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CamJam1 · 08-29-2020, 12:05 PM

I've had my coach for about 18 months and am just now starting to go though and get everything working. Never had a need for the inverter before, but now that I've gotten rid of the boat anchor TV for a modern LED TV with low current consumption, I might actually watch TV from the inverter at times. Unfortunately, the inverter outlets in the entertainment cabinet seem to work only on shore power, and not on the inverter, so I went to investigate.

The light on the inverter switch lights up ok, but looking in the bay in front of the entry door I don't actually see an inverter, unless it's one of the component looking things without covers on it... certainly nothing that looks like any of the store bought inverters I'm familiar with. I do see a space where it looks like one might have been (red arrow). Is this where the inverter would have been?

Also, these electrical outlets on the left side of the bay... would one of these plugs have connected to the output of the inverter?

If it's what I'm thinking it looks like the inverter has been removed and bypassed.

Thanks in advance.

Skip426 · 08-29-2020, 12:27 PM

It would appear that an inverter ( with battery charging ) has been removed and a converter installed in it's place.
A large inverter would have been wired in with house type wiring not a plug.

The unit above and to the left of your arrow( black cord from outlet with cooling fan visible) Looks like a converter / charger .
Can you get make and model info off that unit and add it to your post .

Richard S. · 08-29-2020, 12:34 PM

In 2004 dolphin and lx models a 600 watt inverter was standard and the 2000 watt inverter was optional. you may have a 600 watt in the overhead cabinets or tucked away.

Richard S. · 08-29-2020, 12:49 PM

link to National RV brochures Index of /wp-content/uploads/National

TJHUB · 08-29-2020, 02:34 PM

In my 2004 Seabreeze, that tan plug is for the TV circuit, and is currently plugged into my inverter. If you were to remove the inverter, you would have to plug that tan plug into an outlet or your TV would never work. Try unplugging it and see if your TV circuit goes off.

Those component looking things without covers are your Battery Control Center and slide out relay boards. Those have nothing to do with the inverter circuit.

Are there any large battery cables taped off and not connected to anything in that cabinet?

CamJam1 · 08-29-2020, 04:22 PM

Yes, the box with the fan is a power converter (can't see the brand or model number without removing it) and the tan plug does indeed go to the TV, so it does look like the inverter was removed.

Interesting that the B.O.M.B. still works without shore power, so it must be a 12 VDC device.

I'm thinking the large "taped off" wires mentioned are probably the wires that are now connected to the power converter.

Thanks for all the responses. I think that confirms that I need to get another inverter!

Skip426 · 08-29-2020, 09:06 PM

It would appear that yours was a manual bypass inverter much like the AV system inverter ( 400 watt ) that was the base unit in my Newmar .
If all you want to do is power the TV and related equipment then adding a 400/600 watt inverter is all that's required . If you want the remote activation then the $$$ goes up .

CamJam1 · 08-29-2020, 09:28 PM

Went through the original file case of all the brochures that National supplied with each coach, and it looks like mine originally had a Dimensions Unlimited DUI-12/600, which is a 600 watt modified sine-wave inverter. I can get a 500W full sine wave for less than $100 on Amazon. That would be plenty for the LED TV, speaker bar and a laptop computer, but I'm thinking it might be nice to run the Dometic fridge on the inverter too, but only when going down the road. How much do those things draw when running on electric I wonder?

Skip426 · 08-29-2020, 09:58 PM

Find the fridge manual and see what they list the 120 volt heater as ( probably given in watts ) . If it's in amps , there is a conversion ( Amps x 120 volts = watts ) and allow a cushion of 25/30 % .

Getting the power from the inverter to the fridge is most often the real challenge .

EDIT: Found some info from my manual , didn't find the actual heater amps , but the control board mounted fuse for the, 120 volt heater circuit is 5 amps . So a 600 watt inverter would be the minimum 800 or 1000 watt preferred.

twinboat · 08-30-2020, 05:11 AM

The gas/electric fridges running on electric draw 350 to 500 watts depending on its size. They rairly shut down.

350 watts, at 12 volts is 30 amps, plus losses, from the inverter. 500 is over 40 amps.
Not that bad for the alternator but if you forget and don't have shore power plugged in, you will have a dead battery by morning.

For the tiny bit of propane you save, its not worth it.

TJHUB · 08-30-2020, 08:56 AM

Quote:

Originally Posted by CamJam1

Went through the original file case of all the brochures that National supplied with each coach, and it looks like mine originally had a Dimensions Unlimited DUI-12/600, which is a 600 watt modified sine-wave inverter. I can get a 500W full sine wave for less than $100 on Amazon. That would be plenty for the LED TV, speaker bar and a laptop computer, but I'm thinking it might be nice to run the Dometic fridge on the inverter too, but only when going down the road. How much do those things draw when running on electric I wonder?

