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We can have 50 amps or I can charge my batteries (on 30 amps), but not both?

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(I also posted this in the Victron Community Forums, but hoping to double up on potential viewers for more answers and suggestions.)

To lay the groundwork for the question:

  • We have a 50 amp fifth wheel.
  • We bought the unit used from a private seller, very happy overall.
  • The solar / Victron was installed by the seller or he had it done.
  • We have 4x Battle Born 100ah LifePo4, 4x 190W solar panels, 2x MPPT, SmartBMV and the Victron 12/3000/120-50
  • We (the wife, the dog and I) are fulltimers, three months now!

We have been, in the past three months, mostly on shore power, and always on (confirmed) 50 amps.  We found that one of the monitor panels (not listed above) showed us at 30 amps continually.  Reached out to seller, he indicated that if I had the inverter on, I'd be limited to 30 amps.  Turned it to Off, and I'm back to 50 amps and I can run the air conditioners.  Excellent for the Texas heat we'd been dealing with.

Two days ago, we relocated to a park, and were fortunate enough to park in the shade.  Sure, solar will be very much reduced, but that's okay:  we have 50 amps.

Tonight...the generator kicked on.  Turns out we ran down the batteries to 50%.  Direct DC usage in the rig, like lights, whatever else is straight DC, ran them down.  With the Victron set to off, the shore power doesn't recharge the batteries.  If I turn the Victron to just "Charger" (not Inverter), it will recharge the batteries, but I will still be limited to a 30 amp system.

This feels wrong to me.  I'm a programmer, have been for 30 years.  I'm decent at debugging, but I haven't examined all the the wiring and gotten a deeper understanding of the layout.  It just feels wrong that it's this way.

When we have good sun, the batteries always get charged up the next day, even on cloudy days.  We've been here, in the shade, for... two full days, I think.

I'm trying to determine if one or more of the following are true:

  • Is this a standard solar implementation scenario?  That there is only ONE possible charger/converter to replenish the batteries installed at one time?
  • Is there a possible wiring / schematic / system design oversight or bug.  (I don't have a schematic yet, I have reached out to get one, if available.)
  • There would have been an original charger/converter installed on the rig, before the Victron, etc. was installed.  Does anyone ever have that still wired into the system?  
  • Really, my only choices are "have sun" or "be limited to 30 amps even when 50 amp shore power is available"?  This cannot be right.

I'm trying to determine that, if the Victron being on limits me to 30 amps, is there a different way to charge the batteries when on shore power?  I know my question might be difficult to many without y'all knowing more about how it's wired up.  But I'm hoping I kept my questions as free of the implementation as possible and focused on generalizations, and typical scenarios.

For the moment, there's a chill coming into the area tonight and I don't need two A/C's.  I'm okay with the 30 amps for now, and I'll get my batteries replenished.  Not a long term solution.

I truly appreciate any help anyone can put forth, or any education I can glean out of your answers.  I did do extensive research into solar, DC, AC, converters/chargers, inverters, MPPT, etc. before we bought the rig.  I feel sort of comfortable in my general knowledge.  I was a little sad I didn't get to do the install myself so I'd REALLY know it, inside and out, but the deal was just too good to pass up and our seller was a pleasure to work with.  But I lack the intimate knowledge that installing it myself would have gained.

Thanks in advance for any assistance.

- Will B.
Somewhere in Kansas at the moment.


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Got to be something wrong in the set up. The inverter has a pass thru switch in it for shore power. But for know you should still have the factory installed converter in it. Just plug it in and it will keep batteries up.

Edited by GlennWest
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2 minutes ago, GlennWest said:

Got to be something wrong in the set up. The inverter has a pass thru switch in it for shore power. 

Do you have any specific information on that?  A link I can research, etc?  Maybe a manual?  :)

Thanks, Glenn.

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Either the previous owner installed the system incorrectly or as Glen mentioned, there is a setting that is improperly set on the inverter.

