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StillRod · 04-09-2015, 10:52 PM

I'm hoping someone here has info on subject converter/charger.

Our new Airstream, a 25 Rear Twin Flying Cloud, came standard with the Parallax 8355, and the included literature reveals virtually nothing about its performance characteristics. The Parallax website is equally void of detailed information.

Do you know if this is another single-stage unit, or is there more to this one? My new batteries are already acting flaky, so I think I already know the answer to my question, but then again there's always operator error to be considered.

Thanks for any insight you might provide.

Cheers!

Rod

idroba · 04-09-2015, 11:37 PM

It is a single stage converter/charger. It will work but probably should be on your list of things to change out to a better 3 stage charge unit as time goes on. If you leave it on and in USE mode keep track of the water level in the batteries. The single stage units have a tendency to cause the water level to drop. I would check battery water level weekly or bi weekly if the Paralax is left on. We all used single stage units in Airstreams for many years prior to three stage units becoming available. Yes, more batteries were replaced than necessary, but with some management I had a lot of good hours in my Airstreams without unnecessary battery replacement. I just never left the things on 24/7.

If your rig sat on a sales lot with the batteries left connected, there is a possibility that the batteries have been run down, or left at a low state of charge causing damage prior to your purchase. What kind of "acting flaky" are you experiencing?

Tincampers · 04-10-2015, 06:19 AM

I sold mine on eBay when I replaced it with a PD. Almost covered the cost of the new PD.

Wayne&Sam · 04-10-2015, 06:25 AM

I always thought I'd replace it in my '07 if it ever failed, but it never did. My original batteries lasted 7 years. I also only had to top off the water in the batteries a few times in those 7 years. So it's not clear cut that they are bad converters, you just can't leave them plugged in 24/7/365. In the off-season, I keep at 3 stage charger on the batteries.

I'd also be hesitant to replace it while your Airstream is still on warranty.

But that's just me, YMMV.

dznf0g · 04-10-2015, 06:28 AM

I use mine for a 12v work bench power source.

AWCHIEF · 04-10-2015, 06:49 AM

My 2006 Safari still has the original converter. I keep my trailer plugged in most the time when I am home and camping at full service parks. It puts out a constant 13.74 Volts DC. So far no noticeable issues boiling the batteries. I have not had to add water in the 6 months I have had the current batteries. It is on my to do list to swap it out for a better model and upgrade the batteries to a pair of 6 Volts. That is going to take some major mods of the battery box.

lewster · 04-10-2015, 06:52 AM

Chief,

I'm starting a solar/battery upgrade today and will take some shots of the battery box upgrade.

It's not as difficult or invasive as one might think.

Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

jbxx · 04-10-2015, 08:13 AM

Great! I'll be watching for those details / pics also!

J.B.

ckottum · 04-10-2015, 08:44 AM

We use the factory solar system to charge our batteries, never the original converter, by placing the Battery Disconnect Switch in the "STORE" position when plugged into external power, and "USE" position when not plugged into external power.

The original systems and AGM batteries are working perfectly going on 4 years, 30 months of actual camping and travel. So the original converter is certainly usable to provide 12 vdc power for the Airstream when combined with a solar or other charging system for the batteries. It's just not a good battery charger.

cheryl

dznf0g · 04-10-2015, 08:47 AM

Quote:

Originally Posted by ckottum

We use the factory solar system to charge our batteries, never the original converter, by placing the Battery Disconnect Switch in the "STORE" position when plugged into external power, and "USE" position when not plugged into external power.

The original systems and AGM batteries are working perfectly going on 4 years, 30 months of actual camping and travel. So the original converter is certainly usable to provide 12 vdc power for the Airstream when combined with a solar or other charging system for the batteries. It's just not a good battery charger.

cheryl

Can't you just unplug the converter from the wall outlet and keep you store switch on...to use all the 12V system?

