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Inverter Wiring Question

electrical wiring inverters solar

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#1 Rojo

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Posted 06 June 2020 - 01:00 PM

Finally got my inverter and have a wiring question.

 

I am going to install it with a 30a outlet to the exterior and plug in the main power to it to access.  In order to do this I must install a relay to disrupt the converter/battery connection.  When the inverter is powered up the relay will open and the charger will no longer provide power to the battery.  So, as is obvious, I am neither an electrician nor electrically inclined, and therefor want to get a clarification before I go slicing and dicing. 

 

Investigation has shown that the 12v controller panel block has four wires (black, similar for white) in the same block.  I have identified them as:

 

A. to the converter,

B. to the controller

C. to the battery

D. to the trailer hookup harness.

 

It looks to me as if I install the relay somewhere in the black wire between the panel and the battery I can accomplish what I want, disconnecting the charger from the battery without disrupting the remaining 12v service. 

 

The only other complication is that the solar panel goes directly to the controller as does a separate set of wires from the battery but I think this is drawing from the battery and has nothing to do with charging.

 

Am I correct in this or am I overlooking something?


Edited by Rojo, 06 June 2020 - 01:01 PM.

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#2 Euphoria

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Posted 07 June 2020 - 08:58 AM

Just a point of clarification. There are "Inverters" which convert 12 vdc to 120 vac. Then there are "Converters" which converts 120 vac to 12 vdc. You mention both in your post, but I'm thinking that you are referring to the latter, as these are what our trailers come with. That said, first, it would be helpful to know exactly what converter you have. Some pictures would be nice too!

 

I installed a new Progressive Dynamics 4-stage "smart charger" lower unit in my existing 2008 Parallax 7300 Series converter. I also installed a 30 Amp "Marine style" twist-lock shore power cord fitting, which makes it much easier to hook up and break down when you're done.

 

I also installed a Progressive Industries 30 Amp Hard-wired EMS, (electrical management system,) on the shore power line between the back side of the twist-lock outlet and the converter as well. However this is not required whether you connect or disconnect your shore power. To install it, I only needed to cut the shore power cord inside the trailer, leaving about a 3 foot end, which then was connected to the terminal lugs on the back of the twist-lock plug I installed. The rest of the remaining shore power cord was fitted with a new female 30 Amp twist-lock end for plugging into the outlet on the trailer, and will continue to function as it would if it was all just a one piece wire from the converter to the power pedastal.

 

What I'm not understanding from your post, or at least it is somewhat confusing, is why you would think that you would need a relay to break the charging circuit to the battery when you hook up or disconnect the power cord. Just disconnecting your shore power cord from the trailer automatically breaks the battery charging circuit since there is no power available to perform the charging function. If your purpose is to isolate the battery from the charger, whether to prevent overcharging or draining the battery, a simple battery cut-off switch is all you need. 

 

As an aside, having a larger access hatch to replace the small power hatch the trailer comes with will help immensely with your new proposed installation. Here's some pics and info on my conversion.

 

JR Products ZE102-A Polar White Large Key Lock Multi-Purpose Access Hatch (This is currently out of stock on most sites I checked, but this is the hatch cover you want.) It is the same width as the existing shore power hatch, just taller.

 

https://www.amazon.c...l/dp/B002UC6RSA

 

https://www.amazon.c...n/dp/B000NUYZQC

New Electrical Hatch2.JPG New Electrical Hatch1.JPG New Electrical Hatch3.JPG new 007.JPG new 008.JPG

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  • BatteryCutoffSwitch.jpg

Edited by Euphoria, 07 June 2020 - 09:07 AM.

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#3 Tombrown

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Posted 07 June 2020 - 05:49 PM

What Euphoria said! Just use the existing 120vac wire from the external power source.



#4 vermilye

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Posted 09 June 2020 - 08:13 AM

I could be entirely off base, but I believe the OP is planning to run his inverter so it feeds the entire trailer by plugging the trailer power cord into the inverter output.  If you do this, you must shut off the converter, otherwise you have a loop where the converter is trying to charge the batteries using the inverter power.

