I blew up my inverter

Chuck2205

Last year, I sold everything and moved to the Philippines.  Most everything is cheap here, except the electric.  So, I had a Solar PV system set up with battery back up.  The inverter/charger is a Must PV3500 pure sine wave solar inverter that apparently has a 12KW capacity.  Now, when I was in the states, I had a grid-tie system for 17 years and that was zero maintenance, forget about it and love your electric bill.  I thought this system would be the same.  The electric goes out a lot here, so I wanted the battery backup, but I seem to be in over my head as this is a whole different animal.   I took a shower with an insta-hot electric water heater (well after dark, so the inverter was shut down) and 3 minutes into the shower, the inverter apparently started shooting out fireballs.  It turns on, but it apparently can't boot up into a working state.  The installer says neither he nor the manufacturer is at fault and it will need a new controller board at about US$1400.

It seems to me that any decent inverter would have a safety that would shut itself down when there's too much draw instead of blowing itself up.  Is that a silly thought, or should I look for a competent installer or perhaps an inverter that's not made in China?  Or am I totally naive?

mcgivor

Sorry to hear, is this the 4KW version, if so the 12KW rating is for 20 ms. What is the wattage of the shower heater, there are so many, some exceed 4Kw, should it have protected itself? It should have but there may be something else. Tropical climates have geckos, they love to crawl into devices, I lost an inverter due to them, all my equipment is now protected with stainless steel mosquito mesh and play dough stuffed into condiuts. As far as the quality goes, no idea with Must equipment, but $1400 for a replacement board is close to what a Schneider Conext 4024 230 costs, but it requires a separate charge controller and control panel add around  $750, just for comparison with quality equipment. Tell us more about your system, there may be other factors.

Is this the unit you have? https://www.mustups.com/pv3500-mppt-series/

jonr

Yes, a good inverter will protect itself from overload, especially with a simple resistive load.   So barring damage (like geckos), it's either a poor design or defective.   I'd replace it with a good name brand inverter.

Estragon

Just to clarify, is this basically a solar and battery backup connected to grid power, or totally off-grid?

Lots of possibilities for a dead board. Was there any lightening in the area at the time?

As Mcgivor notes, now might be a good time to look at overall system needs and plan accordingly in buying replacement gear.

Chuck2205

I really appreciate the comments.  
Yes, the unit I have is the one you linked, mcgivor.  We do have a lot of geckos.  The installers tell me the system is well grounded for lightning and it was not storming that day, so no lightning.  The heater is a Smart 18E, which pulls 3.5kW.  So, I guess that's going to max the inverter right there.
https://www.alphamalaysia.com/18e

We are not off-grid.  The inverter switches to grid power at night to save the batteries for when we lose grid power (which happens often here).  There are 8 gel-type batteries 19.2kW.  The solar panels are 18 Maharlika 280W panels.

I have since moved the shower heater to the grid-only breaker box where I already had 2 huge air conditioners wired because I knew the inverter couldn't handle those.

Mainly, I'm wondering if I should trust the installers to replace the board, or if this is going to happen again because the inverter isn't protected as it should be.  Note: the actual board is about US$915.  Customs charges are $300.  Then there's taxes and I'll need to get the technicians here by boat - it's definitely not Kansas anymore.

mcgivor

It's easy to make suggestions from the comfort of an armchair so to speak, but perhaps looking into Schneider, not because that's what I use, but because they're an international company, most likely with local company offices and retailers, at least that was my experience in Thailand, the prices were comparable to prices in the US, a Conext 2524 230 was US $1200 locally. Paying large amounts for a repair could exceed the cost of a more professional unit, worth looking into, at very least.

Estragon

I wouldn't sink $1200 into a new board, and would instead look for a new inverter better suited to the environment. Outback, for example, makes "sealed" versions of ther inverters which may be less prone to geckos meeting their maker in them.

Dave Angelini

Chuck if you are connecting a battery based inverter to the grid in the tropics you also have to use surge protection on AC and DC.
I would guess there is a bigger chance of this than anything else causing your problem. I too would start fresh and not try and repair the old one. Save it and see if it can be failure analized by a pro later.

