Does this make sense for a battery bank?

[Biscuitsjam]

I want to make sure we have the wiring diagram correct and this makes sense as a system. I purchased most of the components already, but if you have a strong recommendation that I change things, it's not too late to do returns.

1. Does this make sense? Is anything installed in the wrong place or the wrong way to work?

2. Did I create a short or something dangerous? Do I need more fuses or different fuses or in different places?

3. Is this appropriately flexible to later be able to add solar power, a generator, or more batteries if we decided to do so down the road?

4. What gauge wiring should I use? My reading sounds like 8 gauge is sufficient but 4 gauge is recommended. Does this sound right? Does the wiring requirement change if I later add solar power?

5. I will need to winterize next September. If we plan to not use the bus, the recommendation seems to be to bring the batteries inside. If we want to go somewhere in Alaska in the winter, what are your recommendation to keep the batteries functional at -20 to -50 degrees Fahrenheit outside? Are there any other components I should be worried about in the battery compartment?

Thanks

[Biscuitsjam]

More information:
Charging: a 4-stage battery charger (Iota DLS-45) while connected to shore power or from the alternator while driving (Sure Power 12023A Isolator). I've read that I may not get much charging power off the alternator this way while driving - thoughts? In an emergency situation, I could idle the bus (about 2/3 gallon per hour), but I don't know if I could get enough power that way to be worthwhile.

AC Power: Automatically switches to use shore power when connected (Xantrex ProWatt SW Auto Transfer Switch). Otherwise, I will be using a 2000 watt true sine wave inverter (Xantrex ProWatt 2000). Running off AC power will be a residential refrigerator, the control panel for a gas stove, a 700 watt microwave, a crock pot, a laptop computer, a coffee maker, and some outlets (and possibly a washer/dryer, but I don't think I want to give up the space. No air conditioning needed in Alaska).

D/C: Running off DC power will be lights, CO/smoke detectors, the composting toilet vent fan, and water pump(s) (and possibly some control systems for our heating solution - haven't finalized it yet).

Battery Bank: 4x inexpensive golf cart batteries give me 430 A/H at 12 volts (Duracell GC2). This should allow us to boondock for a couple days if we are frugal on electricity.

Disconnects: A manual disconnect in the battery compartment (180A continuous/1000A Surge Disconnect Switch) disconnects everything (I've heard that it is a bad idea to turn off while the engine is running). A Remote Inverter On/Off Switch in the cabin turns off AC Power but does not disable DC power (Xantrex ProWatt SW Remote Switch).

Battery Monitor: An inexpensive unit that monitors voltage and the current (Bayite DC 6.5V-100V LCD). I think it is sufficient for now, but it wouldn't be hard to swap out later with a Trimetric if I think I need it.

Fuses: One in-line fuse at shore power and one in-line fuse just after the battery bank. Is this sufficient? (ANL-500A). Currently, I do not have plans for any circuit breakers inside the cabin and was instead planning to just use surge protectors on A/C for this initial trip (the cabin will have appliances, bedding, and seating installed but will not really be "finished" until arrival in Alaska).

[Twigg]

From the shore-power, the power comes in at 110-120V. The fuse should be 30 to 50 Amps, not 500 Amps. The larger fuses are usually only on the 12V side of the system.

[Biscuitsjam]

Makes sense - that's an easy change.

[o1marc]

Thanks for that. Electric are not my strong suit and I was hoping to find a diagram like this before I got started so I would know all I needed and where to put this. This helps tremendously.

[Defjr333]

Just a question....Why did u go with separate transfer switch, charger, and inverter? Preference? 2K watt inverter/ chargers with built in transfer switch makes for much easier install, plus saved me $......mine was $730. And btw, go with 0awg minimum. 00awg if u can. Also keep the power cable from battery bank to inverter as short as possible....under 5 feet mine says @00awg. Its 3k watt tho. Hope gave some ideas.
Doug

[Biscuitsjam]

The charger, inverter, and transfer switch were $620 altogether for name-brand components, (plus $25 for the remote power switch) although I just discovered I could have saved $75 or so by shopping around more. If something fails or I want to do an upgrade, I don’t have to replace the whole system.

On the flip side, the wiring could get expensive and that big gauge stuff isn’t a lot of fun to work with.

This chart is interesting, though it doesn’t show the big gauge wires:
https://www.windynation.com/cm/wire_size_fig3wn.jpg

[JDOnTheGo]

Originally Posted by Biscuitsjam

1. Does this make sense? Is anything installed in the wrong place or the wrong way to work?

Yes, makes sense. If one were to get picky, AC power is not really +/-, it is hot, neutral, and ground. Not a big deal from a diagram perspective - just be aware when you start connecting things.

Originally Posted by Biscuitsjam

2. Did I create a short or something dangerous? Do I need more fuses or different fuses or in different places?

The important point to remember about fuses is that they are there to protect the wire. Therefore; they are placed at the 'power source' end of every (in theory) wire (e.g. battery).

Originally Posted by Biscuitsjam

3. Is this appropriately flexible to later be able to add solar power, a generator, or more batteries if we decided to do so down the road?

