Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby FarmerJohn » Wed Aug 21, 2013 8:28 am

I had one of the Rich Electric transfer switches. It lasted 10days before it stopped switching.

My conclusion is that it was not designed for Australian conditions - yet had been sold in Australia. By this I mean that my grid voltage is often 253V and on reading more closely I found that this was technically outside the stated tolerable range for the device.

Unfortunately due to the non-standards compliant test bed I was using, I was foul of the warranty conditions.
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my hybrid system...

Postby Tracker » Wed Aug 21, 2013 8:59 am

.
As described earlier, my hybrid system has been working for some months now.

Yesterday, I took a leap of faith, and connected the office to the system..
My concern was that because the computers are there, I did not know how they would react to the regular jumps from GRID to PV...

Well, I did not have to wait long ..
I have. Based the whole concept on using a LATRONIC Mains Transfer Switch. ( contractors)
It works by applying a priority to power connection.
Grid is the default, but if alternative power is available, it changes over to that source, with a fair clunk from the contractors.

I had found that the fairly mechanical refrigerators, were unaffected by the specified 40mS changeover time.
I wondered how that 40mS might affect an electronically controlled device.. eg. The air conditioner does drop out.
I suspect that one could modify power supplies in such devices, adding more capacitance to reduce the susceptibility to transient .. but all too much trouble at this time..

Anyway, back to the office.. I did not have to wait long... the first clunk, and it was over for the computers.. much as I expected..

So the challenge in developing a really reliable "hybrid-use it-or-lose it" system, is a FASTer ATS..

Anyone found a solid state device.. Surely, someone must have a solid state version that would have better than a 1 cycle transfer time.. ie 20mS.. ( but, will a computer PSU react to a 1cycle dropout..?)

PS .. I overcame the problem..
we had a small ALDI UPS.. :shock: ...... and I just shoved it in line.. problem solved.
A spin off is that I will have even better protection for the computers..
( looks funny with the small UPS sitting beside a 200AH battery - yes the old battery had died after some few years in service)

Still... the challenge... to find a cheap solid state. ATS...
..
.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby Tracker » Wed Aug 21, 2013 9:05 am

FarmerJohn wrote:I had one of the Rich Electric transfer switches. It lasted 10days before it stopped switching.
....'. By this I mean that my grid voltage is often 253V ..... I found that this was technically outside the stated tolerable range for the device. ....


What a relevant post and how well timed.. you can expect that I was looking at them, seriously, and had suggested them to some...

Did you determine just what failed.. was. It a voltage or a current problem..
..
.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby davidg » Wed Aug 21, 2013 9:42 am

FarmerJohn wrote:I had one of the Rich Electric transfer switches. It lasted 10days before it stopped switching.

Hmm, out of interest what died in it? I have no intention of getting one just interested. The warranty on their products is not very good overall.

Latronics have a decent changover switch with a decent changeover rate. HS Changeover even made in Australia approx 12ms for most equipment that's fast enough. Thats just over one a half of one cycle in AC @ 50hz

It will be interesting to see how they (Rich) go with the changes required for compliance with AS4777 revisions once they become mandatory, things like DRED, while it might be a pain on the surface, I think it will also have some real upsides for some things, Such as in hybrid sytems when/if power fails and for off-grid solutions. Intelligent power control is an absolute winner for those situations.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby Tracker » Wed Aug 21, 2013 10:10 am

.
Buggar... that's a new one. 12mS.

I have the ACTS3, said to have a changeover of <20mS...

I suspect that is a little generous.. :cry:

DRED... I hear Pauline saying it... " please explain "
( for us who no longer read AS as general reading..)
..
.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby FarmerJohn » Wed Aug 21, 2013 11:12 am

davidg wrote:
FarmerJohn wrote:I had one of the Rich Electric transfer switches. It lasted 10days before it stopped switching.

Hmm, out of interest what died in it? I have no intention of getting one just interested. The warranty on their products is not very good overall.


I'm sorry I don't have the knowledge or equipment to work it out.

I still have it though, I can send it to you if you can do the science.

Background: A few months ago my small prototype solar system failed when I wasn't there due to three days lack of sun and stupid mistake on charge timer which topped the batteries up off-peak. This ruined the content of the recently refilled freezer, together with a substantial part of my credibility. I was not a popular husband and the PR for my off-grid initiative took a severe beating.

I decided that I wanted to install a failsafe that would switch back to grid, if the inverter ever stopped producing again when we were not there.

I think I should have gone for the Latronics - but I didn't, since Jaycar are just across the road from where I work.

Rather than try again with a Latronics, I simply accelerated the project and went off-grid anyway, money was spent and large heavy gel batteries were delivered. I was not able to get domestic clearance for a LiFePo4 solution - on the basis that everyone understands Pb and all my experience and research and instrumentation had been based on Pb. Due to the freezer incident I was low on material with which to win this argument, so Pb it was :)
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby Gordon-Loomberah » Wed Aug 21, 2013 1:49 pm

You should have used my thread on Lithium vs Lead as evidence for the Lithium!
I did a quick calc for some off the shelf Raylites vs my Lithiums the other day- Lithium gave 15% more usable energy for the same 8 year life (3000 cycles), and cost 50% less! ...and that's not even considering the extra available energy from a given sized PV array due to the better efficiency of the LiFePO4s.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby FarmerJohn » Wed Aug 21, 2013 2:18 pm

Gordon-Loomberah wrote:You should have used my thread on Lithium vs Lead as evidence for the Lithium!
I did a quick calc for some off the shelf Raylites vs my Lithiums the other day- Lithium gave 15% more usable energy for the same 8 year life (3000 cycles), and cost 50% less! ...and that's not even considering the extra available energy from a given sized PV array due to the better efficiency of the LiFePO4s.


I did read that thread. It was the one that got me seriously thinking about doing it.

The argument was not about the cost savings which we all agree are very very real, it was about the support arrangements for when I am not around to do it.

The simple fact is, it was either Pb or a turnkey LiFePO4 system that could be supported by those other than myself.

Even the local battery specialists are only just getting into LiFePO4, and I am doing my bit to encourage them. If they had been able to supply and support a LiFePO4 system, that would have clinched it.

LiFePO4 is a game changer.
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby franks » Wed Aug 21, 2013 3:08 pm

Indeed, I agree today double PV and half battery size if LIFePO, lucky I got a mid cost flooded battery bank, due to replace in 6-7 years, Will get LiFePO for sure :)
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Re: Going Off-Grid.. AC / DC Coupling - What, How, Why - A Plan?

Postby davidg » Wed Aug 21, 2013 4:03 pm

FarmerJohn wrote:A few months ago my small prototype solar system failed when I wasn't there due to three days lack of sun and stupid mistake on charge timer which topped the batteries up off-peak.

You needed an inverter that if it fails, shutsdown or something goes wrong it simply reconnects to the grid by default to cover that issue, possible problem, if the grid is available. It really works!

FarmerJohn wrote:I decided that I wanted to install a failsafe that would switch back to grid, if the inverter ever stopped producing again when we were not there.

As above :)

FarmerJohn wrote:I think I should have gone for the Latronics - but I didn't, since Jaycar are just across the road from where I work.

Or an inverter that has it all in it already :)

FarmerJohn wrote: I was not able to get domestic clearance for a LiFePo4 solution

We live with what we are allowed to do, controlled by SWMBO :(

Where are you in NSW in relation to "Hay, NSW"?
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