inverter selection

[ians]

I learnt a few things today.

They say RCT ...meccer kodak are all similar.

It happened ...the RCT 5 kva inverter went bang and there was a puff of smoke.

Here is the difference which might help you choose the unit you purchase.

RCT ...1 year warranty and no service repair centre (Rectron Durban RCT) ...I certainly will not even consider this company.

Meccer ... 1 year warranty and they do have a repair centre and a technician who is very helpful (Mustek Durban) i might consider a meccer .... butr the fact that parts are a challenge to source... mmmm I dont know.

Kodak ...2 year warranty ...they collect the unit and send it to a repairs centre which stocks replacement parts.

None of the companies entertain out of warranty repairs.

That leaves victron ...gona look into service and repairs of these units ...what i am hearing it it sounds like you get what you pay for ...and victron might be more expensive but in the long run ...there is nothing worse than sitting with an R11000.000 unit and no repair centre and no spares available in the country...or repair cost so high that you might as well buy a new inverter

[ians]

lead acid maintenance free batteries ... well another learning curve ...the next set of maintenance free batteries i purchase... i will be checking how easy it is to access the top up plugs.

What happens with inverters ...if one or 2 batteries go faulty and you dont know ...the batteries will boil due to overcharging... which will result in all the batteries releasing acid via the discharge vent.

So a tip ...

make sure you have some sort of battery monitoring system in place to monitor the SOC and battery voltage at each battery.

Make sure you have a fuse link for the batteries which has a handle to disconnect the batteries both + and -

dont not stack the batteries close to each other ...allow a gap for heat.

[Justloadit]

Having the proper protection devices, circuit breakers and fuses, does limit the damage when something goes wrong. In these circuits, if a FET dies, it normally goes into short circuit, which mens that the incoming power sources are shorted. If it is on the PV side, then limited damage occurs because solar panels are current sources, so that shorts are in the region of 10A, which incidently is the operating current when the sun shines at its strongest. However if it is the battery or the mains side of things, then huge currents flow as these are voltage sources, and the current is limited by the protective device in circuit. Most battery installations have no circuit breaker/fuse in line, or have an AC breaker, so that when a fault develops, the weakest link in the system is burnt/destroyed.

Fortunately with the Lithium battery packs, there is a built in short circuit detection which disconnects the battery.

Yes I have looked at some of these, and they use many Chinese made FETs and IGBTs which are only sourced in China, and if you have a friend, they can give you an equivalent part number for the device used.

If the board is not damaged, then once can replace the blown FETs or IGBTs, however if the controller or some of the other support devices are damaged, then there is no repair.

I have found that if you have a relationship with the Chinese manufacturer, they do supply spares for after sales service repairs. The question is rather how many technicians out there have the correct tools and knowledge to do a quality repair .

[Justloadit]

Last night had a Lead acid battery cook on me.
I smelt this light rotten egg smell waffling in my office, and thought that it was one of the customers that left one behind or maybe me , only to realise a little later this bulging Lead Acid battery releasing water. I had been used the night before, and it had discharged completely because I forgot to switch the load off, so was in the process of recharging. I have only used this battery a few times in the last 3 years, so never even thought that this was going to be an issue.

I have noticed that a number of Lead acid batteries I have stored unconnected, never been used, are no longer holding charge.

So another reason that I dislike lead acid battery.
I have Lithium stored here for over 8 years, and are still performing to above 50% of their original capacity.

[ians]

Just got feedback from a company which is trying to repair my 5 kva RCT inverter... it is dead and cannot be repaired ...no spares available for the unit.

Let this be a warning ...stay away from RCT inverters ..Rectron do not have a service centre and cannot provide spares for RCT units.

Mustek can normally supply replacement parts ...however they have no stock and cannot provide details at this point in time.

I am told all these units may look the same ... however the internal components are not the same.

[Justloadit]

From my experience, if the PCB is not burnt, then there is a high chance that the unit can be repaired, just needs patience to strip down to the place in which one can get to remove the faulty FETs/IGBTs. In most instances it is more profitable to sell a new unit.

There have been occasions where the control card is faulty. In this instance then there is no hope for repair.

What I have also noted, is that some FET/IGBT part numbers are in house Chinese part numbers. Sometimes one can be lucky and find the original part number and replacement of the same does bring the equipment back to life.

[ians]

Apparently the IGBTs/FETs were replaced and they just popped again...i was told the board has to be replaced... no boards available... i am not convinced the techs are suitably trained....so they replace what they think could be the cause and if it doesnt work ...just tell the customer the inverter cant be repaired.

