400 inverter parasitic drain?

pthomas745

A couple of 400 owners on FB have reported their batteries have drained when they left their trailers parked, apparently with the battery switch off.  They return to a trailer with an inverter alarming and a depleted battery.

I looked over the Unofficial 400 Resource Guide and the writer points out the battery switch does not turn off the solar to the battery or turn off the inverter.  The inverter, apparently, has to be turned off separately. 

So, what would the parasitic drain of the inverter be?  Anyone know? 

N7SHG_Ham

Looks like 1.2a in standby with no loads.

https://www.aimscorp.net/1200-Pure-Sine-Inverter-with-Transfer-Switch-UL-458.html

TNOutback

There is a fan on the inverter.  I failed to recognize I left the inverter turned on after arriving home from a campout.  I found it the next day when I went into the camper and heard the fan on the inverter running.

jkjenn

So, this tells me that the inverter is wired directly to the battery and not the battery switch. Probably means if you have a Victron battery monitor you are also missing any power being drawn or added by the inverter on the monitor.

pthomas745

@N7SHG_Ham @TNOutback @jkjenn thanks.  1.2 amps ....per hour?....no wonder the batteries are draining quickly!  The instruction manual posted above specifically states to turn the inverter off.  And, as Jenn points out, the Victrons are not picking up that amp draw, this can lead to a nasty surprise.

4.Once finished using the inverter, turn off your electrical appliance and the inverter.The indicator lights should be off.

5.The cooling fans inside the inverter do not work until the case temperature reaches approximately 104°F.

6.Ifyou do not plan to use the inverter for a long period of time, disconnect it from your battery bank.Leaving the inverter on and connected for long periods of time may harm the equipment and over discharge the battery.

Deb55

OK, total newbie question. What is the inverter? Do I have one in my 400 if I don't have solar? If so, what do I need to do? 

pthomas745

I'm going to guess you may not have an inverter installed, but I could be wrong.

All of our trailers have a CONverter.  It converts ordinary household current, or shore power, to provide current to charge our batteries, and run the things in the trailer that use 12 volts:  the lights, the pump, the television, etc.

An inverter is connected to the battery, or plugs into the 12v "cigarette lighter" plugs in the trailer.  It takes that 12 volt current and turns it into ordinary household current (120v).  It will have regular household plugs that you can just plug things into.

I have small 300watt inverters that plug into the cigarette lighter plugs, and use them for small jobs like battery charging or my laptops.

https://www.rvbasics.com/techtips/rv-inverter-basics.html

(PS:  this is the short version of this topic!)

It seems if you do have an inverter in your trailer, you should always make sure you turn it off if you park your trailer for an extended period.

rh5555

@pthomas745, I measured the parasitic drain of the inverter when turned off at the control panel by the front door.  It was less than 10uA.

NorthIsUp

After reading this, I'm on my way to the winter storage lot 100 miles away to turn off the inverter. Thanks for the heads-up. It's been there for about 13 days. Let's see. 

jkjenn

I think if I bought a 400, I would change the wiring so that only one outlet was wired to the inverter and so that it ran through the Victron shunt.

rh5555

My Victron is wired in the negative battery lead and measures the inverter current consumption just fine.

While I'm here, some notes on the inverter:

Our 2020 TAB has an AIMS PWRIX120012S inverter.  It powers 3 outlets (at bed, at front door and in bathroom). These outlets are dead, even when connected to shore power, unless you turn the inverter "on".  This can lead to problems:  You're on shore power and want to use one of the aforementioned outlets, so you turn the inverter "on" using the button by the front door.  When you leave camp, you disconnect shore power and the inverter now powers the outlets from the battery, drawing 1.2A even if you have nothing plugged into the 120V outlets.  You have to remember to turn the inverter "off" when you break camp!

AIMS has now superseded this inverter with the PWRIX120012SUL.  I haven't played with one of these, but my understanding is that it now automatically powers its outlets when on shore power, so no need to turn the inverter "on" in this circumstance.  Much better.  I don't know if any of these inverters are installed in TABs, but it will certainly add to the confusion when they do!

PamandJohnUpNorth2

While we are on the topic of parasitic drain I have a question for this knowledgeable group. Would the Victron Charge Controller also be using power even with battery shut off? If stored under  a cover or in a dark building over the winter, should the solar panels be disconnected (or switched off) and then the Controller itself be disconnected to prevent battery discharge? 

Horigan

PamandJohnUpNorth2 said:

While we are on the topic of parasitic drain I have a question for this knowledgeable group. Would the Victron Charge Controller also be using power even with battery shut off? If stored under  a cover or in a dark building over the winter, should the solar panels be disconnected (or switched off) and then the Controller itself be disconnected to prevent battery discharge? 

