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I am converting a 2017 Ford transit cargo van into a camper. I am doing a DIY electrical system with a leisure battery. This is my system schematic, I think I’m on the right track but have no experience with this and am worried I am missing something and don’t want to blow up my rig. Any advice on how it looks? And specifically, how do I know when and where to ground the system?
Any information helps, much appreciate it!
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Welcome to the forum!
I suggest to attach the ground to the designated places in to the chassis and NOT run a wire to the battery directly (looks like the ground wire is used as a shunt resistor by ford).

Manual
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One more thing, try to keep all the fuses in or near the same place ... (it might be my OCD organization).
 

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Discussion Starter #3
Thank you for your reply! Do I need only one ground in the system or more? My inverter already has a ground wire coming off it, will that suffice for the entire system or do I need to add anything else?
 

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You also need a chassis ground attached to your negative bussbar. Consider replacing some of your fuses with bussman breakers. First on my list would be the one going to the DC fuse box.

You can drill your own hole for your chassis ground. There is no need to use the BEMM points in my experience.
 

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You also need a chassis ground attached to your negative bussbar. Consider replacing some of your fuses with bussman breakers. First on my list would be the one going to the DC fuse box.

You can drill your own hole for your chassis ground. There is no need to use the BEMM points in my experience.
I'm pretty sure I saw a note in the BEMM about why you should use the recommended ground locations to avoid chassis signal noise and CANBUS errors.
 
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Discussion Starter #6
You also need a chassis ground attached to your negative bussbar. Consider replacing some of your fuses with bussman breakers. First on my list would be the one going to the DC fuse box.

You can drill your own hole for your chassis ground. There is no need to use the BEMM points in my experience.
Thank you, that’s helpful. So for my second grounding wire, I need to run one directly from the chassis to the negative busbar, correct?
This is the schematic I based mine off of, it seems that he has what he calls a grounding connection going from the neg. on the starter battery, to the negative busbar. Why is that considered a grounding connection, when it isn’t connected to the chassis?
 

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Discussion Starter #7
Thank you, that’s helpful. So for my second grounding wire, I need to run one directly from the chassis to the negative busbar, correct?
This is the schematic I based mine off of, it seems that he has what he calls a grounding connection going from the neg. on the starter battery, to the negative busbar. Why is that considered a grounding connection, when it isn’t connected to the chassis?
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The negative battery terminal is also connected to the chassis. Connect to the negative battery terminal or the chassis, as far as electrons are concerned it is the same thing.

There may be reasons to only use the BEMM points, but i haven't seen any adverse effects. If there is a BEMM point close by, why not use it. However, i wouldn't run 8' of 2/0 cable to get to one.
 

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Just in case, I follow the recommendation of an engineer who has put some time and effort to write a manual ... He / she might have a strong design reason for doing so. ;)
 

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I also would recommend a chassis ground attached to your negative bussbar. With that negative wire added, there is no need to run a negative wire all the way to the starter battery. Also be sure and fuse your positive cable as it comes off of the started battery.
 

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I am converting a 2017 Ford transit cargo van into a camper. I am doing a DIY electrical system with a leisure battery. This is my system schematic, I think I’m on the right track but have no experience with this and am worried I am missing something and don’t want to blow up my rig. Any advice on how it looks? And specifically, how do I know when and where to ground the system?
Any information helps, much appreciate it! View attachment 139330 View attachment 139330
I'm having a very similar discussion going on at my thread, you might benefit from checking it out. Electrical Design Review request - Common negative for...
 

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Thanks all! I also was told the other day that 2/0 wire was way overkill for my system, and recommended that I use 2AWG instead, due to the ease of buying it locally and the fact that running all my loads at the same time shouldn’t be drawing more than around 50 amps, and 2AWG us rated for 95. Thoughts on wire size coming off a 200ah AGM deep cycle battery?
 

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The 1500 watt inverter by itself will use ~ 150 amps and could hit 200 amps.

2/0 is much more correct than 2 awg.

If the current battery that you have selected can keep up or not - that is a separate question. The answer is probably no.
 

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My 2/0 wire gets warm with heavy charging and inverter use. I thought it was slightly overkill at first but I'm glad now that I went so heavy.
 

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The 1500 watt inverter by itself will use ~ 150 amps and could hit 200 amps.

2/0 is much more correct than 2 awg.

If the current battery that you have selected can keep up or not - that is a separate question. The answer is probably no.
Thanks for your reply. The inverter that I have currently actually came with the van, and already came with the 2awg wire running to the battery. The 200amp fuse for that circuit was also already in place... would I be able to get away with using the same wire size as long as I fuse appropriately to protect the wire?
 

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Thanks for your reply. The inverter that I have currently actually came with the van, and already came with the 2awg wire running to the battery. The 200amp fuse for that circuit was also already in place... would I be able to get away with using the same wire size as long as I fuse appropriately to protect the wire?
A number of companies post ampacity charts. They are a good "guideline". This is an example one:



A not perfect but close enough way to read the chart is to look at the column marked "75 C" for copper wire. This is not "optimized for low losses, it is a "minimum safety level" kind of information.

Using this chart, the current ratings are:
  • 2 awg = 115 amps
  • 2/0 = 175 amps
If you have 2 awg and reduce the fuse size to the suggested safety level ( 115 amps or similar) then that is a safe way to do it.

If you are going down that path, I would replace the fuse with a breaker such as a blue sea 187 type. That way when it trips you just reset it instead of getting out the tools.



There are other breaker options. That one is pretty decent. You should be able to find it online for ~ $60.
 
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