Inverters with remote wire

[johntaves]

I am reviewing the Samlex, Magnum, and Victron offerings in order to understand the difference between low frequency and high frequency types. I hope to have a rough guideline for comparing the surge ability thus a rule of thumb to adjust their wattages (e.g. maybe a 3000w HF is similar to a 2000w LF).

Also, I am trying to get a feel for what the charge circuit and logic costs. My theory is that without lead acid requirements, the charger is much simpler and thus less costly.

(I am not interested in transfer switch (2 AC inputs), continuous power during switch over, combining of the AC loads, prioritizing the different loads)

--------Samlex
Samlex has gaps in their line, for example there is no 3000w 24v inverter/charger, but they have a 3000w 24v inverter.

PST-2000-24 is about $600 (just an inverter)
EVO-2224 is about $1100 (2 AC input, inverter, charger)

Both are 2000w 24v and thus this supports my belief that the charger and associated logic for dealing with lead acid is not a trivial addition to an inverter, although the EVO has a transfer switch too.

Samlex has a PST-3000-24 for about $850.
-----------Magnum
Magnum has:
MS2024, inverter charger: $1500 but this is a low frequency type that puts out 8000watts at 1ms and 4000 watts at 100ms
High frequency csw2024 inverter only: $700 has a max surge of 4000watts (I assume this is equivalent to the 1ms. Their spec sheets seem to detail the surge power of the LF units but just list the max for the HF units.)

They don't have a HF 3000w 24v inverter that I can compare the cost to the LF 2000w. I suspect these would have more comparable surge capabilities.
-----------Victron
They don't really have any high watt 24v inverters for 110v. The big Phoenix units are 220v. So I am unable to learn much from Victron's offerings. Either I replace my multiplus compact with the multiplus, or I don't get victron

---------------Summary
My impression is that to start a fridge and AC units, the 3000w cheap ones would be similar in performance to the 2000w low frequency units, but sadly, as soon as you get up in price, they throw in the damn charger which elevates the cost even more

I will see if I can find similar stuff from the chinese units

 

[dgjonesy]

What options do some of you guys have

I use this 12V 2000W Renogy inverter with my ElectroDacus SBMS0 and am able to have the SBMS0 turn off the inverter when battery drops below a programmable SOC.

I can’t vouch for the quality of this inverter as I haven’t used it much but when testing it has no problem with my 1500W heat gun turned up all the way

 

[Craig]

Good work! If you just need AC and rerigerator get the wzrlb/reliable. It will work fine the question is for how long. If you want better reliability get the samlex inverter only models. Twice the cost but worth it long term in my opinion. Looks like you do not need a magnasine or evo inverter/charger

 

[johntaves]

I looked up the specs on my AC units. They have a 50amp (@120v) max locked current. I assume this happens for a fraction of a second while the motor starts moving. This is 6kw, so a 3kw inverter that surges to 6kw is not going to cut it.

WZRELB brand on amazon (A.k.a "reliable" and Yueqing Reliable Electric Co):
All are 24v
3k 17"x10"x4" $350
4k 21"x10"x4" $500
5k 21"x14"x5" $550

None of these have a remote power control, but the power switch is a position switch, and I am comfortable rigging up a relay in place of that switch.
The specs say 1.5A no load draw, but I have not found different numbers for the 12v vs 24v units. I assume it is 1.5A @12v (18w)

Low Voltage Shut Down

9-10v/18.5-20.5v/41-43v

I cannot tell if this is adjustable, or just "hey, we'll shut down somewhere between 18.5 and 20.5 depending on the mood of the inverter"
However, 20.5 for a max voltage shutdown seems low to me. That's 2.5v on each cell. I would rather have the inverter shut off before the BMS kills it and nothing critical will be running from the inverter, so no harm in shutting off well before low batteries.

They say they have smart fans, so in theory they are not loud when things are cool.

