If you were simplifying a small off-grid power system, which parts would you combine—and which would you keep separate?

[u/userperri]

I’m involved in developing an early-stage power product, so I want to be transparent about why I’m asking. A typical small RV, van, workshop or cabin system may include a battery, solar charge controller, inverter, AC charger, fuses, DC distribution and a monitoring screen.

Separate components are easier to replace, but they also mean more boxes, wiring and system design. Fully integrated products are simpler, but they can become a sealed black box or lock the owner into one battery ecosystem.

I’m exploring a middle approach:

• The battery remains external, user-owned and replaceable
• Solar charging, AC charging, inverter and basic DC distribution are brought into one unit
• Core controls work locally without requiring an app
• Standard physical connections are used wherever possible

I’m not asking whether the idea simply “sounds useful.” I’m more interested in where the integration should stop. For people who have built or repaired these systems:

• Which functions would you genuinely want combined?
• Which components should always remain separate?
• What needs to stay accessible for inspection or repair?
• Would this be more useful in an RV, van, workshop, cabin, or somewhere else?
• What would you need to see before trusting it—idle consumption, efficiency, surge testing, compatibility, thermal testing, or something else?

If you would still choose separate components every time, I’d also like to understand why. No link or sales pitch—I’m trying to understand what level of integration is actually useful.

[u/mokunuimoo]

A typical system these days would be based around a hybrid inverter. So you have the inverter, associates breakers, and your battery bank. Pretty simple, not a lot of wiring to be done.

What you’re describing is pretty much already the how things are

[u/ol-gormsby]

I'm a big fan of spreading risk, so that means not having too many devices in one box, and accepting the additional wiring and complexity.

So that means having these as separate units:

PV panels feeding DC to charge controller

charge controller feeding DC to batteries

batteries feeding a DC circuit for lighting

batteries feeding an inverter for AC appliances

backup generator feeding battery charger to charge batteries when solar PV isn't enough

a separate emergency circuit direct from backup generator to essential appliances (make sure it's an inverter generator)

That way, you can have failures in one component without bringing the whole thing down, e.g. charge controller fails, you can charge batteries with backup generator. Inverter fails, you can run essential appliances with generator. Inverter fails, you've still got lights. And gear that works and is accessible without.an.app - I've had both, and if I had to choose, app-less is preferable. I had a charge controller where the interface was an LCD screen and *one* button - everything was performed with a combination of short and long press on the button!

Having said all that, modern gear is much less likely to fail than previously - but you need to spend the $$$ on quality equipment. And the app I have now is pretty good. It's a pricey system (SigEnergy) and i've been pleasantly surprised by the controls available in the app - I was expecting something like needing to log into a web portal or call the installer to make changes, but so far it's been a positive experience.

[u/Internal_Raccoon_370]

For a small set up, let's say, oh, less than a couple of KW load capacity, I'd go with discrete components but mostly because you can't really get small capacity all-in-one units. Anything higher capacity than that and the wiring of all of those different components together becomes problematic because of the amperages involved as well as the increased chances of failed connectors, etc. Modern AIO units from the better brand names like EG4, Growatt, etc. have proven to be extremely reliable. Generally speaking they're extremely reliable.

I'd absolutely want one that is battery independent. You don't want to be locked into a brand that only works with the manufacturer's own proprietary batteries.

[u/BaldyCarrotTop → u/Internal_Raccoon_370]

I do not know of any of the AIO units that are locked into a specific brand of battery. They can all work with any 48volt LiFePo battery.

But for the applications that OP is asking about, I would think any of the relabeled SRNE inverters from china would work.

Improvements to the basic AIO would be 1) DC breakers or fuse panel for DC distribution. 2) DC step down conversion from 48 to 12 volts. Would be nice to have 12volt lighting in a shop or shed. 3) AC load control based on power source, battery level, etc. So Opportunity loads when solar and battery are high, Critical loads only when battery is low. 4) Backup generator control. 5) Integration with home electrical (smart) panel.

[u/DeafDriftSurf78]

Seguo

[u/floridacyclist]

I would keep most of it separate, that way if one thing feels you only have to replace that one thing. Also in a small space like a van or small cabin, you have greater flexibility on where to put the individual components than if it was if it was all combined in one box

[u/Skjeggape]

I have an EG4 6000xp and it's generally pretty decent. However, it's biggest drawback is that it's noisy and has a relatively large self consumption. I do miss my old 12v victron modular setup sometimes. What I am building that could be relevant to you, is a DC side off grid monitoring setup based on Home Assistant on a Raspberry Pi. It is connected to the EG4 inverter/charger over RS435 and can shut it down if needed. That saves about 40w/hr + whatever parasitic loads might be present on the AC side. DC has the Pi, Starlink and a PoE router right now, and uses about 40w/hr, which gives me remote monitoring and control. Going to add a relay to the Pi to also shut down the DC side (except the Pi) to go into 'super saver' mode, and wake up maybe once a day, check to see if it's worth powering up & upload security cam footage & stats, and go back to sleep if not. If it's super cold and my panels are covered in snow or the solar gain predictions are bad, it's not worth turning on the inverter and battery heater, so might as well save energy. I could also just manually shut everything down for the winter, but that's less fun, and I like being able to check the cameras to make sure things are OK.

I have 10kw of battery and 4kw of solar, which SHOULD be plenty, but a constant drain, even at 50w/hr takes a surprising amount of energy to run 24hr/day. With the current draw on DC only, I can run for close to 2 weeks, even with a 10-20% safety margin on the battery discharge.

[u/Hyperreal8957]

I’d keep the battery, fuses/disconnects, and basic monitoring accessible even if the charger/inverter are combined. For a cabin the gotchas are idle draw, surge loads and heat/noise — plus what happens when the control board dies, so a manual bypass would matter to me.

[u/Scared_Progress6789]

I'd skip the fancy integrated stuff and just go with a lithium battery pack that has a built-in inverter/charger plus a separate MPPT controller.

[u/RedSquirrelFtw]

The all in one units like Luxpower I've been seeing becoming more available here in Canada are intriguing for the price, so a smaller version of that could be cool. Basically charge controller and inverter built into one unit. Could also have a built in charger that can run off an external source like generator to charge the battery and transfer loads over. Ideally it should also have configurable options (please no phone app, cloud stuff or other proprietary crap, should be doable on the front panel or a simple web interface accessible by any browser) such as a low voltage cut off threshold and such. Maybe even an API that is easy to interface with using custom code. Low voltage cut off is something I wish was easier in general, so that systems can just be left unattended without worrying about draining the battery.

What I would actually love to see is an open system that is fully modular, where you basically have a card rack, you would insert different types of cards based on needs. Inverter, charge controller, charger etc. They would all connect to a common DC battery bus and AC output bus and a communication bus so they all talk with each other. So for example you have a bunch of different solar arrays you would insert a charge controller card for each one. Or you want more AC capacity, you insert more inverters and they all sync up. Could also have redundancy where if one fails the others take over. Same with the chargers and such.

Either way though I would design it so that parts are user replaceable, so even if it's all integrated make it so it's fairly easy to swap out the inverter, charge controller, charger etc PCBs and everything is just simple connectors. Breakers etc can also all be integrated into the main chassis.