 

While adding a 30 amp receptacle to the output of the inverter and plugging in the trailer power cord is a easy solution, you do need to avoid running the converter & any high power devices.  Some simply flip off the necessary breakers at the converter, but forgetting can be a problem.  Adding the relay you suggest would work, but a better solution is to add a transfer switch (which is also a relay).  The advantage of the transfer switch is you never need to remember not to run the high power appliances since they are not connected to the output of the inverter.

 

The usual solution for this is to add a transfer switch to the output of the inverter and connect the 120V receptacles you want on the inverter to the output. When the inverter is off, the transfer switch gets its feed from a breaker in the converter.  When the inverter is on, the transfer switch "switches" the input to the inverter.

 

If you are looking at powering one or two receptacles, a plug in 15 amp transfer switch is practical. For more receptacles or multiple circuits, add a breaker box & a larger transfer switch.

 

My trailer uses a separate breaker panel with 2 15 amp breakers that power the trailer receptacles.  The high power appliances (water heater, air conditioner, etc) are never on the output of the inverter since that would overload most small trailer systems.


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#5 Linda & Bob, K4TAX

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Posted 09 June 2020 - 09:45 AM

I think the use of terms and application is getting the topic confused.  

 

DC to AC Inverters. Also known as power inverters, DC to AC inverters are designed to change DC (direct current) power supply {battery} to an AC (alternating current) power supply.    These use the 12 volt DC source from the battery and produce 120 VAC at 60 Hz.  These can be a square wave {less expensive} model, modified sine-wave {more expensive} model, and pure sine-wave {most expensive, and most efficient} model.    Normally, one does not power the entire trailer system from these devices.  And they are typically located inside the trailer at some convenient location.  Each installation is usually custom, depending on ones intentions  for using AC powered devices.  Most DC to AC inverters have 2 to 4 outlets on the unit,  to which one can plug in various 120 volt items.  They are rated in watts which defined how much power they can provide.  DO understand that a 1000 watt inverter will draw some 75 amps of current from the battery.  Of course the load on the battery is dependent on the load on the INVERTER.    At rated output, this requires very large wire {#2 AWG minimum} and big terminals  that are connected direct from the inverter to the battery.   Also a load such as a hair dryer or microwave, for example, will deplete a battery rather quickly.  To operate one of these items the INVERTER should be rated at 2000 watts minimum. 

 

And then you have Converters that are used normally to supply 12 volts DC to charge the battery and operate the various DC power items, such as pump, lights, refrigerator on DC, and furnace fan.   The converters are powered from the 120 VAC source in the trailer.  Typically they are part of the power distribution panel.   Europhia has excellent pictures of his installation showing the unit below the fuse and wiring panel.  This unit receives 120 VAC from shore power and is wired to 120 volts using one of the circuit breakers.   He has done a very nice job of adding the 30 amp connector for the shore power cable.   Thus the converter is used  to charge the battery and operate items such as water pump, lights, and refrigerator if switched to DC.  

 

With either system correctly installed, there is no relay, and no switching required. 

 

Here is the source I used to replace our old Converter with a new solid state multi level charging system.  Works great!

http://www.bestconve...ml#.Xt_FK0VKhdh

 

I have added a 2000 watt pure sine-wave INVERTER to our trailer.  It is dedicated to supply the refrigerator power, as the original and very defective 3 way refrigerator, was replaced with a 120 volt, 5.0 Cu.Ft. under counter model.    

 

Hope this helps and doesn't confuse anyone. 

 

Bob



#6 vermilye

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Posted 09 June 2020 - 10:04 AM

I think the use of terms and application is getting the topic confused.  