I figure that if I am careful about making sure the fridge and water heater are off, I should be able to start the AC with the 4k unit. I doubt I will use the AC very much.

 

[Dzl]

I am reviewing the Samlex, Magnum, and Victron offerings in order to understand the difference between low frequency and high frequency types. I hope to have a rough guideline for comparing the surge ability thus a rule of thumb to adjust their wattages (e.g. maybe a 3000w HF is similar to a 2000w LF).

Some good info on LF and HF inverters scattered throughout this thread. From the bit of research I did HF inverters = 200% surge for a few milliseconds. LF inverters seem to often be able to handle 300% for a few milliseconds, but can also handle lower surges for longer periods of time, the Samlex Evo for instance can handle a 140% surge for 1 minute.

 

[Steve_S]

Inversion Methods Explained: High Frequency vs Low Frequency | Magnum Dimensions

Understand the difference between high frequency and low frequency inverters with this quick article.

www.magnum-dimensions.com

 

[johntaves]

I have researched more regarding the High Frequency vs Low Frequency and feel that I can spot them without trouble.

If it is square in 2 of the 3 dimensions, then it might be a low frequency unit. The low frequency transformer is a big heavy doughnut that demands a square section. If the thing is thin in one dimension, it is certainly a high frequency unit. The high frequency ones always state that they have double the rated watts for surge. The low frequency ones usually brag about how long they can maintain excess wattage. The LFs are heavy at about 60lbs. The internals of an HF unit is much more busy than an LF. The LF will have the big doughnut then some ordinary circuit board. The HF will have several transformers and heat sinks and mosfets and bla bla. Surely the HF has to be less reliable just because of the part counts, but if it is designed right, you shouldn't be able to break either.

I am thinking that a 2000w LF unit would be just fine for my 1600 watt air-conditioner, and a 4000w HF unit would be acceptable (maybe the exact break even is somewhere at 2/3.5). Of course this applies for just about any dumb (no soft start) motor.

I am also concluding that nobody has made something that works well for the Electrodacus style BMS where no amps go through it. With the in-line BMS you essentially are matching all your components, or rather the BMS is sized for your biggest amps. The inverter/charger will handle a certain amperage and the BMS had better handle that. The solar cannot pump in more either. With the Electrodacus, the BMS can survive whatever upgrades (except jumping to 48v) you can throw at it. This makes total sense to me because the inverter depends on what loads you will put on it and really has nothing to do with the battery capacity or solar panels. The solar and battery capacity really depend on what climate you are in. If I was exclusively in AZ, I would have half the battery and half the solar and would not bother with a charger. In the pacific NW, I have more panels and more battery. I want to be able to run the batteries up if the sun makes an appearance so my ratio of load amps to charge amps is going to be a different mix than other situations. I also want a charger just in case for when the sun disappears for months. I will just plug in for an hour to add an arbitrary amount of charge.

I also get the sense that they are using some common components to build these things. Some youtube videos show how you can build your own inverter. At the core is a common $8 board that generates the "pure" sine and takes feedback from the output to adjust. So, for example, I have found some 200-300$ LF inverters from Alibaba and they have the same protections (low volt, high current, etc) but are "hard wired". The more sophisticated ones add on a controller that can set those values dynamically. However, those more sophisticated ones always have chargers built in and were designed for lead acid. I need to figure out whether the charger functionality is symbiotic to the inverter or simply sharing wire connections.

EDIT: yes, of course the charger is symbiotic with the inverter. They use the same transformer, just in reverse, right? So, yes, a charger/inverter in one is going to be cheaper than two separate ones.

I am highly tempted to get one of those LF 3000w beasts for $250ish and open it up and figure out how to adjust the low volt cut-off and wire in the signal from the BMS to shut off. The representative that has these inexpensive LF units was telling me that they can charge LiFePo4, but they are assuming that there is a BMS in series such that the amps goes through the BMS allowing the BMS to kill the power when individual cells are out of whack. They seem to have no awareness of the Electrodacus design.

