Please review my high-capacity motorhome upgrade plans

[Backroads4me]

I have an older motorhome and I'm hoping to significantly upgrade my off-grid camping capacity before I move into it fulltime next year. I'm very capable mechanically and electrically, but new to large Ah lithium. Every website or YouTube video seems to suggest I need to buy everything that Victron sells, but I'd much rather spend that money on batteries. I've read 100's of forum posts and have a pretty good grasp of what's needed, but with this level of investment, I need some help pulling it all together.

# Current system

• 6 x 8D 12v batteries
• 2 x Outback VFX2812M inverter/chargers
  • In "Outback stacking" mode (series) for a combined 5,600 watts and 250 amps of charging capacity
• 340-amp industrial alternator
• 10-year-old battery isolator separating the chassis and house batteries
• Automatic voltage sensitive switch that connects when either battery is charging or if the starter battery needs a boost

# My plan

• 4 x 460Ah "smart" Epochs (B12460A)
• Keep the Outback VFX2812M's
• Victron Cerbo GX (no screen for now)
• Victron 500A Smart Shunt
• Remove the VSS and isolator
• Victron Orion XS 50A DC-DC charger
• Solar someday ...

# Questions

1. Am I on the right track?
2. The Outback VFX2812M's are ten years old, but the charge settings are fully adjustable. Any reason why I should use a newer lithium charger?
3. I'd like to replace the VSS with some ability to boost the chassis in an emergency. Are there any good options or just a manual switch?
4. Is it a problem that the Orion is so undersized? Should I add 2 or hopefully not 3? I've looked at the Sterling 120, but that's a big jump and I can just stack the Orions.

I'd really appreciate any help and suggestions from those more knowledgeable!

 

[Suijkerbuijk]

Wy the cerbo gx ?

You can go for.
Raspberry Pi
Or you can go for a other gx units

Here a list of Victron gx models

Victron GX product range [Victron Energy]

www.victronenergy.com

 

[Skypower]

What is the amp rating of that isolator? Older isolators have some voltage drop under high loads but that might not be a bad thing. With four big ass hungry lithium batteries at a low state of charge, you could potentially over work even 340 amp alternator. The isolator or long cable run could act as a current limiter (so long as they don’t overheat). If that alternator has temperature protection, it for sure is safe. A lot of things need to have eyes on testing under anticipated extremes to monitor and be ready to shut down if things aren’t playing well(hot or out of ratings). Better than it happening on a road trip.

 

[Backroads4me]

Wy the cerbo gx ?

You can go for.
Raspberry Pi
Or you can go for a other gx units

Here a list of Victron gx models

Victron GX product range [Victron Energy]

www.victronenergy.com

The Cerbo is primarily to trigger an auto generator start but also for the connection to the Victron remote portal and remote monitoring paired with Starlink. I would normally prefer to go the Raspberry Pi route. Infact, I ultimately want to build out voice lighting control using a Pi and this would have paired nicely. However, my hand has been forced due to battery failure and I need to do this install much earlier than I was anticipating, and I need to make it as easy as possible on myself.

 

[Backroads4me]

What is the amp rating of that isolator? Older isolators have some voltage drop under high loads but that might not be a bad thing. With four big ass hungry lithium batteries at a low state of charge, you could potentially over work even 340 amp alternator. The isolator or long cable run could act as a current limiter (so long as they don’t overheat). If that alternator has temperature protection, it for sure is safe. A lot of things need to have eyes on testing under anticipated extremes to monitor and be ready to shut down if things aren’t playing well(hot or out of ratings). Better than it happening on a road trip.

I don't recall the specs on the isolator, but it's massive. No label unless it's in on the bottom mounted side. However, I agree with your concern about extremes and that alternator, and the batteries are just way too expensive to risk. I feel like I need the DC-DC charger, I'm just not sure if I should go for a large Sterling (or some other brand?) or stack the Victron's. The good thing about stacking is I can add additional later after my credit card has stopped smoking.

