Thoughts on how to rebuild large electrical system

[justinm001]

Previously my RV was at my home plugged into shore and now its in storage. I also rarely use it and plan on leaving it in random campgrounds around the country for weeks/months at a time so need something as stable as possible. My problem is the 48V quattros use 80w at idle so 2kwh a day just to have 120V power in the coach. I have various automations to turn things on/off based on power so I can turn 120V appliances on when SoC is high and off when low which helps. Even with 5000w solar with rainy and winter its hard to get full charge of batteries. The system doesn't seem very stable and lots of components.


I'm wondering if I should add another pair of 48V batteries and setup the 48/12v DC converters then make sure the 12V is always topped off. Then maybe even change the inverters to turn off when below 20% SoC. This way the 12V will work on 48v and 12v. I also plan on adding a ATS and a lead acid battery to add a redundant system to keep 12V on.

Previously I had half the outlets running of the 12V inverter and the other half running off the 48V inverters. With 6 ACs and everything else I could pick the devices I want to run based on which system is charged. Then when on shore AC power ran from the 48V to the 12V and charged both systems and all outlets.


48V SYSTEM
Currently I have 50A shore connecting to 2x quattro 48v 5000w in split phase. Also a 20KW genset set to 240v/80a I rarely use. Running 2x 48v SOK 100AH rack batteries for 10KwH. This connects to my main breaker panels using 4ga wiring so can run 100a without issue.

48v Solar:
6x320w panels plugged into 150/100 MPPT (driver)
6x320w panels plugged into 150/100 MPPT (pass)
10x100w panels plugged into 150/35 MPPT (middle)

12V SYSTEM
2x100w panels plugged into 100/30 MPPT running 2x12V EG3 400AH rack batteries for 10KwH. I have about 500w or so 12V load with wifi/cell, lights and other RV stuff.

Other parts
separate genny 12v battery with 120V AC charger to keep topped off.
120V AC charger for the 12V system
12v quattro 5000w for the 12V system but its dead and need to RMA it. Not sure if I should use it.
24/12 and 24/48 DC DC converters to charge from alternator (1500w to each)
2x 48/12v DC DC converters 20a each not used
Both systems have CerboGX, shunts and everything else.

The 48V is in a bay 30ft from the 12V and I have 1 4gauge wire coming from the 12V to 48V bay (used for the alternator DC converter). It'll be a huge pain to run more wires but possible.

 

[HRTKD]

First world problem right there.

I run my Quattro all the time in the winter to keep my side-by-side's batteries charge. Otherwise, the Quattro isn't doing much on the AC side. I let the RV just sit there. No heating, no internet. I trust the system to take care of itself without my intervention.

If you can't get the current batteries charged, how is adding more batteries going to help? It's a rhetorical question, don't answer that.

 

[justinm001]

First world problem right there.

I run my Quattro all the time in the winter to keep my side-by-side's batteries charge. Otherwise, the Quattro isn't doing much on the AC side. I let the RV just sit there. No heating, no internet. I trust the system to take care of itself without my intervention.

If you can't get the current batteries charged, how is adding more batteries going to help? It's a rhetorical question, don't answer that.

I have about a 50w ac load and 50w dc load. Mainly the fridge and other little gremlins. Add the 80w inverter idle load and I'm at 4kwh per day with everything off.

If I add batteries I can get a bigger buffer and prevent the system from turning off. If it turns off I lose the automation. Since I have things turning on and off depending on SoC if I can have more batteries I can turn things off at 30% and still have enough battery to last a rainy day or so and not need to turn off the inverter hopefully.

I'm tempted to swap the 12v LFP to 48v by rewiring and putting a new bms but not sure if best.

I also need tank and battery heaters to run as it's in the cold (Ohio) I'm assuming I'll be storing in warmer areas to travel to so that'll be fixed sometimes. Also this wasn't a real issue in summer where I had mostly sunny days.

I should configure the generator to autostart but not sure if someone will say something if the RV is alone in a park and genny starts up. It's quiet but not silent

 

[LakeHouse]

My problem is the 48V quattros use 80w at idle so 2kwh a day just to have 120V power in the coach. I have various automations to turn things on/off based on power so I can turn 120V appliances on when SoC is high and off when low which helps. Even with 5000w solar with rainy and winter its hard to get full charge of batteries.

