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2021 3500 high roof ext (on order)
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Discussion Starter · #1 ·
After 8 months of waiting, our 3500 high top ext finally arrived. Right smack dab in the height of freezing temperatures of course, so we're trying to do what we can in advance of spring. Towards that end, I've pieced together a simple electrical plan (not simple to me, I struggled for months) that incorporates some of the items we purchased while waiting for the van. Those items include: (2) 105 amp lithium batteries, 40 amp Renogy DC to DC charger, Renogy 3000W pure sine inverter, Progressive Dynamics 45 amp converter/battery charger, and 15 amp shore plug. We don't plan to start out with solar, but may add portable solar panels in the future to try and capture some of Alaska's elusive summer sun.

I would love feedback, even harsh criticism of my electrical plan, as the last thing I want to do is burn down my van, or ruin my lithium batteries right out of the gate.

In hindsight, I would have probably gone with the more expensive charger/inverter combo, but I didn't, and I can't send what I have back now, because the van took forever to get here, so I'm installing what I have. I also realized the inverter I purchased is oversized for my battery bank, but see reasoning above, I'm stuck with it. I bought the 3000W thinking we might try an induction cooker, but electricity is not my jam, so here I am. I guess that leads to my first question, which is will the larger inverter harm my coach batteries even if I'm not trying to draw a full load off of them? I plan to install a disconnect switch to the inverter so it's not drawing at all when not in use.

My other questions have to do with fuse sizing between coach batteries and + bus bar, and between bus bar and Inverter. I should probably add a battery shunt and monitor as well, and am wondering if I can just run them off the negative bus bar, or is there a more appropriate place. Lastly, should I run a ground from the inverter to the chassis ground, or is the ground from the bus bar sufficient, as I am also grounding my initial run to the DC to DC charger, back to the van battery compartment.

I've included our DC loads on the wiring diagram, and think they are, and should remain modest, but we plan to be out for days/weeks at a time, and are too old to be miserable, as misery is always optional.

Thank you in advance to anyone who takes the time to read this, yet alone respond. Come on spring, get here already.
 

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An oversize inverter won't hurt anything as long as you don't draw more than the max amp draw for your batteries. Check their specs. Mine are 100A each for a total of 200A, or about 2000W. That's another good reason to get a battery monitor. The shunt needs to go between the batteries and everything else. So, before your negative buss bar.
 

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As long as the batteries are fused below their max discharge rate an oversized inverter won't hurt them.

1. It is best practice to have a fuse on the van battery and another fuse/breaker on the same line closer to the DC/DC. Makes it easier to shut off and disconnect.
2. Depending on your batteries, they're probably rated for a 1C discharge rate. For 100AH batteries that means 100A per battery, or 200A max. I'd fuse below that (what are your batteries?)
3. None of your other fuses should be larger than your battery fuse.
4. Having an on/off disconnect for your batteries is helpful.
5. I really appreciate having (quality!) breakers between my items and the bus bars. Makes shutting individual items off really easy.
6. No need to run a negative line back from your DC2DC, instead run that negative to your negative busbar (which goes to ground). The chassis completes the connection.
(unless you really want to!)

That's all I got!
 

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I am absolutely NOT an electrical expert either - so take this and look for more guidance. I used the Renogy "50 amp dc-dc mppt" controller in my install - and - instead of running a cable from the negative terminal of the van battery to the controller I simply ran a short cable to ground on the the truck frame. Saved a lot of time and cable. :)
 

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2021 3500 high roof ext (on order)
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Discussion Starter · #5 ·
I am absolutely NOT an electrical expert either - so take this and look for more guidance. I used the Renogy "50 amp dc-dc mppt" controller in my install - and - instead of running a cable from the negative terminal of the van battery to the controller I simply ran a short cable to ground on the the truck frame. Saved a lot of time and cable. :)
Thank you sir, I had considered this as well, and may go that route at the end. Looking at cable now and it isn't cheap, but compared to the van costs, thought a little redundancy might be worth a few bucks.
 

