Author Topic: Replacing components (inverter, charger) in a badly damaged off-grid system  (Read 4951 times)

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Offline ays

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I am living off-grid in Vanuatu. We are on a farm, house is wired for 220 volt. We have just had a lot of things damaged by a major cyclone. The most immediate problem is that our (cheap chinese 48 volt) inverter has failed, and we need electricty to run our water pump. I do not know what is wrong with the inverter and we have not been able to get a tradesman to come and have a look, so i am looking to replace this.

Right now money is tight - we need to fix our generator, replace panels, and just prior to the cyclone were having battery problems -  so our storage capacity is also a problem (right now we have 4 12 volt 200 a/h batteries that seem ok. the new batteries we bought are 6 volt 225 a/h, but they were sold with corroded terminals and we have had 2 terminals overheat and melt).

big loads the inverter needs to cope with are running the water pump (0.37 kw), washing machine and fridge.

We could go 24 volt, or stick with 48 volt. We are also looking at inverter/chargers - or and inverter plus a charger for the PV. Our PV array is currently about 16 65 watt panels. I will be looking to add 2000 - 3000 watts to that.

advice here is get an outback, but that is expensive. given issues with getting warranties respected i have tended to go for cheaper equipment and replace if it fails.

I have looked at the a number of threads re powerjack inverters - it seems that if a small mod is done to reduce the idle current these are not bad? My husband came across voltacon inverter/chargers on ebay and liked the look of them, although I could not find much product info and the specs make them look quite inefficient http://voltacon.com/sites/default/files/13796%20VOLTACON%2016pp%20BROCHURE%20AWv4.pdf

I have also been struggling to find Australian websites with prices.

If anyone has advice on inverter, inverter/chargers, chargers or suppliers who would be good to contact (does not matter what county they are in so long as they can supply to vanuatu) we would appreciate the advice. Sorry if this sounds like I am not doing my own basics with research, but we are a bit tired here and internet is limited. Right now I don't trust myself to think through "off-grid systems 101" properly.

Thanks

Offline oztules

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I live on a small remote island, and fully understand that a warranty from a proven supplier is worthless once freight and time is taken into account.

I use a powerjack for the house. It runs all loads, and your stated loads are tiny in comparison.

As a remote islander, i can only say that the cheap power jacks are a godsend for this environment. An inverter is only 400 to 800 dollars, free shipping world wide as a normal thing.
They are robust provided you READ THE NOTICES about battery charging... ie turn the inverter off connect to generator, then start generator THEN turn on inverter.. and to turn off inverter THEN disconnect generator, turn on inverter again.... all will be well
The complete insides are light and cheap for about  $179AUD you get the whole lot. If you drown it or kill it somehow then.... just lift out the power board and control card and replace, and your good to go again.

You will only need to do this if you ignore the warning above about charging... otherwise mine has done many many megawatt hours without a problem.

I believe there is no longer a need to make the conversion, they have read the stories on here and elsewhere and done it now from what I understand.

Make no mistake they are NOT going to do their rated power for more than perhaps 10 seconds, but they will do half their rated power continuous, and start very large loads easily.... your loads are tiny in comparison, and that included your start up. You could easily run all those appliances and start them at exactly the same time, and the 8kw units and 6kw units would not hesitate in the slightest.

eg. http://www.ebay.com.au/itm/LCD-8000W-power-inverter-LF-pure-sine-wave-DC-48V-AC-240V-charger-LCD-UPS-/221724592680?pt=LH_DefaultDomain_15&hash=item339fd0ca28

MAKE SURE IT IS A LF inverter not a lighter HF inverter.... The LF is heavy, the HF is light.... always a LF for heavy start ups and raw power. the extra weight is worth every penny of freight.... around the 30 or more kgs ( over 60lbs)


They don't send to Vanuatu. But if you have a decent rating on ebay, then email them. I have bought from Blooming inverter before a few times, and the person there (Cher) seems very reasonable, and may decide to give you a go if you outline the problem.... otherwise you will have to get it sent to the closest place they do, and then on forward it.... islands are a nuisance sometimes, but worth the hassle I think.

The cheaper PJ inverters are transformer challenged, same electronics, but only 1 transformer instead of two, it may be better to buy the dearer of the same one is what I have found... ie some 8kw units have only 1 transformer, should have 2.. etc... there is a bit of get what you pay for with some of the PJ sellers.... but some of the cheapies are the real thing too... hard to tell, but talk to the seller first, see what you are buying.... and how heavy is it? etc. Most of the weight is the transformers.

Quality control is questionable from some of them. I don't know how or why they sell as they do... so open it up when you get it and check it is all tight, no floating parts. Once going, they are very very tough units.

For a remote location, I don't see how you could get better reliability and ease of replacement without down time... ie buy an inverter and spare cards.

I would always stay with 48v. 24v gives you absolutely no gain in any part of the system... only losses from the higher currents, and double the current, quadruple the losses in the wiring, battery plates, panel wiring, fet losses and the list goes on.

Thats my answer and I have seen no better alternative for remote locations... or I would have done it. When your on an island, your on your own, so have redundancy built into your plans. The nights are long and dark without power.... I have built 5 spare inverters ( all a bit different each time) just for the hell of it...... but I have never needed any of them... but if I did, I'm good to go.

 I have seen very expensive $8000 dollar inverters fail early on in their life ( some just weeks), and their owners have been without power in those cases for weeks.... trying to get warranty done..... not the fault of the manufacturer, but island transport is not a simple thing for heavy stuff, and ships are erratic here too.


.......oztules
Flinders Island...... Australia

Offline ays

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Thank you so much for this - this is very very helpful. I wil ltryo Bloming inverter and let the board know how I get on. 

Offline off the wall

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I have bought from Blooming inverter before a few times, and the person there (Cher) seems very reasonable,

oztules should actually be known as OZRULES as he's spot on with everything and a hero.

Cher is a star. I only ever deal with her and she really does look after her customers. She's wholly conscientious and she's on email powerjack.cher )at( %^gmail^% dot *%com%* and she sincerely does her best to make sure that you get what you're buying.

Best wishes

OTW

Offline oztules

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.... no Oztules is the village idiot.... and he was first in line for the job well before he attained that position :).


..oztules


Flinders Island...... Australia