 

DC to AC Inverters. Also known as power inverters, DC to AC inverters are designed to change DC (direct current) power supply {battery} to an AC (alternating current) power supply.    These use the 12 volt DC source from the battery and produce 120 VAC at 60 Hz.  These can be a square wave {less expensive} model, modified sine-wave {more expensive} model, and pure sine-wave {most expensive, and most efficient} model.    Normally, one does not power the entire trailer system from these devices.  And they are typically located inside the trailer at some convenient location.  Each installation is usually custom, depending on ones intentions  for using AC powered devices.  Most DC to AC inverters have 2 to 4 outlets on the unit,  to which one can plug in various 120 volt items.  They are rated in watts which defined how much power they can provide.  DO understand that a 1000 watt inverter will draw some 75 amps of current from the battery.  Of course the load on the battery is dependent on the load on the INVERTER.    At rated output, this requires very large wire {#2 AWG minimum} and big terminals  that are connected direct from the inverter to the battery.   Also a load such as a hair dryer or microwave, for example, will deplete a battery rather quickly.  To operate one of these items the INVERTER should be rated at 2000 watts minimum. 

 

And then you have Converters that are used normally to supply 12 volts DC to charge the battery and operate the various DC power items, such as pump, lights, refrigerator on DC, and furnace fan.   The converters are powered from the 120 VAC source in the trailer.  Typically they are part of the power distribution panel.   Europhia has excellent pictures of his installation showing the unit below the fuse and wiring panel.  This unit receives 120 VAC from shore power and is wired to 120 volts using one of the circuit breakers.   He has done a very nice job of adding the 30 amp connector for the shore power cable.   Thus the converter is used  to charge the battery and operate items such as water pump, lights, and refrigerator if switched to DC.  

 

With either system correctly installed, there is no relay, and no switching required. 

 

Here is the source I used to replace our old Converter with a new solid state multi level charging system.  Works great!

http://www.bestconve...ml#.Xt_FK0VKhdh

 

I have added a 2000 watt pure sine-wave INVERTER to our trailer.  It is dedicated to supply the refrigerator power, as the original and very defective 3 way refrigerator, was replaced with a 120 volt, 5.0 Cu.Ft. under counter model.    

 

Hope this helps and doesn't confuse anyone. 

 

Bob

If you are willing to unplug things from the trailer's built in receptacles & plug them into the inverter, it is true that you don't need a relay.  But, if you want to use the same receptacles on either shore power or the inverter, a transfer switch is the way it is done.



#7 Linda & Bob, K4TAX

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Posted 09 June 2020 - 10:55 AM

 

I think the use of terms and application is getting the topic confused.  

 

DC to AC Inverters. Also known as power inverters, DC to AC inverters are designed to change DC (direct current) power supply {battery} to an AC (alternating current) power supply.    These use the 12 volt DC source from the battery and produce 120 VAC at 60 Hz.  These can be a square wave {less expensive} model, modified sine-wave {more expensive} model, and pure sine-wave {most expensive, and most efficient} model.    Normally, one does not power the entire trailer system from these devices.  And they are typically located inside the trailer at some convenient location.  Each installation is usually custom, depending on ones intentions  for using AC powered devices.  Most DC to AC inverters have 2 to 4 outlets on the unit,  to which one can plug in various 120 volt items.  They are rated in watts which defined how much power they can provide.  DO understand that a 1000 watt inverter will draw some 75 amps of current from the battery.  Of course the load on the battery is dependent on the load on the INVERTER.    At rated output, this requires very large wire {#2 AWG minimum} and big terminals  that are connected direct from the inverter to the battery.   Also a load such as a hair dryer or microwave, for example, will deplete a battery rather quickly.  To operate one of these items the INVERTER should be rated at 2000 watts minimum. 

 

And then you have Converters that are used normally to supply 12 volts DC to charge the battery and operate the various DC power items, such as pump, lights, refrigerator on DC, and furnace fan.   The converters are powered from the 120 VAC source in the trailer.  Typically they are part of the power distribution panel.   Europhia has excellent pictures of his installation showing the unit below the fuse and wiring panel.  This unit receives 120 VAC from shore power and is wired to 120 volts using one of the circuit breakers.   He has done a very nice job of adding the 30 amp connector for the shore power cable.   Thus the converter is used  to charge the battery and operate items such as water pump, lights, and refrigerator if switched to DC.  

