Axpert failure

[Noobie]

My expert decided to make a loud bang, start smoking and stop working this morning!!!

Ive had the system running since December 2015 and have never had any issues since the install but today at 10:00am something went horribly wrong. The funny thing is that there was no power failure that I am aware of?

I have had to bypass the inverter and its displaying a error code 09

I got the inverter from Mustek in December so I am sure its still under guarantee, I will contact them on Monday and see where to from here.

Any ideas what could have caused the inverter to pop? I can only imagine one of the relays which switch between council and solar input has failed causing 

 

[___]

The repair manuals are under downloads on this forum and I think it documents the errors. My guess... it popped a FET. Take pictures of you do open it.

Sent from my GT-I9195 using Tapatalk

[Noobie]

I would love to open it up but I don't want to void my warranty 

I will let you all know what Mustek finds

[___]

Error 9 simple means that internal components failed.

[Noobie]

Thanks Plonkster, I see other forum members have had this same issue with error code 9 and the supplier suggested earthing the PV panels.

My panels are all earthed already so I am keen to see what Mustek finds

[Noobie]

So I collected the inverter from Mustek today, they replaced the main board and couldnt tell me why it popped. 

They said that it may well be a factory fault.

I have connected the inverter up again and when setting it up I noticed that there was a new option available to me.

Program 38 displays NEC and gives you the option to enable or disable it 

I can't find option 38 in the manual or online. Does anyone have any idea what this is for?

[Chris Hobson]

1 hour ago, Noobie said:

Does anyone have any idea what this is for?

Best you ask Mustek. I have never seen it and the Infinisolar V series jumps from program 34 to 95.

[Noobie]

Thanks Chris, I will give them a call when they are open on Monday 

[Jaco De Jongh]

@Noobie Did you by any chance see if there is a new or different communication port on this Main Board that wasn't on the old one.

NEC is a term often use where a device is connected to one or more remote Keypads/displays that will allow the user to remotely access (Read) or change (Write) the parameters of the device.

Some Axpert/Infini models does have this function and the device look like this.

 

It is just called a Remote Control Panel.

I guess your setting 38 might be to enable control from the above panel, but i also think that your Inverter should have the communication module installed for said parameter to be available. 

This is just a guess......

 

[Noobie]

1 hour ago, Jaco de Jongh said:

@Noobie Did you by any chance see if there is a new or different communication port on this Main Board that wasn't on the old one.

NEC is a term often use where a device is connected to one or more remote Keypads/displays that will allow the user to remotely access (Read) or change (Write) the parameters of the device.

Some Axpert/Infini models does have this function and the device look like this.

It is just called a Remote Control Panel.

I guess your setting 38 might be to enable control from the above panel, but i also think that your Inverter should have the communication module installed for said parameter to be available. 

This is just a guess......

 

Thanks Jaco,

I didn't get a chance to have a look at the board I'm afraid.

I know my old board didn't give me this option so it could be an upgrade?

I have been following your geyser element thread with great interest. I have now set my Axpert to UTI so that it acts as more of a UPS, this way the fans are not running as often and it doesn't switch between solar and grid etc as often.

I was thinking of installing a DPDT DC relay onto my solar panels which will be controlled via Eskom mains. The idea would be that if there is Eskom power the relay would send power to the geyser element (possibly to a geyser wise MPPT unit) and warm the geyser. In the event of an Eskom power failure the relay would disconnect the geyser and connect the PV panels to the axpert inverter to keep the batteries charged up.

I did some fiddling today and it seems that the axpert will function in this way.

I just can't seem to find a high power DPDT direct current relay!

The relay needs to be 150v DC and 20amps with a DPDT switch configuration, any ideas?

I am very keen on the geyser wise dual element as it will allow me to have 2 independent supplies.

Jaco, are you running your PV panels directly to your geyser element, or are they running through an MPPT?

 

 

[Jaco De Jongh]

@Noobie Nope I am going to run the geyser straight off the inverter (220VAC). It will be controlled by a timer and only allowed to heat up between 10Hoo and 15Hoo . The element arrived yesterday afternoon, but I will only fit it next weekend. I am on standby till Thursday and dont want to risk draining the geyser and then getting called out, leaving the house without any hot water. Will update with pics when I completed the job.

