What I would like to do is warm a greenhouse or just some seed trays. Not to
tropical temperatures, obviously, but I'd be interested to see what can be
done.

First thoughts are... one of these
http://cgi.ebay.co.uk/12V-200W-CERAM...mZ330220350669
attached to a car battery which is charged by an alternator and fan set-up
yet to be built.

8x7 greenhouse. Would it raise the temperature much? I'm thinking not much,
considering it's only 200w.

Alternatively what about a 12v heat mat powered by the same means?

Si

"Mungo "Two Sheds" Toadfoot" wrote in message
...
What I would like to do is warm a greenhouse or just some seed trays. Not
to
tropical temperatures, obviously, but I'd be interested to see what can be
done.

First thoughts are... one of these

http://cgi.ebay.co.uk/12V-200W-CERAM...BOAT-CAMPING_W
0QQitemZ330220350669
attached to a car battery which is charged by an alternator and fan set-up
yet to be built.

8x7 greenhouse. Would it raise the temperature much? I'm thinking not
much,
considering it's only 200w.

Alternatively what about a 12v heat mat powered by the same means?

Si






600w metal hylide bulb is about the right temp for cannabis?

HI SI

On Sun, 23 Mar 2008 20:01:21 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

What I would like to do is warm a greenhouse or just some seed trays. Not to
tropical temperatures, obviously, but I'd be interested to see what can be
done.

First thoughts are... one of these
http://cgi.ebay.co.uk/12V-200W-CERAM...mZ330220350669
attached to a car battery which is charged by an alternator and fan set-up
yet to be built.

8x7 greenhouse. Would it raise the temperature much? I'm thinking not much,
considering it's only 200w.

Alternatively what about a 12v heat mat powered by the same means?


The smaller the area (volume) you're heating - the higher the
temperature rise you'll be able to achieve.

If you're looking at raising seedlings in seed trays then you could
construct a simple sand bed with a heating cable running through it -
and put the car battery across the cable.

Trouble is - standard car batteries don't like being fully discharged
- 'leisure' batteries (caravan batteries) work better in this mode.

If you're stuck with a car battery then it might be an idea to design
some sort of circuit that disconnects the battery when its voltage
drops - to avoid completely flattening it...

In the 'It's hard being green' series they built a heat-store into a
greenhouse, by blowing warm air from the top of the greenhouse through
a rock store in the floor of the greenhouse - this heat was then
released overnight - keeping the greenhouse warmer overall...

Another way round would be to build a mini-solar-water system -
and use that to heat a decent volume of water stored in the greenhouse
- seed-trays could sit on top of the water tank, maybe....

In its simplest form, black-painted oil drums, placed in the
greenhouse & filled with water will absorb heat in the daytime and
release it at night....

All depends on what you're trying to achieve......

You'll get losses as you convert wind energy to electrical energy -
and then convert that again to heat... will be less efficient than a
simple water-based system

Adrian

George wrote:

600w metal hylide bulb is about the right temp for cannabis?

Is it? I've never understood why people want it.

Si

Adrian wrote:

HI SI

'Ello Ade,


The smaller the area (volume) you're heating - the higher the
temperature rise you'll be able to achieve.


Yup.

If you're looking at raising seedlings in seed trays then you could
construct a simple sand bed with a heating cable running through it -
and put the car battery across the cable.


It's mainly for chilli seeds, some of which need the soil to be at around 90
degrees F before they'll germinate.

Trouble is - standard car batteries don't like being fully discharged
- 'leisure' batteries (caravan batteries) work better in this mode.

If you're stuck with a car battery then it might be an idea to design
some sort of circuit that disconnects the battery when its voltage
drops - to avoid completely flattening it...


As it's very often windy here I was thinking/hoping that a fan-powered car
alternator, running through a voltage regulator, might be able to keep the
battery happy and charged as I'd have thought a heat mat or two would be
less demanding than a car's electrical equipment.

In the 'It's hard being green' series they built a heat-store into a
greenhouse, by blowing warm air from the top of the greenhouse through
a rock store in the floor of the greenhouse - this heat was then
released overnight - keeping the greenhouse warmer overall...


I saw that - I think it's a bit late to build one now as the greenhouse is
on decking and I'm buggered if I'm taking that up or cutting holes in it )

Another way round would be to build a mini-solar-water system -
and use that to heat a decent volume of water stored in the greenhouse
- seed-trays could sit on top of the water tank, maybe....

