Bonding common to ground and where?

Seedsca · July 2012

Hi all. I have finally gotten the battery wires and system set up for the inverter charger to go in. Now I have ran into another issue. I hope this makes sense.

I will be using a generator to charge the batteries until I get the PV system set up. Not really planing on using grid power. The grounds for the AC and DC seem to be going to the chassis. They are bonded at the AC panel in the fifth wheel. I have relocated the AC input to where the Xantrex ProSine2 will be. I have two questions.

1. Should I also ground the frame of the inverter to the chassis?
2. I have the option of leaving the ground and common unbonded at all times in the inverter or having them bond automatically when it detects shore power, for me it will be a generator. Does this not create two point where the ground and common are bonded? And is that not something I want to avoid?

I don't think I need to actually put a ground rod in, do I?

Maybe silly questions, but I'm not %100 on this part.

Cariboocoot · July 2012

Re: Bonding common to ground and where?

Grounding the inverter frame to the RV chassis is a good idea. Having two neutral-ground bonds is not.

Since RV's do not actually have Earth grounding rods (a bit difficult to arrange in a mobile application) I would not have any neutral-ground bond: leave the AC "floating". The auto-bond when shore power is detected is for "real" shore power where the ground is actually tied to Earth. Without that, the bond simply "energizes" the chassis with one side of the AC creating a potential shock hazard should someone become a conductor between the chassis and Earth (touching the metal with their wet feet on the sand for instance).

vcallaway · July 2012

Re: Bonding common to ground and where?

My inverter instructions stated for mobile use to have the earth ground lug attached to the chassis.

My inverter runs 24/7 even when we are plugged in. It is a true sine wave inverter and our TV, Sat receiver and computer run off of it. That way I know they are getting clean power no matter what the grid is doing.

Your inverter manual should have instructions for grounding for mobile use. They are not all the same.

Seedsca · July 2012

Re: Bonding common to ground and where?

Ok I got it hooked up and the panel lit up. No explosions yet

I haven't turned the inverter or the charging features on. I still have to configure it to my specific system.
One last question. I notice on the AC panel that the ground and common are bonded, but also they are connected to the breaker box frame. Should I remove all three wires that interconnect them? One connecting the ground and common and one going from the common and ground buses to the breaker box frame.

Thanks for your input, it's invaluable.

Cariboocoot · July 2012

Re: Bonding common to ground and where?

The grounding can be connected to the box frame; it's all "chassis" at this point. The neutral AC line should be disconnected from the box frame.

Seedsca · July 2012

Re: Bonding common to ground and where?

All hooked up! Thanks. Now on to trouble shooting the charger not seeing the AC in....

Seedsca · July 2012

Re: Bonding common to ground and where?

I am at work now but will be trouble shooting this tonight. I hope it's not the charger being bad. The display pannel indicates no input voltage and the diagnostics say that the input voltage is lower than anticipated. When I disconnect the generator it still indicates no voltage but there is no diagnostic error. The very little bit or research I've done so far indicates it might be a grounding configuration or just a bad charger. Not sure yet.

Any thoughts on what to check? All cables and connections seem to be tight.

Cariboocoot · July 2012

Re: Bonding common to ground and where?

Is this the stand-alone charger from Sears or the Prosine built-in charger?

For a stand-alone, it's pretty easy to detect in/out. Make sure you haven't plugged the thing into the inverter's output; that will just go 'round and 'round not charging 'til the battery is dead.

For a built-in, it's a bit more difficult. You can check the Voltage at the AC in and make sure, again, that "in" isn't wired to "out". It can get confusing, especially with generator/shore power inputs or if there's a "Voltage converter" like many RV's have.

Grounding shouldn't enter in to it, unless something is drastically wrong in the AC wiring department (ground and neutral mixed up to the power so it's trying to get AC from "Hot" and ground instead of neutral + no or weak neutral/ground bond).

Seedsca · July 2012

Re: Bonding common to ground and where?

This is only referring to the xantrex inverter/charger. The neutral and ground are not bonded anywhere, that's what you had recommended right? Also the generator outputs 60v from each leg adding to 120v, would this be an issue? The converter never worked, so I removed it.

Thanks for your input!

Cariboocoot · July 2012

Re: Bonding common to ground and where?

What sort of generator has 120 split into two 60 Volt legs?

That is suspicious right there.

Try feeding the Prosine from grid power if you can and see if that fires it up. Then you'll know it is good and there's something wrong with the gen or wiring.

"The converter never worked, so I removed it." That's a phrase that sees frequent use. :roll:

Seedsca · July 2012

Re: Bonding common to ground and where?

It's a Honda em2500. I just tested it and it gives me 58v when I put the meter from ground to hot and the same from the ground to neutral from it's output plug. It's been powering the fifth wheel just fine... maybe not? I am on a fully off grid site so no chance of plugging it in to the grid. I will try and borrow another generator ( actually just like your eu2000) and try. Sound suspect as when I was testing the voltage seemed to jump around a bit.