So in short the PV reaches the geyser through the inverter. No special mods. If PV isnt  enough on a cloudy day, the invertor will just top up the remaining power demand from the grid.

EDIT: @Noobie I only now saw the part where you want to switch your PV from element to Axpert automaticaly. I am pretty sure I have read somewhere that it is not advisable to switch PV under load. Just wait for the guys thats been into solar longer than i have to comment on this point. You might want to rethink that idea.

[Noobie]

Good thinking, don't drain the geyser while you are on standby. Murphy tends to cause havoc we you least want him to

I know that arcing is an issue when connecting and disconnecting DC. I am hoping that if I make use of a suitably rated DC relay this will be OK.

Someone once mentioned that you could use AC equipment on DC as long as you derate it, I'm not too sure I want to try this out!

I am still searching for a DC relay that can handle the current, I was hoping to find out what relays the axpert has inside and then ordering a couple of them.

[___]

Eish, quick look at RS, that's a R3000 contactor!

I was thinking you could use a FET... well two FETs, essentially a SSR. Thing is, if those ever burn through and you end up connected to both the geyser and the Axpert... I would feel safer with the physical interlock of a contactor.

Then, there are ways to handle with arcs. One way is to put a capacitor over the contacts. When the contacts open, the capacitor is discharged and forms a low impedance path. The capacitor charges up and becomes a high impedance, but in the time it takes to do that the contacts had time to open. The capacitor literally sucks up the arc.

Would I be happy to try such a thing and let it go up in flames? No. :-)

[Jaco De Jongh]

@Noobie You must just make sure about the voltage of the DC element, I know with that system that you are interested in, they normally sell a separate mppt. so I guess the element is working with a lower voltage than the PV voltage. If you want to switch your pv directly unto the elment, the voltage might be to high.

My other concern is your inverter. I am not that worried about arcing, that can be dealt with, but i dont know how your inverter is going react to your plan. Under normal conditions the PV volts and amps increase over a period from early morning and decrease towards late afternoon , that is what the inverters internal MPPT was designed for. With your plan, you might disconnect the PV at full power from the inverter that might be feeding at close to full capacity, I can just imagine the spikes and or surges  that can be created  on either side of the system. even reconnecting the PV that is sitting at full voltage, might cause some issues. I am just afraid that the unit will prematurely fail and that we might read trough a post called "Axpert Failure 2"

Please get some advice from the supplier also before you attemp it, I personally will not take that risk with my own equipment.

[Jaco De Jongh]

@viper_za & @superdiy & @plonkster & @The Terrible Triplett & @Chris Hobson, your inputs will be appreciated!! I recall reading some advice from some of you on something similar, but I just never seem to find a discussion when I need the info.

Please help, I am worried that @Noobie might dammage his inverter with this plan, if its not the case I will also learn from it.

[Noobie]

Thanks @Jaco de Jongh I will find out what voltage the geyser wise DC element is before going any further. I will have to chat to Mustek and see if switching the PV input could cause damage to the inverter. I really hope not!

I got the price list and install sheets from geyser wise and they have 2 options when using PV with their elements. The first option is to use their MPPT and the second option is just to have the PV panels connect to the element through a SSR only, the SSR would be controlled fiat the geyser wise. Attached extract from their manual. 

As the DC element is 900w and my PV array is 1500w (2 strings of 3 x 250w series connected panels) I think I won't need to use the MPPT

@plonkster I couldnt find the correct relay one on the RS site, could you send me the link? I agree with the physical interlock idea, rather safe than sorry!

@TinkerBoy Do you have any contact details for Johan Booysen? Perhaps some more info on this device he builds?

Just a big thumbs up to you all for your advice and assistance 

 

 

 

3458_Dual-thermostat-instructionmanual_web pg7.pdf

[Noobie]

@Jaco de Jongh I found this video, you are correct he mentioned the DC element is 24-48v. I will have to parallel my panels to get an acceptable voltage

 

[Guest]

5 hours ago, Jaco de Jongh said:

With your plan, you might disconnect the PV at full power from the inverter

Never EVER disconnect panels under load ... ever, unless it is a dire emergency and you had no choice at all.