Yes, solar is simple to wire in as the output from the charge controller connects to the battery bank.

Originally Posted by Biscuitsjam

4. What gauge wiring should I use? My reading sounds like 8 gauge is sufficient but 4 gauge is recommended. Does this sound right? Does the wiring requirement change if I later add solar power?

It depends on the power that must pass thru the wire and the length of the wire. Use any of the online wire size charts (or size calculators) to determine the correct size to achieve a 3% voltage drop (or less). For example, with a 2000 watt inverter, you can expect to pull 2000 watts from the battery bank (at full load). At 12.5 volts, this is 160 amps. If the wire/cable length from battery bank to inverter is five feet or so, you would need 2/0 cable.

In the case of AC wiring, assuming a 30 amp (at 120VAC) input, 10-2 wire is sufficient. If you are plan to push that 30 amps and your length is long, you might consider 8-2.

Originally Posted by Biscuitsjam

5. I will need to winterize next September. If we plan to not use the bus, the recommendation seems to be to bring the batteries inside. If we want to go somewhere in Alaska in the winter, what are your recommendation to keep the batteries functional at -20 to -50 degrees Fahrenheit outside? Are there any other components I should be worried about in the battery compartment?

I've been told that a battery will sit unused at those temps without any problem. However; it is not good for the battery when you start discharging/charging at those temps. I would bring them inside if that is an option. Nothing else comes to mind as being temperature sensitive.


Doug; regarding your question... I went with separate inverter/switch so I could replace one without having to replace the other - assuming they both will not fail at the same time.

[Defjr333]

Great stuff. Yeah, no wrong way about it.....just figured I would ask if it was a specific reason. Upgrades are def a reason
Doug

[Biscuitsjam]

So, let's see if I got this right?

- 2/0 for all the wires connecting the batteries and to/from the charger, isolator, inverter, and ground.

-8ga for all the AC wiring (cabin power, plus shore power to/from charger)

-12ga for all the interior DC wiring (to lights, smoke detector, etc.)

-50amp in-line fuse for 120 VAC input, 500A in-line fuse for 12 VDC output

1. Do I need to add circuit breakers for the cabin wiring?

2. Should I ground the AC wiring? If so, where do I insert that in my wiring diagram? There is lots of stuff about wiring the circuit breaker panel ground to the chassis and making sure the neutral isn't bonded to the ground. If no circuit breaker panel, then what?

3. Is an in-line fuse sufficient for the power input? I see a lot of articles about people buying $400 Autoformers or $100 surge protectors.

[Biscuitsjam]

Originally Posted by JDOnTheGo

I've been told that a battery will sit unused at those temps without any problem. However; it is not good for the battery when you start discharging/charging at those temps. I would bring them inside if that is an option. Nothing else comes to mind as being temperature sensitive.

From my research:
A fully charged lead acid battery will not freeze until -76 degrees fahrenheit (or -92, depending on the source). A 40% charge will freeze at about -16 degrees, and a 0% charge will freeze at 32 degrees. If the batteries freeze, they are ruined.

A lead acid battery will provide about 50% power at 0 degrees. I could not find numbers for -20 degrees or lower, but I assume they are abysmal. So, a cold battery will discharge faster, then, once the little bit of heat created dissipates, they will freeze and be ruined.

It is recommended to charge lead acid batteries at temperatures over 50 degrees. Below 32 degrees does not work well and below 0 degrees is basically impossible. Charging at cold temperatures may also require a different voltage. Charging does produce a little heat, so using a battery blanket and charger would probably work for moderately cold temperatures, but not for extreme cold or when boondocking.

Many heating systems require DC power to run. No batteries = no heat! For this reason and others, I think it is important to have a backup heat system that requires no electricity.

What all this tells me is that house batteries should be inside a heated space if used in extreme cold weather (a box inside the insulated cabin vented to the outside may make the most sense). Additionally, if the heat is ever turned off long enough for the batteries to get cold, they better be fully charged.

[Twigg]

Originally Posted by Biscuitsjam

So, let's see if I got this right?

- 2/0 for all the wires connecting the batteries and to/from the charger, isolator, inverter, and ground.

-8ga for all the AC wiring (cabin power, plus shore power to/from charger)

-12ga for all the interior DC wiring (to lights, smoke detector, etc.)

-50amp in-line fuse for 120 VAC input, 500A in-line fuse for 12 VDC output

1. Do I need to add circuit breakers for the cabin wiring?

2. Should I ground the AC wiring? If so, where do I insert that in my wiring diagram? There is lots of stuff about wiring the circuit breaker panel ground to the chassis and making sure the neutral isn't bonded to the ground. If no circuit breaker panel, then what?

3. Is an in-line fuse sufficient for the power input? I see a lot of articles about people buying $400 Autoformers or $100 surge protectors.

The cabin wiring (12V?) usually has automotive type fuses in a distribution box.

The 110V circuits are grounded through the supply while on shore-power, and through the inverter ground when not.

[BlackJohn]

Originally Posted by Biscuitsjam

So, let's see if I got this right?

