Unity Electrical Upgrade

DiverBob

2018 Unity TB
I moved the refrigerator breaker to the other bus so it switches to AC if the generator or external AC is applied. Thanks for the idea! Still need to redo the breaker labels.
I am supposed to get my 4th BattleBorn battery today. In preparation I removed the 3 installed batteries since I need to set them in the compartment in a different footprint. This means I have to move the main fuse as the batteries take up almost the full width of the compartment. I have space in the front of the compartment so I’ll put it there. I got more 4/0 wire and crimpable lugs so once I get the new battery I’ll measure and cut the wire for the new arrangement. It looks like I can reuse most of the previous wires and only have to add 3 or 4 new connections.
 

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DiverBob

2018 Unity TB
BattleBorn loves you!
The price per battery is down $25 from the last time I bought them!
I’m stuck at home waiting for FedEx to show up so I can sign for the battery. In the meantime I’ve been trying to figure out how to get everything to fit inside the compartment and not have to replace wires. I think I’m going to put the battery cutoff switch on the back wall beside the shunt. There is still plenty of room in the compartment but the wires are hard to bend to certain positions so that limits where the wires and thus the components attached to them. Plus the need to have the negative wire to the shunt come off the first battery in the chain and the positive wire come off the last battery in the chain tends to dictate where certain items can be placed....
Interesting jigsaw puzzle to play with while I’m waiting, at least its getting a bit warmer outside for this kind of fun.
 

DiverBob

2018 Unity TB
The new battery arrived a day late but it is packaged very well. It took a while of experimenting all the different options of where to put the shunt, disconnect switch and battery fuse. I wanted to be able to reuse as much of the existing wiring as possible. Although using 4/0 gauge welding wire is relatively flexible, it still needs space to make turns. It took a while to find a setup that works but I think I have a working solution now. The shunt ended up staying in the same location along the back wall above the battery tops. I put the battery disconnect switch beside the shunt on the wall but put the switch on a block to keep the wires from interfering with each other. I ended up with the fuse block being bolted to the floor support, it already has a long slit that I could use to bolt the fuse block onto without having to drill holes.
I made up a new 4/0 cable to run from the fuse block to the battery. However when I got back home from getting the new cable lugs crimped I realized that I needed another positive and negative cable to finish connecting the 2 rows of 2 batteries together..... Oh well, I’ll get the insulation stripped and ready to go tomorrow morning. Should be able to finish this project up and start enjoying 400 Amp-hours of power!
 

DiverBob

2018 Unity TB
A bit of delay finishing up as it was pouring rain all day, didn’t want to play with electricity while being wet. Got the final two wires put in and after tracing all the wires again to make sure I didn’t make any mistakes, I turned on the battery disconnect. Since there was no evidence of smoke from anything I then turned on the solar disconnect also. I checked the read outs from the Victron Venus GX and everything seemed to working just fine. I updated the Victron battery monitor to tell it I have 396 Amp-hours of battery and all seems well.
I tested the system by heating a bowl of water in the microwave, battery voltage went from 13.65v to 12.58v at 130.9 amps. But the voltage and current held steady during the 2 minute test.
 