Also just to clarify. Right now I have the neutral and ground NOT bonded anywhere and the ground is just to the chassis.

Cariboocoot · July 2012

Re: Bonding common to ground and where?

Okay, there's your first problem. It's a 120 VAC generator. You do not measure Voltage from ground to hot or neutral. The Voltage is from neutral to hot. On a free-standing generator there is no actual Earth ground, so there's a Voltage potential from either of the output terminals to ground. Ignore this. Just take the 120 VAC from neutral to hot. The Prosine should work in charge mode with that applied to its input.

This is one of the reasons you don't want the neutral-ground bond: it makes the Voltage potential between hot and any part of the RV's chassis 120, and from the chassis to "real" ground 60. Either could give you quite a shock.

BB. · July 2012

Re: Bonding common to ground and where?

Typically, there is enough capacitance (stray and possibly filter capacitors) that you will see ~55-60 VAC from either "hot" to frame ground on the genset (assuming less than ~3,500 watt rating--Large gensets should have a hard neutral connection to frame from the factory).

If you are concerned, that a 120 VAC filament light bulb (4-100 watts) and attach the bulb to earth ground and then attach to one of the "floating" hot leads. In theory, once lead should go to near frame ground (the one "grounded through the lamp") and the other should go to 110-120 VAC.

If the lamp lights/glows instead, then there is really a hard connection somewhere in the system to a center-tap neutral bond (either on purpose or a short circuit).

-Bill

Seedsca · July 2012

Re: Bonding common to ground and where?

Doesn't look too good. I checked the AC in at the splice right before going into the inverter and it has 120v. The inverter still does not see any incoming AC and the cables are hooked up right. In to in, out to out. Might it be a dud? The AC worked fine before I meddled with it. So I would assume (yeah I know what it stands for

) that all that is fine. The AC output when inverting works fine also. It does not seem to think there is voltage coming in. Only indication of Voltage in is the diagnostics mention that there is too low a voltage to charge and only some times.

I am not looking forward to the next step. Dismantling and taking the Xantrex apart to see what I can find... Or am I jumping the gun and should try something else first?

Thanks again for your quick responses, I was sooo close....

Cariboocoot · July 2012

Re: Bonding common to ground and where?

Question: with it all hooked up and not working, is there 120 VAC at the AC IN on the Prosine?
If there is, it should work. If there isn't, something's wrong with the wiring. If there is and it doesn't work something is wrong with the inverter. To that end it may have an internal fuse/breaker which has popped due to some misconnect or other abuse. If that's all that's wrong you can probably fix it. Beyond that and you're in trouble.

Seedsca · December 2012

Re: Bonding common to ground and where?

It's been a long while but I have great news. I finally had the time to "clean up" the wiring and decided to take apart the Prosine2. I fund my self with mixed emotions when I found a cable deep inside the belly of the beast not plugged in. Long story short, it is now charging like a champ!

Problem now it that looking at the settings for charging the batteries, I slightly lost.

I have six Interstate 6v part number GC2-XHD-UTL batteries in series parallel to form a 12v system.
This gives me 232ah x 3 or 696ah, right?

As I'm setting up the Prosine2, it all seems to make sense. Except the value I should put for Max Current (%C) on all of the charging settings. I left those settings alone.

This is what I have so far. ANY help would be greatly appreciated.

This is from page 82 of the manual

Battery Size: 690ah would not let me put in 696ah

Default Battery Temp: Warm

Battery Type: Flooded

Bulk Mode Settings:
Max Voltage: 14.4
Max Current (%C): 30% left these default
Threshold Voltage: 15.2 so after 3 minutes it goes to Absorption
Threshold Timeout: 3 min

Absorption Mode Settings:
Max Voltage: 15.3
Max Current (%C): 30% left these default
Max Timeout: 4hr
Threshold Current (%C): 2.5%
Threshold Timeout: 3 min

Overcharge Mode Settings: Not sure what this Mode even is. It seems to be referenced as Absorption/Overcharge in the manual.
Max Voltage: ?
Max Current (%C): ?
Threshold Timeout: ?

Float Mode Settings:
Max Voltage: 13.4
Max Current (%C): 200% left these default
Max Timeout: 21 days
Threshold Current Voltage: ?
Threshold Timeout: 15 min

Equalize Mode Settings:
Max Voltage: 15.6
Max Current (%C): 2.5% default
Max Timeout: 2hr
Threshold Voltage: .1
Threshold Timeout: 30 min

Constant Mode Settings: don't think I'll be using this
Voltage Setpoint: ?
Current Setpoint: ?

Anyone with a Prosine2 or lots of knowledge have more of a clue than me?

Bonding common to ground and where?

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