Super low-hanging fruit here would be to run only a single inverter continuously. I'm guessing you have an appliance or two that requires split phase (dryer, range?). When you aren't using those, you don't need the second Quattro. It's unclear from your post if you still run a 12V inverter. If you do, dump it. Wire all your 120 Vac to run off a single Quattro. Only turn on the second when you need 240 Vac. I think the 'eco' mode on the Quattro can do this for you automatically, but I'm not 100% certain when they're wired in split phase.
If a single 5kW Quattro isn't enough power, then your problem isn't idle draw, it's that you're using too much power.

I'm wondering if I should add another pair of 48V batteries

This won't help solve the problem that you're using more power than you're making. It'll change the timeline of when you run out, but that's it.

setup the 48/12v DC converters then make sure the 12V is always topped off.

This would probably be a good idea. But I would only run the things that are absolutely necessary off the 12V system; 12 Vdc lights, etc. Ditch the 12V inverter.

 

[justinm001]

Super low-hanging fruit here would be to run only a single inverter continuously. I'm guessing you have an appliance or two that requires split phase (dryer, range?). When you aren't using those, you don't need the second Quattro. It's unclear from your post if you still run a 12V inverter. If you do, dump it. Wire all your 120 Vac to run off a single Quattro. Only turn on the second when you need 240 Vac. I think the 'eco' mode on the Quattro can do this for you automatically, but I'm not 100% certain when they're wired in split phase.
If a single 5kW Quattro isn't enough power, then your problem isn't idle draw, it's that you're using too much power.


This won't help solve the problem that you're using more power than you're making. It'll change the timeline of when you run out, but that's it.


This would probably be a good idea. But I would only run the things that are absolutely necessary off the 12V system; 12 Vdc lights, etc. Ditch the 12V inverter.

I don't think you can easily swap Victron from split phase to running a single inverter. If this was possible I'd be all over it as I could just run half the outlets and save 40w.

I don't have anything 240v currently but want it as I'd like a 240v range. Also have a buddy plug I like being able to use for others as well as to charge the tesla. Also nice for emergency if I need to power large loads I can use the 240v with my shore cord.

The original goal was to backfeed solar to my house and offset the electricity usage a bit. Since it was at my house I could turn most off and if needed manually turn stuff on.

The 12v inverter isn't working and disconnected from AC. I need to rma. Before I could run just that so I only used 40w instead of 80w/120w and only some outlets worked.

My coach is a powerhog designed to run the 20kw genny 24/7 I've cut a lot of gremlins but there's still a bunch I can't find, mainly on 12v

 

[LakeHouse]

I don't think you can easily swap Victron from split phase to running a single inverter. If this was possible I'd be all over it as I could just run half the outlets and save 40w.

I think you're misunderstanding what I'm suggesting. You can still be wired for split-phase, just run all your 120V loads on the same phase, and operate that Quattro continuously. The second Quattro would be wired to the second phase, and you would only run it when you need 240V.
A third (and maybe better) option would be an autotransformer; wire both the Quattro's as 120V to the AT, and then run your future 240V loads from the AT.
This would complicate running off of 240V shore power or the generator, but with 10kW of inverter you probably don't need to worry too much about having to pass power through. Instead, you could use a chargeverter (or two, or a few 48V rectifiers) to charge the 48V battery when you're on shore power or running the generator. Slightly less efficient than passing through, but when you're on shore or running the generator, efficiency isn't all that important.

Writing this all down now... Here's exactly what I would do: install an AT and wire the split-phase of the AT to your current split-phase panel, and wire the two Quattro's in parallel to the 120V side. One Quattro is always on, the other can run on-demand when you need more than 5kW.

 

[justinm001]

I think you're misunderstanding what I'm suggesting. You can still be wired for split-phase, just run all your 120V loads on the same phase, and operate that Quattro continuously. The second Quattro would be wired to the second phase, and you would only run it when you need 240V.
A third (and maybe better) option would be an autotransformer; wire both the Quattro's as 120V to the AT, and then run your future 240V loads from the AT.
This would complicate running off of 240V shore power or the generator, but with 10kW of inverter you probably don't need to worry too much about having to pass power through. Instead, you could use a chargeverter (or two, or a few 48V rectifiers) to charge the 48V battery when you're on shore power or running the generator. Slightly less efficient than passing through, but when you're on shore or running the generator, efficiency isn't all that important.

Writing this all down now... Here's exactly what I would do: install an AT and wire the split-phase of the AT to your current split-phase panel, and wire the two Quattro's in parallel to the 120V side. One Quattro is always on, the other can run on-demand when you need more than 5kW.