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2021 3500 high roof ext (on order)
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Discussion Starter · #6 ·
An oversize inverter won't hurt anything as long as you don't draw more than the max amp draw for your batteries. Check their specs. Mine are 100A each for a total of 200A, or about 2000W. That's another good reason to get a battery monitor. The shunt needs to go between the batteries and everything else. So, before your negative buss bar.
Thank you sir, I will add the shunt and battery monitor. Good to know the inverter won't harm my batteries, I've been worrying about that for weeks and wasn't getting a definitive answer from my web searches.
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
I like your diagramming technique!

The wire from you positive busbar to the DC to DC charge should have a fuse or breaker located close to the busbar. The reasoning for this is that fuses are there to protect the wiring, so in the case of this wire, if you have a short to ground (say a short to the chassis), the house battery will provide just about unlimited power to the wire and will melt it and potentially start a fire.
In general any wire from a current source (a battery) should be protected by a fuse located close to the current source. You locate the fuse close to the current source because the length of wire between the current source and the fuse is not protected from a short to ground.

Same logic applies to the wire to the 12 volt fuse box. The 70 amp fuse is fine, but it should be located close to the + busbar. Same logic for the inverter. If you only plan to use only part of the inverter capacity, you could use a smaller fuse and wire gauge - in fact, you don't want it fused to a value higher than the max current draw for you batteries.

Same logic for the 45 amp charger - fuse located close to the + busbar.
You show the shore power only hooked up to charger. If you decide to have 120VAC outlets in the van, then I'd read up on bonding of the neutral to the ground - or (easier) keep the shore power outlets in the van separate from the inverter outlets in the van.

Gary
 

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2021 3500 high roof ext (on order)
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Discussion Starter · #8 ·
As long as the batteries are fused below their max discharge rate an oversized inverter won't hurt them.

1. It is best practice to have a fuse on the van battery and another fuse/breaker on the same line closer to the DC/DC. Makes it easier to shut off and disconnect.
2. Depending on your batteries, they're probably rated for a 1C discharge rate. For 100AH batteries that means 100A per battery, or 200A max. I'd fuse below that (what are your batteries?)
3. None of your other fuses should be larger than your battery fuse.
4. Having an on/off disconnect for your batteries is helpful.
5. I really appreciate having (quality!) breakers between my items and the bus bars. Makes shutting individual items off really easy.
6. No need to run a negative line back from your DC2DC, instead run that negative to your negative busbar (which goes to ground). The chassis completes the connection.
(unless you really want to!)

That's all I got!
Thank you for your response,
I will add a battery disconnect/circuit breaker between the van battery and DC to DC charger.
My coach batteries are Lion Energy brand 105 amp lithium. As to quality fuses and breakers, there is a marine supply place close to the house, that carries Bluesea products, I'll buy my incidentals from them.
 

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Discussion Starter · #9 ·
Hi,
I like your diagramming technique!

The wire from you positive busbar to the DC to DC charge should have a fuse or breaker located close to the busbar. The reasoning for this is that fuses are there to protect the wiring, so in the case of this wire, if you have a short to ground (say a short to the chassis), the house battery will provide just about unlimited power to the wire and will melt it and potentially start a fire.
In general any wire from a current source (a battery) should be protected by a fuse located close to the current source. You locate the fuse close to the current source because the length of wire between the current source and the fuse is not protected from a short to ground.

Same logic applies to the wire to the 12 volt fuse box. The 70 amp fuse is fine, but it should be located close to the + busbar. Same logic for the inverter. If you only plan to use only part of the inverter capacity, you could use a smaller fuse and wire gauge - in fact, you don't want it fused to a value higher than the max current draw for you batteries.

Same logic for the 45 amp charger - fuse located close to the + busbar.
You show the shore power only hooked up to charger. If you decide to have 120VAC outlets in the van, then I'd read up on bonding of the neutral to the ground - or (easier) keep the shore power outlets in the van separate from the inverter outlets in the van.

