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travellerw
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# Posted: 24 Apr 2023 09:49pm - Edited by: travellerw
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Well.. After 45 different solar plans I find myself with 3 different inverters. Definitely a loss for my pocket book... but a win for testing since I have ended up with 3 "popular" choices of inverters. Since I have the inverters and the testing equipment, I thought "What the hell, lets test them and see if we can confirm or dispel some myths (i.e low frequency = low draw, no name Chinese = high draw, all-in-one = really high draw). So here are the candidates.
1. Novopol 24V 1000W (Chinese Amazon Cheapy).
2. Growatt 48V 3000W All-In-One (Chinese Amazon Cheapy).
3. Victron Phoenix 48V 375W Low frequency inverter
The goal of my testing was to see what each inverters stand-by draw was. This means each inverter powered up and ready for a load, no eco or automatic search mode. Each inverter was powered by a bench top power supply with a DMM in series to verify the power readings from the power supply. Frankly, I found the numbers fascinating.
1. Novopol - 25.6V @ 0.47A or 12.03W
2. Growatt - 51.2V @ 0.89A or 45.57W
3. Victron - 51.2V @ 0.19A or 9.8 W
So it seems that not all the "cheapy chinese" inverters have high draw. Sure, the Novopol was higher than the Victron, but are talking like 2.5w. Trivial considering the higher SUSTAINED load capacity of that unit (I capitalized sustained as the Victron has a crazy high surge capacity being low freq). It seems some of the companies have figured out some good low draw high-frequency circuits.
Victron is Victron though.. It pulled almost exactly what it said in the spec sheet (.2W lower in my test). Its built like a brick dunny and could probably be used as a home defense item if needed (not kidding, the darn thing weighs 3 times the Novopol).
As to the Growatt.... Ya, not great. Almost 50W to just sit there doing nothing is not great. A trade-off for sure though in value. It would be impossible to get an MPPT solar controller, inverter, automatic cut over switch and 80A battery charger as discrete components for anywhere near the price of it (more like 3 times the price). You pay for it in power though.
All in all, still happy with my "current" plan. It means that we can have all the amenities running when we are there on the weekends. However, the Victron will power the cameras and security while sipping power in the times we are away. Still WAY cheaper than a full on Victron solution.
Anyway.. I thought there would be a few people here interested in those numbers.
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gcrank1
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# Posted: 24 Apr 2023 10:10pm
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Always like your 'take' on these kind of things, Trav.
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travellerw
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# Posted: 24 Apr 2023 10:18pm
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Quoting: gcrank1 Always like your 'take' on these kind of things, Trav.
Thanks fella! I enjoy your "take" too. I love to hear how other people are successful as there is millions of ways to skin the cat!
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gcrank1
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# Posted: 24 Apr 2023 11:17pm
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Well, I made toast at the cabin last week, regular 120vac household toaster 600w, iirc, off an inexpensive 750w msw inverter hooked to the 100ah LFP. I will fire up the gen to run the microwave or vacuum but for 'short bursts' like the toaster the gen seemed a bit much. Msw is ok for resistance type devices, I had it so why not try it. I dont leave it on, no need, just switch on when ready.
For everything else we have been doing well for the past couple years with a Bestech brand (supposedly) psw 300w inverter. Stuff that 'complains' when on msw runs fine on this little unit. We run led lights, small old tube TV/VCR combo unit, radio, etc.
Ive become fond of using an inverter fairly closely matched to the draw. The idle consumption is really low (iirc about like a 6w led light).
I run the shoestring 'elec' system, my wife thinks things arent really dif than at home on grid.
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Brettny
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# Posted: 27 Apr 2023 10:00am
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I'm not sure if you can really compare those inverters like that. There wildly different in input voltage and output.
The specs on my xantrax freedom X1200 is about. 0.18a @12v.
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gcrank1
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# Posted: 27 Apr 2023 11:18am
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I take it as not a comparison as much as real-world testing (of what Trav has on hand) rather than just believing the specs.
After this past year of reading online about folks who got aio's or built a component system that sucked most of their available ah's/watts out of the bank mid-winter leaving them literally cold Im leary of marketing claims.
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travellerw
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# Posted: 27 Apr 2023 01:52pm
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Quoting: Brettny I'm not sure if you can really compare those inverters like that. There wildly different in input voltage and output.
Watts are watts.. That is what is really important. Knowing the standby draw in watts.. but yes, it was what I had on hand, and they represent the wide range you find people building with. Input voltage 12, 24, 48 should have little impact on stand-by draw at idle (in watts).
I guess that is why I posted. In many other forums people are throwing out lots of specs and numbers. Some are even testing, but with flawed methods (you will find numbers for the growatt from 15-50W). The only real way to measure is with a DMM in series with the unit (or a very expensive clamp meter). It just helps people understand the differences, even when sizing an inverter.
As to your Xantrax.. Have you measured that with a DMM? That is insanely low (2.4W), especially for an inverter that is only %87 efficient with auto switching. I would be shocked if it actually met that spec (remember, not in auto, eco or hunt, or whatever their name is. Powered up ready to run sub 1w loads). If so, good on them, they have found some magic sauce.
