Looking for inverter/charger/MPPT, 12v/120v

So, with my small travel trailer, I’m starting to look around to put in a 12v LiFePO4 with the capability to charge from shore power, if available, as well as hook up a few solar panels if I’m remote for a while. Ideally in one modest sized (since my needs aren’t huge) integrated piece.

I’m looking at 12v (~100Ah LiFePO4), 120v AC (say, 500-100W pure sine wave continuous), charge the battery at up 25-50a (depending on available power), and PV input of 500+W (I’m shooting to have headroom in case I need to add more panels later). Minimum of 12v (18v VoC) panels, but if it’ll do my current old house panels I got real cheap (I think 58v VoC) in parallel or serial that’d be the cherry on top.

I’ve found Victron Easy Solar and Easy Solar II GX, but they only do 220v unfortunately. And they are a bit vertical/long to be honest. Bit over specced, but not crazily.

Renology has a 48v/3500W, which obviously won’t work for me and is ridiculously over specced.

Otherwise looks like the Victron Smart Solar 150/35 or 150/45 plus MultiPass 2000VA, although the 12v version has the highest (80a) charge rate(??), which is weird and way more than a single battery can handle. Victron has other separate chargers and inverters that I’ve looked at.

So in short, it looks like I need to piece together either a charger/inverter + MPPT, or a charger + inverter + MPPT separately. Complicating factors is it’d be really nice to allow charging from the 30a hot wire from the 7-pin (trailer does have brakes) connector while towing.

I’m also ground mounting the solar panels, rather than putting them on the roof, and I figure I’ll just completely disconnect the battery from everything with a cut-off switch, and I won’t be leaving it out crazy long (6+ months) without hooking up either to shore power or solar. In theory I could get a small 12v “battery maintainer” 10-20W panel type and leave that secured to the tongue to keep the battery topped up.

So, @Syonyk, have I stumped you for a single integrated part (even if inside, under the hood, it’s made up of separate parts)?

And yes, I know I’m looking at real $$$$, I’d rather spend the money for a properly integrated system that I KNOW will be reliable and safe, rather than a complete hash of DIY waiting for a fire to happen or kill the battery.

I personally preferred separate components for each of those functions in my off-grid application. If/when one breaks or you want to replace it or whatever the others aren’t out of commission. And since they are separate functions, there’s no gain in integrating them in a small, simple system, really. Get a good MPPT solar charger, a good shore power charger, and one or more good inverters. Combine them if you like (shore power charging and inversion is easy to combine) but I wouldn’t worry about separate systems for MPPT charging at all. Ran that for five years with zero problems and the redundancy came in handy several times. Multiple inverters is useful for efficiency - I had a low power 300W and a high power 2kW inverter and used whichever was necessary at the time.

It’s not that weird. The 12v one charges at 14.4v * 80a = 1152w compared to the 24v version (for example) which does 70 amps charging 28.8v * 70a = 2016w.

Many reasonably sized 12v parallel battery banks would benefit from 80a when they first start a charging cycle from 50% DoD.

You’ll almost certainly need a separate DC-DC charging component for that function.

In Victron gear, the part you’re looking for to do that would be https://www.amazon.com/dp/B07ZKG396Y

For 12V, yes…

For 24V or 48V and overkill, https://midnitesolar.com/pdfs/MN3024_3548_frontBack.pdf works.

I’d be inclined to go with Aims for the inverter/charger, just because I’ve beat the hell out of them and they work fine, as have some other people on this forum I know.

If you’re plugged into shore power, it will pass that through and charge, if not, it will invert. There’s a 600W one too they have, don’t buy from their website, you can find them a lot cheaper elsewhere.

Your 30A trailer wire could potentially go straight to the battery… not sure how that works if it tries to pull more than 30A, really. I’m not as familiar with those systems. But a DC-DC charger really is the right option there.

The Midnite Kid looks like a good small scale charge controller for that system. Add the WbJr if you want good state of charge reporting.

