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Considering Replacing GD1620 2000w inverter with Victron MultiPlus II

Ben and Kathy

Well-known member
Hello All!

We recently purchased a slightly used and much loved 385FL (Unit #2 off the assembly line) and are considering replacing the installed GD1620 2000w inverter with a 3000w Victron MultiPlus II. The RV came with a generator.

The initial goal:
  • Be able to run any of the 120v outlets while not connected to shore power or firing up the generator with the exception of the AC units
  • When stored:
    • we plan on having some level of camper automation (home automation on wheels) monitoring the environment
    • a cellular connection running at all times for remote access
    • a small residential dehumidifier (or the new Colman unit if it ever comes out and makes more sense)
    • potentially some security cameras
  • We currently do not boon dock though that is a future consideration
  • We do want to be able to use the microwave at a rest stop
Additional info:
  • We will be installing 1050 watts of solar on the roof
    • Two sets of three 175w Renogy flexible panels wired in series wired in parallel
    • Based on the math the above configuration will work with the factory installed GoPower solar wiring which is spec'd at 30amps
      • I have not yet laid eyes on the physical wire to verify that it is at least 10 gauge
  • To start there will be two Enduro Power Baja Series 12V 200Ah Deep Cycle LiFePO4 Lithium Batteries wired in parallel with the potential for a 3rd to be added (to support the use of a single air conditioner off grid)
  • I have all of the major parts to complete the solar install and am considering adding the MultiPlus II for AC power flexibility (and visibility to power consumption which will be logged and monitored by the home automation system)
My initial sanity check before investing in the MultiPlus II:

The breaker panel is separated into two sections, 1) Shore Power / Generator and 2) Shore Power / Generator / Inverter with specific outlets and the residential refrigerator.​

Based on the above I believe I need to do the following to install the MultiPlus II: (and remove the GD1620)
  1. Disconnect and cap off the AC wires coming from the GD1620
  2. Disable/disconnect the battery charging circuit on the RV electrical panel inside
  3. Connect the output of the transfer switch (shore / generator) to the MuliPlus II AC in connection
  4. Connect the AC line that was originally connected to the transfer switch to AC 1 output of the MultiPlus II
  5. I have not yet pondered the changes required for the 12v side of this conversion yet
Aside from the 12v part, what is not clear to me on paper (haven't pulled the AC panel in the RV yet to look at it) is how #2 (inverter block of circuits) of the breaker panel receives power when on shore or generator power?

Currently the RV is in winter storage without any power (the existing pair of lead acid batteries have been removed - actually they were accidentally drained to zero 2x before we realized that the battery disconnect didn't fully disconnect all power from the batteries, so they are essentially trashed)

Would appreciate any thoughts feedback from those experienced with this type of upgrade.

If there is interest I will create a new thread to track progress as we do the upgrade.

Thanks!
-Ben & Kathy
 

Trent Mills

Well-known member
I like your plan, this could be a long thread!
Just to clarify, you are going to go with a 12 VDC system? If you are looking at growing, I would consider a 24 VDC system. You could add a second string of 200 Ah batteries in the future (and a second Multiplus II if you ever wanted to go above 3KW).
You are right, air and heat (fireplace, electric heater) are huge long term loads. Standard estimate is one, 100 Ah 12 VDC battery to run one air conditioner one hour. Or, 1.5 hours of your solar at 100%. A lot depends on duty cycle, efficiency of the AC, ambient temp, insulation of your rig (drafts closed?), etc.
There is a solar estimate spreadsheet you can play with loaded on one of the Alliance Facebook groups Files section, I will try to find the link for you.
 

Ben and Kathy

Well-known member
I like your plan, this could be a long thread!
Just to clarify, you are going to go with a 12 VDC system? If you are looking at growing, I would consider a 24 VDC system. You could add a second string of 200 Ah batteries in the future (and a second Multiplus II if you ever wanted to go above 3KW).
You are right, air and heat (fireplace, electric heater) are huge long term loads. Standard estimate is one, 100 Ah 12 VDC battery to run one air conditioner one hour. Or, 1.5 hours of your solar at 100%. A lot depends on duty cycle, efficiency of the AC, ambient temp, insulation of your rig (drafts closed?), etc.
There is a solar estimate spreadsheet you can play with loaded on one of the Alliance Facebook groups Files section, I will try to find the link for you.
Thanks, I'm hoping it is a long thread with opportunity to share as we go!

