Power inverter upgrade

A couple of you have commented that if my trailer still has the original Magnetek power inverter/charger that an upgrade to a modern unit would be worthwhile. Is it as simple as buying one of these https://bestconverter.3dcartstores.com/PD4635-35-Amp-Converter-Upgrade-Section_p_350.html and installing it? Or do other parts of the electrical system need to be upgraded at the same time.

Also...how do I track down where the power inverter is located in my trailer? 1988 Alpenlite FW. I know where the batteries are, but the power unit has been elusive so far.

Finally found it. Ended up being under the shower and had to pull the insides out of one of the storage cabinets.

It's a Magnatek TU-740-2. From what I've been reading, this would be a good replacement: http://www.bestconverter.com/XADC-40A-ConverterCharger-_p_326.html

I only have room for two 12V batteries in the battery compartment.

Any comments about this Xantrex unit? Do I have to replace the fuse panel or can I just change out the converter itself and possibly upgrade the feed cables to the batteries?

Is it as simple... Two answers depending on which version of the install you do, plus one direction.

There are basically two or 3 upgrades and which one you do determines the answer.

Now, if you were to say switch to a PD 9245.. This is a stand alone converter. you hook it up most anywhere in the 12 volt system on the battery side of the fuse block (or direct to the battery via a proper fuse) and .. cut the power to the Magnetek's converter section (in fact I'd pull the Magnetek's converter 120vac wire off the breaker and use the very same breaker to feed the PDI.

You then have the option of removing the "Guts" of the magnetek and bypassing it (Easier than it sounds) or just leave it be in case you ever have issues with the PDI and need to charge.

The next level of conversion is described on the best converter web site,  It's under "Extra Info" which is on the left if you scroll down

This is where you remove the converter "Guts" from the magnetek intergrated power distribution/converter panel and replace it with a PDI or other 3-stage.

The final level of conversion is where you remove the entire Magnetek distribution center/converter and replace the whole magilla.. I do not recommend this.  Reason.. No need to replace the breaker/fuse panels.. Just the "Guts" so it's a cost thing

Though I do like the looks of PDI's panels.


One final comment: If you stick to about the same size as the original converter (Which you indicated you are doing) there is no need to upgrade beyond the converter itself

If you were upgrading to say a 60 or larger amp converter.. You'd need better wires and possible bigger batteries.

The poor quality Magneteks mentioned previously are the 6300 series, which is notorious for ruining batteries by overcharging till they run dry, yet slow to recharge under normal conditions.  I don't know if the 700 series shares that defect or not.  If you are  not having problems with the water boiling off the batteries when left on charge for a few weeks  at a time, you may be ok with what you have. If, however, your battery life is short, or the converter is objectionably noisy (loud hum), you should consider replacing it.

The Xantrex you cited is one of several excellent converter/chargers. Some others are Iota and Progressive Dynamics. Parallax Power, which is the new name for Magnetek, recommends the Parallax Power 7400 series as the replacement, but it's only a two stage charger whereas the others are three (superior).

The Magnetek 740 is a 40A charger of the ferro-resonant type. It should be easily replaceable with the Xantrex if there is physically room for it - I think the Xantrex is a slightly different shape. It was later replaced with the 900 series (e.g. 940) and that was a decent converter/charger. Can't find any good info on the 740, though. Here is the Parallax Power page that has a bit of info on their obsolete chargers:
http://www.parallaxpower.com/ferro.htm

The Xantrex will have two large wires that go to the battery terminals or to an electrical bus terminal that leads right to the battery) plus a 3 wire 120vac power cord connection (a standard 120vac power plug is optional on that model). If your current converter hooks up the same way, its a snap.

I have heard nothing but good things about the Xantrex converters, and their specifications look impressive.

Replacing the existing distribution panel is just extra work and I'd leave it.  John has summarized the choices that make sense.  Just be sure that you mount the new converter someplace where there is airflow.