Summary:
1) the inverter certainly has a low voltage cut off because it was built from that same DNS, and therefore I want to set it as a backup cut-off if the BMS dies. I also want the inverter to be shut off by the BMS. And that should be a very simple thing to have.
2) the charger just needs max current setting, voltage setting, and high voltage cut-off (for redundancy) and BMS signalled shut off.

 

[johntaves]

After much searching I concluded that there aren't a lot of good reviews. Almost nobody plops an oscilloscope on these. I had 2 choices.

1) A LF 3000w 24v 120v inverter/charger.
AMPINVT $600 --
EDECOA $220 -- one reviewer showed how his computer and tablet behaved like crap with this. I concluded it has a noisy wave. If I had an oscilloscope I would have bought this and returned it if I did not like it's output. It seems believable that many people buy this and have no problems because their computer manages to not freak out from that noise. It also seems logical that they are lacking some expensive inductor that does the final smoothing.
Sungoldpower $660 which seems to be built by this Chinese company They wanted $250 for same, but $400 shipping.

I concluded that I was not confident I could wire in an on/off for both charge and invert. These seem to have momentary switches or in the case of the AMPINVT a 2 position switch which seems identical to my current Victron Multiplus Compact.

2) WZREBL HF 4000w 24v 120v inverter
There are a ton of HF choices and I had trouble finding reviews where they actually took it apart and put an o-scope on it. So, I stuck with WZREBL.
I found this on ebay and bought it for $406 + tax.

Thinking:
a) It has a simple position switch for power, so I am confident I can put the SBSM0 signal in series with that switch to turn it on/off
b) I found a review of the WZREBL that compared the 4000w to the 3000w version and the dude felt the 4000w looked like if the 3000w was rated correctly, then the 4000 was probably closer to 4500w given the mosfets. However, as usual, he did not plug the thing in under load and watch the wave and heat. Ugh. So, yea, this is an idiotic warm and fuzzy belief of mine that the 4k unit is more capable than it's rating says.
c) I found another review of a WZREBL inverter of 800w where he liked the wave and performance under load.
d) I am concerned about these units slow start. With an inverter/charger that has the ability to switch the mains to the output, they also will switch on the output when the voltage is up to spec. The WZREBL (and probably any invert only unit) does not have that relay and therefore the AC will ramp up for a few seconds.
e) the LF units are 60lb. The HF are less than half that. This means I can mount the lighter unit on the ceiling of my water bay, which will move any noise away from the interior.
f) I was torn between the 2 main choices, because I felt I wanted the charger and auto transfer. However, I will get the mean well 7500-24 charger if I conclude I want a charger. In other words, the inverter + charger is the same as the LF units, but without the auto transfer and about the same cost. I realized that I could not care less whether the mains goes straight to the loads or going to the converter and then through the WZREBL.

The charger will only deliver 660w, so it won't be able to keep up with the air conditioner @ 1600w. However, I don't see why I have mains and it is hot enough that I need AC. If it is hot, then I have sun, and my solar should do the trick. I will probably get a transfer switch that will let me easily move the AC units to/from the mains/inverter.

 

[Steve_S]

Your fighting two different issues and lack some clarity.
Pure Sine versus MOD Sine or Square Sine. First things first. Pure Sine is what is needed to run fine electronics, even advanced LED Light Bulbs, TV's & Computers. Square & Mod Sine will cause interference & noise, and can damage fine electronics. NOT great for motors either (think compressor on fridge) which will buzz and make noise & heat shortening it's life.

