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Axpert MKS 3000 24V Overload Bypass Enabled/Disabled


AJM

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Hi Guys

I have something strange happening with my inverter setting overload bypass=enabled it fails over to the grid to support the load which is normal but what is strange for me is if I disabled the overload bypass it actually runs the load without shutting down for instance when i start the microwave I have tested this with both settings and when overload bypass is enabled it will go to grid as I think the initial load is to high but when disabled it stays on the batteries without shutting down the inverter and actually handles the load.

This is just something I noticed.

Regars

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Here is an update it actually seems like overload bypass=enabled or disabled always go to the grid when something like the microwave kicks in what I did now is dropped the mains breaker so that it cant go to the grid then it seems to work fine without shutting down any idea what might be causing this?

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1 hour ago, andriesmalan said:

 

The inverter always goes to grid mode when a high load occurs. It does not shutdown when overload bypass is disabled as it should.

 

andries I think you are misunderstanding how this should work.
It's not an overload of the kw rating of your inverter but rather to protect your batteries.
From the manual: 
Overload bypass:When enabled, the unit will transfer to line mode if overload occurs in battery
mode.
From this you can see it won't shutdown the inverter it will just swap to line/bypass(grid) mode

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I think what may be happening is that the long term load of the microwave is not too much for the inverter to handle, but there is a short term overload.

Many microwaves have a large 50 Hz transformer. (I believe the ones with an inverter do not.) Any large transformer will have a high inrush current to establish the magnetising current. The magnitude of this current will vary with the part of the AC cycle that it starts on; counterintively, the magnitude will be least if it starts at the maximum voltage point. So experiments with this sort of thing have a random component to them.

So perhaps the surge from the microwave is enough to trigger bypass if bypass on overload is enabled, but not enough to trigger an overload fault if bypass on overload is disabled. But it's also a mystery as to why the bypass doesn't come off (with bypass on overload enabled) shortly after the overload is no longer detected.

So I don't think that there is much wrong with your setup. Perhaps when it comes time to replace the microwave, consider a model that has an inverter inside, so you're not needlessly bypassing to grid so often.

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12 minutes ago, TinkerBoy said:

So what should the inverter do if that setting is disabled? Why have it if it alwyas goes to line mode?

If left disabled it would just continue on battery mode unless it reaches your back to grid voltage with a high load.
I suspect that's why it went to line mode for him.

edit
Why have it?
To protect the batteries if you really want to against high loads, would have been nice if it swapped back to battery mode after the high load drops off but it does not :(

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6 minutes ago, TinkerBoy said:

OK so this is what we were asked to add to AICC. If the load is to high on the bank then switch to the grid and then if the load is lower for a certain time then switch back.

Yes that would be nice, maybe add n customizable value for what a high load is and also a detection time(before it would swap) to not do this on devices with high startup current ;)

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Hi Guys

This use to work my main board got replaced and since then is does not work like it is suppose to. Is there anyway I can do a factory reset on the Inverter or upgrade the firmware maybe this could work.

The battery voltage when the microwave kicks in is above 25.6 so no issues there.

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You repaired board likely has the latest firmware, so upgrading firmware is probably not an option.

A patch could be developed, but I don't have a 24 V system, so you'd have to wait for someone else to make one. This doesn't seem likely, unfortunately.

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@andriesmalan How your inverter is currently behaving is exactly as the manual says it should.
Maybe because your previous faulty mainboard had an issue before it finally failed that caused it to "shutdown" on overload like it did.

See here from the manual

Capture.JPG

Then the reason I would think it would shutdown for is if the following occurs. It needs to be longer than the times below

Capture.JPG

Edit
also have a look at what this option of yours is set at

Capture.JPG

Edited by viper_za
Edit
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It seems to me this is simply a problem of "too little provision for adjustment". A one size fits all approach where you go to the grid for several minutes when there has been an overload event lasting only a second or so is bound to get on your nerves... :-)

Knowing a little about where you are heading, let me show off the situation on planet blue.

