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Plugging RV 30amp cord into MPP LV2724

OnTheFlyPDX

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I just asked a complicated version of this in the beginners section before realizing this is probably a better place to ask. I’ll try to simplify. We have a 18’ travel trailer that currently has a 200ah 12v AGM on the trailer tongue. I’m building a 8s 200ah 24v lifepo4 battery bank with JBM/Overkill smart BMS. Looking to install ~600w of solar panels as well. Battery and PV will be connected to a MPP PIP-2724LV-MR (https://usamppsolar.com/product/top-pants-upper/). For simplicity, I don’t want to wire the MPP unit into the trailer’s circuit panel. I also don’t want to directly wire the 24v lifepo4 battery into the trailer’s 12v DC system (I know I’d need a 24v-12v converter to do that anyway). Instead, I’d like to keep the 12v AGM battery running the DC system separately and plug the trailer’s 30 amp shore power plug (the pig tail) into the MPP’s inverter. Here are my questions:

Will this work, like I think it will, to power the trailer as if it was connected to shore power? Am I missing something?

When running the whole trailer off the inverter, do I need to turn off the circuit breaker for the trailer’s built in battery charger? It will be charging only the AGM battery on the tongue, so there isn’t the issue of a power loop drain that people on here have warned about when a single battery bank -> inverter -> RV’s shore power input -> rv’s built-in battery charger -> back to battery bank.

I’m also thinking about installing a disconnect switch on the AGM battery so I can avoid draining it while using the MPP-inverter for “shore power.” I need to double check this next time visit our storage lot, but I’m pretty sure the trailer’s DC system is fully functional while on shore power, even if there is no 12v battery hooked up. I think I can keep the AGM battery charged with the truck’s inverter while driving to our next location. Anything I’m missing here?

Hope I explained everything okay. Happy to clarify if not. Thanks in advance for any and all responses.
 
You should disconnect the converter from the Lead Acid battery when using the LIFEPO4 as your shore power.
Unless the Lifepo4 is charged up and the lead battery needs charging. Leaving the converter connected just loses power during conversion.
My opinion. Also the Overkill BMS 24v unit I see has a 100 amp charge / discharge limit. 25 amp x 120v = 3000 watt in inverter
3000 /24v = 125 amps draw from battery which exceeds the bms cutoff. If you get past about 20 amp 120v draw you will max the bms. Firuring in conversion losses it is more likely around 18 to 17 amps 120v. But yes this will work
 
You should disconnect the converter from the Lead Acid battery when using the LIFEPO4 as your shore power.
Unless the Lifepo4 is charged up and the lead battery needs charging. Leaving the converter connected just loses power during conversion.
My opinion. Also the Overkill BMS 24v unit I see has a 100 amp charge / discharge limit. 25 amp x 120v = 3000 watt in inverter
3000 /24v = 125 amps draw from battery which exceeds the bms cutoff. If you get past about 20 amp 120v draw you will max the bms. Firuring in conversion losses it is more likely around 18 to 17 amps 120v. But yes this will work
Thanks! I ended up scrapping most of this plan once I realized that switching to a fully integrated system off the 24v battery bank wasn’t all that much extra work. Here’s the last diagram I made, but it needs some updating. Using the LV 2424 Hybrid instead of the 2724. Going to install 3x 360W panels in parallel. Just ordered a 40A 24V-12V buck converter to run the trailer’s DC system. Now I am (im)patiently waiting for the lifepo4 cells to arrive and I’m ready to build.
 

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plug the trailer’s 30 amp shore power plug (the pig tail) into the MPP’s inverter
That's practically what I'm doing.

disconnect the powercord from Powercenter and directly connecting it to the All-in One - then just going with AC to the Powercenter.

My Converter charger needs about 40wh a day to run all the time - but I'm supplementing the 12V system with a Separate Solar Panel, which was already installed.


all-in-one-rv-system-png.63145
 
I’m also thinking about installing a disconnect switch on the AGM battery so I can avoid draining it while using the MPP-inverter for “shore power.” I need to double check this next time visit our storage lot, but I’m pretty sure the trailer’s DC system is fully functional while on shore power, even if there is no 12v battery hooked up. I think I can keep the AGM battery charged with the truck’s inverter while driving to our next location. Anything I’m missing here?

when you got enough Solar Power to keep the converter on it's not hurting the AGMs.

Just measure how much power your Converter needs with and without the AGMS - for 48-72h period - I've just plugged in the RV into Kill-A-Watt power meter
Turn on a few lights and let it on the cord for 3 days.
 
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