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When your inverter goes booom


isetech
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The inverter goes boom ...the first thing we do is look for the warranty.

It seems there are few things to consider before you rush out and install a solar / inverter system yourself ...especially if you hope to claim within the warranty period.

We are looking into upgrading a system installed at a customers house...I wouldnt even consider an RCT (1 year ...no repair centre)  ...maybe a meccer (also 1 year...with a repair centre in Durban and very helpful technical department...but limited spares)  but it seems that if plans to spend money on one of the cheapie systems the kodak (2 years and they collect the unit and carry spares for their units) might just be the better option ...with regards to warranty ...but first check the warranty ...you might think installing the unit DIY is easy ...the question is if the unit goes boom within the warranty period will you be able to supply all the correct documentation...for example the MCS installation certificate...and if it burns your house down ...will the insurance company cover the repair costs.

4. Warranty Claims Procedure To make a warranty claim the following information needs to be provided:

• Completed RTM Inspection Form • Product Model (i.e. KODAK Off Grid Inverter, OG 5.48) and Product Serial Number (ie. 36101010101)

• Copy of the invoice for the inverter

• Copy of the installation report and MCS installation certificate The authorised reseller will liaise with the Company regarding repair or replacement. The cost of unit repair or provision of replacement unit will be borne by the Company provided the Warranty has been validated and the Warranty period has not expired. Where repairs must be effected at the Company’s headquarters, the Company will endeavour to minimize the down time for the Goods. All rights reserved by Blue Mountain Energy Ltd. This information is subject to changes without notice.

https://thepowerstore.co.za/products/kodak-solar-off-grid-inverter-vmiii

https://cdn.shopify.com/s/files/1/1776/7837/files/SegenSolar-VoltronicPylonWarrantyValidation_RI_rev_01.pdf?1076

 

The next question ...what happens if the inverter does boom and you are not home and the house burns down... will your insurance cover damage cost. 

Lastly ...what causes the inverter to go boom.

After watching a video on a 8000 kw unit which goes boom ...the supplier replaces the unit and the guy unboxes the unit ...connects it to his system and the unit goes boom again.

This got my attention ...so what is causing all these units to go boom ... I thought my unit was maybe one of a couple unfortunate incidents ...it got old and as most people I have spoken to seem to indicate that its electronic and shyte happens... but i am starting to wonder about this.

So what are the mains causes of units going boom -

Old age?

bugs shorting out the PCBs ? (apparently this is common ...the fan stops the bugs get in and boom) 

Incorrect connections ?...I am sure there are the incidents where inexperienced people connect the unit and it goes boom.

bad batteries ?... one battery goes south and takes the rest down with it... overcharging ...which results in overheating ..which results in batteries running dry if not monitored...I am sure there are other issues which occur to to faulty batteries.

But the one i am interested in is overloading ...due to a motor start up...fridge compressor switching on... aircon ...washing machine...chop saw (as illustrated in the video i watched)maybe even the tumble drier... if the maid is not aware of load shedding and its raining outside. ..what effect does that inrush current have  on the inverter ...are they designed to withstand the inrush current...if there are 3 units in parallel will it soften the effect of the inrush current....what would happen if the inverter was switched on with a full load...the RCT unit has a 40 amp overload protection.

Why does a unit make a funny buzzing sound and then boom... could it be if you switch on the unit under load that it destroys the unit...why has the units not got some form of protection? 

I noticed in one of the videos i watched ...the guy made it clear that if you connect the PV ...you must make sure the batteries are connected first.

So it got me thinking ...how does it work ...there is a charge capacitor which will take a few seconds to charge up ...so in theory you would need to first connect the battery then the mains in ...then the ouptut... with the output isolated at a main switch or nothing plugged in the socket ...if the full load is connected at the time the unit switches on could it go boom ? Surely they would have a delay timer connected to the output to prevent the unit being overloaded during the start up period....if the 5 kva unit is rated for 22 amps why does it have a 40 amp fuse protection?

 

 

Edited by isetech
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4 minutes ago, isetech said:

So what are the mains causes of units going boom -

Old age is a big one. Most electronics have this problem. They have electrolytic capacitors, which age the fastest, especially where higher temperatures are involved. I have had many an appliance blow up because the capacitors are too close to the hot parts, and this includes computer motherboards and internet routers. This was also one of the big issues with the earlier Axpert MKS units. They had capacitors on the DC bus rated for 63V, 2000 hours. When they ran hot, they blew up every 6 months, which is roughly 2000 hours at 12 hours a day 🙂

Of course this issue is one of design. The designer decides how long he wants it to last, and selects the component accordingly. Over time, the engineers, bean counters, and support dept. reach some sort of an agreement and that is what you get.

9 minutes ago, isetech said:

bugs shorting out the PCBs

Saw a report of a Victron unit that failed its relay test repeatedly. Turns out a bug managed to sacrifice itself across the Life/Earth contacts.

11 minutes ago, isetech said:

Incorrect connections ?...I am sure there are the incidents where inexperienced people connect the unit and it goes boom.

Accidentally wiring 23VAC to the output... yes that can happen. Accidentally wiring 24V to a 12V inverter, I've seen that too. Reverse polarity will destroy some units too (adding a diode causes too much of a power loss, and adding a reverse diode/FET plus fuse adds cost). Some inverters are pretty robust though, and it takes real ingenuity to get it wrong.

But let me say this: A good inverter should never ever blow up because it was overloaded. A good inverter switches off when it is overloaded. You fit breakers to protect the cabling against overcurrent, but never to protect the inverter. It is pointless in any case: A breaker can take tens of seconds to trip. The inverter must be able to deal with an overload and protect itself. This is non-negotiable.

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10 minutes ago, plonkster said:

You fit breakers to protect the cabling against overcurrent, but never to protect the inverter.

I had a silly idea the other day. I use gel batteries 4 x 12V(120AH) so I have a 125A circuit breaker to disconnect my batteries from inverter. (I don’t have those nice fuse link disconnector yet). But if I add a extra inline fuse of about 100A dc in between my battery bank say between battery 2 and 3 to cause a open circuit should one of my batteries decide to go south, would that add extra protection against battery boom’s? 

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