When the Quattros are configured for split phase, one won't turn on until the other is on, so you can't just run 1. You need to reprogram them each time which is a pain.

I'm not sure if I stack Victron inverters in parallel if I'm able to just turn 1 on without needing to reprogram. I assume so.

Even the 100a autotransformer can only handle 32a neutral so I don't see how this will work. I can have a massive electrical load and max out 50a shore all the time (thank goodness for powerassist). I have no clue what happens when you go over 32A on neutral. I know neutral is only the unbalanced load but I have 6 ACs so I'd have to make sure I run them in pairs on separate legs. It would work if I put most loads on the 120V, bypassing the AT then only use that for specific outlets.

Basically to save 40W idle I'd need to use an AT on some loads and setup with a chargeverter or two (or use an ATS). Only $1000 which isn't horrible just more components and more room. My original setup was to do similar with the 12V quattro and use this for main loads then the 48V inverters off unless I'm using it. The 48V batteries will charge the 12V. When on shore the 240V Quattros will run then it runs 120V 50A to the 12V quattro to fast charge and pass those loads.

 

[justinm001]

BTW this is my typical rainy day at 2:19PM. 250-350 watts of solar, 48w of AC loads and charging 121watts. 64watts missing. 12V solar brings 8w (of 200) 54w idle load so discharging 46w. I can kick on the 200w AC to 12V charger and get pretty efficient charging, maybe 20w or so lost. Currently its set to turn on when 48V is 80% and off when 30% which its not hitting 80% SoC so not turning on automatically.

 

[HarryN]

If you run the vehicle - stand alone, for 2 weeks, will the pack SOC remain above 30% ?

It is nice to always have the pack full, but for Li it isn't always required.

The auto generator start might be a viable path, assuming it turns on for 1 hour and then turns off.

Or perhaps put a quieter generator in a small trailer ?

 

[LakeHouse]

It would work if I put most loads on the 120V, bypassing the AT then only use that for specific outlets.

Not most loads, all loads except the 240V loads. No need to worry about balancing at all. But, the 32A limitation on the neutral would mean you could only do 3800 W of 240V, which might not be enough to run your future range.

But in light of this:

I can have a massive electrical load and max out 50a shore all the time (thank goodness for powerassist).

Yeah... The AT idea won't work for what you're trying to do.

 

[justinm001]

If you run the vehicle - stand alone, for 2 weeks, will the pack SOC remain above 30% ?

It is nice to always have the pack full, but for Li it isn't always required.

The auto generator start might be a viable path, assuming it turns on for 1 hour and then turns off.

Or perhaps put a quieter generator in a small trailer ?

It depends on solar. I need 4kwh or so per day and some days i'm getting 8kwh and others like 1. Before winter I was getting 10-15Kwh which was plenty and batteries were maxing out so stopped grabbing solar.

The generator autostsrt will work provided the system is stable as if I lose power then the cerbo won't be able to start.

 

[justinm001]

Not most loads, all loads except the 240V loads. No need to worry about balancing at all. But, the 32A limitation on the neutral would mean you could only do 3800 W of 240V, which might not be enough to run your future range.

But in light of this:

Yeah... The AT idea won't work for what you're trying to do.

Yeah at that point the best option is to just get another 48v inverter with real low idle consumption like mp2 3000. Use this for all the small stuff and keep the big inverters off. But even then I'm thinking autostarting the genny is best. A ground solar isn't going to help if my 5kw on the roof can't get enough

 

[HarryN]

At first glance, it looks like:
- Put the generator on a timer
- Turn it on every 3 days in the morning
- Run for 2 hours

Would solve 90% of the issues.

Don't even bother trying to use the cerbo to turn it on - at least when you are not there.

Not perfect, but simple.

Then the main question is fuel capacity or run hours for maintenance.

What kind of auto start setup do you have in place ?

 

[justinm001]

At first glance, it looks like:
- Put the generator on a timer
- Turn it on every 3 days in the morning
- Run for 2 hours

Would solve 90% of the issues.

Don't even bother trying to use the cerbo to turn it on - at least when you are not there.

Not perfect, but simple.

Then the main question is fuel capacity or run hours for maintenance.

What kind of auto start setup do you have in place ?

Genny burns about. 68 gph at 50% load (10kw), 1.5gph at 100% (20kw). 180gal or so tank so maybe 150gal before it gets to low and cuts fuel.