In its simplest form, black-painted oil drums, placed in the
greenhouse & filled with water will absorb heat in the daytime and
release it at night....


I did see a couple of radiators offered on Freecycle and considered a water
system but that wouldn't work when I need it most - now. Chillies need as
long a growing season as possible and it's starting germination that's the
problem so electrical or paraffin is probably the way to go, but I wondered
if I could make use of wind power as there's quite a lot of that.

All depends on what you're trying to achieve......

You'll get losses as you convert wind energy to electrical energy -
and then convert that again to heat... will be less efficient than a
simple water-based system


But it would be easier to build and install... probably.

I've just found a 240v heatmat under the stairs that we bought yonks ago and
it's only 11-13w so if it heats the compost sufficiently I'm thinking a car
battery should cope with a couple of 12v jobbies easily. Can't easily get
mains to the greenhouse though.

Si

Mungo "Two Sheds" Toadfoot wrote:

As it's very often windy here I was thinking/hoping that a
fan-powered car alternator, running through a voltage regulator,
might be able to keep the battery happy and charged

Of course, that means sourcing a suitable fan. Fan? Impeller? Turbine!
That's the fella! I wants a turbine! )

Si

Mungo "Two Sheds" Toadfoot wrote:
Mungo "Two Sheds" Toadfoot wrote:

As it's very often windy here I was thinking/hoping that a
fan-powered car alternator, running through a voltage regulator,
might be able to keep the battery happy and charged

Of course, that means sourcing a suitable fan. Fan? Impeller? Turbine!
That's the fella! I wants a turbine! )


HFM!?

I'll start them indoors on the 240v heat mat, eh?

Si

HI Si
On Sun, 23 Mar 2008 20:58:27 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Adrian wrote:

HI SI

'Ello Ade,

Cheeky !
g



The smaller the area (volume) you're heating - the higher the
temperature rise you'll be able to achieve.


Yup.

If you're looking at raising seedlings in seed trays then you could
construct a simple sand bed with a heating cable running through it -
and put the car battery across the cable.


It's mainly for chilli seeds, some of which need the soil to be at around 90
degrees F before they'll germinate.

Gosh - that's hot.
I've got one of those electrically-heated propogators - the 'just
smaller than 2 seed-trays' variety grrr


Trouble is - standard car batteries don't like being fully discharged
- 'leisure' batteries (caravan batteries) work better in this mode.

If you're stuck with a car battery then it might be an idea to design
some sort of circuit that disconnects the battery when its voltage
drops - to avoid completely flattening it...


As it's very often windy here I was thinking/hoping that a fan-powered car
alternator, running through a voltage regulator, might be able to keep the
battery happy and charged as I'd have thought a heat mat or two would be
less demanding than a car's electrical equipment.

Maybe.
Many, many years ago (when I was in the Scouts!) - I set up a
multiple-tent-lighting system with low-wattage bulbs and a car battery
-
which lasted a surprisingly short time before it went completely flat.
As I understand it - a car battery is designed to give a couple of
really high-currrent blasts, and then be recharged, rather than suffer
from a slow discharge.....(sounds nasty!)


In the 'It's hard being green' series they built a heat-store into a
greenhouse, by blowing warm air from the top of the greenhouse through
a rock store in the floor of the greenhouse - this heat was then
released overnight - keeping the greenhouse warmer overall...


I saw that - I think it's a bit late to build one now as the greenhouse is
on decking and I'm buggered if I'm taking that up or cutting holes in it )

Ah - I see your point !


Another way round would be to build a mini-solar-water system -
and use that to heat a decent volume of water stored in the greenhouse
- seed-trays could sit on top of the water tank, maybe....

In its simplest form, black-painted oil drums, placed in the
greenhouse & filled with water will absorb heat in the daytime and
release it at night....


I did see a couple of radiators offered on Freecycle and considered a water
system but that wouldn't work when I need it most - now. Chillies need as
long a growing season as possible and it's starting germination that's the
problem so electrical or paraffin is probably the way to go, but I wondered
if I could make use of wind power as there's quite a lot of that.

Yes _ I get that effect with chillies g
Seriously though - how about starting them off indoors (where you do
have mains) and then taking them out the the greenhouse once they're
big enough ?


