Is anyone using an arc welder with an offgrid system

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hary
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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Fri, 10 May 2019, 03:19

Hi Dave.

It seems you are THE man that has faced any offgrid situation !

So unlucky you're not in France anymore, it would have been a pleasure to talk and share with you.

You had a 3.5HP vacuum cleaner ? Even at my factory I don't think we have such a big vacuum cleaner !
Harold.

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Fri, 10 May 2019, 03:28

Dave,

You said earlier "I have successfully designed inverters to several kilowatts"

<<So, what's the reason that decided you to buy this present LF inverter, instead of building your own ?

Your ZOE charger should have an inrush current limiter if well designed ? If so, why didn't you choose an HF inverter instead ?

Harold.

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Fri, 10 May 2019, 05:22

Hi hary,
This LF inverter is cheaper than I could design and build. Maybe I could assemble the parts for that cost but even that is doubtful. Then factor in testing, blowing up a few parts etc- I have other things I wanted to do with my time. The maximum I have done myself is 3KVA but I wanted around 5kVA with surge capability. I looked at several HF inverters but ones in this price range had inadequate terminals, busbars and I am by no means certain that they would have a long life. I have been sufficiently busy with the BMS and efficient charging. I also decided that if I blow this up, I'll redesign some of it myself including the incorporation of "Magic Sines" (which you can Google) which I have found very successful in the past.

Yes, Zoe has no inrush. The current builds up from about 3amps over several seconds.

The second purpose for this inverter is backup when the grid fails. I expect this will become more frequent with Australia's appalling lack of strategy and planning in the electricity sector. Indeed, they have sold off most of the generation, most of the "poles and wires" and what's left is a mess. There are so many "middlemen" each making a profit. Plus some amount of the profit goes to offshore tax havens. Just in my area, there are about 30 electricity "retailers" who offer little value and just take a percentage of the dollars. No wonder we have very expensive electricity here. So a LF inverter will be a more useful backup tool. I might end up using it to run some of my garage equipment in summer. That includes angle grinders, drill press, hand tools, jigsaw, TIG welder.

Cheers,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Fri, 10 May 2019, 13:47

Hi Dave.

Ok, I see, your decision for going with this buy has been well thought.

About the Magic Sine Wave, I mainly find mathematical stuff, which I'm not good enough at it to understand.
I can't find a real example inverter that would have been made this way ! I don't see the difference with PWM LF inverter. But please consider I'm far from being an expert ... :(

Do you know these guys from the backshed forum ?
https://www.thebackshed.com/forum/forum ... FID=4&PN=1
They build some different inverter.

Does your inverter has RS232 port and/or remote Led/LCD ? They seem to be optional and I wonder if they could be of any use, and maybe I should get them ?

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Fri, 10 May 2019, 14:07

Hi Hary,
You do not need to worry about Magic Sine Waves. However, they are very clever and I have implemented using them and was delighted with the result. They are derived from and related to fourier transforms and LF inverters would use some approximation to that. Programming was somewhat complicated and I needed to use a reasonably powerful PIC with good timers and interrupt handling and I generated quick lookup tables. It was a bit different from the LF inverter because I was driving a full bridge using IGBTs and regulating 400V DC to supply the bridge.

No, I do not know that forum. Thanks for the info.

My inverter has a COM port but it is not connected anywhere. If you can get that option then I think it would be worthwhile. However I do not know what sort of protocol they use. But they would probably tell you. Also the remote LCD would be useful if the price was right. If I had the com port then I would probably not use my own charger which is max about 60A and I would use the inverter one and integrate it into my BMS, battery controller and excess solar. My charger/controller/BMS is on WiFi and I access it all the time, even from far away. If you succeed in getting the com port plus information, I would be interested and would ask them if I can buy it separately and install it myself.

I am mounting my inverter behind a wall where it is a little difficult to access. The remote control that came with it is good and has a very long cable and I will be mounting that in a convenient place. A LCD panel would be nice.

Cheers,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Fri, 10 May 2019, 20:36

Hi Dave.
From the following link,
https://www.tinaja.com/glib/msintro1.pdf
I cached these few element :

■ Fewest switch events for highest efficiency. (that I understand as one of the problem with inverter is switching high power at high frequency so the output look like a sine wave)

■ Any chosen number of low harmonics are zero. (I don't really know what are harmonics)

■ All digital and highly low end micro friendly. (I understand that these kind of inverter don't need big processing microcontroller. but you're saying the contrary from your own experience. You said "Programming was somewhat complicated and I needed to use a reasonably powerful PIC with good timers and interrupt handling ")

You also say : " It was a bit different from the LF inverter because I was driving a full bridge using IGBTs and regulating 400V DC to supply the bridge."
So you were like doing the same what does the second stage of an HF inverter ? Right ? No voltage boost needed, only sine wave generation from a DC voltage.

