Should batteries be disconnected when on shore power?

There isn't much reason to disconnect your batteries. In my opinion, as others have stated, the battery life you think you gain in the long term will be negated with one accidental full discharge.

In terms of the power supply/ vs charging arguments: The progressive dynamics units are really both. Since they are nicely filtered DC output that is always at a higher voltage than the batteries, the converter is indeed a power supply. Yes, it will run the 12volt side fine without batteries but just don't do it for the reasons already discussed.

In the past, poor linear ferroresonant converters had a laughably low charging current, like 2-4 amps... And they only acted as a charger because eventually the output voltage of the charger would rise up high enough to actually charge the batteries if there were not too many other dc loads powered on in the rig.

Executive summary: leave batteries hooked up when on shore power, check fluid levels once a month. Disconnect batteries if storing rig more than a day or two without power, to avoid parasitic drain.

To the OP
Think of this
Your camping at some campground, you got hookups you disconnect the battery
Your asleep and the power goes out, wind, car crash, thunder storm, doesn't matter, no power,
Well no battery means no fridge, no heater, no lights
You don't know it until you wake up
Then you have to go outside? And connect your battery

And any of these I always disconnect my battery people have been dann lucky if they have not run into this situation

Any extra battery life days/weeks I might gain by doing this are not worth, going out in the weather at 3am to hook them up
Or
In the middle of the afternoon either

The batteries are supposed to be connected, the batteries are your power, the converter is there to keep them charged, not substitute for the batteries

The unit is a PD 9200 Series with Charge Wizard. I'm not sure of the output watts. The instruction manual states:

"The INTELI-POWER 9200 series of converters are primarily desinged for use with a battery, however, the output of the INTELI-POWER 9200 converters are a regulated, filtered D.C. voltage that can power sensitive electronics without the need for a battery or other filtering."

I'm thinking I like batteries connected when running furnace motor loads...but maybe disconnect in warm weather when 12v loads are light :h

westend wrote:

I still can't understand how two GC2 T-105's are getting overcharged with a converter.

I think that statement is being made by someone who doesn't really understand what overcharging IS.

Sam Spade wrote:

TomG2 wrote:
We digress. The question was what to do when connected to shore power.

And the answer is an emphatic and absolute NO.
The 12V system isn't designed for that to be done.

Fixed that for you.

I still can't understand how two GC2 T-105's are getting overcharged with a converter. It may be that the converter is doing an equalize charge, occasionally. It also may be that the cells are over-filled. It matters not. If the user has a functioning system and good battery longevity my nose needs to be somewhere else. :C

TomG2 wrote:
We digress. The question was what to do when connected to shore power.

And the answer is an emphatic and absolute NO.
They aren't designed for that to be done.

We digress. The question was what to do when connected to shore power.

skipro3 wrote:

Second, there is no reason to disconnect your batteries during the normal life of the RV unless maintenance or replacement is required.

Well join the crowd. There is another terrible bit of advice. :E

If they will sit unused for more than a few days in a place where external power is not available to maintain a charge, they absolutely should be "disconnected" to prevent parasitic drains from making them dead.

Well, close. But the wizard jumps the voltage back and forth between bulk and float quite often.

And to clarify, the PD 9100 series w/o the charge wizard plugged in, is a fixed voltage converter 13.6-8 volts.

The PD 9200 series, is a 3 stage converter because the charge wizard is built in. The only thing that can be plugged into the 9200, is the pendant, which does nothing more than give you manual control over the charging stages.