To specifically answer your questions, see below:

3 hours ago, Will B. said:

I'm trying to determine if one or more of the following are true:

  • Is this a standard solar implementation scenario?  That there is only ONE possible charger/converter to replenish the batteries installed at one time?

If the system came from the factory with an inverter charger and solar (not a typical factory installation), then the inverter charger would be the only option to charge the batteries from shore power.  The solar is a completely separate system that also charges the batteries, but requires sunlight to work.

  • Is there a possible wiring / schematic / system design oversight or bug.  (I don't have a schematic yet, I have reached out to get one, if available.)

It is possible the previous owner wired something incorrectly, but it is more likely a setting in the inverter is set incorrectly.  A call to the previous owner to see if he ever experienced the same issue would be first on my list.

  • There would have been an original charger/converter installed on the rig, before the Victron, etc. was installed.  Does anyone ever have that still wired into the system?  

Typically when an inverter charger is added to an OEM system with an existing converter, the converter is left in place as a back up.  It is usually either unplugged or it’s breaker is turned off (at least this is how I always do it and recommend that others do as well).  Without seeing your specific installation, I can’t say for sure it was done this way.

  • Really, my only choices are "have sun" or "be limited to 30 amps even when 50 amp shore power is available"?  This cannot be right.

If your system were set up properly, then no those would not be your only options.  When on shore power, the Victron inverter charger should charge the batteries.  It can also be set to hybrid mode and provide additional 120 volt power from the batteries if say you were only plugged into a 15 amp outlet while moochdocking in someone’s driveway.


Do you have a Color Control GX remote in your system.  If you do, then you can change some of the inverter settings through it.  When the inverter is set to off, it does absolutely nothing.  When it is set to on it should charge the batteries only.  When it is set to invert it will invert power as needed.  There is another setting that lets the inverter know how much power is available from shore power.  This is used in conjunction with the hybrid capability of the inverter and tells it to only pass through that much power and invert additional power as needed to make up the difference.  It can only make up the difference up to 30 amps so if that is set to 30 amps, then that is all the power the inverter will produce.  In normal operation when plugged into 50 amp shore power that function should be set to 50 amps.  If you have a color control GX remote, this setting is on one of the main screens of the remote in the lower left hand corner.

Edited by Chad Heiser
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4 minutes ago, podwerkz said:

For now, I would just carry around a portable charger and use that.

Portable charger.... for what?  The batteries?  What power source are you suggesting?  Confused.  These are 4x 100ah Lithium batteries.  Not talking triple-A here.  I appreciate the help though, I just don't understand! :)

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@Chad Heiser and @GlennWest  I wanted to try to reply to some of your specific suggestions.  I do have the color control panel.  So, if you'll recall from above, when I'm on either "Charge Only" or "Inverter" or "On" (for both), I get the 30amp limit.  I put it in that scenario, here's the (lies) I'm being told.  Heh.

Image link, simpler: https://www.dropbox.com/s/2ks5ldw1lhymk3t/2020-06-10 09.15.56.jpg?dl=0

Having said that, here is the indicator I'm using to determine the 30 vs. 50 amps. (Also, the fact that this same device, when using "Scroll", will show that the system is "shedding" power to various items when on the 30.  (Never on the 50, which of course, is really 100 amps.)

On 50 amps (Victron in "Off" mode)
https://www.dropbox.com/s/xk8cte53hzf3p5a/2020-06-10 09.14.59.jpg?dl=0

On 30 amps (Victron in any of the above modes, other than "Off")
https://www.dropbox.com/s/cmwhinw5s044jbx/2020-06-10 09.16.04.jpg?dl=0

So, as far as I can tell, the input on the Victron color panel is showing "Yes, getting 50 amps", but when it comes out the other side (to where the other monitor panels sees it), it's dropped to 30 amps.

