Adding a shore power option?

[RobOfYork]

My main source of electric is going to be solar. But when available I want to be able to plugin to shore power.

Any good tutorials that cover options to adding shore power?

So far everything I have seen just adds an AC powered battery charger that connects to the system in place of your solar battery charger.

Is that the common way to do it? Or is there a better way?

Seems like going from AC to battery then back to AC through a inverter is strange. But I am new to this.

[Booyah45828]

You want an inverter/charger combo unit. When it isn't connected to shore power, it creates the AC voltage you're after, like any normal inverter does. But when you connect to shore power, it transfers the loads onto shore power and then also charges your batteries.

If you already have equipment, then buy a transfer switch of some sort and put it between your inverter and shore power conenctions. They make the switches in both automatic and manual selection.

[kazetsukai]

What inverter are you looking at? Some inverters have all-in-one functionality- inverter, battery charger, automatic transfer switch.



If your inverter is "just an inverter", you can add the battery charger, and then a transfer switch to choose between shore and solar. This is what we do currently- we plug in, then on the inside use a switch to determine where we want our power coming from. Our new inverter which will arrive in the coming weeks has a programmable ATS function.

[Drew Bru]

Originally Posted by Booyah45828

You want an inverter/charger combo unit. When it isn't connected to shore power, it creates the AC voltage you're after, like any normal inverter does. But when you connect to shore power, it transfers the loads onto shore power and then also charges your batteries.

Yup, that's just about the simplest option. Its pretty seamless in operation. We got a Xantrex inverter/charger after going through a nightmare situation with a failed Aims inverter/charger. Buyer beware on the cheap equipment with a strong social media influencer presence.

[flattracker]

In my case using three sources of power is/has been part of my design from the beginning. Priority one has been doing it safely. One does not want hot wires or electrical shock issues to contend with.
I am wiring my Crown with an outside electrical power connection going to an electrical panel.
I am wiring a 6.5 kw generator to the same panel. the source of power in the panel is selected by pairs of mechanically ganged circuit breakers. Only one of the two sources of power can physically be connected at a time. A second panel takes the power from the first. The second panel has two mechanically ganged breakers like the first one does. In the second panel one selects either generator/outside power or inverter power. In the first panel, power is supplied through a breaker to an RV charging system that will supply up to 65 amps of current to the RV batteries. I also am installing 1 kw of solar panels on the roof that through a charge controller, keeps the RV batteries charged. I have a second alternator installed on the Crown's engine to charge the RV batteries.

With the above described systems, I have three sources to keep the RV batteries charged, and provide power of any DC circuits, and run the inverter. I can run one of my rooftop AC units going down the road like this.

It is of note, that in this entire electrical system description, NO mention of charging/using power from the bus batteries. The RV/bus electrical systems are separate, for a reason. There will be a cross-connect provision through a battery switch to charge the bus batteries or start the bus, but only as a backup should the bus batteries get a low state of charge.
This setup is simple to use and safe. It may sound complex to implement, but it isn't.
Some of my reasoning for doing this level of effort is based on experience.
If you are interested I can provide part number info at a later time.


One last thought I use larger wire than minimum required. Yes it costs more, but there is less voltage loss, and less heat in wires.

[RobOfYork]

Thanks everyone. It's starting to get a little clearer to me.

If I am plugged into shore power and have a battery charger charging the batteries and supplying power to my 12volt circuits, should the solar MPPT charger be disconnected from the battery?

If so, should I have a disconnect for the solar panels that should be turned off before disconnecting the MPPT from the battery bank?

Hope that made sense.

[Drew Bru]

Originally Posted by RobOfYork

If I am plugged into shore power and have a battery charger charging the batteries and supplying power to my 12volt circuits, should the solar MPPT charger be disconnected from the battery?

Nah, you're good to go. The chargers know what to do and take care of all that junk.

[RobOfYork]

Anyone use this battery charger while connected to shore power or a generator? Will this work for charging my soon to be homemade LiFePo4 battery with a BMS added?

https://www.amazon.com/AIMS-Power-CO...language=en_US

[Stargazer7020]

Originally Posted by flattracker

In my case using three sources of power is/has been part of my design from the beginning. Priority one has been doing it safely. One does not want hot wires or electrical shock issues to contend with.
I am wiring my Crown with an outside electrical power connection going to an electrical panel.
I am wiring a 6.5 kw generator to the same panel. the source of power in the panel is selected by pairs of mechanically ganged circuit breakers. Only one of the two sources of power can physically be connected at a time. A second panel takes the power from the first. The second panel has two mechanically ganged breakers like the first one does. In the second panel one selects either generator/outside power or inverter power. In the first panel, power is supplied through a breaker to an RV charging system that will supply up to 65 amps of current to the RV batteries. I also am installing 1 kw of solar panels on the roof that through a charge controller, keeps the RV batteries charged. I have a second alternator installed on the Crown's engine to charge the RV batteries.

