Parallax converters

[whitegs]

The general opinion on these forums is that the original equipment Parallax converter should be replaced with a multistage converter. On the other hand, here is a quote from the Parallax website:

Q: Does my Converter/Charger completely shut-off when the battery reaches full charge?
A: When the battery reaches full charge, its internal resistance will stop, or resist the current being provided by the converter and current entering the battery is between 20 and 25 milliamps. Fully charged batteries will self-discharge themselves and will always accept some small amount of current to offset this self-discharge

They then go on to say:

Q: Can I leave my Parallax converter system constantly connected to 120VAC power? Will this damage my batteries?
A: Parallax converter models deliver a nominal "float voltage" output of 13.2 -13.8 volts DC. Leaving the RV connected to 120VAC and the converter output connected to the battery should present no problems as long as this "float voltage" is between 13.2 - 14.1 volts DC and recommended battery maintenance is performed.

(Does that mean constantly refilling battery water?)

Finally:

Q: My friend has a "smart charge controller" that plugs into his converter system. Why hasn't Parallax offered a "smart" charger option for my unit?
A: The issue we have with "smart charger technology" (when used in an RV) lies more with the application of the technology than the technology itself. In a typical RV 12 volt electrical system, the converter/charger and the battery or battery bank is connected in parallel with the rest of the 12 volt distribution system. In "parallel" means where the charging source (converter/charger) positive and negative output is electrically connected to both the battery bank positive and negative, and the 12-volt distribution system positive and negative, at the same time. The voltage output of the converter "smart charger" is based on a "detected" battery voltage. The converter "smart charger" claims to "monitor" and respond to battery condition while connected to the entire 12 volt system. Unless the charging source (converter) has a separate or isolated charging output, we do not agree that a converter or charger can effectively differentiate requirements of the batteries from other 12 volt loads while simultaneously connected to the rest of the 12 volt distribution system in the RV.

Detected use or voltage change on the RV 12-volt load system (i.e. lights, pumps, etc. being turnedon) generally keeps these devices at a 13.6 -13.8 "float" voltage. This raises the question whether any real additional benefit is being provided to the battery bank unless the coach remains in a "non-use" storage condition. If a converter "smart charger" is only connected to the battery bank and can therefore monitor only battery voltage or current, and is not also connected "in parallel" with the 12 volt distribution system, we have no problem with the application of "smart charger technology".

So I'm confused. Is Parallax blowing smoke? Or can I sleep at night and not worry about my batteries without changing out the converter?

[Tyvekcat]

Well there is a lot of information on the Parallax, distilled down, its a good power supply for you to power projects & radios, but not to proficient as a 4 stage charger. It will boil your wet cell batts. Here are a couple links to discussion and replacement.

http://www.airforums.com/forums/f449...am-126429.html

and a project for the Parallax:
http://www.airforums.com/forums/f449...on-141598.html

you can search, there are more and tons of info,
Have a good one

[wulfraat]

Ditch that piece of junk parallax converter… It boiled one set of my batteries and killed the second set. Spent a couple hundred bucks on a progressive dynamics replacement converter and haven't looked back.

[Wayne&Sam]

If my Parallax convert ever bites the dust, I'll replace it with a 3 stage. But until then it works fine for me. My first set of batteries with a Parallax lasted 7 years.

[switz]

The single stage OEM Parallax converter unit was on my list of things to replace on our new 2013 25FB International Serenity along with the GYM tires as soon as I got the unit home from the dealership in October of 2012.

While the replacement multistage unit fit as advertised, the relocation of the incoming wire connection posts on the new board required some creative efforts to gain several more inches of "loose" wire in order to make those connections under the cross frame queen bed.

[Trailbob]

I have a PD4655 sitting on my bench, waiting for me to install it. The reason I am changing out the stock converter is to be able to charge faster from my generator, when needed. From what I have read, the stock converter does not put out enough volts to quickly or properly charge the batteries. For storage, I have been using a Battery Tender or Ctek maintainer, so I was not concerned about the stock Parallax overcharging the batteries.

[KevinFH]

There have been a few kind words for the Parallax converters, but I wouldn't buy a replacement.

Both Interstate AGM batteries were down to 9V in parallel. They were old and near/at death when the converter failed. I put new batteries in and the converter would not charge them.

I replaced the converter with a boodndocker; problem solved.

