Orion XS 1400 for cruising sailboat w/AGM start, LFP house and solar

DIY
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1

Short version is, should I turn off the engine shutdown detection?

Long version:
My goal is to keep the AGM start and LFP house topped up by: solar when anchored; the alternator when running the engine; the inverter/charger when in a marina; and whichever is most expedient when house demand requires.

Reading about the OXS 1400, I replaced my old AGM house batteries with a non-Victron LFP battery and ran all charging sources to the start bank, then through the OXS 1400 to the LFP house.

For my first test, I followed the basic recommendations of various docs and videos and set the OXS 1400 input for AGM, the output for LFP, and turned on the engine shutdown detection. Now, my observation is that the LFP is not charging fully, from any source. The Victron app says the charger is off due to engine shutdown, and the LFP sits at 13.3V while the start bank is at 13.6V (which is also the output of the MPPT controller at the moment).

FWIW, I don’t think the LFP has gotten anywhere near its ~14.2V 100% SOC, even on days running the engine all day (or overnight with shore power to the Xantrex FSW 2012 inverter/charger, although I think more research on my part is needed about that).

Reading here, I think I’m seeing the recommendation to just turn off the engine shutdown detection, which I think makes sense, but I’m concerned I may be missing something important.

If all charging sources are running through the AGM start bank, is turning off the engine shutdown detection ok and the right thing to do?

Also, a follow up would be regarding that, in the Victron app, although it shows some historical event data, it doesn’t show when the events occurred, so I can’t correlate whatever it’s trying to tell me with what operations have happened on the boat. If I added a Victron shunt (or other particular Victron component), would I get better event logs with some kind of time stamps?

Thanks much, I appreciate your time and assistance.

2

Have you ever had a look around the VRM??

Post the data here.

3

I have, briefly, but it seems like the long way around for just this one time bit of info on the OXS functionality. If in the future I have to replace other systems and get more of a Victron ecosystem in place I’d get into the VRM just for fun (seems mostly overkill for me) but for now, everything works fine on its own.

I say this because, from my understanding of the VRM/Venus GX literature, getting data from my Renogy MPPT or Xantrex inverter/charger would be a whole other level of effort and potentially not even possible. They already have their own monitoring, I can see they’re putting out as usual, but their output is not being delivered through the OXS to the LFP.

Is there something I’m missing? If dropping in a Venus GX solves all my problems, I’d gladly do it, I just don’t see how it would.

4

Some information about Li systems:

5

Is it really necessary to keep the AGM battery constantly charged? I would set the Orion XS to charge the LiFePO4 battery only when the engine is running, and connect the PV charge controllers to the LiFePO4 battery. If necessary, you could connect a small Orion charger in the opposite direction to charge the AGM battery.

6

Probably the simpelest and most cost effective solution is to replace all other MPPT and chargers for Victron equipment. In fact just the shore charger 12 V 10 And the MPPT charger(s) fot the PV panels. All tombe connected directly to the LFP battery. The newest models can all communicate with each other through the Victron smart network. This can be activated through Victron connect (the little gear symbol in the upper right corner) . They will all use the same voltage levels for charging i.e. 14,2 volT

Cerbo or GX device not necessary.

The “old” MPPT can still be used to charge the starter battery if so required.

7

Thank you, KH, I will look those over.

8

Thank you, R.L. This is a possibility but the project design intent is/was based on some needed updates to the 40yr old wiring, suddenly made urgent by a flooded compartment that killed the 4 AGM house batteries. Plugging in a 314Ah LFP battery behind the OXS theoretically lets me keep running all the old systems (alt, solar, inv/charger) that may not be configurable for LFP, as long as they stay wired to the AGM start bank.

Much of the time the boat sits out on a buoy, year round in the PNW, so having topped up start batteries feels important.

As long as I haven’t misunderstood the OXS’s capabilities, I think it’s supposed to be able take whatever excess charging not needed by the AGM and pass it on to the LFP. If that’s true, then it feels like I’m just missing a config setting or two or three in the OXS and should be at least good, if not great.

9

Thank you, EvSC. You’re probably not wrong about going all Victron may be better/cheaper in the long run and if I had that budget I’d probably go there. As it is, all the old equipment still works fine so my plan has been to replace it as needed, especially as this technology keeps getting better at a pretty rapid pace. Plus, although I love sailing, I enjoy messing around with boats pretty much, so it’s not torture for me to tinker my way through creative solutions that others might avoid. FWIW, I’ve shopped the Victron line pretty hard and if it comes down to it, I’m prepared to fall in line with your suggestions.

10

Hi Vtonian,

I’m also a bit of a tinkerer, sailor and techie, and I’m not afraid of unconventional solutions. I can meet all my needs quite well with Victron equipment. It doesn’t have to cost a great deal and works very reliably with that smart grid.

A simple Victron Smart battery charger, 12 V 10 A, costs around €100, and a SmartSolar MPPT 75/10 around €50. Ideally, a BMV-712 Smart battery monitor could also be added (or do you already have one?). The most expensive part is probably a 230-volt charger/inverter (a MultiPlus-II, if you wanted one) depending on the power rating.

11

Make an inventory of what is available and what isn’t.

Also include what you’re planning.

Some of this can be implemented in Victron, while other parts cannot. Nevertheless, some devices would still be controlled via relays.

12

Thank you, all. I think what I’m reading here is the OXS is not quite what I thought it was from reading the brochures: a relatively simple hack to intermediate between a boat full of older battery technologies and a new LFP house bank. You’ve prompted me to read up more in the OXS/Victron manuals, and I’m starting to better grasp the challenge in finding a suite of OXS settings that will both send the available charge sources to the LFP as needed/available and also not suck the start bank dead if/when the LFP has become significantly depleted.

That became immediately obvious when I decided to just try turning off the engine shutdown detection and see what happens, which triggered the sudden realization that, without the engine running or AC charger turned on, the ~100Ah start bank would probably get tanked trying to top up the 1/3rd depleted 310Ah LFP. I had been thinking w/o the engine on, the solar would kick in as the trickle charger it was always intended to be and the OXS would only take whatever current was available above the fully charged start bank. Not sure if that’s even an accurate understanding of the OXS design intent but at this moment, not being sure = more reading required.

Once I have a better grasp of how the OXS is intended to function, and see if/how I can reconfigure my existing systems to integrate with those functions, I’ll get back to trying to plan out the best strategy. It might be as simple moving the solar to the LFP as R.L. suggested and trusting the start bank will survive several weeks on the buoy in winter w/o a visit, with a Plan B to charge them from the LFP if necessary. Or maybe biting the bullet and adding some more Victron components actually makes better math than trying to stay with my older but higher capacity components.

Thanks again, I appreciate your time and input and will post back when I have a better idea what can be done with the OXS.

13

Take a good look at this in your own time.

A networked system from a single manufacturer is better than a collection of dumb devices.

Otherwise, you’ll have to modify and/or rebuild things every time you expand it.

A Victron system grows effortlessly with your needs.

14

If the AGM battery is in good condition, it is sufficient to disconnect the negative lead. If the battery is fully charged, it will also survive a year in storage. For Plan B, you can connect 50 A Anderson connectors to the OXS and the batteries. Then you can simply connect it the other way round.