EG4 3kw vs MPP 3048 vs ?

[DirtybumOak]

Hello.

I am at a tossup between the EG4 3kw all-in-one inverter and the MPP 3048. Let me give you a bit of background.

I'm grid tied, and currently I'm over producing ~150kwh/month. I recently bought an EV, and as a result my electrical needs will be going up. Due to being in California, I'm buying power for ~$.30, and selling it for $.08 - so there is a discrepency there. I typically am using power when my PV is not running, as nobody is home during the peak PV hours. My grid tied PV is grandfathered into a Net meter agreement, so my Off-grid setup is going to be on a "solar trailer" - and is very limited in terms of how many panels I can use. I think at most I could squeeze 4x 250w used panels (which I could get for nickels), or 4x 350w panels (which I'd have to buy new). I'm interested in two things...
1. selling less energy back to the grid (ie Storing it!)
2. Being able to charge my EV overnight (~12 hours of charge).
3. We get a brown-out a few times a year, and it would be nice to keep my deep freezer, a refrigerator and modem running. I don't need a lot of juice during a brown out ... 3kw would be excessive.
4. I'd like my standby/idle consumption to be low. Since my PV can't put out a lot, I'd rather not lose a ton of watts for the ~15 hours a day that sun isn't shining on my panels.

I'm on a very strict budget. This lends itself to the math I've been doing regarding battery size vs inverter size. I'm going to be using a 280ah 48w battery - so that gives me ~13kw. I can only produce 5-7kw/day.
1. I only need 3kw during a brown out, and 3kw (even at 75% for inverter health), is sufficient for my EV charging.
2. My Off-Grid PV size is only 1000-1200w/hr and so that means my main bottleneck is PV production.
3. My Excess grid production is only .2 or .4 kw, so again, my main bottleneck is PV production. Even with using the excess grid power, I'm only able to charge my battery to 100% every 2-3 days.
4. I can charge my car for ~12-15 hours a night, which means that I could drain my battery daily. Again, this points me in the direction that I don't need a higher power inverter.
5. If I doubled my battery capacity (+$2k), I'd only need a quarter of that to double my inverter capacity, so economically, my second bottleneck is my battery capacity. Doubling my batteries almost doubles my system cost, so for now I'd like to say that this is not a plausible scenerio.

So in conclusion,
I only need 3kw, I can only use 3kw, and I can't even charge 3kw.... so therefore a 3kw inverter is plenty. If I needed additional output, I could double my system output for $500-800, but doubling my battery capacity would be $2k+

So If I'm really only able to use 1kw constantly (15 hrs/day), whats the better inverter? I'd like to access the grid (to use the .2-.4 kw overproduction) but I don't need to sell back to the grid. I'm only using 3-4 panels, so I (think I) need a low VOC capable system. 120v, with 160v of panels is asking a lot of sun to even start my system, as opposed to 60v of a 160v system. The 3048LV does 60-115v. The EG4 3kw does 120-500v. I can't realistically see a situation where I'd be able to connect more than 4 panels to this system since its an urban off-grid system. I legally have to pull permits for anything attached to any sort of roof, and I'm in an area where they look at these sorts of things.

So far I'm looking at the:
EG4 3kw from signature solar
3048LV from watts 247
and maybe the Pip2424 Hybrid from Watts 247 (Although its 24v, it has a lower VOC of 30v to start my already limited voltage solar system, and technically satisfies my power requirement. Also my battery could be split into 2x 24v batteries as opposed to 1x 48v)

*huddles in the corner as he waits for replies, knowing he probably typed a ton of Newbie/halfThought/Ignorant questions....*

 

[Mark Halvorson]

I have a pair of the EG4 3K inverters, they have been perfect. The setup was easy. The only negative is the monitoring software, that works, but is not the best. I do not know the other inverters you listed.

 

[DirtybumOak]

I have a pair of the EG4 3K inverters, they have been perfect. The setup was easy. The only negative is the monitoring software, that works, but is not the best. I do not know the other inverters you listed.

What idle consumption have you been getting from the EG-4?

For many reasons I'd like to use that one, but the 120v minimum for me would be hard to reach. I have ~160v of panels in series, which means they would need to be at 75% before they even start producing...