Gary
Thank you sir, My diagramming "technique" is called not being smart enough to figure out a way to do it on the computer. I will make sure my lines are fused close to the current source. The shore power connection is only intended as another charge source for the batteries. We shouldn't need a dedicated AC panel/fuse box, as we don't intend to run any big power consumers in the van build. I'm not even sure we need the inverter, but I already bought it.
 

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Thank you sir, My diagramming "technique" is called not being smart enough to figure out a way to do it on the computer. I will make sure my lines are fused close to the current source. The shore power connection is only intended as another charge source for the batteries. We shouldn't need a dedicated AC panel/fuse box, as we don't intend to run any big power consumers in the van build. I'm not even sure we need the inverter, but I already bought it.
Hi,
I went with the whole inverter/charger and an AC distribution panel feeding half a dozen 120VAC outlets around the van that worked off the inverter or shore power.

Big waste of time and dollars - we hardly ever use the AC outlets. A single AC outlet from the shore power and a powerstrip plugged into the inverter would have been fine.

Gary
 

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Hi,
I went with the whole inverter/charger and an AC distribution panel feeding half a dozen 120VAC outlets around the van that worked off the inverter or shore power.

Big waste of time and dollars - we hardly ever use the AC outlets. A single AC outlet from the shore power and a powerstrip plugged into the inverter would have been fine.

Gary
Us too ,,, in 2018

fast forward to 2022 & there must be something wrong in m head, cause I could not resist at least “running the wire” for the 120v 💸💸💸. About $130 in 12-3 (100’ roll) & about 4 extra hours pre-wiring before insulation.
 

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Us too ,,, in 2018

fast forward to 2022 & there must be something wrong in m head, cause I could not resist at least “running the wire” for the 120v 💸💸💸. About $130 in 12-3 (100’ roll) & about 4 extra hours pre-wiring before insulation.
1) why do you need 100 feet?
2) how is it 4 extra hours?

What are you doing, running 16 outlets all around the van?
 

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1) why do you need 100 feet?
2) how is it 4 extra hours?

What are you doing, running 16 outlets all around the van?
I ran; 2 separate plug outlets, 1 fridge outlet, 1 hwt outlet, 1 inverter line, 1 line to the back pillar, & 1 spare

the 4 extra hours was a guess on my part (I did not actually time it). How long do you think those 7 lines would take to run & secure?
 

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Your decision to use a separate inverter and charger is the same approach that I use in van electrical builds.

I view it as safer and more reliable, especially if you plug into outlets with potentially poor quality power. It is quite a good method for reducing the potential for external power surges from entering the van power system, as well as hackers.

While it doesn't pull a lot of power at any given time, a 12 volt compressor refrigerator is one of the largest total power users in a van. They are great for van owners who have access to plentiful sunshine and have the challenge of living in hot climates

IIRC, @RV8R faced the same general challenge that you do and I "think" his solution was to use a propane type refrigerator.
 

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I installed 4 AC outlets. We use 3 of those all the time. It really depends what you need AC for, and where it's located relative to your inverter and converter. In our case, one outlet powers our induction hob and tea kettle. Another powers the AC backup for our hotwater heater and e-bike charger. And while on shorepower at home, the third powers an electric space heater and trickle charger for the starter battery. AC is a daily need for us, but others use it rarely, if ever.

We have an inverter-charger combo so I don't know how to wire and operate separate units. @HarryN will know if you need an auto-transfer switch for them. The one in our combo unit is definitely convenient, I just don't know if it's important safety wise.
 

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Your decision to use a separate inverter and charger is the same approach that I use in van electrical builds.

I view it as safer and more reliable, especially if you plug into outlets with potentially poor quality power. It is quite a good method for reducing the potential for external power surges from entering the van power system, as well as hackers.

