Replacing magnetek 6300 with inverter/charger

[nakedgun]

Hello all,

I have a 1994 coachmen class B RV which I'm in the process of re-modelling. It has a stock magnetek 6300 converter. It has been upgraded with solar and a battery isolator for charging the house battery when driving.

My goal is to be able to use all of the built in outlets whether on-grid/off-grid. We mainly boondock so 80% of the time this is going to be without shore power. But having this as an option is handy.

I've found a relatively good deal on a xantrex 2000 pure sine inverter/charger which I'd like to hook up. My plan was to remove the charger on the magnetek 6300 but re-purpose the AC/DC distribution panels.

Does anyone know whether this is safe? Or is it better to remove the entire unit and add a new AC/DC distribution panel instead?

I have mainly worked with DC systems before (very basic) so still learning. Appreciate any advice or tutorials which might be relevant here!

Pictures of the magnetek panel:

***Link Removed***
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[nakedgun]

enblethen wrote:
Why not get a dc/DC power supply for laptops. Why inverter DC to AC, then AC to dc in laptop power supply?

We have older Macbooks. DC charging for Apple laptops is basically 2016 onwards. If this was possible wouldn't be bothering with an inverter.

time2roll wrote:
Not sure why you want to power everything up just to shut it down.

Not entirely sure what you mean. There are 4 outlets in the van which are nicely positioned. Simply want to be able to turn the inverter on and use them when needed - and turn off the inverter when not in use (to avoid idle draw). It's literally for laptops only - we have no other AC appliances (at least for now).

Obviously connecting to the inverter directly is the easiest solution. It's just the placement of the outlets which makes them desirable for using.

[Gdetrailer]

enblethen wrote:
Why not get a dc/DC power supply for laptops. Why inverter DC to AC, then AC to dc in laptop power supply?

I did mention that, however OP did mention after my comment that they have older "i" laptops.. And with all "i" products, everything is proprietary and costs an arm and leg and not a lot of low cost "aftermarket" support.

One of many reasons I stay away from "i" products..

There most likely is some 12V car supplies directly from the "i" vendor available and to cut down on the battery needs that would be much better than inverter to power supply to laptop..

[wa8yxm]

Most of the knife switches I've used... even USA ones. not that great.

OH one thing on the Converter/power panel there are two wires, I ***THINK*** red and blue. Need to be joined one is 12 volt from battery the other from to house.
If you remove the junk electronics I think the blue goes to selected (need clean power) stuff and the red to "i don't care how nasty it is" like lightbulbs.

[Gdetrailer]

2oldman wrote:

Gdetrailer wrote:
you also have a real danger posed by flash over when making or breaking the contacts..

So I shouldn't break contact with the a/c running?

I don't know if you are trying to be funny, if you are, you are not funny.

In reality, most breakers are not rated to be used as "switches", that is not the main reason they are there.. Using most breakers as a switch under load can shorten their life..

Breakers are there to prevent fire due to overloading to the wiring as their main reason, the manual switching action is just a "side benefit".

Breakers give up their "life" to prevent you from losing your life due to wiring fire.

Oh, sure you can do that, but overtime it will eventually lead to a failure of the breaker much quicker than it should have.

There are breakers designed for that type of service but your not going to find those in a RV by default.

[Gdetrailer]

DrewE wrote:
For a transfer switch, the ground line should not be switched. Only switch the hot(s) and neutral.

Technically that is correct.

However, in reality, many cheapo inverters may not appreciate having the RV wiring with the equipment ground connected and requires a "floating ground" AND a "floating neutral". So basically isolating the ground via a switched connection may actually be needed in order to get some inverters to work properly since they were not designed to be wired into an electrical "system".

Have to understand that in a RV even though the breaker panel maintains separation between safety ground and neutral, it DOES connect the safety ground to the trailer frame AND that means the 12V battery negative terminal is at the same potential.. Some inverters may internally bond the safety ground, neutral and battery negative ground and may not like that when you plug the entire RV into the inverter and may refuse to work or even go up in smoke..

The reason for that?