If you check the Backshed forum, you'll find some guys building the "Stepinverter". It's an invereter made of 3 or 4 transformers, and switching them ON or OFF in series adding or subtracting their own voltage, they built up the Sine Wave. Of course the inverter made of 3 transformer has coarser "steps" than the one with 4.
One even has been made with no uC at all.

About the SUMRY inverter, I'm now asking the seller about the RS232 com port's protocol details and remote LCD/LED panel.
But you know, getting technical information from Chinese is really hard !
Shouldn't it be easy to add an RS232 port to the uC's UART (MAX232 chip) or even better an UART to USB converter (FTDI or CP2102 or CH340 chip)?
I just got the answer from the seller. They don't want to provide the protocol ! Here is their response !
"We do not provide ,pls do not ask us for it"
Do you think of any reason or argument I could give them to get it ?

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Sat, 11 May 2019, 10:44

Hi hary,
It was longer ago than I remembered- in 2009/2010 and the processor was a PIC2620 running on a 10MHz crystal with a PLL so it ran at 40MHz. There were no PWM outputs with deadbands etc so I had to do a lot in assembler code at the interrupt level.
Nowadays, that is a low end processor and even the ones I am using in my BMS and Lithium controller (18F4650) are far more powerful.

I too asked about price for the COM port and protocol. All I got was "Hope you have a nice day". I asked twice.

It might or might not be easy to add a COM port. It depends on whether or not the code is in their uP already and just needs level shifters hooked up to a USART.

I tried to pull apart the remote control but the PCB is stuck in there and I cannot get it out to see the other side. However, it appears that it is very simple with three lines from the RJ11 to three LEDs and the on/off switch to another wire and common.

Regds,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Sat, 11 May 2019, 13:56

Hi Dave.

Yes I understand. ucontroller have evolved so much these days.

I found a picture with all 3 ports on the back of the inverter : LED/LCD remote control and RS232_com_port :
https://sc02.alicdn.com/kf/HTB1qc4RaPLu ... quency.jpg

The one that my actual seller is offering me has none of these physical port. There is a sticker instead on top of the hole.
Communication is very hard with Chinese ! I don't know if they don't want to provide the protocol, or if they just don't have it. I think they might only be assembler company putting PCB all together in the box, but have no R&D and not really knowing what they doing.

Hope you have a nice day. :D

Harold.

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Sat, 11 May 2019, 15:25

Hi Harold,
Mine has the three ports. However, only the RJ11 remote control seems to be connected.
I think remote control is also an optional extra which (fortunately) I have.
Cheers,
Dave

PS- did you get Google LENS going to see if there is anyone in France (or Europe) selling them?

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Sat, 11 May 2019, 19:37

Hi Dave.

when you say RJ11 remote control : Is it LCD or LED because as you can see on the picture there are two RJ11.

My seller's photo has a sticker instead of the 3 port. I wanted to upload a photo but can't find how to do it !

I finally got google lens working on my Iphone after a long update (was on IOS8 and needed to update to IOS12), but on the phone it's not very comfortable to surf on the web with my old eyes !
Plus I only got the same provider from the one I got the picture of !

Maybe I don't use it properly !

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Sat, 11 May 2019, 20:17

One RJ11 is remote control including 3 LEDs and one switch
The other one is remote LCD
The nine pin connector is the COM port
Regards,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Mon, 13 May 2019, 19:29

HI Dave.

I PMed you

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Re: Is anyone using an arc welder with an offgrid system

Post by T1 Terry » Tue, 14 May 2019, 12:31

Hi Dave, do you know if the SUMRY 5kva inverter you have can be paralleled with another SUMRY 5kva inverter?
I have used the PIP 40/24MSP inverters in parallel with great success, but the standby current is greater than the standby current you appear to have with the SUMRY unit. I have also used the Victron units in parallel, but their standby use is even worse so I had to design a method for the system owner to shut down one inverter when they didn't need to run the big full house air conditioner in the dead of winter .... not enough solar due to trees and sun angle.
The people at MPP Solar seem to have a good relationship with the factory so questions are answered within a few days, maybe SUMRY doesn't have such a good relationship with their supplier factory. Most of these places seem to be the store where the factory product is sold and they know next to nothing about the product they are selling.