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DiverBob

2018 Unity TB
Finished up the last of my planned electrical changes today!
I changed the solar panel wiring from parallel to series-parallel to take advantage of my Victron MPPT solar controller. It ended up being a fairly simple job now that its warmed up a bit! Of course the MC4 removal tool and dust caps I got during the winter are not to be found anywhere I looked so I went with the alternative method of removal, tie wraps! This turned out great because with the tool I would have had to remove the Dicor and unscrew the connectors from the roof and then replace the Dicor afterwards. With the tie wraps I left everything in place and only needed to tie wrap the new connections down to the existing wires. I did order some new dust covers to seal the old 3 way MC4 connectors. Thank you to whomever mentioned that tie wraps work also!
I also installed the BIM-225 battery isolation unit under the passenger seat. Using the knowledge gained from others on this website it was an easy install. Since I have Equalizer Levelers I knew about the ignition wire error that did occur and equally important, how to fix the error! I know people have mixed feelings about the isolator, I’ll try it out for a while and if it doesn’t work out then I’ll look into putting in a DC-DC converter instead.
I installed the Micro-Aire soft start unit in the air conditioner. The on-line manual was pretty good and the installation went well. I can run the air conditioner off the battery without tripping the 2K inverter. The air conditioner draws about 138amps from the batteries, well within the discharge specs. This gives about a 3 hour run time if the air was running continuously, which I don’t ever expect to do. An added side benefit is that when the compressor kicks on the noise is much lower than before, not too much more than the fan noise.
That’s all the planned electrical changes for now! I’ll be testing the whole system out with a 4 day boondocking trip where we will be staying in one place for the whole time. Hopefully there won’t be any issues so we will be ready to go for our longer trips this summer and fall.
 

RV2019

2017 Wonder MB
..... Of course the MC4 removal tool and dust caps I got during the winter are not to be found anywhere I looked so I went with the alternative method of removal, tie wraps! This turned out great because with the tool I would have had to remove the Dicor and unscrew the connectors from the roof and then replace the Dicor afterwards. With the tie wraps I left everything in place and only needed to tie wrap the new connections down to the existing wires. I did order some new dust covers to seal the old 3 way MC4 connectors. Thank you to whomever mentioned that tie wraps work also! .....
I mentioned it in another thread (GoPower Solar Panels) and don't know if that is where you saw it. When I needed to check the volts and amps on my panels, I also would have had to remove the dicor, etc as the connectors were mounted with the ears on top and bottom so could not get a tool there. Tie wraps to the rescue!!
 

DiverBob

2018 Unity TB
I have direct proof that changing the solar panel wiring to series-parallel works, typically I haven’t seen the solar controller start providing power to the battery until almost 9AM. Today I see power starting to come in at 7:18AM, significantly earlier than before.
 

woundedpig

2018 Unity MB
Charging via a Victron MPPT controller requires a photovoltaic voltage of at least 5 volts above the resting house bank voltage for the charge controller to even activate/start up. The higher resting voltage of lithium batteries vs lead acid/AGM's complicates this. This is why MPPT charge controllers and parallel wiring of solar panels is not a good combination. Series/parallel wiring schemes increase the voltage coming down from the photovoltaic array, allowing charging to begin earlier in the day, as you are seeing. I'm interested to see how your system performs while boon docking in one place for a while, especially if you run the AC. You have abundant lithium AH capacity but not a lot of solar charging, in the grand scheme of things, in terms of balance. A bit of good news is that a lithium bank doesn't need to be charged to 100% with each charging cycle, unlike lead acid banks.
Also beware of the high alternator charging currents you will see when driving off with the lithium bank in a depleted state. The lithium BIM has its duty cycle charging, but in the end, if you commonly see > 100 amps coming from the alternator when driving, the BIM may not be enough. Since you are all Victron, one of the buck boost DC chargers that Victron has just come out with may be an answer, or a Sterling DC to DC charger.
 

JHMooney

2018 Unity MB
Great job and thank you for being so detailed with pictures, etc. I was thinking of a different layout for the charger/inverter and wonder if anyone has installed a Victron in the existing inverter bay? Does Victron even make one that will fit?
 