BUT!
When I removed the Parallax printed circuit board, there was a transistor mounted on a heat sink (0.5" X 2.0") just laying on top of the converter PCB. There was no connection, this part was dropped inside by mistake during manufacturing. It was laying next to the blown fuse F1 on the circuit board. There was a lot of heat damage to the Parallax board near specific components. Given the damage, it went in the recycle.

Anytime I find extra parts bouncing around inside I know I have junk.

[uncle_bob]

Originally Posted by KevinFH

There have been a few kind words for the Parallax converters, but I wouldn't buy a replacement.

Both Interstate AGM batteries were down to 9V in parallel. They were old and near/at death when the converter failed. I put new batteries in and the converter would not charge them.

I replaced the converter with a boodndocker; problem solved.

BUT!
When I removed the Parallax printed circuit board, there was a transistor mounted on a heat sink (0.5" X 2.0") just laying on top of the converter PCB. There was no connection, this part was dropped inside by mistake during manufacturing. It was laying next to the blown fuse F1 on the circuit board. There was a lot of heat damage to the Parallax board near specific components. Given the damage, it went in the recycle.

Anytime I find extra parts bouncing around inside I know I have junk.

Hi

The gizmo attached to the heatsink is a regulator. They probably intended the far end of the heatsink to be tied to the case somehow. Obviously that didn't happen. The net result is a part that is very prone to failure from vibration. When it breaks off, the converter stops working.

The part is a common one. You *could* replace it. The gotcha is that you don't really know what damage it did bouncing all over the rest of the circuits for weeks on end.

Fun !!!

Bob

[ROBERT CROSS]

The best use for ours is down in the basement where I can keep an eye on it as a standby for the batteries on the emergency sump-pump.

They need to be kept as far away from Airstreams as possible.👍

Bob
🇺🇸

[Gene]

I replaced the cheap Parallax converter pretty early in our ownership—about three years after buying the trailer. Upon the recommendation of Lewster, I bought an Iota with a three stage charger. Never had a problem with it. Replacing it for those without any experience with electrical work can be a challenge. Parking myself in the small space between the bed and walls was a challenge. Now about a decade older, if I lowered my self into that space, it would take several very strong EMT’s and a chain saw to get me out.

[KevinFH]

Originally Posted by uncle_bob

Hi

The gizmo attached to the heatsink is a regulator. They probably intended the far end of the heatsink to be tied to the case somehow. Obviously that didn't happen. The net result is a part that is very prone to failure from vibration. When it breaks off, the converter stops working.

The part is a common one. You *could* replace it. The gotcha is that you don't really know what damage it did bouncing all over the rest of the circuits for weeks on end.

Fun !!!

Bob

No, this part was extra. It never made any connection to the printed circuit. The large regulators on the big heat sinks looked fine. This was a small package like TO-252 size. The leads had been clipped with wire cutters.

It may have been a regulator, but not from this board. It was just a piece of junk (FOD).

[switz]

We replaced the stock guts in the power system of our 2013 25FB International Serenity with the Lewster recommendations of the day. So we missed out on many of the issues others were or are now experiencing.

We replaced most of the Airstream electrical systems in both the 2014 3121’ Classic and the 2015 23D International Serenity within weeks of purchase. All power outlets were upgraded to commercial Hubbell 20 amp GFI outlets. The installed solar systems replaced the inverters and chargers that were stock. The original Magnum inverter chargers have been replaced with Xantrex Freedom units and the solar controls QWERTY all upgraded as well. Several wall displays have vanished into never never land and been replaced with apps on my iDevices. The wiring birds nest have been removed by this new equipment so one can actually see where each wire goes. Sometimes, progress is beneficial.

Electrical stuff is not like wine and does not get better with age……

[ROBERT CROSS]

Ignore the Pic here....

The fact that I had replaced the P-Plax with the IOTA had escaped my brain pocket, the Lax is now in the "if I ever need it bin" and IOTA is charging the aux pump batt's.

Why does getting old take so long?

Bob
🇺🇸

[uncle_bob]

Originally Posted by KevinFH

No, this part was extra. It never made any connection to the printed circuit. The large regulators on the big heat sinks looked fine. This was a small package like TO-252 size. The leads had been clipped with wire cutters.

It may have been a regulator, but not from this board. It was just a piece of junk (FOD).

Hi

Assuming it's FOD Was there a second TO-220 on a 2" heatsink still on the board? If not, there should have been. It connects almost dead in the middle of the PCB (working from memory ...) ..... Indeed the break on the leads is a very clean one in cases like this. The pivot point and break are right at the PCB.

Bob