 

With either system correctly installed, there is no relay, and no switching required. 

 

Here is the source I used to replace our old Converter with a new solid state multi level charging system.  Works great!

http://www.bestconve...ml#.Xt_FK0VKhdh

 

I have added a 2000 watt pure sine-wave INVERTER to our trailer.  It is dedicated to supply the refrigerator power, as the original and very defective 3 way refrigerator, was replaced with a 120 volt, 5.0 Cu.Ft. under counter model.    

 

Hope this helps and doesn't confuse anyone. 

 

Bob

If you are willing to unplug things from the trailer's built in receptacles & plug them into the inverter, it is true that you don't need a relay.  But, if you want to use the same receptacles on either shore power or the inverter, a transfer switch is the way it is done.

 

I believe I stated such in the paragraph on DC to AC inverters.  



#8 Rojo

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Posted 17 August 2020 - 12:55 PM

Sorry for the late reply,

Vermilye is correct, I am wanting to power the entire trailer using the existing wiring thus the need to cut off the recharging aspect while the inverter is running.  While I realize I will be unable to run everything at once, I want the ability to power my microwave OR toaster OR coffee maker OR (hopefully but doubtfully) my A/C without having to rewire or run extension cords.  

I have a XYZ INVT 2500W Pure Sine Wave Inverter - 12V DC to AC 120V with 15ft Remote Controller, Surge Power 5000w, Power Converter for Solar System, Off Grid. (2500W 12V/Remote) and plan to use up my two existing marine batteries before buying new AGM batteries.  Charging is through an existing 150w solar panel. 

 

To accomplish this I am installing a 30 amp receptacle, wired directly to the inverter, on the exterior.  When needed I will plug the shore power plug into said receptacle utilizing the inverter as I would shore power.  This will mean the converter is running from the inverter and the relay is to stop the converter from trying to charge the battery at the same time. 

 

Euphoria, I noticed that your cut off switch was attached to the black wire.  Mine came with a cut off but it was/is attached to the white/green wires.  It disconnects the battery as wired.  Does it make a difference?  I tried to get a larger hatch for the electrical because it is a chore to try to push all the cord back into that little one and my door was torn off when I had a blowout but unfortunately the bigger one you found is currently unavailable.  I guess I will keep searching.

 

Thanks to all



#9 Linda & Bob, K4TAX

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Posted 17 August 2020 - 05:35 PM

Finally got my inverter and have a wiring question.

 

I am going to install it with a 30a outlet to the exterior and plug in the main power to it to access.  In order to do this I must install a relay to disrupt the converter/battery connection.  When the inverter is powered up the relay will open and the charger will no longer provide power to the battery.  So, as is obvious, I am neither an electrician nor electrically inclined, and therefor want to get a clarification before I go slicing and dicing. 

 

Investigation has shown that the 12v controller panel block has four wires (black, similar for white) in the same block.  I have identified them as:

 

A. to the converter,

B. to the controller

C. to the battery

D. to the trailer hookup harness.

 

It looks to me as if I install the relay somewhere in the black wire between the panel and the battery I can accomplish what I want, disconnecting the charger from the battery without disrupting the remaining 12v service. 

 

The only other complication is that the solar panel goes directly to the controller as does a separate set of wires from the battery but I think this is drawing from the battery and has nothing to do with charging.

 

Am I correct in this or am I overlooking something?

 

If you are planning to install a 120V outlet  wired from the output of the 12V to 120V AC inverter and plug in the trailer to that, the easier way to deal with your concern is to flip the converter circuit breaker to off.  This will prevent the CONVERTER from any AC power demand.    This does not require any rewiring, any relay or such.   Much simpler way for a non-electrical type.  Adding a relay between the CONVERTER and battery will not reduce the idle current of the converter.  And with no load on the output of the converter the voltage will not be regulated and may soar to an unsafe value for appliances. 

 

TERMS:  Just to be clear.......... 

