This is totally baffling

[Neuromancer]

I know a bit about electrical but this one has me stumped. I removed the UniVolt and installed a ProTech charger and a separate inverter. The inverter's purpose is to replace shore power so I connect directly to it, when needed, with my shore power line. When connected to utility system shore power everything is fine. When connected to the inverter it shuts down. I have determined that by disconnecting the battery banks (the ones powering the inverter) from the 12 volt system the inverter/shore power connection works fine. While troubleshooting to fix this problem I discovered this truly baffling thing. I have continuity between my 12 volt ground (the chassis) and all three of the wires in my shore power connection! Why does the shore power and 12 volt system work fine when connected to any feed (my generator included) other than the inverter? And why is the trailer not on fire or me dead?

[markdoane]

I don't know what your problem is. I do know that you must not allow a condition where the batteries are powering the inverter, which is providing 120v to the charger, which is trying to recharge the batteries. Do that on a Trace or Xantrex inverter and you will blow out the warranty card.

Make sure you don't have a loop like that trying to develop. Maybe the inverter or Protech charger is smart enough to detect that condition and is shutting down to save themselves.

[Neuromancer]

Thank you. I do have a switch so that I can isolate (power down) the charger to avoid the loop.

In today's work I have discovered that the 12v and 110v systems share a common ground. This explains some of the things I was experiencing. Now I am trying to determine why it was wired that way. My suspicion is that it was original and has something to do with the UniVolt. It may have been an error at a later date, who knows? The questions I'm grappiling with now are: How big a PITA is it going to be to find the location of the 110v ground to chassis (I've already got an hour in that project)? Is there any problem by removing that ground to chassis, when I find it, and letting the 110v be totally isolated from the 12v? The second question comes from the fact that the 12v ground (negative battery terminal/chassis) will also be providing the ground to the 110v inverter and I'm wondering if that will be a problem.

Wish me luck.

[Phoenix]

I'm not sure I understand -- Is the inverter output (110 VAC) connected in parallel to the shore power (110 VAC)?

[ArtStream]

Love C. Gibson....

[mustang]

The inverter is supposed to either get its power from batteries, or shore (AC) But the A/C should have its own breakers seperate.

In essence you have 2 sytems. AC / DC When you plugged into shore, your A/C outlets work, and it powers your inverter to charge the batteries and run 12 stuff ( lights, ect) When your unplugged from shore power only your 12 volt stuff works.

If you are sure, you have it hooked up right, I would start looking for either a mouse ate some wire covering, causing it to lie on metal or be against a ground. Maybe even a screw was put threw wireing. I also wonder maybe the problem existed before, causing you to undertake this inveter/ univolt replacement.

Either it was installed wrong, or there is an underlying problem. Good luck, electrical is tricky.

[Phoenix]

Quote: "I removed the UniVolt and installed a ProTech charger and a separate inverter."

By "inverter", do you mean it changes 12 volts DC to 110 volts AC, or do you mean you installed a "converter" that converts 110 volts AC to 12 volts DC?

If you mean "inverter", and you are connecting the 110 VAC output of the "inverter" in parallel to the 110 VAC shore power, then that may be the problem.

It isn't sufficient that the voltage be the same value, the phase of the two AC power sources must be in synch with each other. Otherwise, the inverter is probably shutting down.

Please provide more information on the "inverter" that you installed (brand, model, etc.).

[Neuromancer]

It is a DC to AC inverter. I can plug my shore power into shore OR the inverter, never both since I use only the shore power cord for either. Input to the inverter is from my house bank. It is an AIMS and the model number is currently buried in the installation. If I disconnect the 12 volt system from the house bank, the inverter operates everything as intended.

Mustang - I am inclined to agree that there is an error and screws/rivets through wiring would be the desired culprit. Finding a mouse's work will be challenging. I replaced the UniVolt only to install a large housebank with current technology smart charging capability for longevity.

Also, thanks to all of you for your interest.