Has to do with the design of the inverters high voltage chopper section combined with a "H bridge output" which may depend on a floating neutral and safety ground and with those you cannot tie either 120V output terminals to the same potential as the 12V battery negative terminal without causing damage. Otherwise known as a "transformerless" inverter..

Simplified Circuit looks like this..


You can read up on transformerless inverter theory HERE

[time2roll]

Not sure why you want to power everything up just to shut it down.
+1 for the charge adapters and USB charge connectors.

[enblethen]

Why not get a dc/DC power supply for laptops. Why inverter DC to AC, then AC to dc in laptop power supply?

[nakedgun]

Gdetrailer wrote:

pianotuna wrote:
Given that 20 amps is possibly too small for an RV, this may be a better choice: Baomain Universal Rotary Changeover Switch SZW26-63 660V 63A 3 Position 3 Phase

Yes, 20A would be "light" for switching entire RV, however, plenty sufficient for switching just one 15A-20A branch circuit which I believe the OP was considering..

Switching the entire RV can become a bit tricky with a inverter since one would have to remember to set the RV fridge to gas only, one would have to remember to turn off the converter circuit and also if equipped disable the water heater electric heating element..

That is a long check list of things to remember to switch off before switching to inverter.

When in doubt, use the K.I.S.S. method (Keep It Simple Silly)..

Actually I'm interested in switching over the entire RV (by toggling from shore to inverter feeding into the main supply line to the AC distribution panel).

It's worth noting that the RV is remodeled. All stock stuff largely removed. Our fridge is 12v (no propane) and the only 120v drain will be from two laptops. Heater is gas only. I plan to add a spst switch to leave the converter OFF - we'll very rarely be using it since we boondock 99% of the time. So basically the rotary switch will be on inverter 99% of the time with the converter off. I plan to add a remote control panel for the inverter so we can leave this off when not in use.

I think the Baomain Universal Rotary Changeover Switch SZW26-63 660V 63A 3 Position 3 Phase or equivalent looks suitable for this use case me thinks?

[DrewE]

For a transfer switch, the ground line should not be switched. Only switch the hot(s) and neutral.

[2oldman]

Gdetrailer wrote:
you also have a real danger posed by flash over when making or breaking the contacts..

So I shouldn't break contact with the a/c running?

[Gdetrailer]

pianotuna wrote:
Given that 20 amps is possibly too small for an RV, this may be a better choice: Baomain Universal Rotary Changeover Switch SZW26-63 660V 63A 3 Position 3 Phase

Yes, 20A would be "light" for switching entire RV, however, plenty sufficient for switching just one 15A-20A branch circuit which I believe the OP was considering..

Switching the entire RV can become a bit tricky with a inverter since one would have to remember to set the RV fridge to gas only, one would have to remember to turn off the converter circuit and also if equipped disable the water heater electric heating element..

That is a long check list of things to remember to switch off before switching to inverter.

When in doubt, use the K.I.S.S. method (Keep It Simple Silly)..

[Gdetrailer]

2oldman wrote:

Gdetrailer wrote:
Is far more appropriate for today's modern safety standards..

Good for you.

Fortunately some of us live in the 2000's and not the 1800's.

Open knife switches while they may give the cool "mad scientist" look and vibe from the late 1800s do not have much of a place in the safety realm of life.. Even with all of the covers, you have a pretty fair chance of making contact with hot connections by accident and you also have a real danger posed by flash over when making or breaking the contacts..

Leave those devices for those high school science experiments with a couple of dry cells..

As having worked in industrial environments with commercial multiple phase high voltage equipment and having to endure many training sessions on electrical safety over the yrs those knife switches belong in protective enclosures, they are not "toys" when dealing with high voltage and or high amperage..

Even something as common as your modern 120V/240V circuit breaker panel, you should never stand DIRECTLY in front of the panel when switching breakers.. Always taught that one should stand off to the side so if one does arc over or explode your entire body is not exposed..

[2oldman]

pianotuna wrote:
this may be a better choice: Baomain Universal Rotary Changeover Switch SZW26-63 660V 63A 3 Position 3 Phase

Excellent.

[pianotuna]

Given that 20 amps is possibly too small for an RV, this may be a better choice: Baomain Universal Rotary Changeover Switch SZW26-63 660V 63A 3 Position 3 Phase