I did look through the manuals, and BOY was I confused.  I'm a programmer; thought I was smarter.  I'm guessing I'm going to have to find a distributor / installer that can maybe make a house call and help me make a change.  I'm hoping, still, to get a schematic from the original owner.

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It is going to be very difficult to find the exact problem without looking at your specific installation and how it is wired.  The Precision unit you show has a module inside your power panel.  It senses when there are opposing phases of current (240 volt or two legs of 120 volt in a typical RV set up).  When it doesn’t sense the opposing phases then it restricts power to a maximum of 30 amps.  With this information I am now leaning toward something was wired incorrectly during the installation.

Does your rig have a sub panel that the inverter powers or is the inverter wired in line with the main panel without a sub panel?

When I install that inverter, I typically set it up with a sub panel.  In this type of installation, the circuits you want the inverter to power are moved from the main power panel to a sub panel.  The circuits you don’t want the inverter to power are left in the main panel.  A breaker is then added to the main panel that feeds the inverter and the inverter is then wired to the sub panel.  When shore or generator power is available, it passes from the main panel, through the inverter, to the sub panel and everything works.  All circuits have power and the inverter charger charges the batteries.  When no shore or generator power is present, the inverter will take power from the batteries and invert it to feed the sub panel only.  All circuits in the sub panel will be energized to the maximum capacity of the inverter.  When limited power is available (like when plugged into a 15 amp receptacle at a friend’s house moochdocking) there will be 15 amps available to the main panel and sub panel.  The inverter can augment this power to the sub panel only by passing through the 15 amps and inverting additional power up to the inverters capacity.

That single 3000 watt inverter that you have is only capable of supplying 120 volts.  If it is wired in line with your 50 amp main panel without a sub panel, it is only capable of supplying 120 volts total to your rig.  Without some additional equipment it will not work properly and will give results similar to what you are experiencing.

Edited by Chad Heiser
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@Chad Heiser  Thanks for that detailed information.  You clearly know your stuff!  I'm afraid that some of this is above my pay grade.  Note the time I'm posting this.

Came home tonight after being out...let's call it....10 hours.  Left a little bit of lights on, but I think I was pulling very little DC, maybe 30 watts, when I left.  When I got home, everything was dark.  No DC anything.  Air conditioners were off, but only, I think, because the DC thermostats were dead.  All the AC electric stuff was fine!  Bug zapper on, microwave clock, even our computers.  But no lights, nothing on the DC side.  Couldn't turn on any panels like the Victron, the One Control house system, nothing.  I look out the window, showing correct green lights on the surge protector, clearly getting my 50 amps.

Wife is distressed.  "What's wrong?!"  I can't explain it other than to say, "well, looks like our batteries are dead".  I go out to start the genny, under the 5th wheel "hood".  I pull the cover (Onan 5500) to get to the manual start button.  I know it will charge the batteries.  I can't start it!  There's not even enough power to do so?  Well, I have a jump starter I carry in my motorcycle.  I connect it to one of the four Battle Borns, hit the "boost".   I see the bedroom lights come on.  (Love that little jumper, such juice!)   I get the genny to prime, then start.  Shuts right off.  After the third time of doing this, I realize that the "quiet hours" are killing it.  I have enough juice to access the phone app, bluetooth, etc. and disable quiet hours.  Restart the genny, stays started.  Close it all up.  Sparse (at the moment) campground be damned, I gotta have air conditioning, it's hot!  I check the panels inside.  The batteries are showing 100%!!!!  What?

I don't know what the hell is wrong.  The night before, about 2am, I heard the low voltage alarms going off.  I clear the alarms, check the percentage, showing 61%.   Turned on the system to Charger Only, batteries are back to 91% this morning.  We only need one air conditioner at night, so 30 amp limitation is fine.   It was about 7:15 am, sunrise (and possible solar charging) was at 6'ish.  But, again, in the shade, and the angle would've been poor.  I feel like some changes I made might've given juice back to the batteries.  