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Tue, 14 May 2019, 14:37

Hi Terry, there is nothing about paralleling in the user manual nor anything else I have seen. Also, there is no evidence of any such control signals ready to be taken off and brought to the outside world. So I would be quite confident that the answer is "no".
As well as the idle current being low, the Eco mode is better still. Basically the inverter turns on briefly for about 2secs every 20seconds and if there is any load it will stay on. Now I tried this with a very light load (just a few watts) and that was not enough to keep it on. In that regard, it is like the Victron that I used to have. Things like phone chargers and the safety solenoids on the gas stove were not enough to trigger it. However, the Eco Victron draw was similar to the Sumry unit in non-Eco mode. For a 5kW inverter, the idle current is very good.
Best Regards,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by T1 Terry » Tue, 14 May 2019, 15:20

Thanks Dave, looks like I'll have to stick with the PIP units and their heavier standby current. The PIP does have that ECO mode as well, but it just causes havoc with anything that uses a digital clock and the start up test current for a few of the freezers isn't enough to wake up the sleeping inverter.
I'm probably better off just factoring in the required battery storage and solar capacity to meet the losses.
I'm still tossing up if I should try one of these in my Hino motorhome. It has a PIP 2424MSP in there at the moment and it struggles if the coffee machine heat cycle and the air cond cycles up at the same time, the added inverter capacity would solve that problem. The low standby current looks appealing, but not the noisy fan, the PIP 4024 is bad enough, possibly upgrade the fan with a mag-lev unit would fix the fan problem as long as it didn't freak out the tacho sensing in the ECU. I don't really need the MPPT controller function in the PIP unit as I'm trialling an Electrodacus 120 amp unit in there at the moment.
I noted the display is virtually the same for the 2 different brand inverters, just the PIP shows a few more things to do with the MPPT solar controller.
https://www.ebay.com.au/itm/24v-4000w-S ... 2573743120
https://www.ebay.com.au/itm/5000W-15000 ... 3451997451

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Tue, 14 May 2019, 15:46

Hi Terry, the fans (one at each end) are only on when under load. I am sure they could be replaced with something quieter. I do not think there is a tacho on the fans- they seem to be on or off. A useful addition probably would be speed controlled fans of a quieter variety.
I think there is a version of the Sumry inverter that has MPPT- saw it somewhere. There is also a split phase version (mainly for the USA).
Yes, interesting about the similar displays. Makes sense to use an off the shelf display of that nature rather than each place doing its own thing.
Of course, this is a LF inverter whereas the PIP is presumably an HF. It would be a bit of extra weight in your motorhome but would sure give you a lot of grunt.
Best Regards,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Wed, 15 May 2019, 19:08

Hi Dave.

I'm on the way to order the inverter.

Would it be possible to get a picture of the remote LCD/LED panel please.

I want to make sure, we understand each others correctly with the Chinese seller. :D

Do you think of any question I should ask by this time ? It's been so hard to get all detail !

If we still need some more info, I must ask before making the payement for sure !

What switch breaker do you have on the back of your unit ? I've seen some equiped with proper modern MCB, and other unit equiped with an old black push reset button style.

Harold.

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Wed, 15 May 2019, 19:47

Hi Harold the remote is a switch and three leds. I do not have the remote display. I have the black push buttons. Sorry I am away from home so no photos.
Regards,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by T1 Terry » Thu, 16 May 2019, 12:55

I wonder is the LCD display can be removed from the unit metal cover and the leads extended using Cat spec cable or similar. Possibly they have a device to output the information to the Ethernet or Bluetooth, depending how far away from the device you need to access the information.
The PIP units have these functions, as does the Electrodacus solar/battery management unit, I just need more hrs in the day to have time to get around to that part.

T1 Terry
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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Thu, 16 May 2019, 13:01

Well, I can't believe it.

We were almost done with the seller, putting all options, costs and fees together on Alibaba.com when I asked him if the transformer was 100% pure copper, and here is his response :

"[03:10, 16/5/2019] Malik Lee: as i told you before,pay on alibaba ,2% fee of order amount +15usd will be charged,this part of fee is included in freight
[03:10, 16/5/2019] Malik Lee: the transformer is not pure copper
[03:11, 16/5/2019] Malik Lee: i think you have too much question that i want to cancel the order
[03:42, 16/5/2019] Malik Lee: i think my inverter is not for your request"


Is that rude of my part to ask Chinese seller if transformer are made from 100% pure copper ?

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Thu, 16 May 2019, 13:58

In a LF inverter, the transformer can either be a toroid (with iron powder core or similar) or a laminated plate type using steel.

The toroid will almost always be more efficient.

The windings can be copper or aluminium or some mixture.

Aluminium is lighter, more difficult to connect and with higher resistivity so larger cross sectional area is needed. But it is cheaper. I used to use aluminium wire in a sensitive detector towed behind an aeroplane- for light weight. We had no problem with that aluminium wire over many years. Indeed I still have some of the wire decades later and it is still fine.