Low Frequency vs High Frequency. Low Frequency uses large Iron Core Coils (that's the heavy part) for conditioning the power. They provide 3X surge capacity as well for a 4000W Inverter will do 12,000W surge. These are by far the best solution for all uses. The HF Units use MOSFETS and other electronics to accomplish the Pure Sine but can ONLY DO X2, so a 4000W Inverter will only be capable of 8,000W surge and they are intolerant to overloads. These are commonly referred to as "Car Inverter's" as they are not intended for 7/24 serious use.
REF TO THIS for clarification:

Inversion Methods Explained: High Frequency vs Low Frequency | Magnum Dimensions

Understand the difference between high frequency and low frequency inverters with this quick article.

www.magnum-dimensions.com

 

[johntaves]

Your fighting two different issues and lack some clarity.
Pure Sine versus MOD Sine or Square Sine.

I am aware of the difference and paid no attention to modified sine inverters.

Low Frequency vs High Frequency....

Yes, I agree. I read that article the first time you posted it. My last post was comparing a 3kw LF to a 4kw HF, which are somewhat equivalent in their surge capability.

Oh, I see the issue. The EDECOA is NOT a low frequency unit. I got it confused with another. Now I cannot edit the previous post. My bad.

not intended for 7/24 serious use.

Um.... I don't think the electricity really knows the difference between serious use and non-serious use, nor do I.

If we look at the things we can compare, there is really not a lot to go on.
1) rated capacity and features
2) components -- We can spot the difference between the HF and the LF fairly easily, but sadly we have tremendous difficulty doing more than that. Any one of these LF devices might have a great lump of an iron core coil that's wound like crap, or has other circuitry that is crappy. The same of course applies for HF.
3) part count -- certainly the part count of the LF is a huge benefit compared to the HF. When you have fewer parts, you have fewer things to fail.
4) reviews -- The reviews on amazon are largely useless. These can vary from "it worked" to more detailed failures. However, we can't really tell whether they are shills or not. "Verified purchase" means little if the seller paid their neighbor to buy one.
5) youtube reviews -- Most are useless unboxing BS, where they tell you about the paint, how to attach wires, and then plug some lame load on it. There are some where they take it apart and talk about the MOSFETS or whatever. Some put a big load on it and showed the wave. Some put inductive loads on it. However, none paid attention to the surge capability with any scientific attention. At best they were like "It started my saw!".
6) brand -- Branding is so tied to emotions and other subtle stuff that has nothing to do with the lump of metal. I ignored that, along with other non serious things.

Which means that I also ended up ignoring units that were significantly more expensive than others. My current Victron Multiplus Compact 24/2000 was over $1000 and is a HF and I am reasonably sure that the $450 replacement will take more loads. I have serious problems paying more than 2x to get the name Victron without any way to judge whether I am getting better performance or longevity.

 

[johntaves]

1) A LF 3000w 24v 120v inverter/charger.
EDECOA $220 -- one reviewer showed how his computer and tablet behaved like crap with this. I concluded it has a noisy wave. If I had an oscilloscope I would have bought this and returned it if I did not like it's output. It seems believable that many people buy this and have no problems because their computer manages to not freak out from that noise. It also seems logical that they are lacking some expensive inductor that does the final smoothing.

Wrong! The EDECOA is a high frequency inverter. Sorry about that.

 

[JoeHam]

So I use 48v but....

I have used a WZRELB 3kw model for 4 years to run sensitive electronics equipment without problem. I just got another 1.5kw one to run my home office equipment and expect years of trouble free use there as well.

I have another application which will require running dual 120v ac motors, 3/4 HP each and a load to get started. For that application I didn’t even consider using WZRELB.

Here is my current choice for that:

Sigineer 48v inverter. 3kw, 120 ac

Anyone have experience with or a reasoned opinion on this inverter? https://www.sigineer.com/product/3000-watt-inverter-charger-48-volt-110v-120vac-pure-sine-wave/ The price is decent and I like that it can go up to 9000 watts for 20 seconds supposedly. I need to start/run dual 120v 3/4 HP...

diysolarforum.com

 

[johntaves]

Besides the product saying that it will do 3kw and surge to 9kw, is there anything that gives us confidence that these units will actually do that for years? I mean if I take a 3kw inverter and plop on a 3kw load, will the damn thing run for years with that load?