Chuck2205

As follow up to this issue, I asked a guy starting up his own solar installation company to come and look at the system and recommend a solution to get it up and running again.  Smart guy.  Works for the power company full time and has done a few installations on the side.  He immediately noticed that the inverter is 50Hz, while all the Philippines, like the US, is 60Hz.  He's not sure that's the reason for the failure, but he said it's a good thing it blew up because it would have degraded and eventually destroyed all of my appliances.  I can't afford him.  He wants $4500 to install a SolaX inverter (another Chinese brand that he told me was UK).  Right now, I'm leaning toward an MPP model made and shipped from Taiwan and doing the replacement myself.  But the breakers it requires are very hard to find:  60VDC/150A from the batteries?  Where do I find that?

https://www.ebay.com/itm/5000w-230vac-48vdc-Hybrid-Solar-inverter-grid-tid-off-grid-PV-input-145vdc/163192198388?_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=53210&meid=a0e363b0b23d4bff97d09878ff84146c&pid=100005&rk=6&rkt=12&sd=132705076145&itm=163192198388&_trksid=p2047675.c100005.m1851

mike95490

Midnight distributes these,

http://www.midnitesolar.com/productPhoto.php?product_ID=197&productCatName=&productCat_ID=16&sortOrder=13&act=p

as panel mount, and these

http://www.midnitesolar.com/productPhoto.php?product_ID=183&productCatName=&productCat_ID=16&sortOrder=18&act=p

as DIN rail mount

 both DC rated, cont duty, usable as a switch.

Not sure how is best for you to order and have shipped.  You will likely need a suitable box, either from a local electrical supply, or from Midnight.

NAWS ships most of the Midnight gear.

mcgivor

Chuck2205 said:

As follow up to this issue, I asked a guy starting up his own solar installation company to come and look at the system and recommend a solution to get it up and running again.  Smart guy.  Works for the power company full time and has done a few installations on the side.  He immediately noticed that the inverter is 50Hz, while all the Philippines, like the US, is 60Hz.  He's not sure that's the reason for the failure, but he said it's a good thing it blew up because it would have degraded and eventually destroyed all of my appliances.  I can't afford him.  He wants $4500 to install a SolaX inverter (another Chinese brand that he told me was UK).  Right now, I'm leaning toward an MPP model made and shipped from Taiwan and doing the replacement myself.  But the breakers it requires are very hard to find:  60VDC/150A from the batteries?  Where do I find that?

https://www.ebay.com/itm/5000w-230vac-48vdc-Hybrid-Solar-inverter-grid-tid-off-grid-PV-input-145vdc/163192198388?_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=53210&meid=a0e363b0b23d4bff97d09878ff84146c&pid=100005&rk=6&rkt=12&sd=132705076145&itm=163192198388&_trksid=p2047675.c100005.m1851

Try here http://m.feeo-solar.com/ I've ordered directly from the manufacturer no minimum quantity, good quality, priced right, attached is the 2017 quotation for their products when ordered , Please note  the certificates may or may not be compatible with local requirements, check before ordering.

Chuck2205

Mike and McGivor, thank you so much for the links and the attached quotation.  They have almost no protection installed.  As I watch more videos from first world countries, I see how you should have protection between everything!

I laughed when you mentioned "local requirements".  There are no local requirements here.  This is the wild west.  Trucks have to slow down sometimes while the guys in the back of the truck push electric lines up so the truck can clear.  Lines drape across metal or thatch roofs with taped splices lying in the open.  There is no such thing as housing inspections - not for structure, plumbing, or electric.  Kids die from electrocution from climbing the wrong tree or stepping in the wrong puddle.  They haven't even thought about regulation for a solar installation.  Anything I do here will be many times safer than the crap they do just to keep the power on in the neighborhoods.

Thanks again for the links.  I will make my installation as close to US standards as I can so at least my kids are safe.