So I am not sure what a 100% copper transformer is, given the transformer in a LF inverter will always have iron powder or steel which will be about 30-50% of its weight. In other words, an inverter transformer will never be 100% copper.

Twice now I have looked inside mine and (not that I was looking for aluminium/copper) and it seemed as if all windings were copper. Certainly the very heavy weight and the good performance and low heat generated even under full load would indicate it is well designed and if it does have any aluminium in the windings this is not a problem.

Rather than asking about a 100% copper transformer, I would be ascertaining that it has a toroidal transformer, which mine has.

I suspect earlier versions probably had laminated plate transformers.

Regards,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Thu, 18 Jul 2019, 21:49

Hi Dave
Íve just got my inverter
It’s a Sumry 6kW but it has no com port

Îm thinking to add one and so I looked inside for an USART connector but none of the free ones are labeled .

Can you say from the picture on what connector is you RS232 interface
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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Fri, 19 Jul 2019, 06:07

Hello Harold,
So you finally got it!
I think the 6kW is a good choice. I am very happy with my 5kW and I have been running it at 4.9kW and it hardly gets warm. The extra kW would be useful.
My old photos show that my unit has a 4 wire cable plugged into the left empty socket on your photograph and there does not appear to be a cable in my right hand socket.
So I cannot guarantee that is the COM port one because mine has the remote LCD and remote control ports. But it seems very likely.
Hopefully yours has a remote control supplied because that makes control of the unit easy and also you could very easily add a small relay to the remote control board.
I interrupt the DC battery supply to the inverter using a 200A 24volt contactor and there have been no problems with that. I probably should have bought a 450A contactor because I am sometimes drawing 215amps. But most of the time it is 195 to 205amps. I am using 75mm2 cables, hydraulically crimped. I imagine you have a 48V unit so the currents will be much lower than for my 24V unit.
Cheers,
Dave

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Re: Is anyone using an arc welder with an offgrid system

Post by hary » Sun, 21 Jul 2019, 16:13

Hi Dave.

I am also on 24V because of the Lithium battery BMS that was available only for 24v.
And it's nice to run most of the house on DC24V (led light bulb, laptop with a small DC/DC converter).

This big inverter is mostly for my power tools and will be also for the small 220V fridge (a little bit overkill for that purpose).

On the 2nd photo, the free socket on the left hand side is populated. It is for the front panel, so I have to unplug it to take the inverter's case apart and take picture inside.
The red stuff on the socket is glue to keep plugs tied in socket, so everywhere there is red glue are populated.

My inverter has no remote control, no remote panel and no serial com port. so from the 2nd picture only the empty without glue socket on the right is available fro something.

The 1st picture is a view of the board below the small board (the one you can see on the 2nd picture).
From this 1st picture, can you see 3 free 4 pins connectors side by side plus maybe one more 3 pins connector more upper right.

So that's
- one 5 pins free connector on the small board (second picture)
- 3 free 4 pins connectors side by side plus one more 3 pins connector more upper right on the below bigger board. (1st picture)

If I understood well what you said, on yours, the 5 pins connector on the small board is also free.

As you have the 3 options I don't have, ( remote panel, remote control, RS232 com port), it seems these 3 option are connected to some of the 4 available socket available on the big board.

Any chance you can have a closer look to check it ?

Concerning the power wires connections, I still need to decide what to do and buy proper material.
I wonder if I should get one of these cheap hydraulic crimping tool for proper cable terminal:
https://www.ebay.fr/itm/10-Ton-Force-Hy ... SwF8BcjJQ4

https://www.ebay.fr/itm/416373-Hydrauli ... Swqhlc~6H-


My inverter will be about 2 meters away from the battery (so about 4 meters line). I was thinking to use 50mm2 wire (5A/mm2@6000W, 15A/mm2@18000W peak/inrush power) , but now you said you are on 75mm2 for your 5000W; I'm doubting I'm right ? How far away is your inverter from batery ?

Harold.

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Re: Is anyone using an arc welder with an offgrid system

Post by doggy » Sun, 21 Jul 2019, 18:43

Hi Harold,
My daughter has a nice offgrid system. 24 * 1200AH German (BAE) GEL cells. Weight 1.7 tonnes. Their average loads are only 20 to 40 amps so the capacity is very large, due to the Peukert effect.

7kW of panels, facing North at the correct angle.

THREE * 5kW SMA inverters.

They have run welders a lot even though the supplier recommends against it. They are HF inverters but only 2 to 3kW inverters.

I like powerful tools. My biggest angle grinder is over 3HP!

Cheers,
Dave

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