Please review and comment: 30 foot Class C toy hauler 3300W PV 48V solar retrofit plan for boondocking mobile office

[dea9]

Hi everyone, I've read all I could over the last few months and I'm seeking advice on my proposed system diagram before I order and install all my components in the next month. Please give me your thoughts.

The basics:

• 30 foot class C toy hauler, meaning the living area is quite small (8’ x 16’)
• I will be living, working, and riding dirt bikes out of this vehicle for a few months at a time
• I’ll be using this in some desert climates, so outdoor daytime temperatures may exceed 100F
• I’ll also be using this in some mountain climates, when the temperatures are just above freezing
• I can generally park in full sun with no obstructions
• Main power requirement will be mini split, secondary will be laptop + monitor + Starlink, no slide outs (biggest 12V draw is starting generator)
• More concerned with simplicity of DIY build than money or pure efficiency in version 1. Just gotta get on the road and see what doesn’t work before premature optimization.

Version 1 plan:

• 3300W of solar on elevated roof rack (6 x 540W panels at 49 VOC, in 6S configuration for 297V PV @ 13.72A ISC)
• Add panels, EG4 300W 48V AIO, and one EG4 48V 5120Wh server rack battery
• Leave existing 12V AGM house battery in place to start generator or starter battery in emergencies
• Wire the output of the AIO into the existing breaker panel to provide 120V (and wire the shore power/generator output cable into the input of the AIO)
• Let the existing Parallax 7300 Series 7345 Converter in the breaker panel provide 12V and keep the house battery full
• Consider accepting the inefficiency of both the AIO idle draw and the PV -> 120V -> 12V conversion for the 12V system and house battery

Future ideas for efficiency:

• Just add a second server rack battery and don’t worry about efficiency at all forever
• Add Chinese diesel heater if overnight winter heat requirements can’t be met with solar and two batteries
• Add 48V to 12V battery charger (cannot find one from a reliable manufacturer, the Victrons are only converters, not chargers)
• Go Victron with separate components to reduce AIO idle draw
• Convert fridge to either AC or DC
  • Current propane fridge is dying, and if I have to leave the inverter on most of the time for the mini split, why not just run the fridge off AC?
• Convert everything to DC
  • Mini split, fridge, Starlink, laptop, monitor, can all be converted to DC

Please let me know if there's anything wrong with this plan to start, you'd strongly suggest different hardware (like Growatt + SOK instead of EG4), or any other insights you might have. Thanks!

 

[RvNaut]

fwiw .. here is the system I just finished building for my RV

Note the 48-12v converter. Leave the 12 battery(ies) in place and set the converter outout to 12.9....

 

[HRTKD]

I don't know the idle load of the EG4, but some other all-in-one devices carry a heavy idle load. In my Victron system, I haven't worried about idle load. It just isn't very much.

I agree with keeping a lead acid battery for starting the generator. That's what I did on my toy hauler.

When my AC/Propane absorption refrigerator dies, I'll put in a DC compressor refrigerator. I haven't settled on which one yet.

My Starlink is 100% deployed outside the RV. I plug the AC cable into one of the exterior outlets and place the router on top of one of the tires, keeping it out of sight and out of the weather.

 

[dea9]

The AIO idle load appears to be about 50W for the 3000W sized inverter ones, like the EG4 I’m considering. It’s a lot of overhead, but Victron doesn’t make an AIO for the US market, so I can’t go that path if I’m looking for simplicity. Part of my theory is that I won’t have heavy energy usage overnight (when the AIO overhead is “expensive”), and during the day the oversized PV array more than covers the AIO draw.

I don't know the idle load of the EG4, but some other all-in-one devices carry a heavy idle load. In my Victron system, I haven't worried about idle load. It just isn't very much.

I agree with keeping a lead acid battery for starting the generator. That's what I did on my toy hauler.

When my AC/Propane absorption refrigerator dies, I'll put in a DC compressor refrigerator. I haven't settled on which one yet.

My Starlink is 100% deployed outside the RV. I plug the AC cable into one of the exterior outlets and place the router on top of one of the tires, keeping it out of sight and out of the weather.

 

[dea9]

fwiw .. here is the system I just finished building for my RV

Note the 48-12v converter. Leave the 12 battery(ies) in place and set the converter outout to 12.9....


View attachment 146171

Right on, we’re doing basically the same thing. Is yours up and running well? I believe Sigineer and EG4 are both using Voltronics internals so we may have the same heart of the system. Have you found that the fans on your Siganeer are really loud? That’s the one thing I need to deal with on the EG4.

Also, are you concerned that Victron says not to use the converter as a battery charger? It’s right in the sales material, but maybe they’re just being conservative. I haven’t been able to find a name brand 48v to 12v true charger yet.

 

[RvNaut]

. Have you found that the fans on your Siganeer are really loud? That’s the one thing I need to deal with on the EG4.

Also, are you concerned that Victron says not to use the converter as a battery charger? It’s right in the sales material, but maybe they’re just being conservative. I haven’t been able to find a name brand 48v to 12v true charger yet.

The Sigineer is in a basement compartment and I do not hear it in the RV. When I had it inside in "bench mode" it was noted... also note that energy saving mode will not see loads below 100 watts, so mine runs 24/7. It uses 50 watts. I also have a starlink running 24/7 so my constant load is 80-120 watts. Sigineer will aloow the alarm screech to be turned off, but not the beep of the control buttons.


I went through a dist here in AZ for the Victron converter. They "set these up like this all the time". When I do use the Jacks or the slides it does knock the one 12v deep I have in place instead of the 4-6v deep down a few tenths, but it isn't working as a charger, and I wonder why you want a charger?? My concern was the 14.x volts coming into the above 12v battery and feeding back up the line to the 48-12 conv, but ws assured that it was not an issue.