[Phoenix]

Sorry to keep asking so many questions, but I need a little more information:

1. Did your current installation run correctly initially, and now shuts down; or has it never run properly?

2. What size is your AIMS inverter (in watts, e.g., 2500 watts).

3. How is the AIMS wired into your 12 volt system?

4. Are you running the AIMS off of the Pro Tech charger, 12 volt batteries or both?

5. Where does the 110 VAC output from the AIMS go (e.g., are you plugging AC powered items like a TV, etc., directly into the AIMS; or perhaps are you powering the Pro Tech charger from the output of the AIMS)?

It would really help if you describe how all of the wiring is routed, as I can't quite tell from the information you have provided so far. There are numerous wiring errors that could cause the problems you are seeing, especially if this is a new set-up that has never run properly.

Perhaps you could draw some block diagrams, or explain the wire routing in more detail.

Thanks...

[Neuromancer]

Sorry to keep asking so many questions, but I need a little more information:

1. Did your current installation run correctly initially, and now shuts down; or has it never run properly? No, it has always required that I isolate the wires that run from the house bank to the 12v bus and ground (the same house bank that powers the inverter).

2. What size is your AIMS inverter (in watts, e.g., 2500 watts). 2500

3. How is the AIMS wired into your 12 volt system? Direct to the house bank w/#2 wire running 4' round trip.

4. Are you running the AIMS off of the Pro Tech charger, 12 volt batteries or both? House bank only.

5. Where does the 110 VAC output from the AIMS go (e.g., are you plugging AC powered items like a TV, etc., directly into the AIMS; or perhaps are you powering the Pro Tech charger from the output of the AIMS)? I plug the shore power cord directly into it at which time the charger is isolated with the on/off switch in the off position. It works fine with an extension cord directly to it and any 110v gear.

It would really help if you describe how all of the wiring is routed, as I can't quite tell from the information you have provided so far. There are numerous wiring errors that could cause the problems you are seeing, especially if this is a new set-up that has never run properly.

Perhaps you could draw some block diagrams, or explain the wire routing in more detail. I'm tech challenged with posting drawings so, two wires from the house bank to the 12v buss and ground, two wires from the house bank to the inverter, two wires from the house bank to the charger, shore pwer plug directly into the inverter, on/off switch between the charger 110v input and the charger for isolation. All wiring that I have installed is to ABYC spec.

[Mrcrowley]

Charger ? I though the inverter did the charging? The inverter provides power to the 12 volt systems and to charge the battery. Where does the charger come in play?

Give us run down step by step on how you got it work properly .

[Mrcrowley]

Originally Posted by Neuromancer

I know a bit about electrical but this one has me stumped. I removed the UniVolt and installed a ProTech charger and a separate inverter. The inverter's purpose is to replace shore power so I connect directly to it, when needed, with my shore power line. When connected to utility system shore power everything is fine. When connected to the inverter it shuts down. I have determined that by disconnecting the battery banks (the ones powering the inverter) from the 12 volt system the inverter/shore power connection works fine. While troubleshooting to fix this problem I discovered this truly baffling thing. I have continuity between my 12 volt ground (the chassis) and all three of the wires in my shore power connection! Why does the shore power and 12 volt system work fine when connected to any feed (my generator included) other than the inverter? And why is the trailer not on fire or me dead?

Ok do you mean converter or inverter because batterys dont run a inverter. I am confused but it could just be me.
Converter makes 12 volt to 110 volts.
Inverter powers 12 volts systems and charges batterys.
It sounds like you have a charger and a inverter and a converter is this true?

[47WeeWind]

Originally Posted by Mrcrowley

Ok do you mean converter or inverter because batteries don't run a inverter. I am confused but it could just be me. Converter makes 12 volt to 110 volts. Inverter powers 12 volts systems and charges batteries. It sounds like you have a charger and a inverter and a converter is this true?

Hi Mrcrowley;

With respect, I think it is you who is confused. Here's a mnemonic I use to remember which electrical device does what. An INverter INcreases voltage from 12 volts to 120 volts AND changes it from DC to AC. A CONverter CONtracts voltage from 120 volts AC to 12 volts DC while also changing it from AC to DC. Some CONverters that are plugged into 120 volt AC plugs also have battery chargers (the best being 3 stages chargers) which charge the 12 volts DC batteries while also CONtracting the 120 volts AC to 12 volts DC to power a 12 volt system.

