New to solar/inverters and transfer switches

[59bisquik]

I recently traded in my 2012 Attitude 27LFS for a new 2020 Attitude 32IBG. When I had my old trailer, it didnt have all the elctronic goodies on it like the new one. When it wasnt in use, we kept the batteries disconnected and it hooked to shore power. We always left the fridge running since we go out atleast once a month.

The new rig is pretty different and I have a few questions. (The dealer could not answer by the way)
1) When plugged into shore power the transfer switch is always energized and hums. Also the inverter is running and you can hear the fans.
I read that the standard transfer switch has the generator as the priority. Does that mean that the transfer switch is not powered when using the generator? It just goes thru the NC contacts? Or does it have a contactor for shore power and generator power.

2) I didnt like that the inverter was running constantly while stored. I did shut off the disconnect switch to it.

Am I doing something wrong or do I just need to change my habits and store this disconnected and the fridge turned off?

BTW, it is stored indoors so the solar is not in the equation while in storage.

[59bisquik]

I went and checked, it was a Progressive Dynamics PD52 transfer switch that is a dual relay design. They are not latching and hum when used. Is there a better 50A unit that has latching relays as mentioned? That would solve the problem of leaving it on shore power when stored and also not have to listed to the hum when trying to sleep. Its directly under the bed!

[2oldman]

59bisquik wrote:
This has a Group 27 Lifepo4 lithium battery.

Excellent!

[59bisquik]

I will have to see what transfer switch it has.

I have always pulled the battery disconnect because my older unit would not float charge and the batteries didnt last very long.

This has a Group 27 Lifepo4 lithium battery.

I am wondering if I can just switch the inputs on the transfer switch.

[2oldman]

Just curious.. what kind of batteries did this new rig come with?

[D_E_Bishop]

59bisquik, I believe that if you are hooked up to Shore Power and Start the Generator, the transfer switch will give priority to the generator and disconnect the shore power.

This provides a certain degree of safety in that you won't have two dissimilar voltage sources trying to operate at the same time and that probably are not compatible. In the event that you are hooked up to shore power and loose power and start your generator, the power from the generator will not back feed into the shore system and feed the shore line back to the point of failure.

An electrician trying to repair the shore power failure could be injured or killed by the power from your generator not knowing that it was there.

[KD4UPL]

What transfer switch do you have? What inverter do you have? They do not all operate the same way. Do you actually have an inverter/charger? If so, and it's actively charging your batteries that would explain the fans cycling on. Some transfer switches have latching contactors that don't use power except to transfer. Some have AC coils on the contactors that hum. Some have DC coils with a rectifier to drive them so they don't hum.
I don't understand why you would disconnect the batteries when plugged into shore power. I would leave them connected so they are kept on a float charge; assuming a good quality charger that is set properly for your batteries.

[Flute_Man]

My transfer switch is de-energized on shore power and energized on generator power.
Jerry Parr
602-321-8141