Yes it does, though the draw is very low and a fully charged AGM battery can easily handle it through the winter from what I remember on another thread on the subject.  Since mine isn't mounted and I only use the bluetooth interface, I just unplugged the display unit from the cable for the winter.

N7SHG_Ham

@jkjenn prior to the 2020 models there was a single inverter outlet at the foot of the bed controlled by a switch beside it.

Same issue through, it needed to be turned off when not in use.

My guess on the newer setup is three outlets hooked to the inverter are providing inverted power ALL the time when the unit is turned on and NOT shore power when you are plugged in, but ONLY a guess. The key is they don't work on shore power unless the inverter is on AND the inverter and shore power can't be supplying power simultaneously because they of electrical code, safety and matching the AC phases.

The Victron line of Multiplus are a line of inverters, chargers, auto transfer switch and power boosting devices for instance that are way more sophisticated than the supplied AIMS unit and at several times the cost they should be. Those can match phase and in fact combine inverted power with shore power if you need more than a low amp shore power can provide for instance. Another example, excess power can be pulled from the batteries and combined with say power from a Honda 2200i for getting short bursts of extra power up to the 30a you can use in the camper, starting the AC, running microwave with AC on, etc. Of course you are limited on reserves for this boosting ability by your batteries.

My plans when funds are available is to add a Victron MultiPlus, but the cost is probably more than most here would consider, but for boondocking could be worth it.

TNOutback

I went and looked at the inverter in my 2020 T@B 400, and if you wire in your battery monitor shunt between the battery negative and the distribution block supplied by Nucamp, you WILL pick up the inverter load.  The inverter is wired into the distribution block immediately downstream of the battery bank.  The inverter is though, wired BEFORE the battery cut off switch, hence the absolute need to be sure it is turned off when not using it.  Several weeks ago when I realized I was hearing the fan on the inverter, I used a label maker to type me a BIG reminder sticker posted at the door that says, “Turn off Inverter When Not in Use” !

MarkAl

I cannot think of a good reason to connect the inverter on the battery side of the disconnect switch.  This defeats one reason to "disconnect" the battery from the trailer's loads.  NuCamp makes quality RV equipment, so what am I missing? If I open the "Main" circuit breaker from the power lines to my house I do not expect some voltage to still come in. Note this battery disconnect would have nothing to do with campground connected power in the trailer (through the Converter).

Though speculating, am I correct in assuming if the battery disconnect switch has removed the battery voltage AND there is no campground power BUT the solar array is producing greater than 14 or so volts will the camper have power (within the solar's output capacity)?

rh5555

The reason the inverter is connected directly to the battery (not via the disconnect switch) is the magnitude of currents that flow when the inverter is being used.  For the 1200W inverter, the current can exceed 100 Amps, and the disconnect switch cannot manage that much.  Even if you put in a bigger switch, you'd still need massive wiring to and from it.

The solar array also feeds the battery directly (not via the disconnect switch), so if the switch is turned off and you are NOT on shore power, then you have no 12V power regardless of sunshine.

MarkAl

Thanks, good to know how it's connected. Since I'm still waiting for my 320 (walk-thru this Thursday), I am asking many questions that may be answered by NuCamp's documentation.  But what the heck w/ the Covid panic I've a lot of time on my hands - still working part time.  Wait there's still a 30 amp fuse the inverter must bypass that also. I "assume" the switch can handle breaking 30 amp loads, not just allow it to flow?

pthomas745

This thread was originally for the Tab 400, which has different wiring from the 320.   I could be wrong about this on your new trailer, but if you have an inverter on your new trailer, just have a good look at how it is wired.

rh5555

You got it.  I don't have any experience with the 320, but if it is similar to the 400 then the inverter has its own 150 Amp fuse, the solar has its own 30 Amp in-line fuse, and everything else passes through a 40 Amp re-settable fuse and the disconnect switch.  The disconnect switch can handle that 40 amp maximum current easily.

MarkAl

Sorry, I derailed this by not knowing more of the 400, there's no standard inverter but my thought was the current for this would also go through this switch / fuse. I'll stop speculating on the 400 now!

bergger

rh5555 said:

Our 2020 TAB has an AIMS PWRIX120012S inverter.  It powers 3 outlets (at bed, at front door and in bathroom). These outlets are dead, even when connected to shore power, unless you turn the inverter "on".  This can lead to problems:  You're on shore power and want to use one of the aforementioned outlets, so you turn the inverter "on" using the button by the front door.  When you leave camp, you disconnect shore power and the inverter now powers the outlets from the battery, drawing 1.2A even if you have nothing plugged into the 120V outlets.  You have to remember to turn the inverter "off" when you break camp!

The 2021 T@b 400 inverter only powers the outlet at the bed so I guess they went back to the old ways with that change.  