All depends on what you're trying to achieve......

You'll get losses as you convert wind energy to electrical energy -
and then convert that again to heat... will be less efficient than a
simple water-based system


But it would be easier to build and install... probably.

g..... probably......


I've just found a 240v heatmat under the stairs that we bought yonks ago and
it's only 11-13w so if it heats the compost sufficiently I'm thinking a car
battery should cope with a couple of 12v jobbies easily. Can't easily get
mains to the greenhouse though.

Hmm
If it's 11w heating at 240V then that'll be .04A
Same heating mat at 12v will give 9/10 of b-all - as in .03W

To get 11W out of 12v you're going to need an amp or so -
only way to see how long it works for is to suck it & see g

FWIW - I managed to flatten the little battery on my '64 moggie by
leaving the interior light on for 5 hours or so while working on the
front doors (doh!) - and I'd guess that the current drawn would be
similar...

I guess the other option is a couple of batteries - one on mains
charge inside the house and the other in use - but I sense a deep
desire here to build a windmill..... am I right ??

Have fun !
Adrian

Mungo "Two Sheds" Toadfoot explained on 23/03/2008 :
What I would like to do is warm a greenhouse or just some seed trays. Not to
tropical temperatures, obviously, but I'd be interested to see what can be
done.

First thoughts are... one of these
http://cgi.ebay.co.uk/12V-200W-CERAM...mZ330220350669
attached to a car battery which is charged by an alternator and fan set-up
yet to be built.

The discharge would be much larger than the charge for most of the
time. A 12v car battery could only keep the heater running for perhaps
2 hours and the battery would soon be damaged by such use.


8x7 greenhouse. Would it raise the temperature much? I'm thinking not much,
considering it's only 200w.

Probably not by very much, the heat losses through the fabric would be
too great.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Adrian wrote:
It's mainly for chilli seeds, some of which need the soil to be at
around 90 degrees F before they'll germinate.

Gosh - that's hot.
I've got one of those electrically-heated propogators - the 'just
smaller than 2 seed-trays' variety grrr


Funny, aren't they? I'm using Poundland 6-for-a-pound ice cube trays and a
squillion-for-a-pound polystyrene cups this year!

Many, many years ago (when I was in the Scouts!) - I set up a
multiple-tent-lighting system with low-wattage bulbs and a car battery
-
which lasted a surprisingly short time before it went completely flat.
As I understand it - a car battery is designed to give a couple of
really high-currrent blasts, and then be recharged, rather than suffer
from a slow discharge.....(sounds nasty!)


Heh! Yes, I just read that and was reminded that they're made to give lots
of amps for a short period of time. I also read that forklift truck
batteries are the things to have. I'll just nip out and get some...

Seriously though - how about starting them off indoors (where you do
have mains) and then taking them out the the greenhouse once they're
big enough ?


Yes, that's what I'll have to do now that I'm thinking realistically! I
might even build a frame to keep the warm in.

I guess the other option is a couple of batteries - one on mains
charge inside the house and the other in use - but I sense a deep
desire here to build a windmill..... am I right ??


Dammit! I wanted a windmill! Ah well, as I haven't got an alternator, a
battery, a fan, a pole, or a metal-working shop I suppose I'll just have to
start my chillies indoors.

Buggrit.

'64 Moggie, eh? Same age as me. Is it as knackered?

Si

Harry Bloomfield wrote:
Mungo "Two Sheds" Toadfoot explained on 23/03/2008 :
What I would like to do is warm a greenhouse or just some seed
trays. Not to tropical temperatures, obviously, but I'd be
interested to see what can be done.

First thoughts are... one of these
http://cgi.ebay.co.uk/12V-200W-CERAM...mZ330220350669
attached to a car battery which is charged by an alternator and fan
set-up yet to be built.

The discharge would be much larger than the charge for most of the
time. A 12v car battery could only keep the heater running for perhaps
2 hours and the battery would soon be damaged by such use.


Thanks, Harry. I've pretty much given up on the idea of free 'letric now.
It's a nice idea though, eh?

Si

Mungo "Two Sheds" Toadfoot wrote:
George wrote:
600w metal hylide bulb is about the right temp for cannabis?

Is it? I've never understood why people want it.

