Insert all-in-one & LiFePO4 battery into RV's existing system with converter

[timblack1]

I'm designing a solar power system for my trailer, to permit me to power my computers during work hours and travel with my family. I want to insert an all-in-one and LiFePO4 battery into my RV's existing electrical system, which includes an AC to DC converter, but I'm not sure about the precise locations where I should insert these components.

A small complicating factor is that I plan to order LiFePO4 cells from China, and they will take a long time to arrive, so I plan to convert my electrical system in two stages, first inserting the all-in-one, then second inserting the LiFePO4 battery, into the system.

My main question is: Where should I insert the all-in-one & LiFePO4 batteries into my RV's existing AC & DC systems? Is the following plan correct?

I believe the existing circuits are like this:

1. DC: converter - lead acid battery - DC fuse box - loads - lead acid battery
2. AC: shore power - AC breaker panel - loads - shore power

I could convert the system in the following 2 stages. Changes are in bold.

1. Stage 1: Insert all in one (connected to shore power, solar panels, & lead acid battery)
   1. DC: all-in-one - lead acid battery - DC fuse box - loads - lead acid battery
   2. AC: shore power - all-in-one - AC breaker panel - loads - (all-in-one) - shore power
2. Stage 2: Insert LiFePO4 battery
   1. DC: all-in-one - LiFePO4 battery - DC fuse box - loads - LiFePO4 battery
   2. AC: shore power - all-in-one - AC breaker panel - loads - (all-in-one) - shore power

Is this the right way to do it?

Tim

 

[HRTKD]

Disconnecting the shore power from the existing main distribution panel and connecting it to the all-in-one is the way I would do it. The all-in-one's AC output then goes to the main distribution panel.

If the all-in-one has a built in charger, then you'll want to disable/remove the existing converter from your system.

 

[thomascleary66]

Disconnecting the shore power from the existing main distribution panel and connecting it to the all-in-one is the way I would do it. The all-in-one's AC output then goes to the main distribution panel.

If the all-in-one has a built in charger, then you'll want to disable/remove the existing converter from your system.

THis is what I did with my small RV and a MPPsolar 1012 (1KVa inverter, 12 v) all-in-one system. It works well EXCEPT my large draw items (microwave and AC) that could run off the shore power (directly wired) now run through the inverter and overload the all-in-one. I am now (this weekend) adding in an lw28 crossover switch to manually bypass the all-in-one for 110 loads. SOmetimes I will leave the 110 going through the MPPsolar, but most of the time, all but the smallest load, triggers the (noisy) fans to turn on. So when I am plugged in I think I will usually let the solar system run my 12 v loads (200 watt panels easily keep up with the fridge during the day) and bypass the MPPsolar for most 110. Specially at night when the fans going on and off keep me awake.

 

[thomascleary66]

I'm designing a solar power system for my trailer, to permit me to power my computers during work hours and travel with my family. I want to insert an all-in-one and LiFePO4 battery into my RV's existing electrical system, which includes an AC to DC converter, but I'm not sure about the precise locations where I should insert these components.

A small complicating factor is that I plan to order LiFePO4 cells from China, and they will take a long time to arrive, so I plan to convert my electrical system in two stages, first inserting the all-in-one, then second inserting the LiFePO4 battery, into the system.

My main question is: Where should I insert the all-in-one & LiFePO4 batteries into my RV's existing AC & DC systems? Is the following plan correct?

I believe the existing circuits are like this:

1. DC: converter - lead acid battery - DC fuse box - loads - lead acid battery
2. AC: shore power - AC breaker panel - loads - shore power

I could convert the system in the following 2 stages. Changes are in bold.

1. Stage 1: Insert all in one (connected to shore power, solar panels, & lead acid battery)
   1. DC: all-in-one - lead acid battery - DC fuse box - loads - lead acid battery
   2. AC: shore power - all-in-one - AC breaker panel - loads - (all-in-one) - shore power
2. Stage 2: Insert LiFePO4 battery
   1. DC: all-in-one - LiFePO4 battery - DC fuse box - loads - LiFePO4 battery
   2. AC: shore power - all-in-one - AC breaker panel - loads - (all-in-one) - shore power

Is this the right way to do it?