Great question Trent on 12 v 24 VDC. We are sticking with 12 VDC for this go around. We've never boon docked; living in Missouri there is less opportunity for open space BLM type camping opportunities (lots of tree coverage). My wife's job requirements prevent her from working remote full time, part time yes but not full, so we're limited on how far we can go without making it a "vacation."

Thanks for the checking on the solar estimate spreadsheet we definitely need to do a power audit. I found a great reference on sizing the solar components and wiring on explorist.life (yes that's the URL). Great resource!

I'm just crazy enough to go DIY on this for the fun of it.
 

Trent Mills

Well-known member
Lots of help on this page, Jim Beletti is a great resource. The sizing file I was talking about is on the "Alliance RV Glamdockers" group "Files" section. If you can't get there, tell me what groups you are on and I can drop it into the files section for you.

I did not want to go to 24 VDC initially, but now that I am I am really glad I did. You are pulling 300 amps at 12 VDC for the 3000 watts you want to run. For the same 300 A at 24 VDC you could be pushing 6000 watts (after adding a second Multiplus down the road). That certainly adds margin to your DC wiring.

Just something to think about.

Link to the sizing file below.
 
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Jim Beletti

Owner Experience Liaison
Staff member
@Ben and Kathy - Hi guys!

WRT this question:
Aside from the 12v part, what is not clear to me on paper (haven't pulled the AC panel in the RV yet to look at it) is how #2 (inverter block of circuits) of the breaker panel receives power when on shore or generator power?

I can't speak for your unit or your build but I can speak in a general sense.

When a generator is supplied, typically, an ATS (automatic transfer switch) is installed. The generator output connects to it as does the shore power from the sidewall inlet. The output of the ATS generally feeds the 50A double-pole breaker in the AC Load/Power Center (breaker panel). So that's typically how shore power and generator power get to your AC circuits. Through the ATS to the panel. In that manner, the entire panel is inverted.

Going back and rereading your post, WRT this point:
The breaker panel is separated into two sections, 1) Shore Power / Generator and 2) Shore Power / Generator / Inverter with specific outlets and the residential refrigerator.

Are you certain you have a split-panel that is marked and wired as you state? If so, I wasn't aware we're doing that, but that's cool if we are. If your just guessing that's what you have, then my guess is you have a typical panel with a single power source connecting directly to it via a double-pole 50A breaker.

Take a picture of what you have and edit your post to add it. By the way, if you don't have a split AC Power Center and want one, you could swap yours out if you have space to do so. Progressive Dynamics and others make split panels.
 
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Ben and Kathy

Well-known member
@Ben and Kathy - Hi guys!



I can't speak for your unit or your build but I can speak in a general sense.

When a generator is supplied, typically, an ATS (automatic transfer switch) is installed. The generator output connects to it as does the shore power from the sidewall inlet. The output of the ATS generally feeds the 50A double-pole breaker in the AC Load/Power Center (breaker panel). So that's typically how shore power and generator power get to your AC circuits. Through the ATS to the panel. In that manner, the entire panel is inverted.

Going back and rereading your post, WRT this point:


Are you certain you have a split-panel that is marked and wired as you state? If so, I wasn't aware we're doing that, but that's cool if we are. If your just guessing that's what you have, then my guess is you have a typical panel with a single power source connecting directly to it via a double-pole 50A breaker.

Take a picture of what you have and edit your post to add it. By the way, if you don't have a split AC Power Center and want one, you could swap yours out if you have space to do so. Progressive Dynamics and others make split panels.
Hi Jim, first thank you for taking the time to respond! I was guessing on the split panel; inference from the way the circuit breakers were laid out and the basic wire diagram for the 385FL (attached). What I missed in the P.D. manual was the auto transfer switch in the P.D. inverter that detects shore power and turns the unit off. I should be able to disconnect the feed from the Inverter to the Load Panel at the panel and be good. Will have to pull it apart to see how it is wired.

So all I think I need to do is take the output from the ATS, run that to the MultiPlus II and from the MultiPlus II to the 50A double-pole breaker in the AC Load/Power Center. If I'm really lucky the current line 50 amp line running from the ATS to the Load Panel is long enough to be shifted to the MultiPlus II (that's assuming that the ATS is located in the front compartment.) :)

Now to locate the ATS...
 