I'll bet everyone will say "NO!" and will tell me about the heat and such, but then what is the expected 24/7 load capability? Similarly, if it says it will surge to 8kw, and I start up some motor that has a locked amp rating that puts 8kw load at the start, how many times per day, week or whatever are we expecting that inverter to faithfully take that load? Is there some inflection point where X amp rated parts are going to last a lot of years with X/2 amps, but over X/2 it longevity falls off a cliff?

 

[Craig]

I have no clue really as to what the answer is.
I would suspect that an inverter could handle 1/3 load forever.
Im sure nothing can run at max load forever. I mean my car red lines at 7000 rpm doesn't mean i can run it at 6900 rpm forever. (These numbers are made up for analogical reasons)

 

[Nickatony]

John,

Have you received your inverter yet? Have you had issues with the WZRELB?

I sincerely appreciate you documenting your frustration and all that you have learned about your experiences when selecting an inverter.

I am in a similar situation; I have a SBMS0, and I am researching "no-frill" inverters and drawing many similar conclusions as you are. I am curious as to how well the 3kW HF inverters would handle an inductive load for a 500W air conditioner.

Let us know how things are progressing.

Thanks,
Nick

 

[johntaves]

John,

Have you received your inverter yet? Have you had issues with the WZRELB?

I sincerely appreciate you documenting your frustration and all that you have learned about your experiences when selecting an inverter.

I am in a similar situation; I have a SBMS0, and I am researching "no-frill" inverters and drawing many similar conclusions as you are. I am curious as to how well the 3kW HF inverters would handle an inductive load for a 500W air conditioner.

Let us know how things are progressing.

Thanks,
Nick

I bought the 4kw WZRELB. $460 on ebay shipped to me.

1) I realized my victron multiplus compact 24/2000 is a low frequency unit. Even though it is rated at 2kw and 4kw surge. My opinion is that Victron underrated it. Neither unit will start my air conditioner. I started it from home power, then turned on the WZRELB. I now have 2 transfer switches in series. The second thinks my WZRELB is a generator so it waits many seconds before it switches it in, so I am sure it was up to 120v. As soon as the transfer switched in the WZRELB, the AC died. The WZRELB showed 70 volts on its AC meter. I have not tried that test with the Victron. I might. This is annoying because the locked amps of the 2 motors in my AC should require 7kw and the WZRELB should surge to 8kw, so you'd think that it is very close to starting the AC. I expected it to be able to take over a running AC.

I am torn up about this. On the one hand, I feel like getting a 4kw low frequency unit. They are about $650. On the other hand, why not get a $300 soft start thing for the AC? This would reduce the surge amps needed and allow faster blow fuses/breakers in the wiring, which would feel safer. The bigger unit would be a lot heavier and that would be a problem in my water bay of the RV where I am putting the batteries and inverter.

I compared my Victron to the WZRELB at starting my small table saw. Both spun it up slower than home power. It seems like the Victron started it a bit faster.

I turned on my water heater which should be 1440 watts, and a 1500watt space heater. The WZRELB showed 118 volts and powered those for several minutes before I got bored. I measured 150amps from the 24v battery which agrees with 3kw of power plus some waste.

2) I had to pick out some hot glue that holds the power switch in the WZRELB and was then able to push it out the front. I had no trouble soldering in series some wires. However, others have reported that the elctrodacus SBMS0 opto isolators (relays) fail to provide enough current to power them properly. Dacien says that the LED volt meter on the inverter is wired in series with the switch and recommends cutting the wire to it. Because I am not sure I will keep the WZRELB, I bought a 1amp relay that is used to trip the WZRELB. I measured a fluctuating 80mAmps through the switch, so I suspect it peaks over 150mAmps which is the SBMS0' opto isolator's max.