 

[Mark Halvorson]

My idle consumption is 50 watts for one and 65 for both in parallel for my EG4. 3000EHV.
The solar panel voltage does not really go up and down with sunlight. Once the sun hits the panels, they go to their voltage. It is the amps that really go up and down with sun. Hot and cold also affects voltage. I think 160 volts will work great.

 

[DirtybumOak]

My idle consumption is 50 watts for one and 65 for both in parallel for my EG4. 3000EHV.
The solar panel voltage does not really go up and down with sunlight. Once the sun hits the panels, they go to their voltage. It is the amps that really go up and down with sun. Hot and cold also affects voltage. I think 160 volts will work great.

Ahhhhhh yes... I knew I was forgetting something. You are right. So that changes my needs slightly.

Have you ever ran them on the power saving or standby mode? My system would mostly be used only when a dedicated load is being used (EV, power tools etc).

 

[Mark Halvorson]

I have never used power saving or standby modes. These inverters and batteries are my main power for my boat that I live on.

 

[Rednecktek]

The 3048's are on sale right now and are pretty tried & trued, can't go wrong. Plus the lower voltage requirements will help with cloudier weather.

 

[Mark Halvorson]

The 3048 is a great price on sale. I have not heard anything about this specific inverter. At that price, it is a good choice.

 

[Rednecktek]

Yeah, MPP has been around for a long time in the AIO world, they just work.

Plus being $200+ cheaper helps with the budget. ?

 

[Mark Halvorson]

Very True. I want a photo once you get it installed

 

[OffGridForGood]

I don't have 3048's but my 6048's are internally twin 3kW MPP inverters, one has run 24/7365 since Feb 2021, the second one since April 2022
I have pushed them hard on many occations, no issues. They draw considerable stand-by power.
That all said, what about a separate SCC to connect PV to battery,
and at night when you need energy you connect the mobile battery to your existing system - or a stand alone small inverter that is off when not needed to cut the standby consumption? at the low numbers your talking an AIO may not be the best answer.

 

[Mark Halvorson]

EG4 Solar Charge Controller MPPT | 500VDC 100A | MPPT100-48HV

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

 

[SignatureSolarJames]

We do include battery cable, breaker and WiFi

 

[Mark Halvorson]

Breakers are built into the MTTP, no WiFi. It is a very simple solar to battery. Easy to control. I have one. Set it once, and let it go.

 

[OffGridForGood]

That all said, what about a separate SCC to connect PV to battery,
and at night when you need energy you connect the mobile battery to your existing system - or a stand alone small inverter that is off when not needed to cut the standby consumption?

At 1200W PV and 3kW output max
I am suggesting you consider separate units for charging and inverting,
Charge controller like an EPever 30A for about $100
and then choose a stand alone inverter to suit your output needs 2-3kW maybe something like the Renogy or WZRELB type small inverters $300-400, and turn it off when not in use.

 

[DirtybumOak]

Well please correct me if I'm wrong. Mark said that the voltage of the system is pretty much constant (varies with temperature), but its the amps that go up and down depending on how much sunlight is hitting the panels in the morning-afternoon-evening. Do I get less volts in the early morning as opposed to at full sun (not talking about temperature here)? Or is it that I get less amps? I live in an area that doesn't have seriously cold or seriously hot weather. 25* is the historical low in my city ... I keep seeing videos/articles about LifePO4 low temperature readings and I just giggle a bit.

If that's the case then my assumptions about a low voltage requirement aren't based in reality. I'd be running 160v (4x~40v panels).

When I've done my math regarding separates, I typically have used Victron as a basis. The cost of Inverter + MPPT (not to mention additional wiring, breakers, etc) doesn't seem to add up to a EG4 or a MPP 3048. A WREZLB alone is $400 vs a $500 3048 or a $675 EG4. EG4 claims 15w in power saving. WREZLB looks like 30-40w which is the same as the EG4 or the 3048, so again no savings there. Renogy is $675 for an inverter/charger with similar idle current. I'll be honest, I'd sleep better with a MPP or EG4 than a Renogy. If it was cheaper I'd consider it, but for the same price I'll give it a hard pass.