I’m sure you can find a small integrated system, but I agree with other people, do it as discrete parts and you’ll get a better system out of it.

Probably ya’ll are right, that shouldn’t look for a One Single Device to rule them all.

Was thinking I want all of them to be the same brand so the same magic monitoring stuff will be all in one, but probably can just use one systems monitoring for input and output and, since if I have shore power, there’s no point in me pulling solar out (since it won’t be roof mounted), doesn’t matter too much how the interaction between MPPT and AC charger or MPPT + DC from 7-pin power. Since it’ll really only ever input from a single one of those at a time, or at least it’s a whole lot easier to control that.

I’ll look more at the Aims inverter/charger, as well as other separate MPPT and DC-DC charging options. And monitoring options. Now to sort through all the various options. Going to have to think carefully about size and placement.

I almost want to skip the inverter/charger initially, as all I can think of for AC usage is laptop right now, and maybe charging up some portable tool batteries. And charging up the battery if I have shore power. I’m just going to convert the current light fixtures (all 2 of them) into 12v. They’re edison sockets, but I believe there are 12v filament LED bulbs that will fit them, and give me the nice neutral to soft look I’ll want for now.

Why? It really doesn’t matter. For something like a camper, you don’t need to keep terribly close tabs on it. Just make sure your charging source won’t badly overcharge the battery, and make sure your inverter won’t beat it up too badly by over-discharging it.

Fine details don’t matter for that kind of use unless you’re full timing in it. At which point you can use a more advanced monitoring system.

You could probably get away with a 5A or so external 12V charger for it, 60W, that’d cover a lot of use if you’re running loads on DC directly.

This is tricky. I almost did this for my moderate size off-grid system I recently put together, but I came to the conclusion that the system as a whole would be way simpler without a transfer switch or manual unplugging/replugging things when I want to run/charge from the generator.

A inverter/charger like the Victron Multiplus takes care of that and is more flexible than separate inverter + charger + transfer switch because you can choose in software between just grid, just inverter, or a even power assist modes where the the power comes from one of those places preferentially with overloads spilling over to the other.

Everybody’s needs are different, but I’m very happy I went with the Multiplus inverter/charger for my use-case.


EDIT: I just realized you weren’t talking about skipping the combined inverter/charger unit in favor of separate ones, but just skipping having an AC system all together. I think that’s a great strategy if you can manage it. Many inverters have a fairly high quiescent (no-load) power usage on the order of 10 - 50w which is worth avoiding if you can.

Those E26 12/24v LED bulbs are great. These are the best ones I’ve found so far;

That’s a good point. Definitely not a full-time system, and with good components and a good LiFePO4 with solid BMS, unlikely to self-discharge too much or end up damaging the battery.

Yup. I mean, eventually I’m going to add an inverter at a minimum, probably an inverter/charger. Most of them have remote off switch, or at the least I’ll have a breaker/disconnect to the inverter to avoid the quiescent load when I don’t actually need it.

As I said, I don’t particularly see having both PV & AC connected at the same time, with my setup, so I can just put in a physical disconnection switch from PV to battery and AC to battery, only connect them when I need to use them, either for charge AC output usage.

I’d like to go on some camping road trips combined with doing some remote work. Initially just staying where I can be assured of good cell reception and/or WiFi available. So I’ll need some AC eventually. Just not at first. I do already have a 600W inverter I can use as needed in the meantime, before I eventually get a charger/inverter combo model.

I was actually looking at bulbs more like https://www.amazon.com/Edison-Equivalent-Voltage-Camper-Marine/dp/B0941417LQ, which will give me better all around ‘horizontal’ lighting with better diffusion/even lighting. Might not be those bulbs specifically, but something in that vicinity is my thought.

This is exactly why I recommend having several inverters of different capacities, that you can turn on and off as needed. 120W, 300W, 600W, 2kW, etc. Choose the lowest wattage necessary for your needs, and turn it on when you’re actually using it, and off otherwise. Samlex makes good inverters too, I had great success with them.