(Note: Dacien's instructions say to wire the switch in parallel, which seems idiotic to me. If the switch is turned on, then the SBMS0 cannot turn the unit off. So a parallel switch is useless, but could be mistakenly put on and kill the batteries. If in series, all makes sense. His argument was that it was easier to solder 2 leads onto the switch. So what, do it right.)

I made a little board that has screw connectors for all the signal wires. I added the relay to it. This board is basically an easy connector spot for: 2 remote switches (for the DC/DC converter and the inverter), 4 signals for the 2 loads and 1 charger and PV from the SBMS0, and 4 signals going to same loads.

The SBMS0 is very annoying in that the EXT IO3/4 are little push in connectors, but EXT IO5/6 require you to solder in a connector to the main board (included) but it uses a ribbon cable. Dacien needs to clean this up and make all outputs available via the same port. Unless I put 3 more relays on my little circuit board, I need all 4 EXT IOs because all 4 charge/loads are different electrical characteristics.

3) I measured 1amp at idle for the inverter (24watts), which seems reasonable to me.

4) The "smart" fan is not the smartest. It is either on or off. When on, it is somewhat loud. It was going on and off with a period of many seconds. I mounted it in the water bay, which is below the main floor of the RV, so I think it will be reasonably quiet there. The Victron had essentially the same sized fans and thus was equally noisy when under load. I don't know the efficiency comparison between the two, or between an LF vs HF. So I assume that a LF unit, with the bigger case could have a bigger fan that could run slower and if the LF unit is more efficient, then it does not have to dissipate as much heat.

In summary, I think I will stick with the WXRELB. I don't relish the idea of taking a chance on a bigger unit. The struggle of fitting it is not worth it and the odds of making a mistake with respect to the remote power switch capability is not worth it.

I could have kept the Victron, but I suspect I will be able to sell it for at least what I paid for the WZRELB. I feel like the WZRELB should handle more resistive loads.

 

[Nickatony]

I bought the 4kw WZRELB. $460 on ebay shipped to me.

1) I realized my victron multiplus compact 24/2000 is a low frequency unit. Even though it is rated at 2kw and 4kw surge. My opinion is that Victron underrated it. Neither unit will start my air conditioner. I started it from home power, then turned on the WZRELB. I now have 2 transfer switches in series. The second thinks my WZRELB is a generator so it waits many seconds before it switches it in, so I am sure it was up to 120v. As soon as the transfer switched in the WZRELB, the AC died. The WZRELB showed 70 volts on its AC meter. I have not tried that test with the Victron. I might. This is annoying because the locked amps of the 2 motors in my AC should require 7kw and the WZRELB should surge to 8kw, so you'd think that it is very close to starting the AC. I expected it to be able to take over a running AC.

I am torn up about this. On the one hand, I feel like getting a 4kw low frequency unit. They are about $650. On the other hand, why not get a $300 soft start thing for the AC? This would reduce the surge amps needed and allow faster blow fuses/breakers in the wiring, which would feel safer. The bigger unit would be a lot heavier and that would be a problem in my water bay of the RV where I am putting the batteries and inverter.

I compared my Victron to the WZRELB at starting my small table saw. Both spun it up slower than home power. It seems like the Victron started it a bit faster.

I turned on my water heater which should be 1440 watts, and a 1500watt space heater. The WZRELB showed 118 volts and powered those for several minutes before I got bored. I measured 150amps from the 24v battery which agrees with 3kw of power plus some waste.

2) I had to pick out some hot glue that holds the power switch in the WZRELB and was then able to push it out the front. I had no trouble soldering in series some wires. However, others have reported that the elctrodacus SBMS0 opto isolators (relays) fail to provide enough current to power them properly. Dacien says that the LED volt meter on the inverter is wired in series with the switch and recommends cutting the wire to it. Because I am not sure I will keep the WZRELB, I bought a 1amp relay that is used to trip the WZRELB. I measured a fluctuating 80mAmps through the switch, so I suspect it peaks over 150mAmps which is the SBMS0' opto isolator's max.

