Sorry this took a while,
The first option Diagram 1, pretty much mirrors your existing drawing, I have added equipment ground for the DMT1230 and Inverter. I also added a chassis ground connection for your bus bar. I also move the voltage wire for Victron to connect directly to the battery instead of a the fuse panel. You really want to monitor the voltage as close to the battery as possible. I did find it odd that the Victron unit uses the power supply line also as a monitor line. Granted the monitor does not use a lot of current, but general good practice is to have monitoring wires carrying no current for accuracy. That said it is a good unit. I also show some dashed lines that can be considered alternate routings. The two equipment grounds could be tied directly to the fame and not go to your busbar if that was more convenient. Also the ground wire from the staring batteries could be implied thru the frame and thus can instead be run to your ground bus bar. I don’t think ether way is better than the other, so I would choose what is more convenient. Also the other alternate is the power wire from the Victron, I have it attached to the protected side of the Class T Fuse (Main) on your house battery bank.
Starting would fusing, I show a 20 amp fuse on the output of the solar panels, I show this close to the panels so a good choice would be a
MC4 inline fuse connector.
I suspect that you could even get away with a 15-amp fuse here.
The next fuse you see is the 50-amp fuse at the starting battery bank. This is considered a main fuse is the first fuse in series after the battery, any subsequent fuse after the main fuse would be considered branch fuses. A main fuse has a different Ampere Interrupt Capacity (AIC) then a branch fuse. Normally I recommend a
Marine Rated Bus Fuse.
They attach easily to the starting battery, but the main reason is that they have a high AIC rating (10,000A), that is good for a main fuse. To figure out what AIC is needed we need to figure out what the CCA of your starting batteries is.
Cold Cranking Amps (CCA) is a measurement of the number of amps a battery can deliver at 0°F for 30 seconds and not drop below 7.2 volts.
Marine Cranking Amps (MCA) is the same measurement at 32°F, it is usually about 125% of CCA.
I believe in a PM that one of the starters was rated at 875 CCA so we will assume that the one on the frame is the same and we have 1750 CCA rating. We usually look for a fuse with an AIC rating of 2X CCA.
Sense, you are attaching to the frame mounted starting battery you may want to use a different fuse such as an AMI fuse
This comes with an AIC rating of 5000A and can be mounted in a waterproof holder such as the
Blue Sea Systems AMI/MIDI Safety Fuse Block, A added plus of this holder is an place to store a replacemnt fuse. This Fuse also provide the fusing for the input of the KISAE DMT1230
The output of the KISAE DMT1230 is specified to be 40 amps in the manual, 8 AWG wire covers at 4 feet with a 1% voltage drop. The ampacity of 8 AWG is 80 amps
We can stay with an AMI fuse and use the
Blue Sea Systems AMI/MIDI Safety Fuse Block again, another alternative could be a
Blue Sea Systems Maxi Fuse You can save a few dollars on both the fuse and fuse holder, the Maxi fuse can not be used as a Main fuse, it should only be used in a branch cicuit.
The KISAE also has an optional ignition on Voltage Sense Overide circuit that much be attached to source that is hot only in run, this should be proteced by a 2 amp fuse, I generally use an
ATO ATC inline fuse holder in this case.
The fuse for the Victron 700 is most likely a AGC glass fuse, and is supplied. I relaity it is supposed to be a branch circuit, which is why I give an alternate routing of it atached after the Class T fuse, so that it is truly a branch cicuit. This loctaion is still close to the battery.
The
ST Blade Fuse Block #5026 is rated for 100A per block, 30A per circuit, the max rated fuse for the block is 125-amp fuse. If we look at the expected loads they add up sixty amps if all circuits are active, in real life this probably won’t happen, but we also have capacity left for future growth. If I was going with a hard fuse I chose an 80-amp fuse to protect the fuse block. This is a real good area to look at the use of a circuit breaker, we could use an
285-Series Circuit Breaker .
This would allow me to use a lower rated current protection and possible a smaller wire to support the fuse block. We can use a 50-amp circuit breaker and cover the 8 AWG wire safely. If you wanted to go higher we want to move up in capacity, you can go with 6 AWG and an 80 amp or 100-amp fuse. If this is needed it will also change our needs in the House Battery to main fuse and wire.