 

[Skypower]

I don't recall the specs on the isolator, but it's massive. No label unless it's in on the bottom mounted side. However, I agree with your concern about extremes and that alternator, and the batteries are just way too expensive to risk. I feel like I need the DC-DC charger, I'm just not sure if I should go for a large Sterling (or some other brand?) or stack the Victron's. The good thing about stacking is I can add additional later after my credit card has stopped smoking.

Yeah I know about the credit card domino, smoke, fire and ashes
Some alternators can use controllers that can connect to Victron or app and make current adjustments. https://arcomarine.com/products/arco-zeus-high-energy-alternator-regulator

If you can hunt down the specs, Id be tempted to use what you got and hook it up with the lithium batteries at the shipped state of charge. Use a DC clamp meter and a temperature gun to check the alternator, isolator and other things. Find out what the 100% safe load and temperature rating are for things. FYI, you never want to ever let the alternator disconnect from battery/load while it’s running because the voltage can go crazy and blow the diodes in it.

 

[Backroads4me]

Yeah I know about the credit card domino, smoke, fire and ashes
Some alternators can use controllers that can connect to Victron or app and make current adjustments. https://arcomarine.com/products/arco-zeus-high-energy-alternator-regulator

If you can hunt down the specs, Id be tempted to use what you got and hook it up with the lithium batteries at the shipped state of charge. Use a DC clamp meter and a temperature gun to check the alternator, isolator and other things. Find out what the 100% safe load and temperature rating are for things. FYI, you never want to ever let the alternator disconnect from battery/load while it’s running because the voltage can go crazy and blow the diodes in it.

Wow, thanks! I had looked at the Wakespeed, but wasn't aware of Zeus. The Zeus actually looks really promising for my application. I guess I know what I'll be reading about for the next few hours!

 

[Skypower]

You’re welcome.
This forum is great stuff huh?
It’s sure helped me.

 

[jberger]

The alternator isn't going to hurt the LFP pack, the pack COULD hurt the alternator.

You say it's an industrial alternator, but what does that mean? Is it like a bus rated alternator that's designed to run all the time at high output or is it a small frame alternator that isn't built for high output for hours?

If you are really concerned for the alternator being burned out, you could swap the "VSS" for something like this relay for LFP use. https://www.precisioncircuitsinc.com/product/lithium-battery-isolation-manager/
This version acts similar to your "VSS" by connecting the house and engine banks when charging, disconnecting on voltage, etc. but adds timer circuit to charge 15 minutes on, 15 minutes off as a way to prevent overheating of the alternator.
Or if your alternator uses an external voltage regulator, you can add a balmar or wakespeed alternator controller to throttle back on output when the alternator is getting hot.

This week I'll be upgrading from a B.I.R.D. Big Boy Solenoid to a solid state relay (BlueSea 7622) on my coach, because the inrush current from the LFP packs causes the solenoid to chatter. It will retain the ability to "boost" the engine batteries from the house bank if needed.

You haven't mentioned amp draw, but you don't have to spend $1800 per battery for typical RV loads, so you might be able to find something $600-800 cheaper per battery. I would absolutely make sure what ever you by can be monitored by Bluetooth just for troubleshooting and testing.
Instead of spending the money on stacking DC/DC chargers, just put in some alternator protection and charge via alternator on the road and the outbacks when you are on pedestal. You'll spend less and it will charge faster, plus less to wire up and manage.

 

[Skypower]

Options, options. Decisions decisions.
Lots of great stuff that just wasn’t available 5 or ten years ago.

 

[Backroads4me]

The alternator isn't going to hurt the LFP pack, the pack COULD hurt the alternator.

You say it's an industrial alternator, but what does that mean? Is it like a bus rated alternator that's designed to run all the time at high output or is it a small frame alternator that isn't built for high output for hours?

If you are really concerned for the alternator being burned out, you could swap the "VSS" for something like this relay for LFP use. https://www.precisioncircuitsinc.com/product/lithium-battery-isolation-manager/
This version acts similar to your "VSS" by connecting the house and engine banks when charging, disconnecting on voltage, etc. but adds timer circuit to charge 15 minutes on, 15 minutes off as a way to prevent overheating of the alternator.
Or if your alternator uses an external voltage regulator, you can add a balmar or wakespeed alternator controller to throttle back on output when the alternator is getting hot.