DiverBob

2018 Unity TB
Great job and thank you for being so detailed with pictures, etc. I was thinking of a different layout for the charger/inverter and wonder if anyone has installed a Victron in the existing inverter bay? Does Victron even make one that will fit?
Thanks for the compliment!
The 2K inverter would fit in the inverter compartment but because of the floor strut I couldn’t get it and all 3 batteries in there. Now that I’ve gone to 4 batteries there’s definitely no room! But you could get the 2K inverter to fit along the back of the compartment but not lengthwise as the Magnum fits. If I remember right the Victron case is about 1 inch too long to fit in there without major modifications to the case and then the door strut would be an issue also if you wanted to put one in like the Magnum. It could still go across the back of the compartment but it can’t fit all the way back against the back wall.
I just checked the dimensions on the Victron 3K inverter, its considerably shorter, 14.3” vs 20.5” for the 2K inverter. The 3K is 8” thick and the 2K is 5” thick, same width on both. The 3K could probably fit in the space the Magnum fits in, don’t know how much room there is with the metal shield in place.
 

DiverBob

2018 Unity TB
Last week was the first boondocking test of the completed electrical system upgrade. I ran from Thursday afternoon to Sunday afternoon, so 3 full days. Since it was overcast and rainy everyday except Sunday, there was minimal solar input and we did not run the RV or the generator during this time. We didn’t take any actions to conserve power other than turning the lights off. We used the microwave several times (the attached graphs show the spikes when the microwave was turned on (about 134 amps at 12v!).
When we left we were down to 22.9% SOC, so we had enough power for one more day before running the battery bank out. The wife’s CPAP was the biggest continuous power draw overnight.
The attached graphs from the Victron Remote Monitoring website show the overall power usage for the trip. If we would have had some sun during the daytime hours I’m sure we would have been able to stay fully charged for the entire trip. But its good to know that even without doing anything we have power for an extended period of time. Now I just have to figure out how to extend the water longer!
 

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DiverBob

2018 Unity TB
I haven’t been posting or reading much lately as we are 6 weeks into a 10 week trip to Alaska. Anyway, the electrical system upgrade has generally performed correctly and as expected with 2 exceptions.
The first problem was directly my fault! One day we stopped for lunch at a turnoff on the road. It was a very hot day (91º) with no wind so we decided turn on the AC unit and run it off the batteries. It started up fine and cold air was coming out of the vents much to our relief. I checked the battery monitor and it was pulling 170 amps from the batteries. After a bit the AC cycled off and after a while I realized that we were getting hot yet the AC wasn’t running. I thought I popped a breaker but everything was ON. At this point we decided to head on down the road and investigate later at our next stop. During the drive we discovered that all the electrical outlets were dead. This meant that the inverter was no longer inverting.... So once we stopped I checked the 250 amp fuse to the inverter, it was fine. I could read voltage at the inverter Positive and Negative terminals but it differed slightly from actual battery voltage. Unfortunately I didn’t think that discrepancy through at that time. At that point I thought that somehow I had managed to fry the inverter. I contacted Battleborn since thats where I purchased the Victron inverter and they had me do a series of tests including removing all the battery cables and getting individual battery voltages. After that didn’t show up anything I started putting all the wiring back together. At this point I was doing voltage measurements everywhere and saw that with the batteries wired up, the DC disconnect ON, there was no voltage at the inverter DC terminals? So I started tracing the wiring and found out that I had run the positive lead to the inverter through the LTV positive terminal back and that was going through a 150 amp fuse. Of course that fuse was blown! About that time I remembered leaving the original fuse in there, intending to replace it with a 250 amp fuse to match the inverters internal 250 amp fuse but forgot all about it. Once that was replaced, everything started working properly again.
Next issue was found when when we lost air conditioning due to the previous problem, I started up the LPG generator and waited for it to pick up the air conditioning. After several minutes and no air conditioning forth coming, we cut lunch short and got back on the road. Luckily the MB air conditioning was working just fine! So we stopped at a full service RV park and found that all the outlets worked and air conditioning in the house also worked to our great relief! As a test I disconnected the power coming into house and tried the generator again. No power from the generator to the house. Of course at this point I was troubleshooting the inverter issue and thought they were somehow related. Once I got the inverter running again I went back to the LPG generator and as best I can tell at this time the problem is the transfer switch is stuck and not sensing the generator output voltage (generator breaker was tested out OK). Luckily I don’t really need the generator and we are no longer having extremely hot days where we need air conditioning.
The last problem is the battery isolation monitor (BIM) under the passenger seat has on 3 separate occasions has not allowed power from the alternator to reach the battery for charging. In each case this happened for one day only, turning the engine on and off did not have any impact, even a couple of times with the engine being off for over an hour while we did some hiking. In each case the battery ranged from 54% SOC to 75% SOC with battery voltage around 13.2 volts each time. Without an explanation for what is causing this (in each case the next day it worked properly, cycling 20 minutes on and 20 minutes off) I am doubtful as to the reliability of this unit and plan on replacing it with a dedicated DC to DC charger from Battleborn. This will have to wait until I get back home in about a month so I have more time to monitor its operation.
Despite some issues I have been very happy with my setup and the options we now have.
 

