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Discussion Starter #1 (Edited)
Ok guys (and gals). I need some help. I've been really busy and it's 3000 degrees outside in Mississippi with 200% humidity so it has slowed me down on the build. Another thing that has slowed me down is that I'm approaching the electrical part of the build and this is something I have zero experience with. I've read tons but there's so much it is overwhelming. I'm just going to start basic and build from there.

First I need to decide exactly where my fuses/breakers/controllers will be exactly. I know the general area. The batteries (2) will go right in front of the box around the driver's side rear wheel well. In this cabinet



The next thing I can't decide is where this panel will go. Here are the three choices. Obviously I'll have to build something to hold it in all three. I really need any of you that have already done this to chime in on the negatives of each location.


In this first location it would always be visible and be on a cabinet front about the size of the top two drawers. A cabinet door the size of the bottom two drawers would give me access to the batteries and other stuff inside. Pros: easy to wire and deal with panel. Cons: hard to access the other stuff



In the second location there will be a full size cabinet door hiding everything so I should have easy access to the entire area. Other than the panel being sideways and having to open a cabinet door do you see any cons to this? I'm assuming mounting the panel sideways shouldn't be a problem.



The third location again would be behind a full length cabinet door that would give good access to everything but the panel may be difficult to wire being that far back in the cabinet.



You can't really tell in the pictures but the second picture the panel is in the middle of the cabinet and the third panel it is in the back of the cabinet
What do you all think?

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Hi Josh,

That cabinet looks large enough that you could use some of it for the electrical the rest for storage.

While you don't want to pack thinks in to tight, I'd lean toward a compact arrangement that leaves as much of that big compartment as possible for regular storage.

My batteries, power distribution panel (same model as yours), inverter, solar charge controller are all together in a pretty compact arrangement in the cabinet under the bed. Does not really take up a whole lot of room, and the compact arrangement did not make the wiring difficult at all.

A picture on this page: http://www.buildagreenrv.com/our-co...y-camper-van-conversion-electrical-and-solar/

Having to kneel down to change fuses or look at how the solar charger is doing is a small inconvenience, but, to me, this is overshadowed by the compact arrangement.

You will end up valuing an storage that you can save now.

Make sure that the cabinet is strongly built and is bolted through the floor with at least half in bolts with BIG washers or plates under the floor to keep them from pulling through. You don't want your couple hundered lbs of batteries and electronics joining you in the front of the van if you crash.
And, if flooded lead acid batteries, you will need to box them in and vent the box to the outside -- easy to do.



Gary
 

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Discussion Starter #3
Thanks Gary. I'm basically going to copy your design and components except that I'm using 2 renogy eclipse 100w panels, 2 Vmax 125AH AGM batteries, a victron mppt controller with bluetooth dongle.

I do like the large panel box but now I'm kind of thinking if I just got the blue sea 12v fuse box that everyone uses and then use something else for my 120V breakers it would save space and everything could mount to on the wall to the right in that cabinet instead of building something for that panel to sit in. Even that that really isn't a big deal.
 

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#3 . Suffer wiring everything up but have the room later. Back that panel with a piece of plywood and bring it forward enough to drill holes to feed wires from behind.
 
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#3 But hinge it so you can swing it down to wire it up and add new. Cut wire long enough for the door in the open position be neat and label the wires at all splices. This will help to track down a problem at a later date.
 

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Thanks Gary. I'm basically going to copy your design and components except that I'm using 2 renogy eclipse 100w panels, 2 Vmax 125AH AGM batteries, a victron mppt controller with bluetooth dongle.

I do like the large panel box but now I'm kind of thinking if I just got the blue sea 12v fuse box that everyone uses and then use something else for my 120V breakers it would save space and everything could mount to on the wall to the right in that cabinet instead of building something for that panel to sit in. Even that that really isn't a big deal.
Hi Josh,

I think the BlueSea 12 volt fuse panel is a good one. But, there is not a lot out there in the way of small AC distribution panels -- this is why I was happy to find the combined one. I'd nail down a solution for the AC part before committing to the BlueSea DC panel.

Gary
 

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Yea. Our little 2-old-men contracting business used to joke when we had no idea how we would do something the client wanted that it was a reverse “Design-Biuld” job. LOL
 

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Discussion Starter #11 (Edited)
Here is my current schematic without the inverter/charger and batteries or solar hooked up.



My inverter/charger and batteries came in today. I just need to pick up my fuses and I'll be ready to install. Here is what I've drawn up as the final schematic.