This week I'll be upgrading from a B.I.R.D. Big Boy Solenoid to a solid state relay (BlueSea 7622) on my coach, because the inrush current from the LFP packs causes the solenoid to chatter. It will retain the ability to "boost" the engine batteries from the house bank if needed.

You haven't mentioned amp draw, but you don't have to spend $1800 per battery for typical RV loads, so you might be able to find something $600-800 cheaper per battery. I would absolutely make sure what ever you by can be monitored by Bluetooth just for troubleshooting and testing.
Instead of spending the money on stacking DC/DC chargers, just put in some alternator protection and charge via alternator on the road and the outbacks when you are on pedestal. You'll spend less and it will charge faster, plus less to wire up and manage.

The alternator is 100% duty cycle designed for a fire truck. I don't think there is any way it could ever burn up from overuse, however, I'm trying to learn more about and definitely don't understand the risk of the batteries being disconnected somehow mid charge as Skypower mentioned in their first post above. Maybe a switch or BMS fails or the Victron somehow shuts the batteries down, beats me. But apparently if that happens the rush of electricity looking for somewhere to go can damage the alternator. However, I think that risk could be eliminated with something like the Balmar Alternator Protection Module APM12-12V

The Precision Circuits BIMs are only rated for 225 amps. There may be a higher one, but I haven't seen it. Even so, using one would cut the charging capacity of the alternator in half. Not the end of the world, but with a large battery bank I'll need every bit I can get.

My bigger concern was the batteries since the alternator would never stop charging without something else in place. I won't pretend to completely understand everything the BMS does, but my understanding is that it basically optimizes the charge for the cells when charging, but it's still up to the charger to lower the charging rate when the batteries are full. I'm not sure how much of changing the rate is for optimizing the charge to 100% vs protecting the battery and extending its life. This is why I thought I originally thought I needed the DC-DC charger. I had originally written the Wakespeed off as too complicated and expensive, but at Skypower's suggestion I looked at the Zeus and now think either one of those two are a perfect, albeit expensive, option. As I understand it, they would allow the full power of the alternator when the batteries need it but will intelligently reduce the charging as the batteries reach 100%. Still trying to learn and compare these products and no idea which is the "best" yet or even if just running without one is "good enough".

As for the amp draw, the RV is all around power hungry and the Outbacks have 5,600 watts of capacity so the max is ~500 amps. A residential fridge, Starlink and electronics are the primary continuous draws plus an AC when it's running so calling that ~200 amps continuous, with spikes from a large water pump, house air system, appliance startups and a microwave. The goal of the capacity though is to be able to run longer without a generator or charging, especially with an AC. The Epoch essentials are likely every bit as good for my situation.

 

[justinm001]

Wy the cerbo gx ?

You can go for.
Raspberry Pi
Or you can go for a other gx units

Here a list of Victron gx models

Victron GX product range [Victron Energy]

www.victronenergy.com

It doesn't make any sense to go with a pi over a cerbo-s GX (if batteries don't have comms). Sure its $217.60 vs $80 but you get all the extra ports/features and a rock solid stable device. Also accepts a huge power range 8-70 so you're not needing to convert 12v to 5v and deal with that headache.

 

[justinm001]

You shouldn't need the smartshunt since those batteries have victron comms. get the normal cerbogx and plug in. Then you're getting temps, SoC and errors right from the batteries.

What model is your alternator? Id definitely recommend going with Orion XS and stacking them over a wakespeed/zeus. If the alternator was dedicated to house then a wakespeed/zeus would work but even then it only really makes sense if you're trying to squeeze every amp from the alternator. These are popular in sailboats where you have small engines and small alternators but huge batteries. They also make sense if you're mass producing vehicles and want to program the alternator and make sure its cool. Plus less devices.

When building your own its nice to have orion XS as you can tweak the amp/volt so it works best for your needs.

 

[Backroads4me]

The alternator isn't going to hurt the LFP pack, the pack COULD hurt the alternator.

You say it's an industrial alternator, but what does that mean? Is it like a bus rated alternator that's designed to run all the time at high output or is it a small frame alternator that isn't built for high output for hours?