Not as practical for an RV use case with limited space, especially not mine, but that’s a useful idea actually, if I have a bigger need with intermittent loads that can vary so much that way.

Thinking about it I am tempted, a little bit, to go for a 24v system, but I just can’t really justify it as I don’t expect to have any very high draw things. Even if I get a compressor fridge like this one, the amperage doesn’t really need 24v. If I were to be going for a big roof top A/C or giant inverter (3000+W) then 24v would be much more useful.

Plus, direct wiring up various accessories either I need to go to more effort to find 24v stuff, or need one or more larger buck to 12v for them.

I use a Wander 30 lithium on my ‘it’s a little tiny camper’ rig. Not MPPT, but do you need it? How many panels are you running?

?? Laptops take DC, and DC-DC is way more efficient than 12vdc>120AC>20/30vdc (or USB-C)

I haven’t found a good (and cheap) DC powered induction burner yet, and that’s my main battery load on the camping rig. Inverter is sized to run the fridge/freezer and that’s about it. (aka extended power out I’m going to run some power cords to keep the perishables intact)

My initial use would be for my 2 old house panels I found cheap, >200W each, and I think 56v Vcc. Eventually I’m thinking I might work out a folding/collapsible rigid framework that I can piece together to put on 2-4 or 2-6 ~100W 12v flexible panels, so if I’m just going out for 2 or 3 days without a huge power need, I can just carry/put up a small amount of panels. Going out for a 7+ days out to something like Burning Man, where I’m going to want to recharge my e-bike batteries, night-time light batteries, etc, run a swamp cooler (figure 0.5-1a), etc. Especially if I add a 12v compressor fridge, I’ll want at least 400W is my bet, possibly more.

I figure the flexible panels so that I can flat ‘stack’ them easier. Use some bungee cord from the grommets to the framework and gaps and securely anchor the framework and it’ll even be wind safe.

I’ve vaguely contemplated trying to do a small vertical axis alternator wind generator, but I’d need to be real careful because of the sometimes extreme wind. Need really great bearings, maybe even automatic braking/disconnect to keep it from spinning itself apart. Smaller footprint than 4 or 6 panels, just do 2 panels + wind (assuming meaningful product at a steady 5+mph wind) in the desert is usually going to suffice, unless it’s an unusually calm day.

True, and easy enough for me to get a boost to go from 12v to laptop voltages, but for the sake of easy/simpler. At least initially. Other thing would be charging up power tool batteries, unless there’s a good 12v charger out there I can just buy.

Why are you looking for an induction burner for camping? Or are you trying to be 100% off-grid including all cooking/heating? That’d be quite a load though, might be better to do 24v at least, probably 48v so you don’t have to have extremely big wiring to handle the current.

Solar is a much more sure-fire strategy since you can estimate pretty well what your production improvement will be with each upgrade and there’s no moving parts to break.

If you get wind working I’d consider it a bonus, not a core part of your energy budget.

In my experience so far, the DeWalt car chargers have been rock solid - if expensive. Not sure about other brands.

Oh nice. Should have figured they’d have some car/12v chargers. I should get one or two.

If you can do things without bringing the inverter online, it’s worth doing that. For a 12V system, a car charger for tool batteries, car adapter for a laptop, 12V LEDs, etc, make sense.

As soon as you’ve got an inverter online, though, you’re paying the idle draw penalty of that inverter if it’s used or not. My office 2kVA inverter idles at 30W. My power trailer 6kVA inverter idles at 100W. Once those are on, it’s going to be far cheaper and easier to run 120V stuff. I keep planning to put a DC power bus in my office, but unless I can eliminate literally all the AC loads overnight, it makes no sense to do so.

Definitely why I’m looking at something with a remote on/off, to avoid the no-load penalty. That said…I’ll probably just start with what I have, the 600W, which does have a remote on/off and if I find I ever need/want more I’ll look at upgrading. Even though it doesn’t have any fancy integrated monitoring/usage/etc stuff. It’s really on the charging and DC side that I care about that, what’s actually going in and out of the battery.