Please let me know what you think. For the inverter to battery and battery to dc panel connections I do plan to fuse right on the battery poles to save space. Any certain fuses any of you recommend?

Also I'm not sure on the wire sizes of a few of the runs
 

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I went with 4AGW from my battery to my 12 volt fuses as I added up all the fuse ratings and if all were being drawn at max it would be 120 amps of 12 volt. I wonder of 10 gauge is enough- thats good for only 30 amps and you have it fused at 75. BTW that fuse should be AT the battery. Mine is 80 amp but my fuse holder can take a larger fuse if I ever use more.
 

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Discussion Starter #13 (Edited)
I went with 4AGW from my battery to my 12 volt fuses as I added up all the fuse ratings and if all were being drawn at max it would be 120 amps of 12 volt. I wonder of 10 gauge is enough- thats good for only 30 amps and you have it fused at 75. BTW that fuse should be AT the battery. Mine is 80 amp but my fuse holder can take a larger fuse if I ever use more.
Thanks. 10 could very well be wrong. I have added up that the total amps used if all my 12v items are connected and running at the same time would be 57 amps so that's why I chose a 75 amp fuse. I do plan to put that at the battery. I just didn't put that on the schematic there. The run is only 2 feet. I put that info in the blue sea systems calculator and it gave me 10 awg. No reason not to go with 4awg and a little bigger fuse though right?

Edit :

Anyone know why the calculator gives me 10awg when it's clear by the chart that 4awg is needed?

Here is the updated schematic.



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Hi Josh,

I get AWG 8 for 57 amps, 4 ft total length, and 90C insulation wire.

This is what the calculator says in the "explain results":

The wire you select must be large enough to meet both ampacity and voltage drop requirements. These are the wire sizes this circuit needs to meet each requirement:

Ampacity
Ampacity (ABYC Standards Only): AWG 8

Voltage Drop (ABYC): AWG 10​

So, AWG 8 is required for ampacity (max current). I think you probably ran it with 105C wire, but I think the wire that HD/Lowes sells is typically 90C. And, remember that the length is the round trip length.

The wire is so short that #10 would be OK from just a voltage drop situation.

We are used to limiting #10 wire to 30 amps from house wiring practices, but the ABYC (American Boat and Yacht Council) ratings are higher than this, and I'm sure they are still quite conservative.

edit: just noticed the 75 amp fuse, so wire must be good for 75 amps, not 57 amps, but still comes out AWG 8.

Gary
 

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Discussion Starter #15 (Edited)
Hi Josh,

I get AWG 8 for 57 amps, 4 ft total length, and 90C insulation wire.

This is what the calculator says in the "explain results":

The wire you select must be large enough to meet both ampacity and voltage drop requirements. These are the wire sizes this circuit needs to meet each requirement:

Ampacity
Ampacity (ABYC Standards Only): AWG 8

Voltage Drop (ABYC): AWG 10​

So, AWG 8 is required for ampacity (max current). I think you probably ran it with 105C wire, but I think the wire that HD/Lowes sells is typically 90C. And, remember that the length is the round trip length.

The wire is so short that #10 would be OK from just a voltage drop situation.

We are used to limiting #10 wire to 30 amps from house wiring practices, but the ABYC (American Boat and Yacht Council) ratings are higher than this, and I'm sure they are still quite conservative.

edit: just noticed the 75 amp fuse, so wire must be good for 75 amps, not 57 amps, but still comes out AWG 8.

Gary
Yes I ran it at 105 because that is what my speaker wire was rated at.

What do I need from mppt controller to the batteries? 10 awg correct? And from battery to battery? I have no clue how to calculate that one.

Why does the blue sea system calculator give 8awg for the run you looked at above but if you look at their DC wire selection chart it says 4awg?



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Yes I ran it at 105 because that is what my speaker wire was rated at.

What do I need from mppt controller to the batteries? 10 awg correct? And from battery to battery? I have no clue how to calculate that one.

Why does the blue sea system calculator give 8awg for the run you looked at above but if you look at their DC wire selection chart it says 4awg?



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Hi Josh,

The max current in the wire from the MPPT to the batteries should be 200/12 = 17 amps.

If I use 6 ft (one way) length, and 90C wire, and 2% voltage drop, the BlueSea calculator comes up with AWG10.
I'd also check the wires coming from the PV panels for voltage drop and make sure the #12 is OK. I'd use 2% voltage drop.