That's the exact same inverter I'm taking out of my Seabreeze. I'm certain it had the "T" option which means it had an automatic transfer switch.

Do yourself a favor and research MSW vs PSW inverters, understand auto transfer switches, and get a size that will be useful for future needs. Also know that only your TV circuit is set up for inverter use. I'm running a new circuit to run both my fridges off the inverter with a separate auto transfer switch.

CamJam1 · 08-30-2020, 04:10 PM

Quote:

Originally Posted by TJHUB

That's the exact same inverter I'm taking out of my Seabreeze. I'm certain it had the "T" option which means it had an automatic transfer switch.

Do yourself a favor and research MSW vs PSW inverters, understand auto transfer switches, and get a size that will be useful for future needs. Also know that only your TV circuit is set up for inverter use. I'm running a new circuit to run both my fridges off the inverter with a separate auto transfer switch.

Yes, from the booklet it appears my original inverter had the "T" option too. I'm a little confused as to why an inverter needs an automatic transfer switch though if the inverter outlets are on a separate circuit, as they appear to be here. My understanding is that the tan plug connects those outlets to the inverter AC output so that they are isolated from the other outlets. I guess the disadvantage is that the inverter has to be operating to watch TV, but I can't think of any other reason for a transfer switch here.

I do have some experience with inverters and electronic equipment. Pure sinewave (PSW) is the only way to go for an LED TV and satellite receiver, though in general I've found them to be more prone to failure than MSW.

I went to the moho today to understand how to connect the inverter to the distribution panel. I was expecting the distribution board to have blade fuses, as I have seen pictured in other threads, but it instead has circuit breakers (see photo). I'm guessing that this was an upgrade made sometime after 4/2002 (the date of the schematic I had). Fortunately, the cabinet door in the bay had the updated schematic glued to the door, and I can see that the inverter +12 VDC line should connect to J11 (red arrow in photo). My voltmeter shows that this terminal is active regardless of the position of the inverter switch inside the entry door, so I guess they must instead be switching the ground. Can anyone tell me where the inverter -12 VDC line is supposed to connect so that the entry way inverter switch works?

EDIT: Ok, I see from looking at the manual for the original inverter that it had a separate line for the remote on/off switch, so I'll need to use an inverter with the same setup if I want the switch to be operable.

CamJam1 · 08-30-2020, 06:01 PM

Can anyone tell me which terminal on the distribution board the violet wire on the Dimensions Unlimited DUI-12/600 inverter connects to?

Also curious where inverter's -12VDC line (white wire) is connected. Not seeing anything in the schematics about these.

Thanks!

TJHUB · 08-30-2020, 09:42 PM

Quote:

Originally Posted by CamJam1

Yes, from the booklet it appears my original inverter had the "T" option too. I'm a little confused as to why an inverter needs an automatic transfer switch though if the inverter outlets are on a separate circuit, as they appear to be here. My understanding is that the tan plug connects those outlets to the inverter AC output so that they are isolated from the other outlets. I guess the disadvantage is that the inverter has to be operating to watch TV, but I can't think of any other reason for a transfer switch here.

I do have some experience with inverters and electronic equipment. Pure sinewave (PSW) is the only way to go for an LED TV and satellite receiver, though in general I've found them to be more prone to failure than MSW.

I went to the moho today to understand how to connect the inverter to the distribution panel. I was expecting the distribution board to have blade fuses, as I have seen pictured in other threads, but it instead has circuit breakers (see photo). I'm guessing that this was an upgrade made sometime after 4/2002 (the date of the schematic I had). Fortunately, the cabinet door in the bay had the updated schematic glued to the door, and I can see that the inverter +12 VDC line should connect to J11 (red arrow in photo). My voltmeter shows that this terminal is active regardless of the position of the inverter switch inside the entry door, so I guess they must instead be switching the ground. Can anyone tell me where the inverter -12 VDC line is supposed to connect so that the entry way inverter switch works?

EDIT: Ok, I see from looking at the manual for the original inverter that it had a separate line for the remote on/off switch, so I'll need to use an inverter with the same setup if I want the switch to be operable.

If you are only planning to run the TV on the inverter, I guess that's fine to only run it off the inverter. The transfer switch in our coaches were able to run the TVs on shore power if available. Is that really important? Probably not. Your decision I guess.

I will be pulling my original inverter out tomorrow. I will take note and pics of exactly how it is connected. My inverter switch never worked, so my inverter was always on. I noticed all new inverters seem to have optional remote panels that are RJ45 connectors or the like. I'm thinking the original inverter switch we have won't be compatible. I'm replacing mine with a whole new switch and plate.