Portable power station to RV main cable question

[EricM22]

I've ordered a Pecron lithium portable power station, 1500w/h, puts out 2000w A/C. Perfect for home emergency use and other uses.

Question is, if I plug it into the main RV power cable - will it ADD to the capacity of the RV's battery bank or will it be used INSTEAD OF the RV's battery bank if left plugged in overnight?

I ideally want it for extra capacity overnight when winter boondocking. As of now, my onboard gas generator auto-kicks in around 4:30am overnight when the battery bank hits 12.0v, shaking the entire RV and waking us up. Draw is from residential fridge, furnace fan, and a few other small draws.

I'd like the portable power to give the RV batteries the extra capacity overnight so that the generator doesn't have to kick in. Is this an "either/or" or an "adds to" situation?

[RogerR]

If you plug it in ( as I understand your post) it will:
Convert DC to AC and output it to your RV
The RV will convert AC back into 12 volt DC and
Then either it will be used to run something or charge the battery.
Then possibly change it back to AC to run the microwave or tv.

Seems like these changes DC to AC back to DC will have a lot of waste at each step

Better to actually power what you need to run off the power box directly.

[EricM22]

Thanks Roger. I get that. Ideally I'd swap all the batteries, converter and BIM out to lithium as the best way to go, but the unit is only two years old and not worth that expense yet.

Say for example, we park for the night at a rest area, and the RV batteries are fully charged. I go out and plug the portable unit into the main power cable and lock the compartment door.

At this point, which of these two options will happen:

1. The fridge etc. use ONLY the power from the portable unit thru the main power cable, and when the portable unit goes empty, will the transfer switch then change over to the RV battery bank?

or

2. The fridge etc continue to draw power from the inverter/battery bank, which is being charged continuously by the portable unit thru the power cable and converter?

[RogerR]

If possible, it would be much more efficient to use the watts directly. If your battery voltage drops to the minimum perhaps you could turn off your main battery and somehow route the 12 volts directly from your battery into the RV circuit.

I am not an electrical engineer but each time you convert from DC to AC and back again there is substantial cost in wasted energy. The numbers I have seen are at least 8 to 10 % each time you change in either direction.

[Jerry713]

Originally Posted by EricM22

Thanks Roger. I get that. Ideally I'd swap all the batteries, converter and BIM out to lithium as the best way to go, but the unit is only two years old and not worth that expense yet.

Say for example, we park for the night at a rest area, and the RV batteries are fully charged. I go out and plug the portable unit into the main power cable and lock the compartment door.

At this point, which of these two options will happen:

1. The fridge etc. use ONLY the power from the portable unit thru the main power cable, and when the portable unit goes empty, will the transfer switch then change over to the RV battery bank?

or

2. The fridge etc continue to draw power from the inverter/battery bank, which is being charged continuously by the portable unit thru the power cable and converter?

I think your answer is #1. I don't think your power station will only supplement your batteries especially if plugged into your shore power cord. Not sure what your answer would be in terms of using your new power station to only supplement your batteries.

Another option might be to add suppressors under your onboard generator and additional sound proofing material around your generator to help with the vibration that wakes you up. Something similar to this for the vibration
https://www.zoro.com/mason-floor-mou...YaAoJnEALw_wcB

[EricM22]

UPDATE: I have the power station now (1500 w/h) and used it this past weekend.

When fully charged, I plugged it into the RV's main power cable - using 50A to 110 dogbone adaptor. Plugged it in right before went to bed for the night.

Boondocking. The auto-switch made the power station pack take over for the batteries, and along with powering the RV it kept the batteries topped off. Not only did the gas generator not auto-kick on in the middle of the night, we still had almost fully charged RV battery bank when woke around 7am in the morning. The solar generator battery was depleted and shut itself down sometime in the middle of the night or early morning.

But what was great was that the switchover from the power station to the RV battery bank was seamless and SILENT. The RV didn't go "dead" for even 10 seconds during the switchover, which I was something I worried about since I thought it might reset the Firefly system and reset the "furnace on" setting - but it didn't reset at all. It was all perfect.