Inverter Installation Wiring Question

capewoods

I asked this question as part of a separate discussion last week, but didn't see much in the way of comments.  I'm hoping creating a new discussion might inspire more responses.  I'm installing an 1100 watt inverter under the driver's side bench in order to occasionally power various AC devices while boondocking.  I was planning on wiring the inverter directly to the master switch I've previously installed a few feet away from two125 amp 12v batteries wired in parallel which are also connected to my solar panels.

Is wiring the inverter to the master switch not advisable for some reason? Could a 60 or 80 amp draw through those wires (which are also connected to solar panels and the rest of T@B) be a problem?  What happens when the trailer is plugged into shore power and therefore powering the DC wires running to the batteries -- and the inverter?  Is there some need to isolate the inverter from the rest of the wiring and only draw from the batteries when not connected to shore power or the TV?

jkjenn

Agree with @ST_Bob. You might want to go with a dedicated circuit instead of a fuse. I could see the potential for tripping it, quite often and you might blow through a lot of fuses.

capewoods

I currently have my AGM batteries located about 3 feet from my battery cut off switch. I use AWG2 wires running first through a 500amp shunt and measure flow with a Trimetric battery controller. The inverter I bought comes with a 150 amp in line fuse and AWG4 wires. My cut off switch feeds my DC bus through AWG2 wires.

Are you saying I need to cut off power to the bus in order to run the inverter?  Shouldn't the100 amps flow through the heavy gage wiring without frying the connected lower gage wires?  Moreover I want to be able to track all flow out of the batteries (whether to lights or to the inverter) through the Trimetric.

And of course I still want to be able to charge through the converter and my TV.

capewoods

Thank you.  That's helpful.  So it is enough to simply make sure that I'm not plugged into shore power any time I turn the inverter on, or do I need a separate cut off switch that isolates the downstream DC bus anytime the inverter is connected to my batteries. The inverter comes with a remote on off that I was going to build into the wall so that I don't have to open up the bench space to access it.  I'm assuming that if the inverter did inadvertently get switched on, it wouldn't be too big a problem as long as there's no load attached to it?  Correct? If full isolation is required, I suppose it would be possible to replace my existing Battery master cutoff which is ON/Off only with one that is ON1, ON2, or OFF.

capewoods

Sorry.  I hadn't really even considered the possibility of connecting my shore power plug to the inverter.  My inverter will be inside the T@B and just to provide for a few AC devices on rare occasions.  I take it the only advantage of powering the T@B 110 system off of the inverter would be to extend 110 to the other prewired outlets  or is there some advantage I'm missing?

capewoods

Bob, I'd just like to say thank you for your advice and expertise.  Electricity might as well be a foreign language, but I've really enjoyed trying to understand some of these concepts.  My existing solar panels (mounted permanently on the roof of my 2006 T@B clamshell) seem to work quite well and keep my batteries charged almost indefinitely.  I'm looking forward to the addition of the inverter to the system simply to allow for the use of an occasional high wattage 110 device when out of reach of shore power.  Again, the wires that now run from the batteries to the cutoff are AWG2 and the ones that will run from that master switch to the inverter will be AWG4.   My only concern was that the DC bus will also be simultaneously connected to that cutoff switch with relatively small gage wires and that the amperage flowing from the batteries to the inverter might somehow harm the converter or my panels -- both of which are wired in one fashion or another to that same cut off switch.  It seems as though that concern is unfounded.

EWizard

ST_Bob said:

I think you are misunderstanding me. If running the inverter off the T@B's battery you are not hooked to shore power. If you simply run a couple of things right off the inverter there's no problem. It's when you try to feed the 30 amp twist lock power connector that you run into trouble. The converter is directly wired to the shore power plug and has all your circuit breakers etc. For the plugs, Aldi system, refrigerator etc. So you need the converter powered to run these 120V loads. You want to turn off the breaker for the converter's 12 volt charger if you hook up the inverter's 120V output to the shore power plug.

Couldn't you install an automatic transfer switch between the shore power plug and the converter, then have the inverter connected to that?
You wouldn't need to worry about whether or not shore power is plugged in or not.

Michigan_Mike

Just a word to the wise and to those of you considering hooking up an inverter directly into the 120 volt system in your trailer.  I've worked in the utility industry for 40 years, have worked directly on high-voltage systems and would exercise caution if you are considering the above.  An inverter is basically a small transformer and steps up voltage (in this application from 12 volts DC to 110 volts AC) and should you make a mistake you could not only damage components in your trailer, but also lose your life via an electrical fire and the consequences therein.  

Inasmuch as people want to make these small trailers a virtual home on wheels, with all the conveniences of home, you need to factor in safety, weigh the consequences of your personal safety, your spouse, etc. and consult with a qualified and competent technician for anything involving cutting an inverter into a 110 volt system.  This involves many factors and considerations and should you backfeed voltage incorrectly over your trailers electrical system you could easily damage on-board components/circuitry, heat up wire and lose your life in the process.  

And true, this is NOT rocket science, this is SERIOUS business and not for the feint of heart.  I have seen some serious accidents, injuries and fatalities in my career and know enough about inverters that I will not cut one into my T@B's electrical system and would opt for using an extension cord (plugging it into an inverter) as opposed to trying to energize the 110 volt system via an inverter.  Obviously the 30' motor coaches do have systems that run off an inverter, but these systems are factory installed by trained technicians who do this work daily and are familiar with the installation of these systems and the parameters and tolerances of wiring and other components. 

So weigh the consequences of this type of endeavor, err on the side of safety, consult with a qualified technician and let a trained individual perform this type of work, as losing your life in a trailer fire isn't worth a cool mod, nor worth the expense of electrical damages that could result via an error and back-feeding voltage across sensitive electrical components.  

Tonydjd

Question along same item. I'm installing a cut off switch. 2015 max s. Does anybody know if the white ground wire from battery into the unit has any taps attached or is it a clean run. It's obvious that the red wire goes from battery to inverter don't believe they would have tapped off that wire.

Thank you

Michigan_Mike

Tonydjd said:

Question along same item. I'm installing a cut off switch. 2015 max s. Does anybody know if the white ground wire from battery into the unit has any taps attached or is it a clean run. It's obvious that the red wire goes from battery to inverter don't believe they would have tapped off that wire.

Thank you

I would guess that the wire run from the battery in to the electric converter would be a dedicated feed and not tapped into.  

Verna

ST_Bob said:

Am I missing something?  Why does it matter if the white (negative) wire goes directly to the converter ground or not.  Normally, the battery cutoff switch should be connected in the positive wire between the battery and converter.  The only wires "upstream" (toward the battery) of the battery cutout switch would be the ones from the Zamp connector and brake emergency switch.

Bob, since you haven't received your T@B, you can't see what our owners see. On this forum, we choose to help. Please do not  "assume" that the T@B is constructed like your larger camper. Tony has a valid question and he received an answer from another owner.  

Tonydjd

Thanks for input reason for question is I'm moving AGM battery to inside unit and I want to re purpose white lead into a hot lead (decided to run a new hot lead just to be safe) Installed a cut off switch outside on cargo boxalso have usb charger outside. Toggle switch next to battery switch activates the 4 led that are pointing towards landing area for Jacks when lowered at night  you can see ground contact.

Tabaz

Question - Is it OK to leave my Zamp 200W solar array plugged into the battery while I'm using my 2,000W inverter to power stuff or should I disconnect the Zamp whenever I use the inverter?  The inverter is mounted outside the cabin and is NOT connected to the trailer's electrical system.

Tabaz

Thanks Bob!