Denny16

No, the Inverter is located close,close,to,the battery, with 12-inch or less cables that have a special large fuse block between the battery and inverter.  This short cable is No. 4 wire.   The negative goes either directly to the battery, or Victron shunt (Newer TaB 400 has a 100 amp negative buss bar) on older units.  The Red Hot wire goes directly to the battery again with a large fuse block between the inverter and battery.

You can see the fuse blocks to the left of the inverter in this shot:

Tundra57

On my tab 400 2019 the aims 1200w inverter has three sockets. None powered unless the inverter is on. The inverter i have has an internal transfer switch which is not used (its only 10amps ac). In theory if it was wired it would power the sockets from shore power if available. Some inverters will transfer shore power with the inverter off and some wont. Not sure about this unit.

When its on but not powering anything, my inverter pulls 2A or more from the battery. Even with solar on in my driveway it will deplete the battery after a couple of months of winter weather.

Dutch061

rh5555 said:

The reason the inverter is connected directly to the battery (not via the disconnect switch) is the magnitude of currents that flow when the inverter is being used.  For the 1200W inverter, the current can exceed 100 Amps, and the disconnect switch cannot manage that much.  Even if you put in a bigger switch, you'd still need massive wiring to and from it.

100% accurate, what could be done is route the wiring for the remote switch so that it is controlled as part of the "Master Perko" battery disconnect. That way, if you happen to leave the Inverter switched on by mistake but you shut the Perko off, it will also shut off the Inverter. I will look at my 2020 400 BDL over the weekend to investigate, but I think that can be easily done.

Brad

Blueespy

I'm soooo confused.  So, we have an early 2019 t@b 400 BDL.  Under out TV is one of the inverter AC plugs and in the center of the plug is an on/off button.  I'm going to "assume" to use the plug it would have to be on.  So question, would having the inverter off (button pressed off) impact the operation of the Norcold 3-way fridge on DC power? 

Dutch061

I can't speak to the outlet and switch. The Invertor operation is irrelevant to the refrigerator but be warned that using an absorption refrigerator on 12 volts will drain the batteries very fast!

Brad

Blueespy

Dutch061 said:

I can't speak to the outlet and switch. The Invertor operation is irrelevant to the refrigerator but be warned that using an absorption refrigerator on 12 volts will drain the batteries very fast!

Brad

Thanks Brad

Oh, yes we understand that.  Normally we just use the 12v system to power the fridge while traveling.  On rare occasions, we've run the Norcold on 12v when we stop a rest centers for an hour or so rest.  Never longer than 2-hrs and never had an issue before. 

pthomas745

The newer fridges in the newer trailers are dramatically more efficient than the 3 way fridge in my 2017:  it will soak up between 11-13 amps per hour.  So, look into your fridge manual and you will be pleasantly surprised to find much much much better than 13 amps!

For example, the 2 way fridge in a 2018 400 is an Isotherm Cruise 65 2 way fridge.  The spec sheet says it can use 360 watts over 24 hours (about 30 amps from your battery on 12v).  Nucamp told another owner the wattage was 275 watts. 

My "old" fridge would use about 10 times that many amps in in 24 hours.  Luckily, propane is a thing for me. Don't overlook the vast improvement the new fridges bring.

@Blueespy send a picture of the outlet, and maybe a serial number of the inverter.  We don't get a lot of questions about them, so some pictures would be useful for those of us who have never seen one.

Denny16

@Tundra57. When the inverter switch at the foot of your bed is off, the inverter is off.  On the 2018/2019 TaB400, the inverter only powers the outlet next to the switch.  To use that outlet, you need to run the inverter on.  The fridge is on its own outlet, not connected to the inverter.  

Cheers

Blueespy

pthomas745 said:

The newer fridges in the newer trailers are dramatically more efficient than the 3 way fridge in my 2017:  it will soak up between 11-13 amps per hour.  So, look into your fridge manual and you will be pleasantly surprised to find much much much better than 13 amps!

For example, the 2 way fridge in a 2018 400 is an Isotherm Cruise 65 2 way fridge.  The spec sheet says it can use 360 watts over 24 hours (about 30 amps from your battery on 12v).  Nucamp told another owner the wattage was 275 watts. 

My "old" fridge would use about 10 times that many amps in in 24 hours.  Luckily, propane is a thing for me. Don't overlook the vast improvement the new fridges bring.

@Blueespy send a picture of the outlet, and maybe a serial number of the inverter.  We don't get a lot of questions about them, so some pictures would be useful for those of us who have never seen one.

Went out today and tried the inverter button.  Heard the inverter start up and the three plugs in the 400 connected to the inverter worked perfectly, so the inverter isn't the problem.  I'm now wondering if one of my batteries are bad.  Nothing indicated on the Victron app but I'm thinking the batteries hold enough of a charge to manage the lights/plugs but not the necessary amps for the Norcold 3-way.  Not that proficient in electrical work but there has to be a way to check the batteries.