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Low-voltage-in grid-tie as solar dump-load?
By DamonHD, Section Homebrewed Electricity Posted on Tue Apr 8th, 2008 at 12:54:09 PM MST
Is anyone dumping 'excess' into the grid this way?

Hi,
The lowest-voltage small grid-tie inverters I'm finding have a minimum input of ~24V, but it would seem a nice way to dump any 'excess' not needed by an otherwise off-grid system (not PWM of course, slow switch on/off with hysteresis).
For sources such as wind clearly there has to be fail-safe dump such as a heater, but it seems to me that this would be a 'nice' thing to do at an earlier stage (lower threshold).
Anyone know of any 12V-in ~200W max UK-approved (G83/1) grid-tie inverters? Nearest that I have found is the Mastervolt Soladin 600.
Rgds
Damon

Low-voltage-in grid-tie as solar dump-load? | 6 comments (6 topical, 0 editorial)

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#1)
by electronbaby (roy<at>windsine.org) on Tue Apr 8th, 2008 at 08:05:48 AM MST
(User Info) http://www.windsine.org

I have not heard of any products that fit your description except for some small 100w or 200w units that probably are not in production anymore. With a system voltage that low, you will have so much loss, that it would be hardly worth it. I would go with a higher voltage if I were you.
Have Fun!! RoyR KB2UHF

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#2)
by DamonHD (d@hd.org) on Tue Apr 8th, 2008 at 08:16:17 AM MST
(User Info) http://www.earth.org.uk/

I really do only want to 'dump' max 100W or 200W.

Part of my madcap scheme to use excess heat from a solar thermal system in summer, as well as from solar PV.

Losses may not be that important truth be told, I'd just rather be doing something slightly productive with the energy rather than just heating already-hot air...

(For example, our night-time load on the grid is ~40W for the whole house for everything including night-lights, server, clocks, etc. If I could be providing that from the excess heat in a very hot DHW tank overnight in summer then I'd be delighted!)

Rgds

Damon

[ Parent ]

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#4)
by Jon Miller (Fieldlines 'at' otherpower 'dot' co 'dot' uk) on Tue Apr 8th, 2008 at 09:59:26 AM MST
(User Info) http://www.otherpower.co.uk

Damon

Could you run a fan off the excess electricity to cool yourself down with the all ready hot air or maybe an absorption type fridge if you can not find a small grid tie inverter. How about charging an electric/scooter?

Just a couple of alternative options.

Jon M

www.otherpower.co.uk "I am certainly not a perfectionist, the thing is to know where you can take short c
[ Parent ]

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#5)
by DamonHD (d@hd.org) on Tue Apr 8th, 2008 at 10:25:08 AM MST
(User Info) http://www.earth.org.uk/

Hi,

Yes, good suggestions...

But I'd rather be nominally reducing CO2 emissions somewhere else rather than just 'wasting' the energy. Leaves us a little more fuel to burn in the winter when we really need it!

Rgds

Damon

[ Parent ]

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#3)
by fungus (info@reenergy.co.uk) on Tue Apr 8th, 2008 at 09:08:22 AM MST
(User Info) http://www.reenergy.co.uk/

There is a Mastervolt Soladin 120 , not 'really' approved for the UK but its safe and has been in the EU .. plugs into a normal wall socket.

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk

Re: Low-voltage-in grid-tie as solar dump-load? (3.00 / 0) (#6)
by DamonHD (d@hd.org) on Tue Apr 8th, 2008 at 10:27:04 AM MST
(User Info) http://www.earth.org.uk/

Hi,

Yes, the Soladin 120 looks quite close to what I want but its input voltage is higher than I'd like and as you point out it isn't approved for the UK.

I have emailed Mastervolt today to ask them what they have...

Rgds

Damon

[ Parent ]

Low-voltage-in grid-tie as solar dump-load? | 6 comments (6 topical, 0 editorial)

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