Re: Wind Turbines and Heating Water

["Andy" <andywhitfield2002@xxxxxxxxxxx>]

Hi Graham,

The batteries won't regulate the voltage!!
The turbine must have a regulator on its output.
Otherwise you'll overcharge the batteries.
Overcharging will destroy the batteries and also produce hydrogen gas!!

I think you mentioned 4Ah batteries.  That is very small indeed.  I
suggest=
much bigger ones.

As for an inverter you can use a UPS in inverter mode.
UPSs in the range of approx 2200va to 5000va are often 48Vdc on the
battery=
bank.  Though not all are this voltage.

I have UPSs and batteries in stock.

Cheers
Andy the UPS Man

--- In ukha_d@xxxxxxx, Graham Kiff <graham.kiff@...> wrote:
>
> Hi Patrick
>=20
> The original reason for splitting the battery banks was to be able to
sup=
ply both 24v & 48v (I didn't realise 48v inverters were so readily
availabl=
e).  The reason for the batteries is purely voltage regulation rather than
=
storage of power.  I therefore think I can revert to just one bank of
batte=
ries.
>=20
> The plan was to use all the power produced to heat my thermal store to
~7=
0c, then once reached, dump the excess load via the inverted to the grid. 
=
I assume therefore I should use an inverter rated to the maximum output of
=
the turbine (1.4Kw in this case) - correct?
>=20
> So my setup will basically be:
> Turbine -> 4x12v batteries (in series) -> SEA24 440Amp relay
->
>  Either 48v DC Immersion Heater
>  Or  48v Grid-Tie Inverter
>=20
>=20
> Cost-wise I should be able buy everything for ~=A3900
> How does this sound?
>=20
> Cheers
> Graham
>=20
> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of=
patrick_o_matic
> Sent: 19 January 2010 13:53
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Re: Wind Turbines and Heating Water
>=20
> Hi Graham
> I have been looking at/designing a similar installation recently.
> Here are some fairly random thoughts:
>=20
> - What is the power storage for? 500W isn't much.
> - The normal rule of thumb is to size the battery store based on the
numb=
er of days 'no generation' that you might have endure. e.g. three-four
days=
successive calm days (or cloudy days for solar).=20
> - Battery life is contingent on depth of discharge. Ideally you want
to s=
ize your batteries so that they're not discharging more than 20% on
average=
, 50% worst case
> - The battery discharge characteristics in off-grid situations such as
yo=
urs are quite demanding chemically. Not sure which Yuasa batteries you are
=
planning on using, but normal leisure-style batteries are not up to the
job=
. Wet batteries are perfered. Traction-type batteries are particularly
well=
suited (e.g. forklift truck type cells). In case you didn't know, it's gen=
erally not a good idea to extend an existing battery bank over time, or
rep=
lace individual cells within the bank.
> - You ask about voltage. Broadly speaking, the higher voltage systems
are=
more efficient (lower resistive losses in transmission). 48V inverters are=
readily available (I think Sunny Boy are available in 48V variants). You m=
ay also want to consider splitting the inverter, so that intermittent
loads=
(e.g. lights) are driven from a load-sensing inverter and continuous loads=
are driven from an independent inverter. Inverter load curves vary, but th=
ey are generally more efficient when operating at the upper end of their
lo=
ad range.=20
> - You will need a dump load as well. It may make sense to use this for
sp=
ace heating?
> - I don't really understand the motivation behind splitting the
battery b=
anks and then controlling charging? What is the underlying driver for this
=
behaviour - is it being sure there is capacity in one of the banks for
esse=
ntial services or something else?
>=20
> Feel free to mail off-list if this is getting too OT for UKHA
>=20
> Cheers
> Patrick
>




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