AWCHIEF · 04-10-2015, 08:56 AM

Lee, I got a good look at a modified box this past week. Owner took one inch or so C channel and riveted it to the original box and replaced the top. Very clean and original looking job.

ckottum · 04-10-2015, 12:01 PM

Quote:

Originally Posted by dznf0g

Can't you just unplug the converter from the wall outlet and keep you store switch on...to use all the 12V system?

The Parallax converter/charger cannot be unplugged. The Battery Disconnect in "STORE" position just isolates it from the batteries; all of the 12v system is in use and powered by the Parallax converter/charger when on external power. The batteries are then kept charged by the factory solar system.

The idea is to protect the batteries from being damaged by the single stage charger of the Parallax cover/charger, saving the expense of replacing it while it is working fine as a 12vdc power supply.

cheryl

StillRod · 04-10-2015, 12:26 PM

I say flaky because, in comparison to our 2012 19 footer, the battery use curve turns south dramatically faster. Whereas we consistently went three nights boondocking, we are lucky to get through two nights in the 25 with seemingly similar usage of lights, water pump, fans, etc.

It makes me wonder about greater ambient loads from the charger fan, the thermistor controlled reefer fan, and the inverter on the one hand and about the charger's workings on the other.

The batteries themselves were brand new as the trailer had been built only three weeks before we took delivery. Maybe we cooked them, which I accept as possible, but I hope not. Our intent is to keep this trailer a good while, and upgrade where appropriate...perhaps starting with the Parallax?

idroba · 04-10-2015, 01:00 PM

If you didn't have an inverter on your 19' and have one now and are using it, you will find a real difference. The power consumption of the inverter, even with no load on it at all, is in the 1.7 to 1.9 amp range, which is considerable. Of course any 120 volt load makes it higher.

The refrigerator fan is another significant load and the amp hours used add up fast.

**wulfraat** · 04-10-2015, 01:22 PM

Junk that thing and get a Progressive Dynamics converter. The Parallax unit cooks batteries. Ask me how I know.

lewster · 04-10-2015, 01:49 PM

You can easily disconnect the converter by flipping it's 120VAC circuit breaker to the 'off' position, thereby removing the 130VAC power to it.

Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

lstepp2 · 04-10-2015, 03:05 PM

Wikipedia has the definition of a Parallax. Parallax - Wikipedia, the free encyclopedia

dznf0g · 04-10-2015, 03:35 PM

Quote:

Originally Posted by ckottum

The Parallax converter/charger cannot be unplugged. The Battery Disconnect in "STORE" position just isolates it from the batteries; all of the 12v system is in use and powered by the Parallax converter/charger when on external power. The batteries are then kept charged by the factory solar system.

The idea is to protect the batteries from being damaged by the single stage charger of the Parallax cover/charger, saving the expense of replacing it while it is working fine as a 12vdc power supply.

cheryl

Wow, I wonder why they changed that. Both my old OEM Parallax and my replacement IOTA DLS just plug into a wall outlet down low under the sofa behind the electrical center. I just unplug it from the wall whenever I want to use solar trickle charging, but still want lights, etc. to work when I walk in.

Wingeezer · 04-10-2015, 04:11 PM

I still have the original charger in our 2005. I put new AGM batts in when I bought the trailer used about 6 years ago and they still seem fine.

I do remove them and bring them to the house when the trailer is in storage, and I also put quick disconnects on the cables and if we are camped anywhere for more than a couple of days, I disconnect them for the duration of our stay. Not really sure if that helps or not with the longevity of the AGM batts, but it couldn't hurt - I dont think!

Brian.

ckottum · 04-10-2015, 05:37 PM

Quote:

Originally Posted by lewster

You can easily disconnect the converter by flipping it's 120VAC circuit breaker to the 'off' position, thereby removing the 130VAC power to it.

That would work too, but then it's up to the batteries and solar system to run the 12vdc equipment. In our case where we are traveling in this rig 7 months a year, the daily discharging of the batteries would take a toll on them.

My suggestion to set the Battery Switch to "STORE" to isolate the batteries from the converter (when on external power) is primarily for those who may want an interim solution for the parallax until they upgrade, or for those who just want to get along with it as we do.

cheryl