Basic electrical setup questions

jjhwick119 · 08-11-2018, 08:51 AM

So most of the diagrams I'm finding are for people planning their all out electrical setup with solar and everything, not so many basic ones out there that I could find. I'm starting to wire mine up (got outlets hooked up and wired to a central spot so far) and I have a few queestions. I have a 12v background but never done something quite like this.

For right now I'm planning on having just my generator as a power supply for the bus. This is temporary while I'm working on the bus and will not be the only power source. A battery bank will also be added before I hit the road and leave the storage lot.

First question is about load centers / transfer switches. I will primarily be boondocking as much as possible, but will still probably have a 30amp shore power hookup. I have no clue what I'm looking at with these things. I bought a 6 space 100amp load center, but I don't think it's ideal because it doesn't have a main breaker, it's just a load center. Can anyone help me figure out what to buy?

If I am just running my generator. which is a champion inverter generator, I was planning on cutting off one end of the 30amp cable and wiring it straight to the load center so I just plug into the genny and I have power. I think I'm missing something though. This would be set up as a super basic electrical system just to have power in the bus and not have to use extension cords and move genny around.

Alternative - wire up a 2 battery bank for now until I can add the rest (was thinking a 6 battery bank)

If I go the route with 2 batteries, will I need to install the charge controller and inverter and everything right away as well? Long term electrical plan is Run the bus off my battery bank, use genny to top them off, and add solar down the line.

Thanks in advance for any help!

nanoplane · 08-11-2018, 10:16 AM

So get an inverter that includes a charger and transfer switch.. I have the AIMS 3000W pure sine wave inverter. It handles a 9000W Surge and includes a 100A (adjustable) charger and transfer switch. You just run shore power through a pair of breakers directly into the inverter, then the output of the inverter goes to your load center. The inverter can be set to either battery priority or Shore power priority and will switch automatically and will automatically charge the batteries when low.

The configuration runs in parallel to your solar setup as well and the Inverter and Charge controllers work happily together.

You don't need to install the solar and charge controllers right away... they can come later if you like.

For your generator, If it's a portable, you can just plug it into the shore power connection on your bus. If you want a permanent installation, you'll need to add in another transfer switch to select shore power or generator. Note, the AIMS inverters also include connections to auto-start your generator when the batteries get low.

Here's my electrical:

JDOnTheGo · 08-11-2018, 10:22 AM

Entirely my opinion... a main 110VAC breaker is not essential (like it is in a house). With a bus/RV, it is very easy to disconnect from shore power or turn off the generator - accomplishing the same thing (disconnect the power from the panel). Obviously this eliminates the primary purpose of any fuse/breaker which is to protect the wire. However; all shore power (that I've seen) and generators have a breaker to do that very thing. So, in my opinion, a main breaker is not required. An electrician will disagree.

You need a load center/breaker box that has enough "slots" to power the circuits you have planned and the circuit breakers to fill those slots. Typically those breakers are 15 amp, sometimes 20 amp. Remember that there are breakers that will handle two circuits (twin or dual CB's) so your 8 slot panel can handle up to 16 circuits.

What you said about a wire from the panel to your generator (or shore power) will work - for the simple system you have described. This can be dangerous when you an exposed/male plug AND an inverter hooked into the system that could be powering the panel (or anything else providing 110VAC). If no inverter, no worries.

With batteries, you need a way to charge them so generally yes, a battery charger/converter connected to your AC breaker panel. However; you might have a generator with a 12V charger (which is generally pretty weak and dumb) and that could be used instead. No, you do not need to install the solar components or inverter now. That said; having a design in mind now might save you some work and dollars later.

Drew Bru · 08-11-2018, 10:40 AM

Quote:

Originally Posted by nanoplane

So get an inverter that includes a charger and transfer switch.. I have the AIMS 3000W pure sine wave inverter. It handles a 9000W Surge and includes a 100A (adjustable) charger and transfer switch. You just run shore power through a pair of breakers directly into the inverter, then the output of the inverter goes to your load center. The inverter can be set to either battery priority or Shore power priority and will switch automatically and will automatically charge the batteries when low.

The configuration runs in parallel to your solar setup as well and the Inverter and Charge controllers work happily together.

You don't need to install the solar and charge controllers right away... they can come later if you like.

For your generator, If it's a portable, you can just plug it into the shore power connection on your bus. If you want a permanent installation, you'll need to add in another transfer switch to select shore power or generator. Note, the AIMS inverters also include connections to auto-start your generator when the batteries get low.

Here's my electrical:

This is my setup as well, but I've got the Aims 2000w inverter. It's nice to have the inverter/charger/transfer switch all in one package. I got a dogbone (adapter) to connect the 20A generator outlet to the 30A shore power cord, which goes to the 30A outlet on the side of the bus, and that connects to the inverter for the pass-thru to the AC panel.

BlackJohn · 08-11-2018, 10:55 AM

Op, I take it you already have your genny? Is it electric start or manual pull start?
This is where you have to decide now for future.
If you have the genny what are the details?

John

jjhwick119 · 08-11-2018, 11:15 AM

It's a pull start champion inverter genny. 2800/3100w with a 30amp hookup

Im possibly selling my SUV this weekend and picking up a cheap truck from a coworker and will have some extra money afterwards. I'm going to put most into savings, but now I'm thinking I should just go ahead and get an inverter charger now, wire in shore plug and then add 2 batteries at the same time so I don't have to rewire everything later.

I can mount the genny underneath, and then just get a cord to plug it into the shore plug on the outside, it won't be hardwired in. The shore plug goes through a 30 amp breaker box, then into the AIMS unit, and then that goes to my load center. Right?