Attachments

  • Alliance 385FL Electrical.pdf
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Ben and Kathy

Well-known member
I did not want to go to 24 VDC initially, but now that I am I am really glad I did. You are pulling 300 amps at 12 VDC for the 3000 watts you want to run. For the same 300 A at 24 VDC you could be pushing 6000 watts (after adding a second Multiplus down the road). That certainly adds margin to your DC wiring.

Just something to think about.
Been thinking, contemplating... I'm strongly leaning towards staying with 12volt. The batteries and the solar will be connected to a Victron Energy Lynx Power in Battery Connector. Starting on the wiring diagram this weekend. Will share my thoughts once I have a draft layout
 

Cggerth

New member
We are in the final stages of getting our RV after 1 year of waiting for the truck and 5th wheel hitch. It'll most likely be the 42V13.

with all the waiting I've had lots of time to consider the whole power setup. We plan on slowly adding to the setup over time

earlier in the thread there was a discussion between 12V vs 24V. How hard is it to start with the 12V but swap to 24V in the future?

I most likely will swap from the included 100AH Renogy to Sok 206AH (price being the main reason). While I'll stick with just 1 or 2 in the near term, I do see myself expanding this in the future to have more power for boondocking.

I know to shift from 12V to 24V would require rewiring the batteries in series/parallel. A DC to DC controller would have to be installed. Would the solar charges need to be swapped as well? I know as I add solar panels I might need to add more solar charges (or upgrade them) but not sure if that factors into a 24V system or not.

(i would most likely have the victron multiplex installed as well during this or before)
 

Ben and Kathy

Well-known member
(i would most likely have the victron multiplex installed as well during this or before)
If you are considering the MultiPlus II (typo on Multiplex?) then they are voltage specific, 12 or 24, and you would have to replace when changing from a 12 to 24 volt system. To reuse your existing 12v batteries later for a 24v system would need at least one pair of 12v batteries in series to give you 24v.

Note also that the MultiPlus II (according to the manual) requires a minimum of 400ah batteries for 12v unit and 200ah for 24v unit. (I do not yet have any experience with the victron hardware, this is coming from the installation manual)

You may want to look closer at the specs on the Sok 206ah batteries to see what the max continuous discharge is rated at; I believe it's only 100ah. Personally I purchased two Enduro Power Baja Series 200ah batteries for this reason; their max discharge is 200ah with a peak of 300ah. These batteries come with a 10 year warranty (no I'm not affiliated in any way with Enduro Power) I was looking at other batteries in the 200ah range and a number of them were actually only capable of discharging at 100ah even though they were rated at a much higher capacity.
 

Ben and Kathy

Well-known member
Well I've done a lot of consider'n and ponder'n and purchase'n with lots of scrapes and bruised knuckles from assemble'n (crimping wire lugs is, well not fun) and test'n here's where I am at: (Also posted on FaceBook Alliance RV Renovations, Hacks, Mods and Upgrades)

Victron Energy Power Conversion - Installation Photos - 385FL (Front Storage Compartment)

DIY install with lots of YouTube research and 50amp RV conversion wiring diagram from Explorist.life. Replaced 2x STD lead acid batteries and factory installed 2000w inverter.