- 2/0 for all the wires connecting the batteries and to/from the charger, isolator, inverter, and ground.

-8ga for all the AC wiring (cabin power, plus shore power to/from charger)

-12ga for all the interior DC wiring (to lights, smoke detector, etc.)

-50amp in-line fuse for 120 VAC input, 500A in-line fuse for 12 VDC output

1. Do I need to add circuit breakers for the cabin wiring?

2. Should I ground the AC wiring? If so, where do I insert that in my wiring diagram? There is lots of stuff about wiring the circuit breaker panel ground to the chassis and making sure the neutral isn't bonded to the ground. If no circuit breaker panel, then what?

3. Is an in-line fuse sufficient for the power input? I see a lot of articles about people buying $400 Autoformers or $100 surge protectors.

"-8ga for all the AC wiring (cabin power, plus shore power to/from charger)"

A vague statement. Branch circuits from panel are rarely #8awg unless feeding 240vac to a clothesdryer. Lights, receptacles,switches,alarms are #14, 12awg and fed from a breaker panel or fuse panel, so yes, everything needs fusing.


"-50amp in-line fuse for 120 VAC input," usually a breaker contained in the house panel, could be a fused disconnect switch before a pony-panel.
The feed for this 50amp however should be at least #6awg, outdoor use cabtire with 3 conductors, buy 4 conductor if you can, min at 50amps.
There is in reality only one incoming 110v feed wire but the wire is shared internally to feed the panel for seemingly 240vac and to split the load more equally in the panel.
The system grounding for the ac for the bus is all done within the green contained in that cable. Use it at all times and connects to a ground bus bar in the panel only.
In your diagram that is simply a ground symbol at the origin of the ac feed wire and also show the ground symbol at the ac panel.
So, not sure how you plan to feed items with no service ac panel?

Inline fuse for incoming ac is ok but a breaker is way more convenient, less work and no need for carrying a spare.

For any grounding questions each service is probably best answered on an
as built basis.
One thing I never see people do is grounding the chassis for genny use and then to ground via a ground rod. That's what I use.
So ac grounding and dc grounding are not the same animal or in your case polar bear!
Hope this helps some, What did I miss?

John

[JDOnTheGo]

Originally Posted by Biscuitsjam

So, let's see if I got this right?

I probably confused you by listing some sizes. I was trying to say - use a chart/calculator and determine the appropriate size based on the length and power. When I mentioned 8-2 for the AC - I meant only from the shore plug to the distribution/breaker panel.

See my note above - all wires should be protected. There are a few exceptions but pretty few.

Some sort of shore power surge/power protection is a good idea. Many folks don't have one and it seems like most of them do just fine.

I better leave question #2 to an expert.

[JDOnTheGo]

Originally Posted by Biscuitsjam

From my research: ....

Excellent info!!

[Defjr333]

I decided to hardwire all my outlets. AC and DC. Only reason was to have breakers/ fuses on everything. Not only does it protect the equipt, but also makes easier to trace if need be and able to kill power to device by just flipping a breaker instead of going to inverter to plug/ unplug a device. Also looks nice. This is what I use. Price went up from $65 to $73.50 now tho:

PD5000 30 Amp AC/DC Power Control Panel

Doug

[BlackJohn]

The only reason I like fuses over breakers is that when a fuse does blow, you have no option but to track down the problem and fix it before trying another fuse.
In that respect they are the safer option and forces you to understand the overload and correct it through sometimes extensive trouble-shooting.
Not all fuses are equal so it helps to know which type to us for your application.
The larger the fuse, the more they cost but so do well designed breakers.

John

[Biscuitsjam]

Thanks everyone for all the help.

I left out some details of course. I'm planning on a month-long 5500-mile road trip from Georgia to Alaska. I am limited on time before starting this initial trip but wanted to get the main components operational. The interior of the bus will be a "temporary" install (no insulation, cheaply-finished floors, limited carpentry, etc.). After arrival in Alaska, a big portion of the "temporary" install will be redone, including the interior wiring.

For the initial "temporary" install, I was hoping that it would be sufficient to a couple surge-protected power strips running off the inverter for AC power and some DC lights hard-wired off of the battery bank. I wanted to reduce the time and money spent on redoing things later.

For the "final" install, I plan to do a circuit panel, outlets, etc. etc.

[Robin97396]

I'm still using power strips and extension cords 2 years later. I know we're supposed to have all those expensive pieces and parts for an electrical system, and like you someday....

[BlackJohn]

So just an inverter, no genny, 2 women, 7 kids, 5000+ miles...appliances, and extension cords, sounds insane.
Better get ample documentation from the 2 spouses not on the trip as to permission to leave the country, even if temporary. Passports req'd for everybody on board, questions out your ying yang...doesn't sound like a day at the beach to me.
What route are they taking and crossing into Canada? You are still looking at pretty cold weather up north and rough roads so figure out towing and expenses, extra rations, water for 9.
Why not just load the works on a C-17 and have Uncle Sam fit the bill, trip over in 7 hours?
Just some other things to consider because this might be considered child abuse at the border.


John