So right now, it's 3am, I'm running the generator.  I'm afraid to turn it off and have plenty of fuel.  (In fact, before parking here in the shade, I'd only run it to "exercise" it.)  I have NO idea why there was no juice to the DC devices in the house if the batteries are truly at 100%.  I made some changes last night via the phone app (Victron), but I couldn't tell you what they were or if they made any difference. 

Chad, if you're part of some installer network, I would love for you to make a recommendation or point someone to me in the Hutchinson (Wichita), Kansas area.  I need an expert to come out here and look at this stuff, paid, of course.  This is the first time in 3 months I've been in the shade, and that is revealing our issues I believe.  Can you point me in a direction to help?  I'm hesitant to just call just any mobile tech, as this is a configuration thing, clearly, on the Victron system.  Not saying they don't know it, but it's pretty specific, I think.  I can do my own checking to find someone qualified, but if you know how to get me in the right direction, it might save a lot of hassle.

I really appreciate the help, everyone.  I'm at wit's end.  It's now 3:39 (I edit my posts heavily) and I guess I'll turn off the generator.  <blink>.


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The CCGX pic (multicolor) is while the generator is running, air conditioner running, whatever else.)  Back to "Charger Only", but generator (Onan 5500), when running, has the other monitor panel showing 45 amps.  (Always shows that when running.)

Blue is phone screen capture after turning off the generator.  "Infinite"!  Implies, I would think, that the batteries are charging from the shore connection.  (What I thought I had managed to change last night.)

Funny, I just realize that when I was having difficulty starting the generator, I also turned off the two 30 amp breakers that are on it.  Don't know what they do, but gotta remember to turn them back on, seems like it's important.



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@Will B. I wish I was closer to you, I would lend a hand in person.  It is very difficult to sort electrical issues without being there. 

A bit of background on my experience (for context).  I am not a professional installer, it is just something I do in my spare time as a hobby (for fun).  I may go down that road after I retire from my “real” job, but that is a down the road decision.  I have done multiple installations with most of my experience coming from working with Magnum products.  I have recently ventured into Victron products and have done a couple of complete Victron systems.  I really like their stuff and my next personal system will most likely be a Victron system, but they take more technical knowledge to set up properly than a Magnum system (in my experience).  That is neither good, nor bad.  It just is.  I give presentations at rallies on solar, batteries and inverters and will be doing so this week at the West Coast HDT Rally in Idaho.  My knowledge is all self taught with a bit of electrical experience from when I was younger working with my dad (an electrician) that helps.

Now back to your specific issues.  There is obviously something not right with your system.  I am still not sure if you have a sub panel in your system, but I am guessing from some of what you are saying that you do not.  If your inverter is wired in line with your main panel, then there needs to be some additional equipment installed with it to get the inverter to function properly with your 50 amp service.  Something like AM Solar’s Smart Phase Selector.  This allows a 120 amp inverter to power a 50 amp (240 Volt) RV power panel.  Without something like this or a sub panel to isolate what the 120 volt inverter is going to power, the system is not going to function properly (no matter what settings you change).  To properly help you I (or any knowledgeable installer) would need to know exactly what components are in your system and how they are laid out/installed.  In other words some type of wiring diagram of what you have to trace how the power flows and is distributed (especially since I can’t see it for myself in person).

AM Solar’s website has a lot of good educational information and example wiring diagrams of how a proper system (with various components) should be wired.  Browsing through it may help you out some.  

You mentioned you purchased your rig used and the previous owner installed the system.  Do you know how long he used the system or if he had any issues with it?  Have you spoken to him about the issues you are having?  He may be able to give some insight as well.

On edit:  Here is a good video on how to power a 50 amp RV with the same inverter you have and AM Solar’s Smart Phase Selector.

Edited by Chad Heiser
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@Chad Heiser

I reached out to the owner, he got back to me, said he didn't have any schematic.  He apparently had it installed by the RV dealer in California he bought the rig from.  I suspect they won't be of much help.