Quattro are 2x70a chargers so 7kw and I really only need to run 30mins to get 3.5kwh then a bit of solar and I'll be good. Meaning I could run for like 300days

I believe I have this genset. It has a "smart start" and a panel inside the coach to start it. Theres a port in that box to the left of the genset for the 1wire remote start needed for the Cerbo. I really only have issues on cloudy/rainy days or if the panels are covered in snow. Cerbo Autostart makes more sense so I only run as needed.

If I plan on running the genset I gotta figure out better cooling for it. Ri too out a massive fan cage for it and put all the inverters and such where it was. I just have a couple radiator fans but cover those up in winter to keep bay warm. Right now I'll run for 10 minutes and let it get hot then shut off. Get 1kwh and then I'm good. Also keeps that bay nice and warm for a while. Behind the genset is inverters and to the right is fresh water tank so a perfect bay heater

20 kW Diesel Generator Details

ENCLOSED CONFIGURATION OPEN CONFIGURATION EPS 20kW Tier 4 Final Diesel Mobile Generator Specifications Configuration Enclosed Open EPS Model Number S10020J4ENC S10020T4C3 KW – Stand-by (1) 20.9 20.9 KW – Continuous (1) 19.4 19.4 120 / 240V

www.enginepowersource.com

 

[HRTKD]

Genny burns about. 68 gph

Looks like the decimal place is out of place.

 

[sumpower]

Yeah at that point the best option is to just get another 48v inverter with real low idle consumption like mp2 3000. Use this for all the small stuff and keep the big inverters off. But even then I'm thinking autostarting the genny is best. A ground solar isn't going to help if my 5kw on the roof can't get enough

I agree that the multiplusII would be a good solution. You just need to have the room to install it and a transfer switch to place all the 120 volt critical loads on it. 11 to 12 watts consumption at idle would certainly help with your situation.

 

[HarryN]

In my mind, there is a difference between "if you are there" and "if you are far away".

Normally, running a generator for 2 hours, 2 x / week would be less stressful on it than 30 minutes each day.

A simple timer is more reliable than the cerbo, just because of complexity, and does not depend on everything else working.

It is always trickier than people think to power and operate things remotely. The people that support telecom infrastructure in the middle of no where, on top of a mountain, know this challenge well.

 

[justinm001]

In my mind, there is a difference between "if you are there" and "if you are far away".

Normally, running a generator for 2 hours, 2 x / week would be less stressful on it than 30 minutes each day.

A simple timer is more reliable than the cerbo, just because of complexity, and does not depend on everything else working.

It is always trickier than people think to power and operate things remotely. The people that support telecom infrastructure in the middle of no where, on top of a mountain, know this challenge well.

Yeah idk how long you're supposed to run a diesel generator. This things meant to run constantly, it has tons of hours like 30,000 hours on it.

The Cerbo is simple to program, I think I already have it done just haven't ran the wire. It'll also run if not ran so I know the generator works. It's not ran remotely it's programed into the device. I can remotely turn it on/off though and reprogram it which would be nice. Like turn it on when I'm omw there so it's 100% and all ready.

As long as I have 12v power there isn't an issue running things remotely. I have 2 Sim cards and starlink so get service anywhere.

There's no point in running the Genny if the battery's charged or on shore which is why I don't wanna use a timer.

 

[HarryN]

Yeah idk how long you're supposed to run a diesel generator. This things meant to run constantly, it has tons of hours like 30,000 hours on it.

The Cerbo is simple to program, I think I already have it done just haven't ran the wire. It'll also run if not ran so I know the generator works. It's not ran remotely it's programed into the device. I can remotely turn it on/off though and reprogram it which would be nice. Like turn it on when I'm omw there so it's 100% and all ready.

As long as I have 12v power there isn't an issue running things remotely. I have 2 Sim cards and starlink so get service anywhere.

There's no point in running the Genny if the battery's charged or on shore which is why I don't wanna use a timer.

That makes sense.

The simple version is that a diesel engine is not designed to go to the corner grocery store, it is designed to go to the warehouse and bring groceries to the store.

A 2 hour run, every 3 days would be less wear on it than a 30 minute run every day.

That is why it might long term be useful to have 2 modes - when the generator is needed not needed vs when the generator "probably" is needed.

I don't trust the cerbo or any other controller to always work, so I tend to go for simplistic solutions.

 

[HarryN]

I wonder if there is a way to have some kind of simple "it is overcast, run the generator tomorrow" sensor that does not depend on the cerbo?