EDIT -
I already bought a 100amp load center with 6 slots, and 15 / 20 amp breakers depending on the outlets on that line. I have some basic 15amp circuits and some 20amp gfci
https://www.lowes.com/pd/Square-D-12...Center/3134331

Details on bus - Propane stove/oven and propane tankless water heater, so don't have super heavy loads from any big electrical appliances. Will have a mini split AC

2martins · 08-11-2018, 12:05 PM

Quote:

Originally Posted by nanoplane

So get an inverter that includes a charger and transfer switch.. I have the AIMS 3000W pure sine wave inverter. It handles a 9000W Surge and includes a 100A (adjustable) charger and transfer switch. You just run shore power through a pair of breakers directly into the inverter, then the output of the inverter goes to your load center. The inverter can be set to either battery priority or Shore power priority and will switch automatically and will automatically charge the batteries when low.

The configuration runs in parallel to your solar setup as well and the Inverter and Charge controllers work happily together.

You don't need to install the solar and charge controllers right away... they can come later if you like.

For your generator, If it's a portable, you can just plug it into the shore power connection on your bus. If you want a permanent installation, you'll need to add in another transfer switch to select shore power or generator. Note, the AIMS inverters also include connections to auto-start your generator when the batteries get low.

Here's my electrical:

I can't see the attachment and I would love to.

nanoplane · 08-11-2018, 01:57 PM

Quote:

Originally Posted by 2martins

I can't see the attachment and I would love to.

It's a PDF, you should be able to see it..

here's the URL: http://rivard.org/images/MagicsKoolBus/Bus-DC.pdf

BlackJohn · 08-11-2018, 02:32 PM

Ok here's the part I don't get. You have a pull start genny at present.

In future, you will be needing a different genny, an electric start type, if you are using grid power at some point. Why not do that now and be done with it. You frame it in now and wire for auto start and transfer switching.

Just trying to save you some hassle because it will be as you close in walls, floors etc. And you have to know it works before you bury stuff.

If you are ok manually plugging your panel in to shore and into genny separately that's cool but it will cost more and be more difficult to install what is proper for auto switching of power sources.

Like can you afford to loose food or air when you encounter a power outage on your travels. Build it for the future and for another owner. That is money in your pocket then.

John

nanoplane · 08-11-2018, 02:38 PM

Quote:

Originally Posted by BlackJohn

Ok here's the part I don't get. You have a pull start genny at present.

In future, you will be needing a different genny, an electric start type, if you are using grid power at some point. Why not do that now and be done with it. You frame it in now and wire for auto start and transfer switching.

John

I know for me, a generator would just be there to charge the batteries if there's not enough sunlight to keep everything running... I'm looking at a portable generator for that task since then it lets me use it for alternative purposes and it means I can get a smaller / quieter generator since it doesn't really need to power everything AND charge at the same time.. well, I can live with that...

jjhwick119 · 08-11-2018, 11:53 PM

Quote:

Originally Posted by nanoplane

I know for me, a generator would just be there to charge the batteries if there's not enough sunlight to keep everything running... I'm looking at a portable generator for that task since then it lets me use it for alternative purposes and it means I can get a smaller / quieter generator since it doesn't really need to power everything AND charge at the same time.. well, I can live with that...

This is my plan as well, I just won't have the solar right away. Since I have to get out of the bus to start the genny I don't mind plugging it in too. My bus is sitting on storage and not being driven until it's done. Just using the power for tools to work on it right now. I don't plan on being on grid very much at all.

turf · 08-12-2018, 11:13 AM

as someone that either plugs in or uses the generator to charge batteries, i'd recommend going solar sooner than later.

smart chargers suck ass when your power is intermittent. lead acid batteries charge slowly, when i have to charge them via the generator, it may be a 2 or 3 day process.

solar guys go to bed every night with their battery bank at 100%.

just sayin

The Nebuchadnezzar · 08-18-2018, 05:12 PM

This is a great article http://www.rv-dreams.com/our-rv-electrical.html.
Also checkout the online manuals for bigger magnum inverters they show a bunch of different wiring configurations. A good inverter with built in transfer switch and 3-stage charger makes life easier.

Michael E James · 08-21-2018, 08:33 PM

I understand the simplest electrical hookup would be a switch between ignition battery and house battery bank. That way you could charge your bank while you drive and switch off the cranker and run your house goodies on the bank. Then charge it the next day while you drive. A bonus is if you need to, you can crank your engine from house batteries in an emergency.

JDOnTheGo · 08-22-2018, 05:39 AM

A typical automotive alternator is not smart (however; smart alternators do exist on newer cars). It simply maintains some reasonable charging voltage (like 14V). This is generally an acceptable approach and handled fairly well by a starting battery. The appropriate battery for a "house" battery bank is different - much different if you have AGM or lithium batteries.

The FLA/SLA/AGM batteries that we typically use have three stages of charging; bulk, absorb, & float. A good charger is able to detect what charging mode a battery (or battery bank) requires. When you connect another battery (or battery bank) to the equation, the charger has no ability to know what mode of charge that bank requires. Since an alternator is not smart, it is unlikely to charge your house battery in the required mode. This means that one of the battery banks is not being charged appropriately - and maybe neither - most likely the more expensive house battery bank. This will eventually damage the batteries - maybe sooner rather than later. This is not a big deal to some folks. A couple cheap batteries every year or two is acceptable. However; those of us that have poured a lot of money into our house battery bank want to get as many years of service as possible from it.

It is common to have an interconnect relay (high amperage) for 'emergencies'. This has proven useful when one set of batteries has been allowed to discharge which means either the engine cannot be started (chassis battery) or the generator cannot be started (house battery).

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