I sent an email to Victron this morning, asking for help in locating a tech, distributor, dealer, whatever that can assist us.  Last night we had that whole weird thing happen again.  I'm now 100% certain we're getting low voltage drops from the campground (this never happened before).  The genny kicks on.  But what's weird is, after a bit, it just shuts off!  And the entire Victron system goes down.  Like...off!  (Which should NEVER have happened!)   Until I put that battery jumper on the batteries, I'm dead.  What's hilarious is that last night, I was watching it all when it happened.  The BB battery bank was at 86%.  After I "jumped" it enough to get the system to turn back on, the dang panel shows the battery bank at 100%.  Which is a straight up lie!  But with just a trickle from the jumper, all the house lights that were on come back on, and panels light up, etc.

The entire thing is just sick.  There's really TWO issues, I'm sure.  There's the "not getting charged well" and this whole disaster scenario that occurs.

Oh, well.  Until I get a tech out here, I won't be able to resolve it.  I truly appreciate all the help you've given me, and product suggestions.  (Though I think an autoformer might be my next step.)  I really have to have someone here who is a qualified electrician, preferably qualified for Victron equipment and makes house calls! :)  I do NOT want to put my full time home in the shop; I'll never get it back.

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I have a similar system, 680 watts solar, mppt 100/50, multiplus 12/3000/120-50, 4 Battle Born 100ah lithium batteries.

 "Input current limit ... 50.0" as shown in your image means the inverter has been set to 50 amps input max.

To understand your system, when connected to shore power

Can you run the air conditioner(s) with the inverter turned "off"?

Can you run the air conditioners with the inverter in "charger" mode?

Can you run the air conditioner with the inverter on ("invert" mode)?

As Chad Heiser mentioned it is important to know whether you have a "sub-panel" installed.  Trace the 120vac input wire from the inverter back to its source.  Is it a breaker sub-panel?   If so it is likely that the breaker that feeds the inverter is 30 amps.  So you are limited to 30 amps input to operate the inverter in "charge only" mode. Open up the sub-panel and look at the main breaker in it to verify.  Looking at the sub-panel box will also enable you to determine what loads in your RV have been wired through the inverter.  Usually the air cond., microwave, entertainment center.  30 amps is sufficient to run the inverter's battery charger.  So you should leave the inverter in charger only mode.

If you can provide the above information I can try to help you.


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  • 2 weeks later...

Hey, everyone.  Great info all around.  I am SUPER appreciate of everyone's help.  Last night, I reached out to Victron directly, after spending a night sweating with no air conditioner and no DC power for lights, etc.  (More importantly, no DC to run the thermostats, which could've run my AC units because I have 50 amp shore power!).

After swapping screen shots and more today with someone in Victron Sales, this was their conclusion:

I can see it (the Multiplus -ed) connected to AC input and charging as one would expect when in Charger Only mode.
Nothing will happen (including pass-through) if you have turned the unit to OFF with the CCGX.  The Multi thinks you want it OFF, so it opens the input relay and shuts off.

Therefore, my original assumption was correct:  I can have 50 amps or I can have charged batteries, but not both.  We are still "in the shade" and at 2:35pm only getting 95W.  I'm keeping lights off to maximize charging.  But you have to have DC to start the generator so I couldn't do that last night.  Jumping it would get it started, but not keep it on, for whatever reason, whenever it wants to shut down.

I am having a tech come out to where we are (middle of Kansas) either today or (more likely) tomorrow.  I am going to determine what it will take to put the original charger/converter back into place so that if I have shore power, I can have batteries getting charged, too.  If the Victron MultiPlus has to be on to charge the batteries and if it's on I only get 30 amps, then that is a DESIGN / PLANNING flaw.  I'm a programmer, it would be like saying you have have your mouse work or your keyboard work, but not both at the same time.  I just can't agree with this installation.