The batteries were dead and bulged when I got the RV so whether that was from the converter damaging them, or if they were just really old and froze at some point, I don't know.

I think I'll leave the converter as/is and keep an eye on the new batteries to find out. Once other things are repaired on the trailer, I'll come back and revisit the charging system.

Good plan!

So I chatted with a person at the local RV shop and I think she cleared things up for me a bit better. Normally you have a power converter that has power coming in, and it charges the batteries and powers anything A/C in the RV. When shore power is unavailable, the batteries only power 12V things like the lights, and most other things would run off of gas like the furnace, water heater, fridge, etc.

So...if I'm out in the boondocks, I'm not going to be running the microwave or A/C unit, right? And expecting any power inverter and batteries to do so for very long is unrealistic. For that, I'd need a generator.

Am I understanding correctly?

Close, the converter charges the batteries and powers all DC appliances and lights.  Without shore or generator power, you would need an inverter to run the AC appliances and devices.  It is possible to run a microwave oven from batteries/inverter for short periods, but A/C is too much of a load to be run without shore or generator power.

When shore power is unavailable, the batteries only power 12V things like the lights, and most other things would run off of gas like the furnace, water heater, fridge, etc.

Click to expand...

Note that all those things require 12v as well as gas. The water heater and fridge use 12v power for their control circuitry and the furnace needs 12v for the fan.  Your a/c, microwave, etc. always run on 120vac shore power. Your converter (not an inverter) supplies 12v only.

There is  a primer on RV Electrical Systems in the RV Forum Library, as well as other articles geared to Newcomers. See RV Forum Library Newcomers Section

Think I have it figured out now. Thanks guys!

So yeah, back to thinking about a converter upgrade again! Is there any real-world difference between the equivalent PD and Xantrex converters? Any reason to prefer one over the other?

Not really. Iota is another top brand.

The more I read, the more options there appears to be. So...what would a Xantrex TrueCharter2 do or not do that a regular converter does? It's a bit more money, but sounds like it would do the best job maintaining batteries.

The TrueCharge 2 has multiple charge profiles, so you can set it for different battery types (flooded, AGM or Gel) and temperature compensated charging (with optional battery temp sensor installed).  It has an Equalization mode too, but the PD 9200 series does equalization automatically. 

There is some modest value to the battery type selection, but I would not pay a lot more for the Xantrex vs PD or Iota. I know you can get a PD 9245 for around $160. How much is the Xantrex TrueCharge 2 40A model? Best I have seen is $307 on Amazon. The Xantrex is a nice unit, but that's a lot more $$.

Gary gave a good explanation of why I give the Xantrex product a "Top of the line" rating.  It is a true 3-stage with multiple charge profiles so it works well with different types of batteries.

Progressive Dynamics Charge Wizard is designed specifically for Flooded wet cells.. It's Good for AGM's but it's best for Flooded Wet Cells. (That is the only profile they make it for,,, Why they don't do the multi-profile bit I dont' know)

The Charge wizard has one special feature that makes it stand out too.  Like most all multi-stage converters it can be manually set to any mode or allowed to operate automatically.

However the special feature is this... Once the batteries are charged up and it goes into float mode a timer starts.. If it remains in float for more than so many hours (I think 20) it goes into a brief "Equalization" mode (I think 15 mintues)

Equalization is a short, controlled overcharge,, It's not long enough to damage the battery, However it does stir up the electrolytic a bit and it can even out a battery that has a cell that does not quite fill up properly...  Now with most quality converters you can MANUALLY select that mode.. but the PDI - Wizard does it automatically..

Though to be honest 15 minutes is not long enough for a full equalization but every day for 30 days... And it works well.

That covers the major differences

Xantrex True Charge 2... multiple configurations
PDI wizard.. Auto-equalize

I have both a PDI 9180 w/charge Wizard AND a Xantrex Prosine 2.0 (inverter/charger) (I have two seperate house battery banks, different types) which also has the multiple configurations feature.... Love 'em both.