 

INVERTER = produces 120 VAC supplied from 12VDC to run appliances.   Depending on the load, it will draw lots of amps from the battery.  Use very large wire and short wire length from the battery to the inverter. Current can be upwards or 100 amps.  

 

CONVERTER = produces 12 DC supplied from 120VAC to charge the battery and run the DC systems. 

 

Good luck with that project.  

Bob



#10 Linda & Bob, K4TAX

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Posted 17 August 2020 - 05:40 PM

Sorry for the late reply,

Vermilye is correct, I am wanting to power the entire trailer using the existing wiring thus the need to cut off the recharging aspect while the inverter is running.  While I realize I will be unable to run everything at once, I want the ability to power my microwave OR toaster OR coffee maker OR (hopefully but doubtfully) my A/C without having to rewire or run extension cords.  

I have a XYZ INVT 2500W Pure Sine Wave Inverter - 12V DC to AC 120V with 15ft Remote Controller, Surge Power 5000w, Power Converter for Solar System, Off Grid. (2500W 12V/Remote) and plan to use up my two existing marine batteries before buying new AGM batteries.  Charging is through an existing 150w solar panel. 

 

To accomplish this I am installing a 30 amp receptacle, wired directly to the inverter, on the exterior.  When needed I will plug the shore power plug into said receptacle utilizing the inverter as I would shore power.  This will mean the converter is running from the inverter and the relay is to stop the converter from trying to charge the battery at the same time. 

 

Euphoria, I noticed that your cut off switch was attached to the black wire.  Mine came with a cut off but it was/is attached to the white/green wires.  It disconnects the battery as wired.  Does it make a difference?  I tried to get a larger hatch for the electrical because it is a chore to try to push all the cord back into that little one and my door was torn off when I had a blowout but unfortunately the bigger one you found is currently unavailable.  I guess I will keep searching.

 

Thanks to all

 

Do take note of the current demand from the battery for a 2500 watt inverter which is powering a microwave, toaster or coffee maker. {about 1500 watts or so}    It will be about 125 amps or more.  

 

Bob



#11 Euphoria

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Posted 18 August 2020 - 06:36 AM

Euphoria, I noticed that your cut off switch was attached to the black wire.  Mine came with a cut off but it was/is attached to the white/green wires.  It disconnects the battery as wired.  Does it make a difference?  I tried to get a larger hatch for the electrical because it is a chore to try to push all the cord back into that little one and my door was torn off when I had a blowout but unfortunately the bigger one you found is currently unavailable.  I guess I will keep searching.

 

Thanks to all

All the cut-off switch does is break the circuit for the 12 vdc battery power. It doesn't matter if it is in the positive or negative line, as either one will isolate the battery from the 12 vdc trailer wiring. Some prefer to install it in the NEG side, I prefer to install mine in the POS leg. Either will work.


Edited by Euphoria, 18 August 2020 - 06:37 AM.

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#12 vermilye

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Posted 18 August 2020 - 06:56 AM

While I'd still prefer an outboard transfer switch as the solution, if you would rather use a relay to disconnect the converter, I'd wire it to the input (120V) hot wire between the converter circuit breaker & the charging section of the converter (it will be a black wire).  This will shut off the charger & is the equivalent of shutting off the breaker.  You will still need to remember to shut off all the high current 120V appliances; the reason for my preference for an outboard transfer switch.



#13 Rojo

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Posted 18 August 2020 - 07:02 AM

Bob, if I flip the breaker for the converter won't I eliminate all the 12v power to the lighting, water pump, etc?



#14 Linda & Bob, K4TAX

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Posted 18 August 2020 - 11:29 AM

Bob, if I flip the breaker for the converter won't I eliminate all the 12v power to the lighting, water pump, etc?

No,  because the breaker is in the 120 VAC line  to the converter and thus the 12V power is still available from the battery.   As to using the breaker, this will eliminate the intrinsic drain of the inverter when it is not charging the battery or supplying DC to the lights..   It is strongly advisable to keep the battery connected to the converter.

 

Bob







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