[Justloadit]

Apparently the IGBTs/FETs were replaced and they just popped again...i was told the board has to be replaced... no boards available... i am not convinced the techs are suitably trained....so they replace what they think could be the cause and if it doesnt work ...just tell the customer the inverter cant be repaired.

Mmmm I have just had the same problem with an inverter I repaired here.
After thinking about this, and have not had any way of verifying this, I have a sneaky suspicion that we are doing it wrong. Simply replacing may work for a short time.

I remember in the 'old days' when we repaired audio amplifiers, we use to get matched pair transistors to ensure proper operation of the amplifier.

I suspect that with respect to the inverter IGBTs and FETs, where a number of them are placed in parallel to share the current, that they also need to be matched. Simply replacing any old how, cause the one IGBT/FET to handle all the current, over driving the device, which then cause it to fail and take out all the opposite side IGBT/FETs as it is now a dead short across the supply.

[ians]

I just wish i could find someone who actually knew what they were doing and who could test and repair the units.

It seems every electronic repair shop are now inverter repair experts ...because someone mentioned it is as simple as replacing IGBT's on youtube.

It seems these RCT ...meccer inverters have become disposable units...at R9000-R13000 ...its a chunk of money to throw in the bin because there is no backup.

[AndyD]

I learnt a few things today.

They say RCT ...meccer kodak are all similar.

.....

Yes, also Axpert. They're all rebranded Voltronic inverters manufactured by Voltronic Power based in in Shenzhen https://voltronicpower.com/en-US/Pro...-Grid-Inverter

[ians]

Yes, also Axpert. They're all rebranded Voltronic inverters manufactured by Voltronic Power based in in Shenzhen https://voltronicpower.com/en-US/Pro...-Grid-Inverter

That is what i also read... until one went boom... i have been trying to source a main board for the RCT unit which went boom... the boards are apparently not the same... or so i am told now that i am trying to replace a main board.

I am looking into installing solar and inverters at my house (i cant see this load shedding ending anytime soon...with a deadly virus heading this way in the next few months) ...i certainly will not be wasting my money on one of the slightly cheaper disposable units ...i am gona rather wait and find the money to get a victron unit.

[Rifrug]

Hi Ians, I’m sorry to read about your bad experience. I also have a Axpert inverter and had no idea what to expect from it when I installed it. I decided against the victron brand due to the sales guys for victron were not prepared to give much info on the inverter as it seems like they don’t want to share any information, and they wanted to do the job, but me being a electrician and not wanting other people working on my installation scared me away from victron. But I can say my Axpert has now been going for a year and boy am I impressed with this cheapy. I only paid R8000 for the 4000W cloned unit and my thinking is if it pops I will just go and buy another one again, hopefully it will last 3 more years than I will recover my entire cost on the system. I also think the design and installation method is very important if you install one of these cheapies so that the protection installed will prevent any damage to the inverter.
Best of luck with your next inverter
Rifrug

[ians]

I am looking for an inverter battery combo box unit 1400 watt 12 or 24 volts complete.

[AndyD]

That is what i also read... until one went boom... i have been trying to source a main board for the RCT unit which went boom... the boards are apparently not the same... or so i am told now that i am trying to replace a main board.

I am looking into installing solar and inverters at my house (i cant see this load shedding ending anytime soon...with a deadly virus heading this way in the next few months) ...i certainly will not be wasting my money on one of the slightly cheaper disposable units ...i am gona rather wait and find the money to get a victron unit.

The boards should be the same as long as you get the same model, they don't change the boards according to the branding, the inverters are just a straight rebrand.

As far as I know there aren't any replacement boards available. The main board is basically 90% of the entire inverter so a replacement, even if it were available probably wouldn't be financially viable.

What went 'boom' on your board? Can you post pics? If it's a mosfet you can try replacing it (and its associated driver resistors) with a suitable component that's available locally. I've done a few of these inverter board repairs with some sucess. The boards I couldn't repair I've kept for spares so if you can identify the faulty component I'll mail you a second hand replacement if I have one. You can mostly fault-find these boards down to component level with just a decent multimeter that has a diode mode.

[ians]

If you just keep trying eventually you will get it right.

I found someone to fix the RCT unit at a small fee R900.

I have managed to find some software solar asssitant and a Pi3 ... after a very frustrating issue with a card reader ... I eventually got the software loaded.

Now to figue out how to connect to the inverters and test the software.

Which reminds me ... time to run a network cable to the workshop.