None of the circuits on your fuse block is high and should be fused with the appropriate size, a minimal of 18 AWG should be used, it has ampacity of 20 amps, for longer runs you may want to move up to 16 AWG with an ampacity of 25 amps
Moving to the inverter, I was a little surprised at the minimal data provided in the Renogy Inverter Manual, they actual provide some 4 AWG wires with the product but provide limited information on the actual unit their specifications do say that it has 85% efficiency. So, our calculations will give us wattage output 1000 watts divided by 85% efficiency or 1176 .5 watts. Their low voltage cutout is programmed to be 11 volts, so we divide input power of 1177 / 11 this gives us a load of 107 amps. I like to use 10.5 as my low voltage cutoff calculation in general, if I use that I get 1177/10.5 or 112 amps for the load. We can see that the 4 AWG wire provided (note 1) meets the load requirement and 125-amp fuse is the best fit. Again, a
Blue Sea Systems AMI/MIDI Safety Fuse Block or
Marine Rated Bus Fuse would be a good choice.
The last fuse is the fuse on the main house battery bank, typically I like to use a Class T Fuse
in this location, they will have an AIC rating of 20,000A. A good Class T Fuse holder is the
Blue Sea Class T Fuse Block with Insulating Cover - 110 to 200A #5007100
The worst case loading of the house battery would be a maxed-out inverter and a maxed-out ST Fuse Block. Worst case for inverter was 112 amps and 5o amp circuit breaker at the STC fuse block which puts us at a total of 162 amps. At minimum I would chose 2 AWG (ampacity of 210 amps) from the house battery to the bus bar fused with a 175-amp fuse. Other fuses that could be used in the location are the
Marine Rated Bus Fuse or the
Blue Sea Systems AMI/MIDI Safety Fuse Block. If we wanted more out of our Fuse block we may have to movbe up in wire size from the battery to bussbar, we would also need to more than likely move up in the busbar and fuse accordingly
I show B
lue Sea PowerBar Dual BusBar # 2020 for your bus bars, You can stack up to 4 connections to each stud, so these will support up to 8 connections. It is limited to 200 Amps , so if you need larger capacity both in ampacity or connections you can go with
Blue Sea MaxiBus 250A BusBar # 2127
As you don’t have a shore charger in this layout, you are in complete reliance on the
KISAE DMT1230 unit, if it were to go bad you have no way to charge your house battery. In Diagram 2 we added a simple
Blue Sea M-series #6006 on/Off switch in the circuit. This will allow us a back up system if the KISAE unit were to fail. While the normal position of the switch would be off, you could switch to on and have your alternator now charge your house battery. This would be a manual process but would at least get you thru a trip if something were to fail midtrip. A secondary option would be to use this as an
emergency start assist from your house battery.
This does come with some changes and additional cost. First, we change the wire size from the Starting battery to the
Blue Sea # 6006 switch to 2 AWG wire, and from the
Blue Sea #6006 switch to the bus bar to 2 awg. We will up the fuse at the starting battery to 175 amps also. Now we change starting battery KISAE power connection to the input terminal on Blue Sea #6006 switch, and the output goes to the output terminal of the Blue Sea #6006 switch. We keep the same wire size and fusing as we had with the previous. It is expected that cable length from switch to KISAE is relatively short, but we still need proper fusing.
You will notice in this diagram I use
Blue Sea MaxiBus 250A BusBar # 2127 busbars.
Diagram 3 is an offshoot of the previous one. Instead of using the straight On/Off Battery Switch #6006, we instead use the Blue Sea m-Series Selector 3 Position Battery Switch #6008. This switch allows you to choose a path that goes thru the KISAE DMT1230, A path that bypasses the DMT1230, and lastly that disconnects both paths. This would add the option to disconnect the house system from the Van system, sometimes useful when having the van in for service.
This diagram also has some other changes, I have increased the wire size from the house battery to the busbar from to 2 AWG to 1 AWG. This increases the ampacity from 210 Amps to 245 Amps, this allows us to increase the fuse size and usage of the ST Fuse block from a 50 Amp Circuit Breaker to an 80 Amp fuse, we could still be using the full capabilities of our fuse block and inverter at the same time. One additional cost of this is because we are now changing the wire size down from the 1 AWG going to busbar to 2 AWG going to the Blue Sea Switch we now need to fuse it for the proper fuse size, so you can see that I added another 175 Amp fuse.
For many of the wire size calculations I use my own
Wire Size Calculator, this is similar to the Blue Sea wire calculator, it has the benefit if you like spread sheets to be in a spreadsheet form.
This allows you to compare the size above and below what it calculates, which I at times find useful. I also just added a feature of cost comparison. Although I will not be updating the actual cost daily the intent is to see how much money a size down may save you or a size up may cost you. Of course, one of the go to tools is the
Blue Sea Circuit Wizard,
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which has the benefit of helping to choose fusing.
Note 1: All wire size calculations are done with 105 °C rated wire