Si


What - cannabis or the halide bulb?

On the hot chillies, I suggest you stick 'em in the airing cupboard
until they've poked their heads up. They won't care it's dark until then.

Andy

Andy Champ wrote:
Mungo "Two Sheds" Toadfoot wrote:
George wrote:
600w metal hylide bulb is about the right temp for cannabis?

Is it? I've never understood why people want it.

Si


What - cannabis or the halide bulb?

On the hot chillies, I suggest you stick 'em in the airing cupboard
until they've poked their heads up. They won't care it's dark until
then.

We recently had new central heating throughout and I was slightly miffed to
find that the temp in the airing cupboard doesn't go above 65-70 now!

Shakes fist Bloody decent insulation!

Si

Mungo "Two Sheds" Toadfoot wrote:
SNIP
I've just found a 240v heatmat under the stairs that we bought yonks
ago and it's only 11-13w so if it heats the compost sufficiently I'm
thinking a car battery should cope with a couple of 12v jobbies
easily. Can't easily get mains to the greenhouse though.

Si

Could you get ELV from the house to the greenhouse, or charge batteries in a
wheelbarrow just ouside the house?

Martin Crossley wrote:
Mungo "Two Sheds" Toadfoot wrote:
SNIP
I've just found a 240v heatmat under the stairs that we bought yonks
ago and it's only 11-13w so if it heats the compost sufficiently I'm
thinking a car battery should cope with a couple of 12v jobbies
easily. Can't easily get mains to the greenhouse though.

Si

Could you get ELV from the house to the greenhouse,

You saying that - I recently ran some 1mm t&e outside to where the bike
lives so I could use a Lidl Optimate-style battery charger (the 1mm is
carrying the 12v). I could get another one and do that again, I imagine.
Hmmm...

Si

Hi Si

On Sun, 23 Mar 2008 21:36:03 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Adrian wrote:
It's mainly for chilli seeds, some of which need the soil to be at
around 90 degrees F before they'll germinate.

Gosh - that's hot.
I've got one of those electrically-heated propogators - the 'just
smaller than 2 seed-trays' variety grrr


Funny, aren't they? I'm using Poundland 6-for-a-pound ice cube trays and a
squillion-for-a-pound polystyrene cups this year!

Probably just as effective !
Mum & Dad always used 'recycled' containers for their tomato seedlings
- all kind of yoghourt pots, cut-dwon fairy liquid bottles &
whatnot...



Many, many years ago (when I was in the Scouts!) - I set up a
multiple-tent-lighting system with low-wattage bulbs and a car battery
-
which lasted a surprisingly short time before it went completely flat.
As I understand it - a car battery is designed to give a couple of
really high-currrent blasts, and then be recharged, rather than suffer
from a slow discharge.....(sounds nasty!)


Heh! Yes, I just read that and was reminded that they're made to give lots
of amps for a short period of time. I also read that forklift truck
batteries are the things to have. I'll just nip out and get some...

You'll need the forklift truck to lift 'em with. g


Seriously though - how about starting them off indoors (where you do
have mains) and then taking them out the the greenhouse once they're
big enough ?


Yes, that's what I'll have to do now that I'm thinking realistically! I
might even build a frame to keep the warm in.

That'd work - expanded poly or somesuch


I guess the other option is a couple of batteries - one on mains
charge inside the house and the other in use - but I sense a deep
desire here to build a windmill..... am I right ??


Dammit! I wanted a windmill! Ah well, as I haven't got an alternator, a
battery, a fan, a pole, or a metal-working shop I suppose I'll just have to
start my chillies indoors.

Ah - yes - you are missing one or two of the vital ingredients.


Buggrit.

Millennium hand & shrimp...


'64 Moggie, eh? Same age as me. Is it as knackered?

I've got no idea or your condition, sirrah ! g
No - she's a good one. Odd bit of rust showing up on the bodywork -
but mechanically pretty good. She's a Traveller - and does sterling
service hauling my stained / fused glass around the local open-air
markets.
Not a weekend goes by without some person 'of a certain age' going all
dewey-eyed and telling me that their Dad / formmaster / uncle had 'one
of those', or that they had one and drove it across America / India /
the continent, or that they learned to drive in one / lost their
virginity on one / were conceived in one..... - what fun !