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Brettny
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# Posted: 27 Apr 2023 03:50pm
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You know I never actualy tested it. I do want to put a shunt meter in my system but I have been saying that for 2yrs now.
My inverter does have a standby mode that needs 50w or so to wake up..but sadly if I come in and turn on a LED light it wont wake up so it's kind of useless for me.
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gcrank1
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# Posted: 27 Apr 2023 09:11pm
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Brett, how about having a small inverter (even a cheap msw) for those 'night-lighting' needs so the big inverter can just idle along as long as possible?
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Brettny
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# Posted: 28 Apr 2023 09:27am
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Quoting: gcrank1 Brett, how about having a small inverter (even a cheap msw) for those 'night-lighting' needs so the big inverter can just idle along as long as possible
That is a good idea but my batteries can handle it and I want the system as hands off and as simple as possible. My whole system is in temporary mode right now yet I dont feel the need to change anything. As of now it runs a fridge, lights, charges phones and runs a microwave. When I arrive I turn my system on and power everything up. Even just one sunny day after a cloudy one and the system is charged and the only other time I touch it is to turn it off when I leave.
When it gets put on a cabin my 700w of pannels will be doubled to 1400w and they will have a few more hours of sun.
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gcrank1
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# Posted: 28 Apr 2023 09:26pm
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Sounds like a well balanced set up, kudo's to you!
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travellerw
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# Posted: 1 May 2023 09:41pm
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Yes, sounds like you have a great system that works for you. That is the great thing about DIY solar, if it works for you, then its "right" (of course it has to be safe too).
I was just at the cabin this weekend working on my solar. Back last year I got a kick butt deal on some fire salvaged panels (not burnt). However, stupid me only bought 5 instead of 6. So I decided to keep the one odd one to charge our RV and instead bought 2 new modern panels. I went with some bi-directional panels to see if I could start generating power earlier in the day. I went a little overboard as I now have about 2300W, but I really wanted to run the AC from solar.
Anyway, sigh, just not enough time to get it finished as I also needed to plant the garden. I plan to go out next weekend and I will grab some pics. I would love it if everyone posted pics of their systems. I think it would be great to show the range of systems that are working!
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Steve_S
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# Posted: 2 May 2023 10:19am - Edited by: Steve_S
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Attached is my Version 5 of my build...
An actual Photo & the Logical Diagram.
This is going to change yet again this spring as another Midnite Solar Classic-150 with 2370W Array gets paralleled in for an additional 94A Charge Input.
Extended details, parts used etc can all be found here:
https://diysolarforum.com/threads/my-diy-off-grid-cabin-setup-in-ontario-canada-24vdc -120vac.1484/
V5 Actual system Photo
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V5 Logical Diagram
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offgrididaho
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# Posted: 2 May 2023 01:13pm
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Thanks for sharing, good info. The tough thing I realized is we're never truly at "idle"... there are always wall wart chargers, CO/propane detectors etc etc so the inverter is always inverting SOME power.
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FishHog
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# Posted: 2 May 2023 02:53pm
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Quoting: offgrididaho Thanks for sharing, good info. The tough thing I realized is we're never truly at "idle"... there are always wall wart chargers, CO/propane detectors etc etc so the inverter is always inverting SOME power.
Your right, which is one of the main reasons I ran 12v for all those things and opposed to converting and then inverting for those things that are designed to run on 12v power in the first place. Everyones needs are very different, but 90% of my power load is 12v, so I only use an inverter for that extra 10%. Works well for us but it is a simple system.
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gcrank1
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# Posted: 2 May 2023 03:47pm
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I still charge some of that that small stuff with the car-port cord in the car we have to drive there anyway.
One small PSW inverter has a direct usb charge port always on even if inv is off.
The recent 12v lfp bats that primarily drive the cabin inv also have integral usb ports.
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travellerw
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# Posted: 2 May 2023 06:03pm
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Nice.. Does the system control the generator automatically?
I struggled to find a decent small generator that can be controlled with a dry relay. In the end I designed and built my own custom circuit board to allow auto start/relay control for most small generators. Would be humbling to find out Champion makes an out of the box unit capable of that!
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Steve_S
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# Posted: 2 May 2023 09:25pm
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Sadly, the Auo-gen-Start is not an option with this one. There is an electric start model with auto-choke which I'm sure could be modded but I don't have that one. In my case, it's not a big deal anyway.
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travellerw
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# Posted: 7 May 2023 06:40pm
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Well.. I finally got out and finished the panels and controllers. I still need to trench some conduit for all the wiring, but I had a 30A RV extension cord I bought at auction that is now my temp install.
So far its working better than I thought. On Saturday we ran the heat pump in AC mode completely off the solar (+28C here). Then this morning we ran it again in heat mode (+14 here, sigh, Alberta). My wife was also making breakfast with the toaster and I happened to look at the Victron BMV. We pulled 3.2Kw out of the Growatt/Batts for like 5 min. Technically over the 3Kw rating but it handled it.
Even with those nasty overcast skies I was still able to put about 200W into the batts after the womping we gave them!
(P.S. One thing I don't like about the Growatt is the switching speed (inverter to generator). Its not fast enough and quite a few of our items reset, including the AC).
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