If you are really concerned for the alternator being burned out, you could swap the "VSS" for something like this relay for LFP use. https://www.precisioncircuitsinc.com/product/lithium-battery-isolation-manager/
This version acts similar to your "VSS" by connecting the house and engine banks when charging, disconnecting on voltage, etc. but adds timer circuit to charge 15 minutes on, 15 minutes off as a way to prevent overheating of the alternator.
Or if your alternator uses an external voltage regulator, you can add a balmar or wakespeed alternator controller to throttle back on output when the alternator is getting hot.

This week I'll be upgrading from a B.I.R.D. Big Boy Solenoid to a solid state relay (BlueSea 7622) on my coach, because the inrush current from the LFP packs causes the solenoid to chatter. It will retain the ability to "boost" the engine batteries from the house bank if needed.

You haven't mentioned amp draw, but you don't have to spend $1800 per battery for typical RV loads, so you might be able to find something $600-800 cheaper per battery. I would absolutely make sure what ever you by can be monitored by Bluetooth just for troubleshooting and testing.
Instead of spending the money on stacking DC/DC chargers, just put in some alternator protection and charge via alternator on the road and the outbacks when you are on pedestal. You'll spend less and it will charge faster, plus less to wire up and manage.

I'm also looking for a replacement for my VSS. Are you aware of a motorized version that does NOT have automatic paralleling. I only want the batteries to parallel if I actually push a button.

 

[Suijkerbuijk]

It doesn't make any sense to go with a pi over a cerbo-s GX (if batteries don't have comms). Sure its $217.60 vs $80 but you get all the extra ports/features and a rock solid stable device. Also accepts a huge power range 8-70 so you're not needing to convert 12v to 5v and deal with that headache.

No problems
I use one my self .
Rockstabel .
And just use a car charger for a phone for your 5volt problem.
Rock here now for days.
If battery have ports just use a usb to come port to make a connection.
You even have if you like even the same extra port and features by pay for a lose modeul that you can connect .

Really if you like you can even beult a full cerbo gx unit for a small price and faster working systeem
The cpu is lot stronger.
You can even set a ups unit on it so if battery go down. It can even run on that.

So no i do not agree with you in this case

 

[justinm001]

No problems
I use one my self .
Rockstabel .
And just use a car charger for a phone for your 5volt problem.
Rock here now for days.
If battery have ports just use a usb to come port to make a connection.
You even have if you like even the same extra port and features by pay for a lose modeul that you can connect .

Really if you like you can even beult a full cerbo gx unit for a small price and faster working systeem
The cpu is lot stronger.
You can even set a ups unit on it so if battery go down. It can even run on that.

So no i do not agree with you in this case

We have hundreds of pis and our failure rate is very high. Typically it's the SD card, bootloader or OS so not sure if venusos fixes much if that or not.

I'm not too sure how raspberry pi connects to vebus, bmscan, vedirect devices but in assuming there's a lot of additional pieces needed. Once you add in all the additional pieces I'm sure you're getting close to that $217 price of the S. Plus way bigger and way more complicated with more devices that can unplug while driving. I wouldn't want my inverter ethernet cable plugged into USB and pop out when driving.

Venusos is designed specifically for cerbogx specs and performance is flawless. Converting 12v to 5v is easy with a car charger converting 48v is a bit harder. UPS and everything can be done with a diode then a battery. I'd suspect the cerbogx uses a lot less power than a pi.

Does the pi have relays and digital/analog inputs? I know it doesn't have relays built in.

Is there any feature the pi has that cerbogx doesn't as they both have venusos? I don't think you can add additional relays or anything.

 

[Suijkerbuijk]

We have hundreds of pis and our failure rate is very high. Typically it's the SD card, bootloader or OS so not sure if venusos fixes much if that or not.

I'm not too sure how raspberry pi connects to vebus, bmscan, vedirect devices but in assuming there's a lot of additional pieces needed. Once you add in all the additional pieces I'm sure you're getting close to that $217 price of the S. Plus way bigger and way more complicated with more devices that can unplug while driving. I wouldn't want my inverter ethernet cable plugged into USB and pop out when driving.