Adrian

On 23 Mar, 20:01, "Mungo \"Two Sheds\" Toadfoot"
wrote:
What I would like to do is warm a greenhouse or just some seed trays.

Soil heating cable. Doesn't cost too much, running costs are much
better than anything else.

Heating the airspace itself is to stop frost killing existing green
growth. For seedlings, just warm the soil.

Adrian wrote:

Buggrit.

Millennium hand & shrimp...


Poor old Terry. How fair's that?


'64 Moggie, eh? Same age as me. Is it as knackered?

I've got no idea or your condition, sirrah ! g
No - she's a good one. Odd bit of rust showing up on the bodywork -
but mechanically pretty good. She's a Traveller - and does sterling
service hauling my stained / fused glass around the local open-air
markets.

You are Jack Hargreaves and I claim my five free phallic farming implements.

Not a weekend goes by without some person 'of a certain age' going all
dewey-eyed and telling me that their Dad / formmaster / uncle had 'one
of those', or that they had one and drove it across America / India /
the continent, or that they learned to drive in one / lost their
virginity on one / were conceived in one..... - what fun !


Heh! I never owned one, or knew anyone who did apart from my father-in-law
but he crashed and killed it before I came along. Good for transporting
stained glass, I hear. Moggies, not father-in-laws. I imagine it's handy
being able to stand in the engine bay beside the engine to work on it too.

Si

Andy Dingley wrote:
On 23 Mar, 20:01, "Mungo \"Two Sheds\" Toadfoot"
wrote:
What I would like to do is warm a greenhouse or just some seed trays.

Soil heating cable. Doesn't cost too much, running costs are much
better than anything else.

Heating the airspace itself is to stop frost killing existing green
growth. For seedlings, just warm the soil.

Ta, but mains = pita.

Si

After serious thinking Mungo "Two Sheds" Toadfoot wrote :
Martin Crossley wrote:
Mungo "Two Sheds" Toadfoot wrote:
SNIP
I've just found a 240v heatmat under the stairs that we bought yonks
ago and it's only 11-13w so if it heats the compost sufficiently I'm
thinking a car battery should cope with a couple of 12v jobbies
easily. Can't easily get mains to the greenhouse though.

Si

Could you get ELV from the house to the greenhouse,

You saying that - I recently ran some 1mm t&e outside to where the bike lives
so I could use a Lidl Optimate-style battery charger (the 1mm is carrying the
12v). I could get another one and do that again, I imagine. Hmmm...

The voltage drop might kill that idea.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

HI Si

On Mon, 24 Mar 2008 12:12:35 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Adrian wrote:

Buggrit.

Millennium hand & shrimp...


Poor old Terry. How fair's that?

Absolutely.....
still - some legacy when it finally takes him.

Just watched the first 1/2 of Sky's Colour of Magic -
quite well done, I thought....


'64 Moggie, eh? Same age as me. Is it as knackered?

I've got no idea or your condition, sirrah ! g
No - she's a good one. Odd bit of rust showing up on the bodywork -
but mechanically pretty good. She's a Traveller - and does sterling
service hauling my stained / fused glass around the local open-air
markets.

You are Jack Hargreaves and I claim my five free phallic farming implements.

g
Had to look that one up - recalled the name but couldn't remember
why...


Not a weekend goes by without some person 'of a certain age' going all
dewey-eyed and telling me that their Dad / formmaster / uncle had 'one
of those', or that they had one and drove it across America / India /
the continent, or that they learned to drive in one / lost their
virginity on one / were conceived in one..... - what fun !


Heh! I never owned one, or knew anyone who did apart from my father-in-law
but he crashed and killed it before I came along. Good for transporting
stained glass, I hear. Moggies, not father-in-laws. I imagine it's handy
being able to stand in the engine bay beside the engine to work on it too.

Somewhere warm & out of the rain to sit when it rains g

I can just about handle the level of technology used in the Traveller
- (have a large hammer and an adjustable wrench!)

- I'm still in shock at the cost of a set of plugs for my 'old' car -
Toyota RAV4. OK - so they last 40k-miles - but !!!

Also - lack of computers in the Mog seems like a definite advantage -
since the argument I had a few years ago with a Merc A-class that was
convinced the windows were wound up shut - when, in actual fact, they
were completely open. (Can you hear me, Hal ?)

Adrian

parafin heater.