Please review my high-capacity motorhome upgrade plans

[Suijkerbuijk]

Victron systeem is make to run from one battery .
If you have more you need a shunt for the Victron to calculate what you use.

The bms from the battery will tell but it can do nothing with it
Just information that is it
Only original Victron bms and battery is full adjust by the gx unit.

 

[justinm001]

Victron systeem is make to run from one battery .
If you have more you need a shunt for the Victron to calculate what you use.

The bms from the battery will tell but it can do nothing with it
Just information that is it
Only original Victron bms and battery is full adjust by the gx unit.

With my sok batteries it tells Victron the charge rate, charging profile, voltage, SoC, temp and any errors. If one battery is turned off or unplugged it cuts the charge limit in half so it doesn't overcharge and blow the bms.

Not sure what you'd want Victron to send to the battery, only 1 way is needed

 

[justinm001]

The alternator is currently shared. I plan to convert the system to a dedicated alternator configuration. Today, the alternator charges everything and all batteries are lead acid. In the not-so-distant future the alternator will be dedicated to the house lithium batteries only, controlled by a Wakespeed or Zeus one. The chassis starting battery will be charged solely by a dc-dc charger powered by the lithium house batteries. My thinking is this allows me to take advantage of the full 340-amp capacity of the alternator to charge the lithium while not damaging the lead acid starter battery. Feel free to poke holes and critique this plan.

Not sure if I'd trust a dc dc converter to power all loads while driving. If it breaks you're doa and can't drive.

 

[Suijkerbuijk]

With my sok batteries it tells Victron the charge rate, charging profile, voltage, SoC, temp and any errors. If one battery is turned off or unplugged it cuts the charge limit in half so it doesn't overcharge and blow the bms.

Not sure what you'd want Victron to send to the battery, only 1 way is needed

Even without a victron.

A bms work standalone.
If 2x Battery are connect in parallel and one bms shutdown thare is no problem.
The bms stop charging and the rest of the charge go to the other battery.

You do not need a Victron gx unit for it.
Only thing that a victron gx unit need to know it the real battery volts and the temperature.
With that a gx if its active mode and not read only mode (most are in read only )
It can optimize the mppt or other chargers from Victron to optimal tell what charge have to go to .
Its like Traffic light .
If the Victron know the output and input from a inverter.
It know the battery real Ah (bms use volt to calculate) inside the battery to a shunt .
It gone adjust more for a stable output

If you have the original battery from Victron with bms .
And special in series .
It can even do cell balance by the gx unit .
And even adjust the charge profile to that battery .
The bms is than in full controle by the Victron gx unit.

And that is the difference with battery setup.

 

[justinm001]

Even without a victron.

A bms work standalone.
If 2x Battery are connect in parallel and one bms shutdown thare is no problem.
The bms stop charging and the rest of the charge go to the other battery.

You do not need a Victron gx unit for it.
Only thing that a victron gx unit need to know it the real battery volts and the temperature.
With that a gx if its active mode and not read only mode (most are in read only )
It can optimize the mppt or other chargers from Victron to optimal tell what charge have to go to .
Its like Traffic light .
If the Victron know the output and input from a inverter.
It know the battery real Ah (bms use volt to calculate) inside the battery to a shunt .
It gone adjust more for a stable output

If you have the original battery from Victron with bms .
And special in series .
It can even do cell balance by the gx unit .
And even adjust the charge profile to that battery .
The bms is than in full controle by the Victron gx unit.

And that is the difference with battery setup.

My inverters charge at 140a and SOK 48v batteries are 95a charge limit so both batteries can charge up to 190a. If one BMS trips or any then it'll pump 140a into a 95a limit and blow the 2nd bms. But because it has comms if one BMS trips or is shut off it automatically switches max charge from 190 to 95. It also tells the inverters, MPPTS and everything the voltages and such all thru DVCC.

I'm not really sure why we'd want the cerbo to tell it to balance the cells or whatever. Thats the BMS's job. I get with Victron batteries they allow it because its sharing the job across its devices.

 

[Backroads4me]

Just to reiterate, I'm still new to this level of LFP. Prior to this my experience has been with RC cars. Same concepts, but much cheaper batteries. I still took care of the batteries the same way, but it wasn't near the priority I feel like it is with this investment. I really appreciate the help pulling these details together.
Based on admittedly not enough research, I was expecting that the Cerbo would communicate with each battery individually and then direct the batteries how to charge based on the entire bank. I don't even know what that would look like, maybe balancing every cell across the bank... whatever. I just thought it would do something. It appears that is simply not the case. It's not a deal breaker for me, the batteries are still very impressive with some great advanced features and a solid design. I also think the comms feature is probably more beneficial if you're only using one battery and not impacted as much by the SOC drift that comes with them in parallel.
Just to explain at least some of my initial confusion and not look totally reckless, take a look at these details. The Epoch Dual Purpose 300Ah does appear to have more advanced Victron communication features. The features are:

• Victron Comms - CANBUS entire string of batteries to Victron Ecosystem
• Communications Box for more (sic) Inverter, (Optional - Coming soon)

Whereas the 460Ah Comms Model sku: B12460A list:

• CANBUS Communication allows BMS to communicate directly with Victron OS

I have to assume the change in the description of the features and the omission of the future upgrades on the 460 was intentional.

Finally, I can only find the Dual Purpose Victron Comms cable for sale at one retailer, but their description says:

• Seamless Integration: Connects your Dual Purpose Battery Series with Victron Energy products, enabling smooth communication and data exchange between devices.
• Optimized Battery Management: Enhance the efficiency and lifespan of your battery system by leveraging Victron’s advanced power management tools and features.

And now I need to get back to figuring out my spaghetti drawing of a wiring schematic.

 

[justinm001]

Based on admittedly not enough research, I was expecting that the Cerbo would communicate with each battery individually and then direct the batteries how to charge based on the entire bank. I don't even know what that would look like, maybe balancing every cell across the bank... whatever. I just thought it would do something. It appears that is simply not the case.

I think you're missing how it works. The batteries tell the Cerbo what voltage and amperage to charge then the devices provide that. The battery bms balances and does all it's stuff automatically.