I hope this non-electrical mnemonic device helps you in the future. Those who know me well would tell you its a wind-powered device or perhaps one that operates on the Stirling cycle.

[47WeeWind]

Originally Posted by Neuromancer

I know a bit about electrical but this one has me stumped. I removed the UniVolt and installed a ProTech charger and a separate inverter. The inverter's purpose is to replace shore power so I connect directly to it, when needed, with my shore power line. When connected to utility system shore power everything is fine.

Hi Neuromancer:

I am not an electrical engineer and don't play one on TV, but perhaps your problem arises because you plug your shore power line into your inverter. That's seems like it would cause some type of double-looping, a non-electrical fantasy term for something I don't understand but which nevertheless sounds wrong. You should only plug your 120 volt appliances into the 120 volt AC outlet on your inverter. Don't plug your shore power cord into your inverter. That may be the genesis of your troubles.

Try running a few 120 VAC appliances directly from the 120 VAC outlet on your inverter and keep your shore power plug unplugged. Then tell us how thing work out for you. With high hopes,

[Mrcrowley]

Originally Posted by Mrcrowley

Ok do you mean converter or inverter because batterys dont run a inverter. I am confused but it could just be me.
Converter makes 12 volt to 110 volts.
Inverter powers 12 volts systems and charges batterys.
It sounds like you have a charger and a inverter and a converter is this true?

Ok I didn't get my second cup of coffee and my brian was asleep I apologize
should have stayed in bed .........

[Neuromancer]

And the answer is..............

Somewhere behind the walls a white 110v (I call it the gound) has contacted the skin or a frame member, uniting it with the 12v ground. I was able to isolate the offending wire with a continuity test. Fortunately, it was connected to a 110v outlet so I had easy access. Disconnected the wire, everything works great and I'm taking a break from maintenance for awhile. Well, except for the wheel bearing repack and brake check prior to next weeks road trip. 2,300 miles and 4 days on two racetacks.

[Phoenix]

If you are familiar with AC wiring, please disregard the following, as I don't mean to offend...

Just a comment, but the wiring color code for 110 VAC and 12 VDC is not the same. Most people are familiar with auto 12v wiring, with red being +12 and black being ground. Did you follow standard AC wiring for the 110 VAC output, which is black is "hot", white is "neutral" and green or green/yellow stripe is safety ground?

If you have a 110 VAC white wire connected to the 12 VDC "chassis ground" (black wire), that is why you are getting shocked. Both black and white 110 VAC wires have voltage on them, and connecting the white wire to ground will probably result in the chassis floating on 110 VAC (a potentially serious safety/electrocution problem).

In a sense, on the 110 VAC wiring, both the black and white wires are "hot", since they alternate polarity, and neither should be connected to the "chassis". That is what the green or green/yellow striped wire is for.

I don't mean to be an alarmist, but the 110 VAC output from even a small inverter can electrocute a person; and if you are unsure if you have a ground fault, you may wish to consult an electrician before having a serious accident.

Inverters are so common now that we forget that they are not like 12 VDC, which usually just throws a few sparks (unless you've ever seen a direct short, which makes things glow and smoke!). And, they can deliver a fatal shock, the same as sticking your finger in a wall socket at home.

Be safe...

[Neuromancer]

Originally Posted by Phoenix

If you have a 110 VAC white wire connected to the 12 VDC "chassis ground" (black wire), that is why you are getting shocked. Both black and white 110 VAC wires have voltage on them, and connecting the white wire to ground will probably result in the chassis floating on 110 VAC (a potentially serious safety/electrocution problem).

In a sense, on the 110 VAC wiring, both the black and white wires are "hot", since they alternate polarity, and neither should be connected to the "chassis".

That's what I was saying in my first post: "......why am I not dead?" I was never getting shocked and still don't understand that. Perhaps between the wood floors and rubber tires I was not getting grounded?