I put a Xantrex Prosine 2.0 in my fiver with the idea of being able to run the TV, VCR/DVD, the microwave, and my electric razor. In my pup, I had used a little portable inverter for the razor. Well whenever I wanted to use the microwave, the batteries were run down too much.
With my new TT, I am taking a different approach. It came with a Jensen stereo system with DVD player that runs off of 12 volts. I just bought and installed a 24" Jensen LED TV that also runs off of 12 volts (draws 3.3 amps). If one had to buy both units, it would be about the same cost as a good inverter setup (remember it is not just the cost of the inverter, but also the heavy duty cables and the mongo fuse). It is also easier to wire up the TV than wire up an inverter (I know because I have done both now).
I still have the portable inverter I used in the pup that I will use for my razor in the new TT (I forgot that razor one time on a weeks vacation -- there is much less blood loss with the electric razor).
Thanks for pointing that out. You are correct that the NC contacts are rated for only 8 amps, or 960 watts at 120v. However, these are the contacts used by the inverter, which is only 650w and which is itself larger than needed for the load (42 inch led tv, sound system, small fridge and phone charger). As the inverter cannot supply more than the contacts can take, I think I am alright, though it would be nice to have a little more margin. The NO contacts used by shore power are rated for 25 amps, so no problem there.
As mentioned, though, I'm no electrician, so take whatever I say with a healthy dose of salt!
We have an AGM battery under the entertainment center with an 1500 watt inverter and small battery charger, when we dry camp we used the battery and can get 4-6 hours out of the TV or DVD. During the day when I run the generator I charge the AGM battery while charging the trailer batteries.We don’t watch that much TV but on a cold or rainy night it is nice to have the entertainment center available and only have to change the plug from the wall outlet to the inverter outlet.
I too wanted to power my TV and DVD player with my inverter, but hooking it up and putting away was a pain with battery cables and extension cords and also then having to deal with them strewn all over.
I knew the inverter had to be close to the batteries, so I mounted it in the front storage area and used short heavy 8 gauge cables to run to the 12V to the tongue area.
I did not know where or how to interface to the individual AC outlet by the TV, so I decided to power the entire circuit at the Fuse/CB Box/Converter. The 15A CB that powers the AC outlet by the TV also powers the one under the Dinette table, the two by the bed and the second TV outlet in the bedroom. That's good, but the issue is it ALSO powers the converter. The hard part was isolating the circuit from the converter which it tied in right at the Circuit Breaker. I removed the length of 14/2 romex from the back of the converter and ran a short length of 14/2 in its place into a switch box that I mounted under the sink.
The 3-way switch allows the current in normal mode (up) to be routed from the Shore Power (or Generator) to the utility circuit and when switched down it routes the power from the inverter to power the utility circuit.
The AC output is routed down through the floor and frame cross-members with rubber grommets and cable clamps. It then goes back up through the floor into the trailer by the Fuse/CB Box/Converter under the stove and into the switch box.
When dry camping, I can access the inverter to turn it on and off by lifting the bed or by reaching into the storage area outside. Then of course I flip the switch to the Inverter position.
Thanks for pointing that out. You are correct that the NC contacts are rated for only 8 amps, or 960 watts at 120v. However, these are the contacts used by the inverter, which is only 650w and which is itself larger than needed for the load (42 inch led tv, sound system, small fridge and phone charger). As the inverter cannot supply more than the contacts can take, I think I am alright, though it would be nice to have a little more margin. The NO contacts used by shore power are rated for 25 amps, so no problem there.
As mentioned, though, I'm no electrician, so take whatever I say with a healthy dose of salt!
Hi dforster,
Your inverter is capable of 1300 watts surge which is above the 8 amp rating of the NC contacts. I understand you may operate within those restrictions, but if others are to do the same install they should fully understand the limitations of your design.
How are you isolating the neutrals from the two power sources. When switching power sources BOTH the hot and neutral must be isolated. In your diagram the neutrals are connected in the inverter switch box. If the shore power is energized and the inverter is powered up with the switch in either position, the smoke should come out of something. I suggest you replace your SPDT switch with a DPDT switch to keep the smoke inside your inverter.
* This post was
edited 05/06/12 12:44am by shooted *
How are you isolating the neutrals from the two power sources. When switching power sources BOTH the hot and neutral must be isolated. In your diagram the neutrals are connected in the inverter switch box. If the shore power is energized and the inverter is powered up with the switch in either position, the smoke should come out of something. I suggest you replace your SPDT switch with a DPDT switch to keep the smoke inside your inverter.
Shooted, In my current configuration, I am not isolating the neutrals. As you have noticed in my diagram, they are common. I am not so sure about your statement "BOTH the hot and neutral must be isolated" as it has been working fine and "keeping the smoke in" for over a year with mixed dry camping and Shore/Generator power.
I do see your point and I did originally plan on using a DPDT switch. But, in order to have an issue, there would have to be a difference in potential across the hot and neutral fed back into the inverter. by isolating the hot only, this prevents that. The only way there could be a problem is if the generator/shore power has a diffence in potential between the neutral and ground for whatever reason AND the inverter has some circuitry that bridges between those.
Thanks for your comment and I'd be interested to hear more thoughts on this.
Isolating power sources is not something to be taken lightly. It is not only prudent but also required by code to isolate BOTH the hot and neutral. If done incorrectly there is a health risk.
NEC 551.33 Alternate Source Restrictions. Transfer equipment, if not integral with the listed power source, shall be installed to ensure that the current-carrying conductors from other sources of ac power and from an outside source are not connected to the vehicle circuit at the same time.
In this application the neutral would be considered a current-carrying conductor, and in the previous post the neutral from the inverter is tied to the shore power neutral with no means of disconnect.
NEC 705.20 Disconnecting Means, Sources. Means shall be provided to disconnect all ungrounded conductors of an electric power production source(s) from all other conductors.
With regards to this topic, the grounded conductor(neutral conductor), is ungrounded.
Many inverters actually read 60 volts between the neutral and ground. If this neutral is not isolated from the shore power cord, the shore power cord will also have this 60 volts exposed on the plug! Ouch! Here is a final reference explaining this. Please read and understand this fully before emulating the previous post. Simply swapping out the SPDT switch with a DPDT switch would resolve the health risks.
Shooted, Thanks for the reply and the link. I never measured my inverter neutral to ground voltage, but that is very interesting about the 60 volts. I am going to replace the switch to isolate the neutral.
I just made sure I found a LED TV that used an external power adapter at 12V instead of the traditional 120V direct connect. I Wired the TV directly to the 12V RV wiring. No more additional step-up power converting loss and a lot cheaper on the wallet.
The difficulty is finding a TV with this setup. Two years ago it was like 1 out of 20 TVs. Not sure what it is today.
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