While it doesn't pull a lot of power at any given time, a 12 volt compressor refrigerator is one of the largest total power users in a van. They are great for van owners who have access to plentiful sunshine and have the challenge of living in hot climates

IIRC, @RV8R faced the same general challenge that you do and I "think" his solution was to use a propane type refrigerator.
Hi @HarryN

I try to spotlight “All Things Heat & also Air Conditioning” to newbies. But refrigeration is not one of those items. For that I find any decent fridge that uses a DB35 now Secop IIRC compressor and a variable speed controller are more than efficient to qualify for my self spec for 12v battery power YMMV of course.

Air Conditioning & All Things Heat; Furnace, Cooking, & Hot Water take loads of energy & for a 12v system like we use it is too much and alters wha we want. Thus we use “Propane” for furnace, & cooking. I would also use propane for a hot water solution (small tank), but I want to find some HWT that is thru floor (intake & exhaust) for combustion air

Our heavy 12v loads are; fridge & Propex Propane furnace (12v blower fan to move air). Our last fridge ran @ about 2.5A IIRC & the Propex @ 2.1A. The “average” for the ARB fridge in 24hrs was “rated” @ 0.87A @ 24hrs = 21Ahrs.

The 21Ahrs roughly “penciled” depending upon conditions (Winter less & Summer more).

Our 2018 build & 250Ahr batteries & 12v use would vary seasonally, but averaged out we could typically go 3 days without charging. We typically charged up every day.

 

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There is no need for a transfer switch when using separate components.

The 120 vac charger is wired in the same way as any other charger or inverter - typically to the bus bars via fuse or breaker. Nothing special about it.

I am assuming that you are using a good quality, AGM marine battery since it is AK. 4 would be better than 2 for what you are doing.
 

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I am assuming that you are using a good quality, AGM marine battery since it is AK. 4 would be better than 2 for what you are doing.
The OP has 2 105Ah lithium batteries, which should be OK (more is always better) just in terms of storage and discharge capacity. But the OP hasn't mentioned their solution for lithium freeze protection. Definitely an issue in AK.
 

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There is no need for a transfer switch when using separate components.

The 120 vac charger is wired in the same way as any other charger or inverter - typically to the bus bars via fuse or breaker. Nothing special about it.

I am assuming that you are using a good quality, AGM marine battery since it is AK. 4 would be better than 2 for what you are doing.
Hi Harry,
If the same 120VAC outlets are powered by either inverter or shore power, how is moving the point where neutral is bonded to ground handled - ie bonded at the inverter when on inverter power and back at the power pedestal for shore power?

Or, did you mean that separate 120 VAC outlets are used for the inverter and for shore power?

Gary
 

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I'm using a separate component for all my gear as well, for reliability. All in-one units save space, but if it goes bad you might be without all features.

I'll re-iterate fusing as close to every energy storage as possible (+ terminals). Preferably all batteries, but if a bank is physically located right next to each other and in adequate enclosure, skipping the paralleled batteries is probably tolerable.

I didn't see anyone else put this out there - your 'house' batteries shouldn't be tied to chassis ground in any way shape or form. Some inverters (my 3k renogy for example which you appear to have chosen as well) will provide a direct short to ground if the house battery (-) is connected to chassis ground. Only the main propulsion battery and inverter casing ground (NOT the inverter (-) terminal) should be connected to chassis ground ideally. If you try to ground something to chassis that you shouldn't on a DC system you'll also likely find out real quick and can vaporize equipment even. I've seen snap-on wrenches vaporize in a blink. Make sure and consult the manuals carefully for each piece of equipment. I know the Renogy manual specifically says NOT to tie into chassis ground. The shared connections between equipment means just because one manual says its 'ok', doesn't mean it is in your specific setup.

I'm surprised nobody chimed in on this, but it probably seems obvious to me because I'm an electrical contractor. I know in automotive and especially trailers it's common to ground everything to chassis to save wire, but never redundantly do that to sources.
 
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