(Note: Dacien's instructions say to wire the switch in parallel, which seems idiotic to me. If the switch is turned on, then the SBMS0 cannot turn the unit off. So a parallel switch is useless, but could be mistakenly put on and kill the batteries. If in series, all makes sense. His argument was that it was easier to solder 2 leads onto the switch. So what, do it right.)

I made a little board that has screw connectors for all the signal wires. I added the relay to it. This board is basically an easy connector spot for: 2 remote switches (for the DC/DC converter and the inverter), 4 signals for the 2 loads and 1 charger and PV from the SBMS0, and 4 signals going to same loads.

The SBMS0 is very annoying in that the EXT IO3/4 are little push in connectors, but EXT IO5/6 require you to solder in a connector to the main board (included) but it uses a ribbon cable. Dacien needs to clean this up and make all outputs available via the same port. Unless I put 3 more relays on my little circuit board, I need all 4 EXT IOs because all 4 charge/loads are different electrical characteristics.

3) I measured 1amp at idle for the inverter (24watts), which seems reasonable to me.

4) The "smart" fan is not the smartest. It is either on or off. When on, it is somewhat loud. It was going on and off with a period of many seconds. I mounted it in the water bay, which is below the main floor of the RV, so I think it will be reasonably quiet there. The Victron had essentially the same sized fans and thus was equally noisy when under load. I don't know the efficiency comparison between the two, or between an LF vs HF. So I assume that a LF unit, with the bigger case could have a bigger fan that could run slower and if the LF unit is more efficient, then it does not have to dissipate as much heat.

In summary, I think I will stick with the WXRELB. I don't relish the idea of taking a chance on a bigger unit. The struggle of fitting it is not worth it and the odds of making a mistake with respect to the remote power switch capability is not worth it.

I could have kept the Victron, but I suspect I will be able to sell it for at least what I paid for the WZRELB. I feel like the WZRELB should handle more resistive loads.

John,

Thanks for the update, I hope that people will come across this in the future when it comes to finding the right inverter for a SBMS system. I was pretty worried after hearing the the WXRELB inverters had trouble spinning up A/C compressors. It's nice to see a real value for the idle consumption too. As far as the EXT IO5/6, I plan on soldering directly to the rear of the board instead of using the included connector because I do not have the female pins.

Due to cost/time, I am going to end up trying to use my Giandel 2kW unit, which seems to be a bit of a different design than most of the other Chinese inverters. I have not tested it on my air conditioner yet.

The only issue is that I can't simply use the EXTIOx pins on the SBMS0 because it is a momentary-type switch. I will try to program an Arduino, powered off of the 5V USB of the inverter, to cycle a relay in parallel with the momentary switch when the EXTIOx opto is open. This will allow me to power down the unit but not power it back up, saving my expensive batteries, but risking spoiling my food in my refrigerator. ?‍

-Nick

 

[gnubie]

I'm late to the party but someone might find this useful anyway.

I have a couple of Giandel inverters, both 24VDC > 230VAC (single phase no 115VAC), one is 2kW, the other 3kW. Why two? In case one fails the other can be put to use and life continues. So far they have worked completely within expectations. They are HF inverters and exhibit the usual sag / slow rise all of these cheapies do when hit with a high current draw but beyond that they run everything I want them to. The 3kW is the primary and holds up my desktop computer, standard domestic 250l inverter fridge, (microwave oven (1.2kW from the outlet) or 2kW electric kettle), tv etc without complaint (as it should considering the power rating!). Overnight it runs my bedroom Fujitsu reverse cycle inverter (USA will call this a heatpump) split aircon.

I know highly inductive high draw loads can give cheap HF inverters grief letting the smoke out but I haven't tried to blow up my Giandels in this way, so I can't comment how they would cope with it.

