especially since Airstream included a 4kW Onan genset from the factory. So a few questions in my mind right now as I contemplate upgrades for the new season:

1. Do I even mess with a new converter right now since the status quo is doing just fine, seemingly. Wait for something to break? Hum too loudly?

2. If I do replace, how big should I go? It seems like 45A is the way to go for the older Airstream units? There's no indication that I can find in my service manual as to rated output in amps for the Univolt.

3. Space is a consideration. Whatever converter I buy would need to fit in the original Univolt space. The moho is pretty much original inside and I'd like to keep it that way, yellow & orange upholstery and all.

4. Iota vs PD vs PowerMax vs Intelli-Power? Suggestions? Obviously I am happy with Iota based on my trailer. Other opinions?

Thanks in advance to all.

[ROBERT CROSS]

WS

I think you'll find the consensus here will be to replace the Univolt. The newer converter/chargers are much more reliable and do a lot better job of maintaining/prolonging the batts.

My converter experience deals only with the original Parallax 7455 2 stage, a Xantrex XADC 40 replacement that failed during the first trip boondocking and the most recent, IOTA DLS IQ4 55a, the IOTA being the only one I will recommend, based on first hand experience.

A 45 or 55a will probably work just fine for your application.

Bob

[Skater]

Originally Posted by WineStream

1. Do I even mess with a new converter right now since the status quo is doing just fine, seemingly. Wait for something to break? Hum too loudly?

If you're very careful about not letting your univolt overcharge the battery (and it's working correctly), then by all means stick with it.

Working correctly means that it's putting out good voltage and enough current to keep your batteries charged.

In my case, in the B190, the original converter was dying, and it had cooked two deep cycle batteries in the time I owned it. One night, at a rally with limited electricity in cool weather, the shore power shut off, and with a bad battery I had no furnace at all. I was out at 2 a.m. in the cold looking for the breaker.

The trailer's converter hadn't gotten that bad, but the voltage wasn't where it should've been, so it was on its way, too.

2. If I do replace, how big should I go? It seems like 45A is the way to go for the older Airstream units? There's no indication that I can find in my service manual as to rated output in amps for the Univolt.

Yes, the 45amp is probably good for most campers. I put a 60 amp in our 30', and even that is probably overkill, but on the other hand we have three batteries.

3. Space is a consideration. Whatever converter I buy would need to fit in the original Univolt space. The moho is pretty much original inside and I'd like to keep it that way, yellow & orange upholstery and all.

The Intellipower 60 amp I put in is much smaller and lighter than the original unit. I also put a 60 amp in the B190 (talk about overkill!), and it fit in the original spot as well.

4. Iota vs PD vs PowerMax vs Intelli-Power? Suggestions? Obviously I am happy with Iota based on my trailer. Other opinions?

Thanks in advance to all.

Both of the ones I did were the Intellipower 60 amp (9260 I think). I was very happy with it in the B190, so I went with it for the trailer, too.

[steverino]

Originally Posted by ROBERT CROSS

Good point Ken,

Curious, does your's have the heat sync on the front, didn't see it on 10's?

I think 10Smiles install is same as ours, you have to open-up to see the LED.
Bob

I'm also going to go the upgrade route to the IOTA with IQ4 built in (to go along with new Group27 AGMs); I figure if I want to see the LED I will either extend the wires to an LED mounted on the front panel of the power center, or maybe rig up a fiber optic light guide to make it visible. I'll know more once I get the equipment, or maybe get lazy and just let it slide. On second thought, there's better things to do while Airstreaming than looking at blinky lights!

[Wayne&Sam]

Originally Posted by idroba

If you go to a Honda 1000 watt inverter generator, you are correct, you will need to go to a 45 amp converter/charger, at least with a Progressive Dynamics Intellapower converter (actual experience here). This is due to the low power factor of the converter and how it interacts with the inverter generators.

Can you explain that or point me somewhere that does explain it?

Thanks.

[ROBERT CROSS]

Originally Posted by Wayne&Sam

Can you explain that or point me somewhere that does explain it?

Thanks.

Basically...for us it just took our 1000 Yamaha longer to full charge the batt's than the current 2000 Honda.

Bob

[steverino]

Originally Posted by Wayne&Sam

Can you explain that or point me somewhere that does explain it?

Thanks.

I'll give this a shot.... dredging up what I remember from a long-ago electrical engineering undergrad class...
I'm not sure about anything specific about interaction with inverter generators, but -

Power factor affects the ability of a source (like a generator, or your local power company) to deliver rated power to a load (like a converter).

Resistive loads (like an electric range or oven) will have a power factor of 1 (a high power factor). Inductive loads (like incandescent lights, converters, anything with a coil or transformer, thus includes our myriad tv's, computers, etc) will have a lower power factor, because these loads affect the flow of current in the electrical distribution system.

In 120 volt AC (alternating current) power systems, voltage swings positive and negative, 60 times per second. Current in the wires ebb and flow as well. Power transfer is most efficient when the ebb and flow of the current is timed identically with the voltage - the current peaks at the same instant that the voltage peaks. When current gets out of phase, as with inductive loads, overall efficiency goes down.

A load, like a 60A converter rated at 1000W input, will thus need more than a 1000W source to adequately supply it, due to losses in the distribution system.

Said a little bit differently, the 1000W generator can't deliver all 1000W the converter needs, so the converter can't operate at rated spec.