If my Voltage vs amps assumptions are correct (that voltage isn't going to change based on Time of Day, its the amps that will....) - the $200 cheaper MPP 3048 downside is that I can only connect 3x 40w panels in series, as opposed to the EG4 I can connect 4x panels (or way more). Everything else points to the EG4 (idle at standby, ability for more PV, etc)

The other question is with the BMS ... If I'm only using a 3kw inverter, and the highest load I'd be looking at is 1600w, then I'm OK with a 60A BMS, right? 10 amp solar charge (at most 20 if I went parallel in the future), and 10a from utility. 30A @ 48v is the max I could charge a battery from the utility in an emergency based on the fact that my home is mostly on 12a 120v breakers. So in terms of charge, I think I'm well below the 60a.

 

[Rednecktek]

If my Voltage vs amps assumptions are correct (that voltage isn't going to change based on Time of Day, its the amps that will....) - the $200 cheaper MPP 3048 downside is that I can only connect 3x 40w panels in series, as opposed to the EG4 I can connect 4x panels (or way more). Everything else points to the EG4 (idle at standby, ability for more PV, etc)

Yes, but if you ran 4 panels you could do 2s2p and the big advantage is that you only need to hit about 60v on a string to start the MPPT charging on the 3048 whereas the EG4 your panels need to get up towards 100v before anything starts happening so in cloudy weather it's a bit of a toss up. The 3048 has a bit less standby consumption than the EG4 so that is something to consider. Since you mentioned you can only fit 4 panels you're pretty much capped on production either way so the standby becomes more of a factor.

I've seen many times here in the Seattle area where a single panel once it's under load pulls the voltage down to the point where the MPPT can't do anything with it and going to a 2s string gets it up high enough to start charging a 12v system. In clear sun the voltage hits peak pretty easily before the amps really can ramp up, but there is a minimum threshold involved.

Either one is a good option, I was just commenting on my thoughts based on budget between the two options.

The other question is with the BMS ... If I'm only using a 3kw inverter, and the highest load I'd be looking at is 1600w, then I'm OK with a 60A BMS, right? 10 amp solar charge (at most 20 if I went parallel in the future), and 10a from utility. 30A @ 48v is the max I could charge a battery from the utility in an emergency based on the fact that my home is mostly on 12a 120v breakers. So in terms of charge, I think I'm well below the 60a.

Well, in napkin math you'd want to plan for full load plus overhead, so 3000w / 48v = 62.5a * 1.25% = 78.12a, or an 80a breaker to be sure you can run the startup surge on an air compressor or skill saw or the like and still be good to go. You'd need a battery with a 100a BMS at least, no point in trying to source one that's an oddball size as 100a is pretty standard.

As to the charging napkin math it'd be 48v * 30a = 1440w / 120v = 12a continuous load which is pretty much the max for a standard 15a circuit in the States. In a perfect world you'd have a 30a AC utility line just so it can do full battery charging while still supporting the output of the AIO. That's often why you'll see recommendations for 2x the capacity for generators.

 

[OffGridForGood]

It is true that the voltage even on cloudy days typically runs close to 'normal' and it is the amps that go for a crap until the sun comes out. In this senario of the OP likely 2S-2P will work best, but it will depend on the other equipment selections.
Working with only 1000-1200 W of PV is a severe limitation on this proposed system. My suggestion (only a suggestion) to consider separate equipment rather than assume an AIO is the way to go, is based on the idle consumption. A typical AIO could use 800W per 24-hr day, likely 20% of their available sunny day PV input, now imagine a couple cloudy days in a row and it looks like too high a price to pay in idle consuption. A separate inverter that is off 16-hours per day, and only on-8hrs during use at night may be a better option.
Some of the AIO allow solar charging while 'off' and I would assume this would drop the idle consumption to near zero as well, but I don't know that for certain. I agree the AIO options are typically less money than separate SCC and Inverter, however saving a few dollars only to see all the collected Watts dissapear as idle consumption seemed to be a good case to consider options that would avoid the Idle losses.

Considering an option is just that, look at the possible consequences, costs, how it may operate compared to alternatives, in your situation, and then dismiss this option or not depending on what your analysis reveals, and what the available options are.

In addition to my main system (discribed in my signature block) I run a smaller portable set up using 24v and MPP 2724 (which can charge battery while inverter is off) and I get a lot of use out of this small mobile set up. The 2724 cost me about $600USD and I built a DIY 304Ah 24v battery to go with it for another 1,200. The 2724 is limited to about two PV panels max, but the portablility makes this set up handy for RV, Camping, and it is out in the greenhouse right now running lights and control system.