#1 Nov. 6, 2015 08:01:36

rogerhoward
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DC Circuits in the Home

I'm now adopting the Moixa philosophy of developing around the home Low/Ultra-Low DC Circuits for my digital devices. So far though, I'm not sure at all sure that the energy savings are as Moixa claim. But Moixa do seem to be attracting a lot of attention, for example https://rorybergin.wordpress.com/tag/moixa

This approach does seem to have the inadvertant benefit of the relevant Building Regulations being virtually single-page only. The missive of ‘no AC Circuits in the Wet Rooms’ (i.e. bathroom) can then be applied in each room.

That's quite handy if, like me, your place is stuck in the last millenium, and only has a single AC circuit upstairs plus a single AC circuit downstairs, held together by a single fuse wire in each!



Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

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#2 Nov. 6, 2015 10:36:17

WendyNorthrop
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DC Circuits in the Home

I looked at the Moixa(Maslow) units but thought that the initial design's inherent storage capacity (circa 5kWHr) was too small for my domestic-purposes… ( I am attracted by TESLA's Powerwall) and though it is not a primary personal concern, it would be interesting to see what a real-world ROI is for such a device (including the installation and maintenance costs of a domestic D.C. network) with reliability/capacity/use curves.
When I envisaged installing a Maslow unit I mentally-sketched using it as a centrally located D.C. power-supply facility for charging mobile ‘phones, tablets, laptop-computers hand-torches and exchangeable/re-chargeable power-cells AA, C, D et cetera and not as a power-network hub(p.d.u.) because I ’assumed' that the provision of a separate D.C. network would initially be quite messy, costly and time-consuming…
My property was constructed in the late 1800's and presumably has the same primitive circuit-wiring schema as does yours, though it has a modern p.d.u. and fairly modern (twin&earth) cabling

Edited WendyNorthrop (Nov. 6, 2015 17:06:05)

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#3 Nov. 16, 2015 23:50:09

rogerhoward
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DC Circuits in the Home

Wendy, there is a Maslow battery thread at http://www.microgen-database.org.uk/forum/topic/342 . I'm not using any Moixa kit personally.

For later comparison purposes, I've initially just concentrated on stabilising my baseline. notably in relation to my modest 3litre hot water dispenser, and my newish ‘manually operated’ hot water immersion heating. Although not on the scale of Microgen data donors practising immersion-switching to a hot water cylinder, I too do feel that a hot water holds more promise as a domestic energy store than a Lithium Iron electricity battery. My 3litre hot water dispenser does at least minimise the heat energy losses that occur over longer periods.

The picture attached in fact seems a slightly better one than at the same time last year despite now using immersion heating (apart from between Oct 27-Nov 3 when I'd gone rather potty due to a psychosis episode at my local hospital), and so too does my ‘PVOutput’ stats for the same recent weeks,
http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=w



Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

Edited rogerhoward (Nov. 16, 2015 23:50:58)

Attachments:
attachment Seaonal_Leccy_Tariffs_Usage_2015.JPG (54.8 KB)

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#4 Nov. 17, 2015 00:16:12

rogerhoward
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DC Circuits in the Home

Moixa amongst others had been quite loudly claiming energy savings of 25-30% for DC home circuits that include LED lighting (whereas all my LED lighting remains attached to my traditional AC fittings). Superficially this sounds quite attractive doesn't it?

From my experience though you are indeed quite right Wendy to ’assume that the provision of a separate D.C. network would initially be quite messy … and time-consuming'. But without it, what is the point in having a domestic battery of even the most modest size?

I now feel better prepared to bring into service my £15 Cerulian 7-port USB 2.0 hub - http://www.maplin.co.uk/p/cerulian-7-port-usb-20-mains-powered-triangular-desktop-hub-n11jb?gclid=CMPUuvqFlskCFacfwwodmWkDTg - for at least some of our 5 volt devices. (My USB hub can probably still only cater for about 1000mA of charging at once in total though.)

What is immediately apparent here though is that our appliances have a huge variety of voltages just amongst our portable battery-charging devices, let alone all the other digital equipment that we have around the home. Arranging appliances around the home in terms of specific DC voltage stepping is looking like quite a challenge to say the least.



Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

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#5 Nov. 17, 2015 09:58:34

Capetown
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DC Circuits in the Home

Quote from rogerhoward, “ what is the point in having a domestic battery of even the most modest size? ” I was wondering that as well! Interesting link though roger, it's dated in 2012 sometime, the blogger talks about converting AC to DC using “Transformers”, when it should be “Rectifiers”. I suppose it proves I read the link though! I still can't believe that battery storage (wether using AC and/or DC ) is viable, I await for someone to show me how it might be!



The gene pool has no lifeguard!

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#6 Nov. 18, 2015 16:46:12

pnews99@hotmail.co.uk
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DC Circuits in the Home

if smart meters are fitted and your energy company increases your peak time tariff by as much as 99 per cent which british gas did in a recent trial , according to the daily mail 18/11/15 . battery systems will become worth having to get you over the 4 to 8 pm peak period

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#7 Nov. 18, 2015 17:10:43

bhommels
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DC Circuits in the Home

@roger: I failed to find the 25-30% savings claim on the Maslow site. I find it hard to believe, as:
* a typical 240V LED driver is around ~90% efficient
* a typical DC-DC converter/LED driver has about the same efficiency
* cable losses will go up for DC circuits providing the same power, unless new thicker cables are laid which is expensive
They probably do some creative bookkeeping to arrive at the quoted figure.

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#8 Nov. 18, 2015 23:31:29

Capetown
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DC Circuits in the Home

pnews99@hotmail.co.uk
if smart meters are fitted and your energy company increases your peak time tariff by as much as 99 per cent which british gas did in a recent trial , according to the daily mail 18/11/15 . battery systems will become worth having to get you over the 4 to 8 pm peak period
Do you recon they will get that one past the regulator pnews?



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#9 Dec. 3, 2015 19:07:41

rogerhoward
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DC Circuits in the Home

Yes indeed … the ‘thicker cables’. Well done for warning people of that too, Bart.
What's worse is that the various company's off-the-shelf Ultra Low Voltage DC LED lighting drivers that you mention from the likes of Homebase, B&Q and especially Maplins all seems to have incompatible LED 12v DC voltage drivers - grr!

Hence there are indeed many reasons why I still haven't got stuck into this yet, and I agree that Moixa undoubtedly did some creative bookkeeping to arrive at their savings %. But there was in fact some interest shown in all this on the Navitron Forum.

I originally saw actual DC Lighting circuits on a tour proudly put on by our local outsourced council homes body (who'd claimed a £2M grant for energy efficiency improvements like this). In the particular council tenant's home that I was looking around, he was in fact quite enthusiastic about his DC lighting circuit(s) - which might have been 12v, 24v or 48v to stay within the aforementioned single-page Building Regulations. Hence why cables losses can be dealt with in principle. But I doubt that they have collected any figures for the efficiency results on his or indeed the whole estate's energy usage.

Personally, the most that I can achieve for the New Year is yet another 10W Homebase kit of modern SMD LED strip lights (to replace some old ‘Xmas Lights’ style LED lights) to string out to the top of the porch outside, for when I'm fumbling about in the dark outside trying to get in here.

Like you, I too feel that DC Lighting circuits are not for everyone's home, but it does seem promising for a small cottage like mine.



Economy 10 tariff provides 6.9p/kWh off-peak import between 12am-5am, 1pm-4pm and 8pm-10pm; http://www.pvoutput.org/aggregate.jsp?id=21047&sid=18934&v=2&t=m on approx. 63% off-peak usage, 22% solar usage, and 15% peak-rate usage.
1,900kWh annually is exported, mostly in summer, on approx. 3,200kWh generation. Approx. 4,500kWh/year is imported, mostly for (a) winter and springtime off-peak Storage Heaters, and (b) off-peak hot water Immersion heating (which is “dumb”, i.e. not linked to the solar PV).
PV array is split East-West. Income is from Phase II 21p/kWh Feed-in-Tariff plus smart metered 3.2p/kWh Export Tariff.

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#10 Dec. 3, 2015 19:32:36

Capetown
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DC Circuits in the Home

pnews99@hotmail.co.uk
if smart meters are fitted and your energy company increases your peak time tariff by as much as 99 per cent which british gas did in a recent trial , according to the daily mail 18/11/15 . battery systems will become worth having to get you over the 4 to 8 pm peak period
Errr have you got any figures to validate that statement “pnews99@hotmail.co.uk”?



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