Venusos is designed specifically for cerbogx specs and performance is flawless. Converting 12v to 5v is easy with a car charger converting 48v is a bit harder. UPS and everything can be done with a diode then a battery. I'd suspect the cerbogx uses a lot less power than a pi.

Does the pi have relays and digital/analog inputs? I know it doesn't have relays built in.

Is there any feature the pi has that cerbogx doesn't as they both have venusos? I don't think you can add additional relays or anything.

Its in the cheap sd card.
Raspberry Pi 5 can use a ssd .
So that problem is gone.

For the rest

https://www.amazon.nl/Raspberry-Power-Expansion-Module-Channel/dp/B072Q5R3NH?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A9VM8DGMD224G

Here is your relay box.

 

[justinm001]

Its in the cheap sd card.
Raspberry Pi 5 can use a ssd .
So that problem is gone.

For the rest

https://www.amazon.nl/Raspberry-Power-Expansion-Module-Channel/dp/B072Q5R3NH?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A9VM8DGMD224G

Here is your relay box.

Are you able to use more than 2 relays in the software?

Fitting that board plus a ssd plus everything else all in a small box and can't be unplugged would be hard. The cerbogx has 7 ethernet type ports, 3 vedirect, 3 usb, 2 relays, and a bunch of inputs. I'm just not seeing a clean setup with everything at much of a discount. Surely you think $100 more for a clean professional device is well worth it. With the whole warranty and proven components.

 

[Suijkerbuijk]

Are you able to use more than 2 relays in the software?

Fitting that board plus a ssd plus everything else all in a small box and can't be unplugged would be hard. The cerbogx has 7 ethernet type ports, 3 vedirect, 3 usb, 2 relays, and a bunch of inputs. I'm just not seeing a clean setup with everything at much of a discount. Surely you think $100 more for a clean professional device is well worth it. With the whole warranty and proven components.

We going really offtopic.
For all things for Raspberry Pi
See link that i have set in my own topic.

Same for the topic starter.
If you like more information see the link .

S

Thread 'Raspberry Pi 4b beult with venus os (series)'

Sep 12, 2024

I have beult my Raspberry pi4b with screen and heatsink's for the victron mppt and inverters
This is a topic how i have beult .
What you need .
How its done easy .
Links from Dutch Amazon parts
But i set the parts numbers with it .

So the start .
Whats is a Raspberry Pi serie
Its really a mini pc arm base systeem that you can beult and program .
In this case we gone make one with Victron venus os support.
Its a cheap solution for the venus gx systeem what cost a lot of money.
In that attach files you see what i use for the this beult .
I set YouTube from other people that help and explain...

• Suijkerbuijk
• Replies: 12
• Forum: DIY Solar General Discussion

• 

 

[justinm001]

We going really offtopic.
For all things for Raspberry Pi
See link that i have set in my own topic.

Same for the topic starter.
If you like more information see the link .

S

Thread 'Raspberry Pi 4b beult with venus os (series)'

Sep 12, 2024

I have beult my Raspberry pi4b with screen and heatsink's for the victron mppt and inverters
This is a topic how i have beult .
What you need .
How its done easy .
Links from Dutch Amazon parts
But i set the parts numbers with it .

So the start .
Whats is a Raspberry Pi serie
Its really a mini pc arm base systeem that you can beult and program .
In this case we gone make one with Victron venus os support.
Its a cheap solution for the venus gx systeem what cost a lot of money.
In that attach files you see what i use for the this beult .
I set YouTube from other people that help and explain...

• Suijkerbuijk
• Replies: 12
• Forum: DIY Solar General Discussion

• 

Thanks really appreciate it! Great job. I love custom solutions but just sucks there isn't any advantages other than saving a couple bucks for a bunch of hours of work.

If I could also run home assistant on the same device and out redundancies to make it enterprise id pay thousands.

 

[Backroads4me]

You shouldn't need the smartshunt since those batteries have victron comms. get the normal cerbogx and plug in. Then you're getting temps, SoC and errors right from the batteries.