Posted similar before: 

 

[___]

4 hours ago, Noobie said:

 I couldnt find the correct relay one on the RS site, could you send me the link? I agree with the physical interlock idea, rather safe than sorry!

Use the filter on the left to look for DPDT relays. There's like 7... and only one of them can do more than 25A. That one has a 24V coil though. I did the exercise more for the price than anything else.

[___]

3 hours ago, The Terrible Triplett said:

Never EVER disconnect panels under load ... ever, unless it is a dire emergency and you had no choice at all.

I am puzzled by that. My first charge controller, a Microcare, has a breaker on each side. When you turn it on, it's battery first, solar last, and when you turn it off, it's the reverse, solar first, then battery. This is required because PV side might be up to 150V, and if you do it the other way round... well things might burn up, as a forum member discovered when a BMS disconnected a Lithium battery.

So if you really cannot disconnect the solar panels under "load" (which is like 16 amps on my setup, that's what the panels do at Vmp), do you have to wait for night time? Surely, if you rate the breaker for 16 amps at the relevant DC voltage ... "never" is a bit too exclusive? :-)

There is however an interesting feature on the blue solar chargers. You can programatically turn the charge current off, ie, remove the load before you disconnect stuff. Now isn't that cool :-)

[Mark]

The Axpert will do this if you go to Grid during the day.  It transfers load to Grid... doesn't need PV therefore the MPPT drops off to almost zero load from panels... then I use my DC Disconnect on the PV side to disconnect it.  In that order.

[Chris Hobson]

8 hours ago, Jaco de Jongh said:

@viper_za & @superdiy & @plonkster & @The Terrible Triplett & @Chris Hobson, your inputs will be appreciated!! I recall reading some advice from some of you on something similar, but I just never seem to find a discussion when I need the info.

Hi Jaco

My system is simple. I have a 200l Kwikot geyser which I have modified to accommodate two 1500W universal elements. In most situations only one port would do. In my system one is powered by the inverter/gennie  and one is powered by an underutilised phase from the gennie. No DC switch etc.

 

 

I have a contactor in the DB that is closed by a relay that in turn uses battery voltage to activate the relay. Contactor closes at 53.5V and opens at 51.9V. At the moment I am doing it manually as I had to remove the DIn rail transformer I was using as a DC power source out of the DB as it was getting too hot.

Video of where I got my inspiration here .

[___]

12 minutes ago, Mark said:

MPPT drops off to almost zero

Exactly, even without special features, the amperage at float might be so low that you really don't have to worry.

I think a more proper warning might be this: Don't be a dumbass!

[Mark]

The challenge with the hybrid or even axpert is it could be floating the batteries but pulling 40plus amps to power loads ... so assuming float means no mppt action may be a big "flash" assumption..

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[Jaco De Jongh]

On 8/13/2016 at 5:53 PM, Noobie said:

I was thinking of installing a DPDT DC relay onto my solar panels which will be controlled via Eskom mains. The idea would be that if there is Eskom power the relay would send power to the geyser element (possibly to a geyser wise MPPT unit) and warm the geyser. In the event of an Eskom power failure the relay would disconnect the geyser and connect the PV panels to the axpert inverter to keep the batteries charged up.

@plonkster I dont think you understand my question fully, you and @Mark just mentioned a nice future that even I am aware of, this is nice in an controlled situation and perfectly safe, I will do that with my inverter 20 times a day if I needed to, My only consern is doing it uncontrolled as noobie explains above. I dont think it will be good for the inverter, disconnecting and re-connecting the PV under load. if there was a way of first lowering the load before disconnecting, yes it will work but not uncontrolled. 

You might create surges (Transients) if you want to call it that, and I have seen on much bigger VSD's (Basicly the same consept) that they tend to fry the electronics when you cut the supply while under load especialy on the DC buss side. I just dont think its safe to do this uncontrolled.

If noobie can engineer that risk out and make sure the load reduces before switching his plan might work