Upgrade old Magnatek converter or replace?

If the 8355 comes with TempAssure already installed, I will return the PD4655V. If it is not already installed, I would have a bear of a time getting the temperature sensor to the battery. The converter/charger is on the wrong side of the trailer, and halfway down the length. On top of that, the belly of the trailer is enclosed, so I can't just go through the floor and fasten it under the trailer.

Chris Bryant wrote:
Owners Manual

Forum is being broken- trying to quote from that, but look at the optional TempAssure module, which I assume Airstream would include, given that they don't really give those things away :)

Parallax 8300 manual wrote:
TempAssure™ (Patent US 7,245,109)

Your 8300 system may include the (optional) TempAssure™ module and sensor
cable. When properly installed, the TempAssure™ system employs technology that
allows the output voltage of the converter to be varied by the temperature of the RV’s
“house” battery system. The benefit of this feature helps to provide a more appropriate
charging voltage for the “house” battery system exposed to varying ambient
temperatures. For example, in cold climates the output voltage of the converter will be
increased, which results in a more fully charged and maintained battery. In hot climates
the output voltage of the converter will automatically lower, which will aid in reducing
excessive out-gassing of the battery caused by the battery requiring a lower “float”
voltage.
Also with the addition of the TempAssure™ module and sensor cable, the 8300 series
converter will automatically start out in a “boost” mode for the first 4 hours of operation
every time the 8300 series converter is powered “on”. The output voltage of a
TempAssure™ equipped 8300 series converter will still be temperature compensated,
even while in “boost” mode.
Your RV manufacturer’s installation may also allow you to manually trigger the “boost”
function by pressing a switch. (optional wiring configuration)
While the 8300 series converter with the addition of the (optional) TempAssure™
module is designed to provide a better means of charging and maintaining the “house”
battery, Parallax Power Supply strongly recommends proper battery maintenance be
performed by the owner on non-maintenance free batteries following the battery
manufacturer’s recommendations.
DO NOT allow the battery cell plates on non-maintenance free batteries to become
exposed to the air. Poor battery performance will result.
Parallax Power Supply will not be responsible for battery failure resulting from improper
battery maintenance.

Doesn't really give a lot of details on voltages, boosts and reduces only. I am going to contact Randy at BestConverter.com and ask his take on the 8355 w/TempAssure. I will post his response.

Parallax removed the voltage curve graph but here is something from Best converter:

https://bestconverter.3dcartstores.com/assets/images/Parallax/4400/4455%20Voltage%20Curves.pdf

Bobbo wrote:
If the 8355 comes with TempAssure already installed, I will return the PD4655V. If it is not already installed, I would have a bear of a time getting the temperature sensor to the battery. The converter/charger is on the wrong side of the trailer, and halfway down the length. On top of that, the belly of the trailer is enclosed, so I can't just go through the floor and fasten it under the trailer.

You are correct that the sensor is on the ring lug that goes on the battery post (ISTR PT insists it matters pos or neg post, but can't remember which) BUT the main thing is to get it to the same temp as the battery instead of inside the rig where it is nice and warm or cool compared with outside ambient.

Way to fussy to say battery temp (higher when being fast charged) is not the same as ambient. Especially when it is mostly the Float voltage that matters if you have Flooded batts and the battery doesn't heat up doing that.

So--just run the wire to the outside anywhere you can get it out from where the converter is and use the same ambient temp as the batteries "feel" for your temp adjustment. Of course if you have AGMs inside where it is also nice and warm or cool compared with outside, then you don't need temp adj anyway--BUT the TempAssure module is more than that--it enables the extra boost, which is a key feature.

Parallax TempAssure adjusted voltages are a bit low in all conditions for expecting a fast charge from a generator. Voltage sag is also poor at full load. Fine if mostly plugged in. Otherwise PD and IOTA are better with no compensation.
JMHO

Bobbo wrote:
If the 8355 comes with TempAssure already installed, I will return the PD4655V. If it is not already installed, I would have a bear of a time getting the temperature sensor to the battery. The converter/charger is on the wrong side of the trailer, and halfway down the length. On top of that, the belly of the trailer is enclosed, so I can't just go through the floor and fasten it under the trailer.

I haven't heard back from Randy yet, but I emailed Airstream to ask if their unit had the TempAssure. This is their response.

Airstream wrote:
Hello,
The Parallax system we run does not have the optional TempAssure feature. We still find that it is a more than capable system. If you have any additional questions about this system or any other system in your new Airstream feel free to email me and I will be happy to assist you. Congratulations on your purchase and welcome to the Airstream Family. Have a great weekend.

time2roll wrote:
Parallax TempAssure adjusted voltages are a bit low in all conditions for expecting a fast charge from a generator. Voltage sag is also poor at full load. Fine if mostly plugged in. Otherwise PD and IOTA are better with no compensation.
JMHO

Despite the voltage being in the low 14s, the Paramode does quite well as seen in my ugly graph here (scroll down) I did have to fatten the DC wires to get full amps 60.x (rated 55) AND it held constant amps properly, which a PD fails to do --but that does not bother some folks it seems :)

IMO Bobbo will like his 4455 if he gets the TempAssure module for it.

http://forums.trailerlife.com/index.cfm/fuseaction/thread/tid/24655789/srt/pa/pging/1/page/6.cfm

BFL13 wrote:
IMO Bobbo will like his 4455 if he gets the TempAssure module for it.

I would have to drop the enclosed bottom off of my new trailer to run the wire to the batteries. I am not willing to do that to a trailer that I haven't even taken possession of yet. I will be installing the PD4655V as soon as the trailer is delivered. I already have the PD4655V.

Bobbo wrote:

BFL13 wrote:
IMO Bobbo will like his 4455 if he gets the TempAssure module for it.

I would have to drop the enclosed bottom off of my new trailer to run the wire to the batteries. I am not willing to do that to a trailer that I haven't even taken possession of yet. I will be installing the PD4655V as soon as the trailer is delivered. I already have the PD4655V.

It is all about RVing and being comfortable knowing what you have works for you, so Bobbo is right. Use the PD you are comfortable with and trust, and pass the 4455 along to somebody else.

As I was trying to say earlier, you don't have to take your trailer apart. EG, on ours the OEM converter is under the fridge, so if I were to put the Paramode in there, I could just dangle the sensor wire out the fridge side vent to capture ambient temp vs the heated temp inside the rig where the converter goes.

(Does require a small hole in the wood floor -behind the fridge where you can get at it from the outside side vent- the fridge sits on, above the Power Centre compartment underneath)

Even if you leave the temp comp where the converter is you are no worse off except in extreme temps. You still get the extra boost having the TempAssure.

Looking at that old thread. That was 5.5 years ago! Seems like yesterday. Egads, we are all doomed. Oh well. I wonder what happened to Salvo anyway. We had a strange relationship here, where I had to pick and choose carefully whether anything he said applied to me at all.

In this case he was sure my actual real life measurements were bogus, when they weren't. OTOH he was very helpful with such things as getting the voltage drops between points along a "path" to reduce your R between converter and battery. He was right about what to do about my thermistor problem too, against some others' advisories as it turned out in the end. I would say on balance that I got a lot of benefit from his participation here.