SSTraveler

2014 LTV Unity Murphy Bed
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DiverBob

2018 Unity TB
Since my last posting I replaced the alternator relay with a 60 amp DC to DC Charger. We are 5 weeks into another trip and so far it has been working as advertised. The only issue I have encountered is that when we were in hotter weather we would get a over temperature alarm occasionally. I think that’s due to the obvious lack of ventilation under the passenger seat. After we get home I will be looking for another, better ventilated location for the unit. Plus I want to get their remote for it as there is no practical way to see the front panel to tell what is really going on without removing the passenger seat.
Another thing that has come up is although the 2K inverter will power up the air conditioner with the Soft Start unit, I get an over temperature alarm on the inverter after it runs for a bit. When that happens the inverter turns off until it cools down enough and then it starts up again. The problem is that its usually hot when we want to run the AC so the inverter is already operating at higher temperatures. So the only option at this time if we want battery powered AC then a 3K inverter is required. That decision I’m leaving up to the wife! My main goal was being able to run the microwave and all the outlets at the same time on the inverter and that works just fine as is. The Soft Start unit is also good in that it greatly reduces the starting noise the AC compressor makes when it starts up so that was a good modification to me.
I thought I had gotten the transfer switch to work and it did while testing at my house but the next time I actually wanted to run the generator the transfer switch would not engage so I need to get that replaced under warranty.
Still pretty happy with the electrical changes so far!
 

DiverBob

2018 Unity TB
I thought I’d give an update on my electrical changes.
First off I determined the Automatic Transfer Switch is no longer activating when the generator is turned on. I replaced the switch with another switch and now that is working properly.
My wife made the request that she wants the air conditioner to be able to run from the batteries so I ordered a Victron 3K inverter from BattleBorn last month to replace the 2K inverter. Unfortunately it was back ordered and finally came in and shipped out. Unfortunately FedEx hasn’t been in any hurry to get it to me so according to the tracking number it’s been about 45 minutes south of me for the last 4 days. The new inverter is the same width as the 2K but it’s about 2 inches thicker and several inches shorter. Based on the preliminary measurements I will have to move several components mounted in the old battery box under the stairs to get it to fit. So new cables will probably be needed also. My wife would like me to get this installed before we leave for Florida at the end of next month so hopefully we will have a couple of warm days coming up soon so I can work on it!
Lastly, for the overheating DC-DC Charger under the passenger seat, I decided to try increasing the ventilation flow to the area first rather than moving the charger. Since the passenger seat sits on a metal box, only the top of the pedestal is available for ventilation. Luckily under the vinyl cover there is a stiff piece of plastic that I was able to attach a small 12v fan over an existing hole in the plastic. To control the fan I got a generic electronic thermostat from Amazon that had good reviews. Unfortunately the thermostat instructions are a poor Chinese to English translation so it took some time to figure out how to properly program it! So everything was tested on my workbench to make sure it was working properly. Everything runs on 12v which I got by tapping into the lines from the lithium battery. I also got the charger remote control since I can’t get to the charger easily when its under the seat. For now I haven’t mounted the remote as I haven’t decided where to put it. I just let the remote sit under the passenger seat out of the way for now. The thermostat isn’t mounted either, I placed it beside the charger under the seat so when the side panel that holds the awning controls is removed, I’ll be able to access the unit.
 