Tim

Hi Tim,
See my other comment too, but I did do mine slightly differently for the DC system: I put the MPP between the battery and the 12v fuse panel (just like you put it between the shore in and the 110 breaker panel). THis way power from the battery OR shore power can run through it to supply all loads, including recharging the battery if needed. And HRTKD is right, disconnect the built-in inverter.

 

[Boondock Saint]

With my Quattro 5kw I can toss my old converter, transfer switch and inverter in the garbage. Anyone want them?

@ Op if you're not already on a 50A service step 1 would be the time to do it.

.

 

[HRTKD]

THis is what I did with my small RV and a MPPsolar 1012 (1KVa inverter, 12 v) all-in-one system. It works well EXCEPT my large draw items (microwave and AC) that could run off the shore power (directly wired) now run through the inverter and overload the all-in-one. I am now (this weekend) adding in an lw28 crossover switch to manually bypass the all-in-one for 110 loads. SOmetimes I will leave the 110 going through the MPPsolar, but most of the time, all but the smallest load, triggers the (noisy) fans to turn on. So when I am plugged in I think I will usually let the solar system run my 12 v loads (200 watt panels easily keep up with the fridge during the day) and bypass the MPPsolar for most 110. Specially at night when the fans going on and off keep me awake.

This sounds like the new all-in-one is undersized for your situation. I would never try to run the microwave or A/C on my 1,000 watt inverter.

 

[thomascleary66]

This sounds like the new all-in-one is undersized for your situation. I would never try to run the microwave or A/C on my 1,000 watt inverter.

It was never the plan to use AC and Micro while boondocking but I would like to when plugged into shore power! The MPPsolar is perfectly sized for what I planned and need and use when off grid, and it does have a bypass mode but the 110v in still runs through the inverter, only bypassing the battery not the MPP all together. Hence the switch I am installing to do this manually when grid tied.

 

[Boondock Saint]

I'm designing a solar power system for my trailer, to permit me to power my computers during work hours and travel with my family. I want to insert an all-in-one and LiFePO4 battery into my RV's existing electrical system, which includes an AC to DC converter, but I'm not sure about the precise locations where I should insert these components.

BACK to timblack1 who's thread this is . . . have you yet purchased an AIO solution?
What models are you considering?
You have a physical location for all the pieces yet?

A small complicating factor is that I plan to order LiFePO4 cells from China

Not complicating if you plan for at least 3 or 4 more US holidays to come and go, a few birthdays, at least Thanksgiving if not Christmas.

 

[time2roll]

Going to need to disable the existing converter as part of stage one.

 

[timblack1]

BACK to timblack1 who's thread this is . . . have you yet purchased an AIO solution?
What models are you considering?
You have a physical location for all the pieces yet?

I've made a diagram of the system I'm designing at https://diysolarforum.com/threads/5kw-48v-system-sizing-circuit-safety-check.23725/. I've found physical locations for each component to be mounted in the trailer.

I haven't bought the AIO yet, but would like to buy an MPP Solar LVX6048, because it appears all the specs match my use case. The one spec which might not work in that design is the LVX6048 can accept a max of either 20A or 27A from solar panels (depending on whether the specs in the manual or the ads are correct), but the solar panels I'm planning would output 24A max.

A couple notes about why I'd like this model - I might want to feed back into the grid someday, and the LVX6048 can do that. I don't mind so much if the LVX6048 has a high standby draw, since it appears I can shut off its inverter when not needed but keep the solar charger running, and the manual seems to indicate it has a mode which might reduce its standby draw. It can handle both 120V & 240V AC input and output, which I think should enable me to use it either as a mobile RV or a fixed home system in the future.

An alternative would be to put 2 Growatt SPF 3000TL LVM-ES units in parallel. But, this model doesn't do grid feedback, and has less AC surge capacity (4.8KW x 2 vs. the LVX6048's 18KW). My air conditioner drew 2.94 KW on startup, according to the Kill-A-Watt meter it killed in the process(!).