Below is the makeshift self-consumption program I run on my Multiplus. This works exactly like the Axpert. In other words I'm not using the hybrid capabilities. It works even on the older multiplus (with the old processor), only caveat is you need at least the 2xx firmware. 1xx firmware still uses virtual switch (which can do the same thing, it just looks different).

Note how I set the overload condition to two seconds. The multiplus can carry 200% of its nominal rating for a second, and the 3kva and larger multiplus can switch to grid in under a second, so it really allows a lot of flexibility.

large.vec.png

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What! No extra software development!!! As is out of the box with the software to set it up for free!?

WOW, that is very cool ... :D:D:D

And BEFORE we go down the rabbit hole about the cost of kidneys, you can pick 2nd hand Victrons up, if you are patient, with a warranty still in place If you want to upgrade.

 

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2 hours ago, andriesmalan said:

Is there a way I can factory reset the inverter?

I would be careful of "factory reset". Power the unit up with no load and no AC input. Ensure that there is no PV supply to the unit. Make your changes (set back to default settings) and then add PV and AC. You may inadvertently set setting to values that do not suit your setup.

The bypass function is there to protect your batteries and if you often have a spike causing it to go bypass then disable it. If however you feel you need the protection then third party software is the way to go. I have mine disabled as more often than not I do not have AC available and when the missus overloads the system there is a shrill alarm that does get her attention.

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Also, as discussed over the phone. Here's some pictures to show how hub-1 can make it behave more like an infini -- with a grid-limiter. Here we're using the hybrid capabilities and you need recent firmware, 3xx or 4xx, cannot remember.

First picture simply sets the grid standard to UK. Technically not the right one buy good enough.

Second picture, add a Hub-1 assistant, configure it, and tell it to run grid-interactive with no feedback. Voila. Batteries always charged, no feedback, solar used in the house.

Legal disclaimer: To do this properly you need to add the Ziehl UFR-1001e anti-islanding device. It compares favourably to the black-market price of a kidney. That is in my mind the last obstacle we face, and it will be gone once the Multiplus gets VDE-AR-N 4105 certification, which is currently in progress.

I think what really sets it apart is that you can chop and change. If this config no longer works... no worries. Reconfigure as hub-4 and add a fancy control component later... :-)

I should apologise for derailing the thread... but then again, an explanation is perhaps all that is needed. Andries is thinking of going blue... :-)

Selection_003.png

Selection_004.png

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@plonkster Can you use the wattage drain from the bank as a condition for when it needs to go to grid.

Example
Say my PV is providing 1500w, load is 1800w then the drain on the bank is 300w (this is acceptable)
Same scenario but my load is 2500w then the drain on the bank is 1000w (not acceptable)

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1 hour ago, viper_za said:

 Can you use the wattage drain from the bank as a condition for when it needs to go to grid.

I checked quickly, and no, it only has AC-watts as option in the relay assistant. Also checked the BMV documentation, BMV relay also cannot switch based on current draw.

You can however switch to grid based on external inputs (Multiplus has analogue inputs), so a simple external unit can be concocted to do this. You could also do it on the CCGX I would think, but then things become a little less simple.

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7 minutes ago, plonkster said:

I checked quickly, and no, it only has AC-watts as option in the relay assistant. Also checked the BMV documentation, BMV relay also cannot switch based on current draw.

You can however switch to grid based on external inputs (Multiplus has analogue inputs), so a simple external unit can be concocted to do this. You could also do it on the CCGX I would think, but then things become a little less simple.

Thanks so not out of the box then, back to kidneys

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18 minutes ago, viper_za said:

Thanks so not out of the box then, back to kidneys

Or Plonkster can modify the new Pi software to do that?

As  matter of fact, if I was interested, I could have it done using SolWEB, reading the BMV values to set the inverter to go back to grid.

BUT, I prefer not to - at the moment - for the last thing I want is  software that has a hiccup and the devices gets stuck on the setting. Need to figure a fail-safe first.

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