Primary Components:
  • Victron Multiplus II 2x 120
  • 2x Enduro Power Baja 200amp hr batteries with heating pads designed for lithium batteries
  • 6x 175 watt (1050 watt potential) Renogy flexible solar panels
  • Cerbo GX (the brain)
  • Cerbo GX Touch 70
  • SmartSolar MPPT 150|85
  • Orion Tr Smart DC-DC Chargers (Bluetooth) - Smart 12/12-30A Isolated (this is the charge feed from the tow vehicle)
  • Victron Energy SmartShunt 1000 amp Battery Monitor (Bluetooth)
  • Lynx 1000amp Distributor
Todo:
  • Still have the solar panels to install but the solar inverter is in place. (I have to run new wire from the roof, factory installed solar prep wire not found, not there
    🙁
    ) Panels will be wired 3x in series, 2x in parallel
  • Also need to run 30amp line from tow vehicle.
  • Also have not installed the touch screen inside. Will have to pull the wall to run the USB / HDMI cable (and ethernet) for that.
  • Need to run power and add a remote switch for the heating pads
  • Need to add a remote switch to power off the inverter
  • Need to add a test button with an LED light for each battery to validate fuse is not blown (Each battery has it's own 250v T-Fuse that is located behind the wall so not easily visible or testable)
  • Test the modified transfer switch wiring for the generator with new system (haven't had time yet)
  • Some kind of additional protection wall to keep items stored in front compartment away from power wall and wiring
  • Mod/hack the Lynx power distribution module so that LEDs show the status of the fuses.
Pics of our nearly completed Victron Energy Power conversion. (missing solar from roof and tow vehicle charge wiring)
  • 1st pic is out camping with Starlink up and running. Starlink router and 5 port ethernet switch will be mounted to the first wall panel. (box contains wall bracket for Router)
Victron Wall with Starlink up and running.jpeg
  • 2nd pic is completion of assembly in the RV
Finished Installed Victron Wall.jpeg
  • 3rd pic is battery shelf and power (I have room for a 3rd battery if we decide we need) Each battery is fused and run separately to the Lynx 1000amp bus bar mounted in battery compartment
Battery Shelf w Batteries.jpeg
  • 4th pic is 12v system power bench test before transporting to the RV
Test bench - 12v validation.jpeg
 
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Ben and Kathy

Well-known member
Some early lessons learned:

Here's the fun part about the above, the first camping run (the day I finished assembly) we set up and plug into a brand new site with 50amp shore power. In line SurgeGuard goes "whir, click" NOPE not allowing AC power to flow. Of course at this point I have no idea whether I have done something monumentally stupid with the wiring or what is going on. After checking everything I could I decided to hook up to the 30 amp circuit and, badabing badaboom SureGuard says yes sir, power is good, and connected... Dug in the bag of spare electrical things that came with the camper and found an old plug in 50 amp surge guard. Stuck that in the pedestal and low and behold, bad plug, very loose wire that if I held the surge guard just right with just the right amount of tension at just the right angle I could get it to light up green. Camp ground offered to allow us to move to a different site, this is after we were completely set up. Yeah right, NO, not doing it, lived with a 30 amp feed. Which led to some discoveries...

Also learned the need to tell the Multiplus II how many amps it has available. If you try to pull over what's available, in this case it was set for 50 and only had 30 available it simply looses it's mind and bad brown out like things happen ( in one case caused an error on the Multiplus II where it thought I had a low battery situation, yikes, but was a false positive) Power share can't/won't kick in as it is expecting to have 50 amps of shore power. Badness! I found this out four different ways. Different power demand scenarios including the best one where I reset the breaker and turned on the one AC it blew again almost immediately and I'm like Whiskey Tango Foxtrot is going on here!?!?!? Turns out that the coach did run off the batteries long enough to drain them a bit and once it had shore power the MP II was also set to feed 50 amps into the batteries to recharge them so it once again exceeded the 30 available amps of shore power. Ah the joys of learning a new system...

I still have not tested a full 50 amp hookup yet with my new setup and due to non RV related travel commitments won't be able to until our next trip in early June... (some level of pucker factor with a remaining unknown funness potential, yes, can't wait)

Bought 50 amp and 30 amp power testers and a 30' 50amp extension cord just in case this ever happens again and I have the option to go to a different power pedestal. Will now always test the pedestal before disconnecting the tow vehicle. We've never in 25+ years of RVing had a power problem like that.

Aside from the above, everything worked as expected without issue. Our 2nd outing this last week was 100% successful (on 30amp) with no issues
 
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Jim Beletti

Owner Experience Liaison
Staff member
@Ben and Kathy - love your setup. My favorite shade of blue :)

Great work. Couple of comments and apologies if some of this is already known to you:
  1. You can change the shore power input from the Connect app or the GX Touch screen
  2. The USB for the GX Touch is for power only and if desired, you could power it locally, nearer to the screen (that's what I did)
  3. You can turn the Inverter off from the GX Touch, saving the need for a remote switch
 

Ben and Kathy

Well-known member
@Ben and Kathy - love your setup. My favorite shade of blue :)

Great work. Couple of comments and apologies if some of this is already known to you:
  1. You can change the shore power input from the Connect app or the GX Touch screen
  2. The USB for the GX Touch is for power only and if desired, you could power it locally, nearer to the screen (that's what I did)
  3. You can turn the Inverter off from the GX Touch, saving the need for a remote switch
Thanks Jim for the compliment (love the Blue as well :)) and info sharing. Yes, I did learn the different points of control but good for everyone to see. Victron can be quite confusing. At the time it was crisis mode so didn't know until I talked to the supplier I bought the MP II from. Thanks for the tip on the USB power for the touch screen. I thought that the touch capability ran through the USB line as well as the power. I was not aware that touch capability could run through the HDMI...