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DiverBob

2018 Unity TB
We got a rare warm winter day of 50º today here in Michigan so I immediately started the latest phase of the electrical changes, changing out to a larger inverter. First job was removing all power sources, solar, batteries and shore power were turned off and verified via multimeter.
I removed the Victron 2K inverter after labeling all the wires coming into it. With the wires removed it was easy to remove the inverter, solar controller and Venus hub from under the step. This really opened up the area and revealed all the dust from last years Alaska and Southwest trips that settled everywhere. After cleaning the dirt up and wiping down everything, I was ready to reinstall all the parts.
I cut a 3/8” plywood piece to slide under the inverter to raise the case up and over the bolt that holds the retractable step so the inverter can lay flat. I also removed the top cover on the inverter to improve the air flow through the unit to the holes I drilled in the side of the compartment. The bundle of wires coming into the compartment from the back middle had to be moved around so the inverter can be as close to the back wall of the compartment as possible. This inverter is 8” thick so it needs as much space as possible. I used a plastic block to prevent the inverter from sliding forward and back. I want to make sure the inverter case will not accidentally touch the positive bus bar!
I moved the solar controller to the left side of the compartment and screwed into the metal floor which should help the controller heat sink. The solar circuit breaker/switch is mounted beside that. The Venus communications hub is a lightweight plastic box mounted to the ceiling of the compartment. The best part is that no new cables were needed and all the original wires could be reused. After mounting everything, all I had to do was hookup all the wires to the right spots and test the individual parts again.
I did find that the latch on the vertical wood piece hits the inverter case so I had to remove it. Now I need to figure out how to cover that hole up.
The Venus unit came up correctly on-line and I was able to verify that everything was working the way it is supposed to. That should take care of all the planned changes for now. We are heading to Florida for a couple of weeks towards the end of the month so that should be a good system test before our much longer summer trip!
 

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DiverBob

2018 Unity TB
Was having an issue with the RV where the outdoor GFCI outlet would pop when I plugged the RV in, however its been too cold to effectively troubleshoot an electrical problem. Because of this the battery has been running down so after it got to around 20% I ran the generator to get it back up to 50%, and cleared the snow off the solar panels so some charging would take place. Today the temperature made it up to 41º and it was sunny so time to do some troubleshooting!
I plugged the RV into the house outside outlet with all the RV breakers open. As late as yesterday the house outside outlet GFCI would trip off, today it didn’t. I slowly turned on each breaker to see if any specific circuit was causing the problem, they all went on OK. Inside the RV I could hear a relay activating every few seconds. Determined that it was the built-in Surge Protector. The display was showing the correct input voltage, 0A and an Error code of E0 (which is OK). After watching this a bit, the display started to show error code PE1. This is supposed to be the previous error that would have shut the unit down, in this case Reverse Polarity. Since the only AC side electrical changes have been a new Inverter, that was my first place to check the wiring setup. I checked the manuals for the surge protector and inverter to make sure of the wiring again. I also checked a photo I took of the inverter with the cover off and sure enough I had the line and neutral wires backwards. Not sure how I missed that simple of task but glad I found it now!
So the new inverter was charging up the batteries the way it’s supposed to, unfortunately the outside outlet is on a 15 amp circuit and it was drawing 17 amps so the breaker tripped. Now the GFCI is popping off again, the GFCI outlet is 23 years old, maybe it needs replacement.... More troubleshooting for later!
 

Meeks

Member
Impressive trouble-shooting! Wish I knew how to do that kind of electrical trouble-shooting. Very handy!


2020 Unity FX/2019 Chassis (March 2020 delivery)
 

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