The wires between the two batteries take the full current flowing out of the batteries -- so, for your case at the very max, it might be 1250/12*0.9 = 116 amps to the inverter plus 75 aps for the DC panel = 190 amps. The calculator gives 1 AWG for 190 amps. If you cut the max current down to 150 amps, which might be a more realistic maximum, it comes out 2 AWG. So, something like 1 or 2 AWG.

Why the wire table on BlueSea disagrees with the calculator on BlueSea is a puzzle to me. I'm going to email them a question on this -- will pass on whatever they say. I like the calculator in that it allows you to account for more variables.

Edit: after playing around with the various BlueSea Circuit Wizard calculator inputs, I can get the calculator to give wire sizes that are as large (or even larger in some cases) than the wire table. The inputs include the duration of the load (wire size goes up with longer duration), is fuse attached directly to wire (larger wire), is wire in a bundle (larger wire), is there thermal insulation around the wire (larger wire).
I tend to just accept the defaults on the above inputs, but its probably worthwhile thinking about each one and entering it to get an accurate wire size.
I'd guess the wire table makes assumptions for each one of these inputs, but they don't really say. For example, they may assume that all loads are long duration.


Gary
 

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Discussion Starter #17
Hi Josh,

The max current in the wire from the MPPT to the batteries should be 200/12 = 17 amps.

If I use 6 ft (one way) length, and 90C wire, and 2% voltage drop, the BlueSea calculator comes up with AWG10.
I'd also check the wires coming from the PV panels for voltage drop and make sure the #12 is OK. I'd use 2% voltage drop.

The wires between the two batteries take the full current flowing out of the batteries -- so, for your case at the very max, it might be 1250/12*0.9 = 116 amps to the inverter plus 75 aps for the DC panel = 190 amps. The calculator gives 1 AWG for 190 amps. If you cut the max current down to 150 amps, which might be a more realistic maximum, it comes out 2 AWG. So, something like 1 or 2 AWG.

Why the wire table on BlueSea disagrees with the calculator on BlueSea is a puzzle to me. I'm going to email them a question on this -- will pass on whatever they say. I like the calculator in that it allows you to account for more variables.

Edit: after playing around with the various BlueSea Circuit Wizard calculator inputs, I can get the calculator to give wire sizes that are as large (or even larger in some cases) than the wire table. The inputs include the duration of the load (wire size goes up with longer duration), is fuse attached directly to wire (larger wire), is wire in a bundle (larger wire), is there thermal insulation around the wire (larger wire).
I tend to just accept the defaults on the above inputs, but its probably worthwhile thinking about each one and entering it to get an accurate wire size.
I'd guess the wire table makes assumptions for each one of these inputs, but they don't really say. For example, they may assume that all loads are long duration.


Gary
I can't tell from your picture but do you have a ground running from the negative on the battery back to the ground bus bar on the 12V panel? If so should it be the same size as the positive wire running to the 12V panel? In my case 4awg. Also since I'm not connecting any of the electrical systems to the vehicle's battery do I have to run a chassis ground to the inverter?

Thanks

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I can't tell from your picture but do you have a ground running from the negative on the battery back to the ground bus bar on the 12V panel? If so should it be the same size as the positive wire running to the 12V panel? In my case 4awg. Also since I'm not connecting any of the electrical systems to the vehicle's battery do I have to run a chassis ground to the inverter?

Thanks

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Hi Josh,

Yes, I have a wire from negative bus on DC panel to the negative terminal of house battery, and its same size as the positive wire that supplies the DC panel.

Yes, connect the ground terminal on the APS 1250 to a good chassis ground. I don't remember what gage wire I used, but I think the manual says something about it. The transfer switch in the APS will switch in this ground when you are on the inverter, but will switch to the shore power ground when you are plugged into shore power.

Gary
 

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Discussion Starter #19
Hi Josh,

Yes, I have a wire from negative bus on DC panel to the negative terminal of house battery, and its same size as the positive wire that supplies the DC panel.

Yes, connect the ground terminal on the APS 1250 to a good chassis ground. I don't remember what gage wire I used, but I think the manual says something about it. The transfer switch in the APS will switch in this ground when you are on the inverter, but will switch to the shore power ground when you are plugged into shore power.

Gary
Do I also need a chassis ground on my batteries?

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Yup. I chassis grounded most everything 12 volt even most of the appliances and outlets. 120 Volt Nope, never! Generator, Maybe its a science into itself, generally yes.
 
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