Internally both inverters aren't a tin of spaghetti when it comes to wiring but as expected use the cheapest electro capacitors they can get their hands on so I expect that will be the point of failure in time, perhaps taking out transistors in the process.

They have remote soft-on support via a simple 4 wire connection. 1 wire for the button, two for status LEDs, one for ground. I have a $5 arduino board monitoring the battery voltage since the LV cut off for the inverter is below the LV cut off for the BMS and I prefer to not have the BMS potentially switching high currents if it can be avoided. The control logic is quite simple. If the desire is to turn the inverter on, check power LED status, if off, pull button line to ground until the power LED turns on and then release. To turn off, check if power LED on, if so, pull button line to ground for 250ms and release. If the fault LED is lit the arduino will not attempt to turn the inverter on. The arduino is isolated from the inverter with 3 opto-couplers.

 

[Nickatony]

I'm late to the party but someone might find this useful anyway.

I have a couple of Giandel inverters, both 24VDC > 230VAC (single phase no 115VAC), one is 2kW, the other 3kW. Why two? In case one fails the other can be put to use and life continues. So far they have worked completely within expectations. They are HF inverters and exhibit the usual sag / slow rise all of these cheapies do when hit with a high current draw but beyond that they run everything I want them to. The 3kW is the primary and holds up my desktop computer, standard domestic 250l inverter fridge, (microwave oven (1.2kW from the outlet) or 2kW electric kettle), tv etc without complaint (as it should considering the power rating!). Overnight it runs my bedroom Fujitsu reverse cycle inverter (USA will call this a heatpump) split aircon.

I know highly inductive high draw loads can give cheap HF inverters grief letting the smoke out but I haven't tried to blow up my Giandels in this way, so I can't comment how they would cope with it.

Internally both inverters aren't a tin of spaghetti when it comes to wiring but as expected use the cheapest electro capacitors they can get their hands on so I expect that will be the point of failure in time, perhaps taking out transistors in the process.

They have remote soft-on support via a simple 4 wire connection. 1 wire for the button, two for status LEDs, one for ground. I have a $5 arduino board monitoring the battery voltage since the LV cut off for the inverter is below the LV cut off for the BMS and I prefer to not have the BMS potentially switching high currents if it can be avoided. The control logic is quite simple. If the desire is to turn the inverter on, check power LED status, if off, pull button line to ground until the power LED turns on and then release. To turn off, check if power LED on, if so, pull button line to ground for 250ms and release. If the fault LED is lit the arduino will not attempt to turn the inverter on. The arduino is isolated from the inverter with 3 opto-couplers.

Gnubie,

You have definitely piqued my interest. You wouldn't happen to have any schematics or parts list laying about for that, would you? How did you power your arduino?

I was probing around the "remote" portion and was getting some weird readings with respect to the voltages. I'd be interested to hear more about how you accomplished that!

Thanks,
Nick

 

[gnubie]

No circuit diagram, but I could sketch something up. There's really not a lot involved though.

Going into the project I used a standard multimeter to check voltages and that's when I decided to use opto-couplers to keep the arduino away from the Giandel as the voltages are all over the place and certainly not TTL 3.3/5v compatible.

The optos that monitor the status LEDs just have their LEDs in parallel with the status LEDs, there is enough current available to drive them as is. I set the Arduino pins I use to monitor them to have their pullups enabled in input mode which let me get away without an external resistor to pull them up and just rely on the opto coupler to pull them down to ground when the status LEDs are on.

The Arduino itself is run via an ebay buck converter direct from the battery. The draw is so low that there's no need, IMO, for any sort of undervoltage lockout on the buck converter as the Arduino etc has such low draw that it'd never be responsible for taking the battery low enough for the BMS to setu in anyway.

I ran a meter over the button pair just now and for my 24VDC input inverter, off shows battery voltage across the button, on shows 14.4v across the button.

*edit*
Battery voltage is sensed with a simple resistor divider connected to an Arduino pin set to analogue in mode.