With the above described systems, I have three sources to keep the RV batteries charged, and provide power of any DC circuits, and run the inverter. I can run one of my rooftop AC units going down the road like this.

It is of note, that in this entire electrical system description, NO mention of charging/using power from the bus batteries. The RV/bus electrical systems are separate, for a reason. There will be a cross-connect provision through a battery switch to charge the bus batteries or start the bus, but only as a backup should the bus batteries get a low state of charge.
This setup is simple to use and safe. It may sound complex to implement, but it isn't.
Some of my reasoning for doing this level of effort is based on experience.
If you are interested I can provide part number info at a later time.


One last thought I use larger wire than minimum required. Yes it costs more, but there is less voltage loss, and less heat in wires.

I am in the planning stages and was wondering if you have any kind of schematic for this set up?? As a total newbie to electrical, I understand a dedicated solar system but really want shore power as well because I'm parked on property half the year

[flattracker]

There are two aspects to the three way power I built into the Crown.

The DC portion of the system:
Sources of DC power -
Batteries - currently four type 31 deep cycle AGM batteries located in the Crown's trunk

Second alternator - A 250 amp alternator mounted in tandem with the Crown's original alternator

Solar panels - 1 Kw of solar panels mounted on the roof of the Crown

RV battery charger - A 75 amp smart RV battery charger mounted next to the main AC electrical panel.
All or some of these sources can supply DC power depending on time of day, bus engine running, outside (shore) power applied or generator running.
All of these sources connect to a 4 terminal bus bar that I made. Included is a wiring diagram for that (minus the RV charger).
DC power distribution:
The terminal bar supplies DC power to a 3000 watt inverter, and to the DC power panel, using aircraft circuit breakers.
The AC power is supplied and distributed through an off the shelf circuit breaker panel.
In that circuit breaker panel some of the breakers are mechanically ganged together.
This mechanical linkage is also off the shelf. Outside power is connected through a 50 amp connector using 6 gauge wire to a pair of 50 amp breakers that are ganged to another pair of 30 amp breakers through which the generator power is supplied. with the mechanical linkage, only one pair of the breakers can be turned on at any time - 50 amp breakers on 30 amp breakers off OR 50 amp breakers off withe 30 amp breakers on. This supplies 240 AC power to the two copper buss bars in the panel, which feeds power to all breakers connected to those buss bars. This allows 50 amp shore power OR 30 amp generator power. There are wires that connect the two bus bars to a pair of breakers connected to a second set of buss bars through a pair of 30 amp breakers that are ganged to a pair of 25 amp breakers, setup like the first pair described above. The inverter supplies power through the 25 amp breakers to the second buss bars OR allows external/generator power to the buss bars.
With this setup some of the circuits won't work from the inverter but that is OK as I don't plan to run the washing machine or dryer from the inverter.
Modes of AC operation:
50 amp shore power OR 30 amp generator power (all circuits) OR 25 amps inverter power to some circuits. I do not use 240 VAC circuits although shore and generator supply 240 VAC.
The solar panels use two charge controllers connected through a toggle switch so that two can be connected to the second charge controller that charges the starter batteries for the bus.
Note the small wires in the panel are used for voltage/current display modules. the current measuring wire have no electrical connection on the box and the voltage monitor wires are separately fused for safety.
The mechanical linkage between breaker are visible in the image.
Outside power is connected through 65 gauge wire and generator power is connected through 8 gauge wire

[flattracker]

A correction to my post: I used 6 gauge wire not 65 gauge wire for the shore power connection.


Attached is an image of the terminal block I fabricated for DC distribution in the "new Crown" The gray block is the front half of the DC power monitor. It has a hall effect sensor to measure current to/from the batteries and monitors the DC bus voltage.
I drew a diagram of the AC power distribution system, which is included in this post. Perhaps this will make the previous post understandable.


Because the inverter is rated for 120 VAC output, two wires were ran to the breakers (one per breaker) to comply with electrical codes.

As seen in the previous post the mechanically ganged breakers can only be one side or the other turned on at any time. Both can be turned off at the same time.


The options are:


Outside/shore power OR generator OR inverter.


All circuits are powered from Shore OR generator.


Not all circuits are powered by the inverter.


I have already run this setup while I have been doing the conversion, including MIG welding. I have been using an extra circuit with a separate box with breakers running from the main box and this worked quite well.

[nikitis]

Thanks for the example and diagrams. I don't have a Crown Bus, but I like looking at different setups people have and comparing. I particularly like your Floor markings in your diagram.

I'm also glad you aren't using 65 AWG as that would be so thin you couldn't see it

[flattracker]

Your welcome.
My approach to the wiring would work on other makes of buses. I am sure that what I did is not the only way to approach the task.