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I wired our setup a little different than many.  I can plug my RV into the inverter and receive power through the inverter or I can plug the RV directly to the hookups without the inverter.  If I want I can plug the inverter into the RV to charge batteries powered by the hookups but the power for the rest of the RV is separate.  I also left the converter so it can be used for battery charging if needed.  We have a residential refrigerator and use a mini split for heating and AC.  Propane is only used for cooking and heating water so I didn't see the need to add an auxiliary breaker box because nearly everything needs the inverter when boondocking.   For boondocking we have 2,000 watts of solar and a generator.

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@Randyretired  Well, based on some above comments, I probably still have my original converter somewhere "behind the curtain".  Hopefully the tech, who I'd MUCH rather have deal with 50 amps of current than me, can put in a switch to make that work for us.

There's simply no reason I should have 50 amp power and have to choose between air conditioning and charging the batteries.  I shouldn't even have to monitor it that closely.  Right now the AC's aren't running so....the battery should charging.  But guess what?  It's not.  The only juice I'm getting right now is from the solar...and that's a measly 60 watts.  In theory, and if not in the shade, I could have up to 760 watts coming in.

When it gets dark tonight, I will flip over to the inverter, run a single AC and hope my batteries get charged.

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3 hours ago, Will B. said:

I am having a tech come out to where we are (middle of Kansas) either today or (more likely) tomorrow. 

I think that you are right to do this as the entire problem seems pretty strange to me. Since I have never owned an RV with solar/inverter power, I have been following this with interest but no comments because even though I have some strong suspicions about things, they come only from the knowledge from my career in electrical service work and my reading on the subject. We did enough boondocking with tents, 4WD vehicles, and horses that when we moved into the modern RV community we pretty much stay where we have utilities. I will be very interested to see your report on what the RV tech has to say. 

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Well, it appears that my problems have been resolved.  Indeed, as expected by myself and other posters, the original converter/charger was still here, behind a false wall that hides a lot of plumbing and the ATS and...another big electronics box.  The tech, after I explained everything, and that my basic problem was "Shore power doesn't charge my batteries", he and I went looking.  

Tracing the power cables, it turns out that there was an empty breaker for it, to which it had been disconnected from.  And that it wasn't "plugged in".  (Weird that there's just a plug for it.)  He reconnected the breaker, plugged it in, and now I have shore power battery charging capability.  Flipping the breaker, we watched the voltage jump a bit on the DC circuits, as expected.  (I had thought that ALL DC input only went to the battery, but he said that there's a cord going to the DC panel, but also to the battery.  That still confuses me.  Unless it's just all shared.)

He only charged a little over an hour's labor.  Most of that time was spent just trying to understand the existing system.  (As a programmer, I get it, you can't just start diving in!)  Repeatedly, he'd stop, shake his head and say "why'd they do it this way?" regarding the Victron installation.   After the Victron sales guy said, basically, "if the Multiplus is off, it does nothing, not even passthrough", I knew that I am completely reliant on sunlight to power the batteries.  Now, if I have shore power, I get what I needed.  I'm ready to survive when the machines (and/or Skynet) darken the sky.

Thanks SO much to everyone here who contributed to this discussion and offered so much help.   We got no low voltage alarms last night, and we stayed on the 50 amp shore power.  (We had been flipping over to the inverter, using only a single air conditioner to be safe. Unless I didn't remember to change soon enough, and started getting alarms before bedtime, in which case the inverter wouldn't WANT to turn on, like the night before, ugh.)  WIthout everyone's help, I might not have really understood what I needed the tech to do.  With this discussion thread, and getting the real info from Victron, I knew exactly what I needed.  (And the tech fixed my sliding screen door on our little side patio, too, that I kept trying to put back on incorrectly after I knocked it off.)

I'm very impressed with the fact that everyone tried to chip in, offered suggestions AND general knowledge.  I have learned more about RV electrical systems, simply due to this problem, than I had expected.

Thanks, everyone!

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