What model is your alternator? Id definitely recommend going with Orion XS and stacking them over a wakespeed/zeus. If the alternator was dedicated to house then a wakespeed/zeus would work but even then it only really makes sense if you're trying to squeeze every amp from the alternator. These are popular in sailboats where you have small engines and small alternators but huge batteries. They also make sense if you're mass producing vehicles and want to program the alternator and make sure its cool. Plus less devices.

When building your own its nice to have orion XS as you can tweak the amp/volt so it works best for your needs.

My understanding from obsessive reading, no firsthand experience yet, is that the Epoch Victron comms are pretty limited. For one, they are apparently taking some liberties with the word communications, it's more like signaling since it's one way. The Victron has no way to control or respond to the batteries. Also, without the shunt, you're not able to get a combined SOC, just individual for each battery. I'd love to be wrong if anyone has more information or experience. With the Cerbo, I get the combined SOC, remote monitoring and eventually a display. I can always connect to each battery via Bluetooth directly.

The alternator is 9 or 10 years old. I definitely do want to get everything out of it and take full advantage of its capacity. I'll need it with the size of the battery bank. My current plan is to have the Zeus or Wakespeed (not sure which yet) drive the alternator charging the lithium then have the Orion charge the chassis. It's starting to be a lot of moving parts! With that said, I'm definitely interested in hearing more pros or an argument for not including the alternator controller. No idea why they are so expensive. Or for that matter, why the Cerbo can't do it.

 

[justinm001]

My understanding from obsessive reading, no firsthand experience yet, is that the Epoch Victron comms are pretty limited. For one, they are apparently taking some liberties with the word communications, it's more like signaling since it's one way. The Victron has no way to control or respond to the batteries. Also, without the shunt, you're not able to get a combined SOC, just individual for each battery. I'd love to be wrong if anyone has more information or experience. With the Cerbo, I get the combined SOC, remote monitoring and eventually a display. I can always connect to each battery via Bluetooth directly.

The alternator is 9 or 10 years old. I definitely do want to get everything out of it and take full advantage of its capacity. I'll need it with the size of the battery bank. My current plan is to have the Zeus or Wakespeed (not sure which yet) drive the alternator charging the lithium then have the Orion charge the chassis. It's starting to be a lot of moving parts! With that said, I'm definitely interested in hearing more pros or an argument for not including the alternator controller. No idea why they are so expensive. Or for that matter, why the Cerbo can't do it.

Is it a dedicated alternator for the house or shared with the chassis? If shared I'm not sure how that'll work. You need an external regulator because otherwise it won't limit the amount of power as lfp batteries can charge everything it gets. Cerbo has no control over the alternator.

If not dedicated then you really need dc dc converters so you just pull the amount of power from the main chassis system and everything's isolated.

Not sure of epoch but it should be 1 way. The battery should tell Victron everything. Typically the batteries connect together but SoC would be the same as it'll pulls from all batteries equally.

 

[Backroads4me]

Is it a dedicated alternator for the house or shared with the chassis? If shared I'm not sure how that'll work. You need an external regulator because otherwise it won't limit the amount of power as lfp batteries can charge everything it gets. Cerbo has no control over the alternator.

If not dedicated then you really need dc dc converters so you just pull the amount of power from the main chassis system and everything's isolated.

Not sure of epoch but it should be 1 way. The battery should tell Victron everything. Typically the batteries connect together but SoC would be the same as it'll pulls from all batteries equally.

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.

 

[Skypower]

I like the idea of separate dc systems. One that runs the engine/chassis and the other is “house”. Keeping the lead acid, for the starter is the best approach. A momentary boost solenoid incase of a dead starter battery is always a good idea.

 

[Backroads4me]

I like the idea of separate dc systems. One that runs the engine/chassis and the other is “house”. Keeping the lead acid, for the starter is the best approach. A momentary boost solenoid incase of a dead starter battery is always a good idea.

The system currently has an automatic BEP VSS. I'm looking for a motorized manual only version. Ideally, I would still be able to push the momentary button on the dash and have the boost engage for a few minutes to help out the starter battery, then turn it off and start the engine. Every motorized version I see is automatic, so I may just go with a 100% manual switch and repurpose the dash button since it's a very rarely used feature anyway.