Why do you want a charger versus a converter?

 

[HarryN]

Just keep in mind that server rack batteries are designed for stationary use, not mobile use.

The same is true for electronics designed for stationary use vs mobile / marine use.

A van / RV is a lot more like a boat than a server room for vibration and temperatures.

 

[dea9]

Just keep in mind that server rack batteries are designed for stationary use, not mobile use.

The same is true for electronics designed for stationary use vs mobile / marine use.

A van / RV is a lot more like a boat than a server room for vibration and temperatures.

I thought the same thing, but there’s a post from EG4 tech support here somewhere where they explicitly say their server rack batteries are approved for RV use. I’m on mobile so I can’t find it right now.

 

[dea9]

The Sigineer is in a basement compartment and I do not hear it in the RV. When I had it inside in "bench mode" it was noted... also note that energy saving mode will not see loads below 100 watts, so mine runs 24/7. It uses 50 watts. I also have a starlink running 24/7 so my constant load is 80-120 watts. Sigineer will aloow the alarm screech to be turned off, but not the beep of the control buttons.


I went through a dist here in AZ for the Victron converter. They "set these up like this all the time". When I do use the Jacks or the slides it does knock the one 12v deep I have in place instead of the 4-6v deep down a few tenths, but it isn't working as a charger, and I wonder why you want a charger?? My concern was the 14.x volts coming into the above 12v battery and feeding back up the line to the 48-12 conv, but ws assured that it was not an issue.

Why do you want a charger versus a converter?

Well I have a deep cycle AGM as my 12V source, so as I understand it you want to have a charger thats aware of your battery chemistry for long term health and maintenance. The chargers know how to do desulfation routines and all that, 3 and 4 stage/cycle chargers that change voltage over time for bulk, absorption, and float phases. Apparently that’s important for SLA battery life.

A converter doesn’t know about that, it just puts out constant voltage, and is mostly used in the case where you don’t have a battery at all and are powering your 12V loads directly from the converter.

In theory the 120V to 12V charger in my fuse box will do that now, so I’m thinking I’ll just let it do it’s thing. Victron very explicitly in their documentation for their converters says that they are not chargers and should not be used that way, but I’m not sure how bad the impact is. Victron might consider a 3% loss of battery capacity or longevity over 3 years totally unacceptable, whereas I wouldn’t care.

 

[RvNaut]

A battery charger is used to charge a battery that is in a very low state of charge. Or maybe a trickle charger which will float at 13.2, but that is either a trickle charger of a std charger in trickle mode.

Again, why do you think you need the capacity of the charger?

What potential harm would it do to the battery, say in my case, where I am feeding a constant 12.9 volts from the converter to the 12v battery?

 

[HRTKD]

The datasheet for the "Orion-Tr DC-DC converters isolated" has this:

Adjustable output voltage
Not intended for battery charging.
Please consider using an Orion-Tr Smart for battery charging.

The Orion-Tr Smart is listed as a charger, not a converter. But there is no 48-12 Orion-Tr Smart.

I think the idea of pumping in a constant 9 amps into a lead acid battery (or any battery?) is not optimal charging.

 

[50ShadesOfDirt]

I don't know how to word this, so may fail miserably, but I'd investigate the "support" capability of whatever main vendor you go with. If I were on the road, with little to no time available for support ... you can look around at various threads on this forum to see how the inverter/battery vendor you choose stacks up.

Victron seems to be a vendor that many folks take on the road, or on the ocean, etc.

Possibly another way around this issue is to have "spares" for key components, while out in the middle of nowhere?

 

[dea9]

The datasheet for the "Orion-Tr DC-DC converters isolated" has this:



The Orion-Tr Smart is listed as a charger, not a converter. But there is no 48-12 Orion-Tr Smart.

I think the idea of pumping in a constant 9 amps into a lead acid battery (or any battery?) is not optimal charging.

Yup, this is what I was referring to. If they made a 48 to 12 charger, problem solved. Thought about buying a 48 to 12 converter and then a 12 to 12 charger. Seems like it wouldn’t be much better than the 120 to 12 charger that I already have, but I really don’t know.

 

[dea9]

I don't know how to word this, so may fail miserably, but I'd investigate the "support" capability of whatever main vendor you go with. If I were on the road, with little to no time available for support ... you can look around at various threads on this forum to see how the inverter/battery vendor you choose stacks up.

Victron seems to be a vendor that many folks take on the road, or on the ocean, etc.

Possibly another way around this issue is to have "spares" for key components, while out in the middle of nowhere?

Yes, this is a really good point. Two EG4 3000s are still much less than all the Victron gear and wiring I’d need, so I had considered bringing a hot spare. But it doesn’t seem that people are complaining that their AIOs are dying, just that they suck for various reasons (high idle draw, bad apps, bad documentation, settings don’t stick when set, etc).

I wish Victron would make an AIO with a high voltage PV input for the US market. Like this EasySolar, but with 500V PV input and 60hz output (I’d probably be willing to convert from 240 to 120 for
Victron).

EasySolar-II GX - Victron Energy

The EasySolar-II GX combines an MPPT Solar Charge Controller, an inverter/charger and control hub in one enclosure. The product is easy to install, with a...

www.victronenergy.com

 

[RvNaut]

My system cost approx $5000 using an AIO, a battery I built myself and used panels.
.
While I admit that I do not have the rock solid reputation of Victron behind me, I would not have this system in place at all if I were to use their products. An AIO *is* taking risk ... less so with a Victron.
.
So far the Sigineer is doing well, but I am only about 45 days in.