Sorry for the treatise, but I'm sure you'll thank me for leaving out the math, which always put me to sleep anyway.

Steve

[Wayne&Sam]

Thanks. In hindsight it was a dumb question. I just never thought the converter would draw so many watts on the input.

[ROBERT CROSS]

"Said a little bit differently, the 1000W generator can't deliver all 1000W the converter needs, so the converter can't operate at rated spec."


I knew there was a good explanation....

Bob

[azflycaster]

I have a Honda EU1000i and when I replaced the converter in my trailer with a PD-9245 I noticed a difference right away. With the old converter, the generator ran at idle speed. With the PD-9245 the generator was running faster when the charger was in "Boost Mode" (14.4 volts). Once the battery was at 90% and the PD-9245 went into "Normal Mode" (13.6 volts) the generator slowed down to idle speed.

The battery seems to charge faster with the new converter.

[TG Twinkie]

The wattage rating on a converter is the power required on the input side of the converter when the converter is at it's maximum output rating. There are losses within the converter that make it less that 100% efficient. The majority of the loss is in the form of heat, thus the need for a cooling fan in most converters. All electrical devices have a certain amount of resistance to the flow of electrical current. In DC or direct current circuits it is simply called "resistance". In AC or alternating current circuits it is referred to as impedance; which is similar to but not the same as resistance. Because AC devices that are not a purely resistive load contain a reactive component found in inductive or capacitive devices.
A DC generator is rated in watts or kilowatts. AC generators are rated in volt/amps or kilovolt/amps. DC power is measured in watts; AC power is measured in volt/ amps.
These units of measure are different for a reason. For example: if you were to connect a heating element to a 120 volt DC circuit it would produce a certain amount of heat. Heat is measured in BTU's. Let's say the heating element produced 1000 BTU on the DC circuit.
If that same heating element is connected to a 120 volt AC circuit it would produce just over 700 BTU, 707 to be exact.
If you were to draw a rectangle on a sheet of paper that is 2" square, then shade the entire area. Let's say this shaded area is 1 watt of DC power. The rectangle represents a period of time.
Now draw another 2" rectangle. Then draw a half circle inside the rectangle from the lower left hand corner to the top and then down to the lower right hand corner. Shade the area inside the half circle. The shaded area represents the amount of power an AC circuit will produce which is measured in volt/amps. The half circle is not a true representation of the AC sign wave since it has more of an elliptical shape. But it will give you an idea of what the difference is and why they are not the same.
The new inverter generators have a permanent magnet DC generator that supplies the power to the inverter (electronic) section of the unit. The inverter section with the use of a micro processor converts the DC to AC. While not exactly the same as an AC generator, the more sophisticated inverters come real close.
I believe the rating of these units is based on the DC side of the unit and not the AC side. This is why a 1000 watt inverter generator is derated to something less.

[vswingfield]

Originally Posted by w7ts

Oh OK,
The problem I had is that I call that a sink, not synch..

...

Ken

Sink is correct, see Heat sink - Wikipedia, the free encyclopedia.

Wasn't going to beat Bob up about it, but it did take me a minute to get in "sync" with what he meant.

I agree with Bob about replacement. The advantages to modern converters make replacement prior to failure worthwhile. I replaced mine a couple of years ago with an Inteli-Power. I'm very pleased with the upgrade.

Also, the still functioning univolt is available for a bench supply of 12vdc if I ever need it.

[ROBERT CROSS]

Originally Posted by vswingfield

....Also, the still functioning univolt is available for a bench supply of 12vdc if I ever need it.

Yep.....still got the 7455 P-Lax sitting on the shelf.
When my Xantex "up-grade" failed I got real good at the install/remove during the diagnosis process.

Bob

[Ag&Au]

I am preparing to use my Parallax with a deep cycle battery across it for back up power for my ham radio. It will not over charge the battery, because the converter will only be on when the radio is in use.

Ken

[ROBERT CROSS]

Bet there's quite a few of 'em out there awaiting a new career.

Bob

[SuperTrouper]

I replaced the Parallax PS a few weeks ago with the IOTA DLS 55 unit from Randy at best converter. I pulled the Parallax unit out, drilled out the top rivets and the standoffs. Removed the guts. Drilled a few extra holes in the bottom of what was left of the box, riveted the IOTA to the box and wired it in using the existing wires. I had to cut the DC wires off the parallax and the plug end of the IOTA AC wire but I had plenty of wire to hook everything up. I’m running 2 Lifeline GPL-4CT (6V) in series and wanted to keep them happy. Other than the minor mods above, the unit was plug and play.

Here are some pictures of the installation.

[boilermaker]

I have just purchased a '75 sovereign 31' and i was told that the converter needs to be replaced. I am an electrical idiot. I have read all of the posts above and don't understand very much of anything.

I found an Inteli-Power 9245 for $128.00 and would like to know if it would be the right product for my AS.

Again, excuse my ignorance, but when you refer to inverter generators are you are you talking about using them to charge the battery?

Thanks Ken

[TG Twinkie]

The 9245 will work fine in your trailer. I believe the old Univolt was good for about 30 amps on the DC side. You will be happy with the 9245 I'm sure.

[boilermaker]

Thanks TGT
As long as I have this trailer gutted, are there any other electrical improvements that you think I should make?

[Ridgerunner3]

I just finished installing a PowerMax 60amp converter along with a group 27 AGM battery from Randy. Easy install. I am looking forward to the improvement this will provide over the Parallax 7455 and wet cell battery.