The GX Touch will not be accessible when the RV is closed up, the touch panel (at least the current plan) will be mounted on the short wall on the kitchen side which is easily accessible (relatively that is) from the front storage compartment where I have my battery storage.

The remote switch for the MP II is really more a nice to have but now that I have the Cerbo GX WiFi password saved on my devices, and can easily pull up the Connect App. I might see if they have any home screen widgets for that available...
 

Ben and Kathy

Well-known member
50' of 4/0 wire, 25' each red / black, I ended up with this left...(I didn't account for the chassis ground off of the power distribution bus and the ground from the MP II) Had to use some Red wire with black electrical tape stripes for the Negative feed from 12v power distribution bus to the MP II. All in all, called it on the total length I needed. Win!!! This stuff is stupid expensive, below scraps = roughly ~$15 ...

Left over wire.jpeg
 

Focker

Well-known member
Touching on the CerboGX further, you can use the "Remote" function on any web browser or your phone that mirrors the display to control your Multiplus II. You can turn it off, to charger, or inverter and change the amps you want from shore power.
I am not sure what you are running the ethernet cable for, that would not be needed for the GX display but maybe it is actually for something else?
Did you do the little wire mod on your Lynx so you can see if any fuses have blown and light the power light? That is a fun, quick project.
 

Ben and Kathy

Well-known member
Touching on the CerboGX further, you can use the "Remote" function on any web browser or your phone that mirrors the display to control your Multiplus II. You can turn it off, to charger, or inverter and change the amps you want from shore power.
I am not sure what you are running the ethernet cable for, that would not be needed for the GX display but maybe it is actually for something else?
Did you do the little wire mod on your Lynx so you can see if any fuses have blown and light the power light? That is a fun, quick project.
Yes, I can pull my phone or iPad out, but was thinking I would add the redundancy just to avoid having to grab a device, especially with grubby greasy hands. So far I've mostly used the remote function to adjust things so the switch remains a nice to have thing for a future small project.

There are several Ethernet cables. One is connected to the ce.bus so I can hook up an MK3 USB adapter so I can run the VictronConnect software from a computer if necessary. There is one from the Cerbo GX to the switch in the compartment which will then be run to our PepLink router.

I have not done the Lynx hack yet, need to add that to my todo list. Wanted to get it done before I mounted the hardware but it was a lower priority vs getting everything up and running.
 

Ben and Kathy

Well-known member
I love the robustness and flexibility that the Victron equipment offers but it can be a bit daunting to get your head wrapped around. I spent the majority of my time designing the component layout, and redesigning the layout, and where to fuse, measuring a 100 times before starting on the wiring. I originally thought I could squeeze everything onto one panel, had it laid out that way to begin with, but decided that the bends the 4/0 would have to take would be challenging not to mention making the wall weigh a whole lot more than it already does so I put the MP II on the adjoining wall and called it a day.

Once the solar and tow vehicle wiring is complete I will be digging deeper in to the Victron control software. I'll be adding Home Assistant to the RV at some point in the near future and will of course connect the Cerbo GX to HASS to capture the energy data from the Victron system not to mention the opportunities it opens up to automate alerting for power anomalies or to automate shutting down non essential things to conserve battery if need be. So many possibilities! I have a Home Assistant Yellow hardware kit sitting on the shelf calling to me...
 

Jim Beletti

Owner Experience Liaison
Staff member
@Ben and Kathy - I too use Home Assistant both at home and in the RV. Have had it in the last 3 RVs. Love it. Exposing all the Victron date (via the Cerbo) to the network via MQTT and picking that up off the network in HA. I have a view with all the Victron stuff in it and then use various Victron entities on cards here and there.

Here's my RV's Home view:

Screenshot 2023-04-20 at 2.46.42 PM.png
Here's my RV's Power view:

Screenshot 2023-04-20 at 2.46.13 PM.png

Where in the Cerbo to set up MQTT:
Screenshot 2023-04-20 at 3.11.20 PM.png
 
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