Inverter - can it run fans and fridge?

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#1414675 27-Oct-2015 14:08

you have to constantly trim tomatoes anyways, i trim my tomatoes weekly and still get a tonne of green off them, its just how they are unless you get determinate ones which grow to x height and stop.

i grow stuff in there till its about 1 foot tall tops then transplant, i use dynamic lifter, nurtifert and sea sol, and never had an issue with a plants stregnth.

personally i dont see the fan helping much. changing how you water might have a more noticeable impact.

timmmay

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#1414722 27-Oct-2015 14:54

I use self watering containers. I do think I want some fans in there, it can't hurt. I guess I'll look around some more for 12V oscillating fans, and might give that cheaper 12V extractor fan a go too.

MikeAqua

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#1415627 28-Oct-2015 17:23

Try marine RV supply stores e.g.

https://www.burnsco.co.nz/searchresults.aspx?q=fan

The main thing I want is a small oscillating fan or two, to move heat around the greenhouse, and because a bit of a breeze encourages plants to grow stronger rather than higher - I'm told. You can get 12V fans made for in cars but they're tiny - my greenhouse isn't huge, 4m long, 2.5m wide, 2.5m high, but I'm thinking something like small desk fan size up to household fan size. Anyone know where I can get them in 12V?

Mike

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#1415632 28-Oct-2015 17:29

Bilge blowers are designed for continuous use while a boat is running e.g. to maintain air changes in an engine room for cooling purposes.

richms:
timmmay:
I want something easy, clean, and compact. It's not a big greenhouse so any big spinning fans would be really intrusive. One of those inline type fans would be the kind of thing I'd look at, but probably a bigger one.

Look for bilge blowers perhaps? No idea how they would go for continuous use tho.

Mike

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#1415634 28-Oct-2015 17:30

I find if I pinch out the top shoot the plant stops growing - although I get more laterals.

Jase2985: you have to constantly trim tomatoes anyways, i trim my tomatoes weekly and still get a tonne of green off them, its just how they are unless you get determinate ones which grow to x height and stop.

Mike

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#1415655 28-Oct-2015 18:02

MikeAqua: I find if I pinch out the top shoot the plant stops growing - although I get more laterals.

Jase2985: you have to constantly trim tomatoes anyways, i trim my tomatoes weekly and still get a tonne of green off them, its just how they are unless you get determinate ones which grow to x height and stop.

yep, but on those laterials do some of those not end up growing into the new main stem?

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#1415689 28-Oct-2015 19:10

Ebay/Amazon have similar fans to the marine places but quite a bit cheaper, thanks for the link though. A couple of cheap ebay fans might do the job. The bilge fan sounds like it could be ok for extraction too.

While I'm asking questions, any recommendation for a thermostat? Or a timer? Or a combined thermostat timer? So I could run the fan between midday and 4pm if the temperature is above 25 degrees? Asking a lot I know! Maybe just a 12V timer would be good enough - plenty of those on ebay.

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richms

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#1415732 28-Oct-2015 20:22

Aliexpress has heaps of 12v thermostats and timers. Cheaper than anything I could make myself.

Richard rich.ms

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#1416035 29-Oct-2015 11:14

You check the plants twice a week and pinch the laterals out. This encourages upward growth, stem thickness and flowering.

When I say 'laterals' I am referring to the shoots that grow from the junction between a main stem and a side branch.

Jase2985:

yep, but on those laterals do some of those not end up growing into the new main stem?

Mike

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#1418166 1-Nov-2015 15:41

timmmay: Thanks for all the thoughts and info. I considered 12V first, it's sometimes a bit tricky to find what I'm after. Maybe what I want is impractical. We already have gas cooking

The main thing I want is a small oscillating fan or two, to move heat around the greenhouse, and because a bit of a breeze encourages plants to grow stronger rather than higher - I'm told. You can get 12V fans made for in cars but they're tiny - my greenhouse isn't huge, 4m long, 2.5m wide, 2.5m high, but I'm thinking something like small desk fan size up to household fan size. Anyone know where I can get them in 12V?

I was thinking about exhaust fans, because it does get pretty hot in there. In summer you're meant to change the air every minute or so, which requires an impractically large fan. Let's say we want to change 10% of the air a minute, 2.5 cubic meters per minute, which is around 85 cubic feet per minute or 1 cubic foot per second. If my calculations are right that $40 fan from trademe would do that, but it's still 1/5 of the recommended change volume. Still, probably better than nothing :)

A radiator fan would be fine as an extrator, but I'd have to get one, mount it somehow, cut holes, etc. Sounds like more hassle than I want to go to!

The warehouse.

I have two usb fans from there. $10 each.

They look like small desktop fans. Not oscillating though but do you really need that or would a handful of fans do?

I have a pair that are cooling hard drives on my file server. They shift a lot of air for a small fan.

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#1418238 1-Nov-2015 18:21

I think oscillating would be better, otherwise it'll just be nailing one or two plants constantly. Thanks for the idea though.

garyasta

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#1418505 2-Nov-2015 08:22

The best bet is to contact an alternative energy company. They will advise as to the loads that each appliance will need.

A fridge will have a significant startup load, so care is needed here.

The battery size, inverter size, solar panel controller, and solar panel size will all need to be balanced to supply a suitable system. The battery will need to be a deep cycle storage type, and the larger the better. If you virtually empty the battery with night-time usage each day, it will not have a very long lifespan. It is better to only use about 20% max of its capacity each day. You will also need to consider that you will lose about 20% of your solar generation from the time the panel produces the electricity, to the time it is available for your appliances.

First of all, do you need to use 240 volts for your system? It is possible to get 12v frigs and a 12v car engine cooling fan may well suit your purpose as your enclosure is not that large and remember that it is an enclosed space. I'm not sure if microwaves come in 12v types.

Go talk to a company that supplies solar systems first.

surfisup1000

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#1418508 2-Nov-2015 08:25

andrewNZ: Electric motors draw significantly more power on startup (up to 6x). The inverter needs to be able to supply that.

It depends. Some motors use start up capacitors. At least, I believe that is the case with our dryer -- -the repair person was telling me about the capacitor which exploded inside ours.

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#1418510 2-Nov-2015 08:27

garyasta: The best bet is to contact an alternative energy company. They will advise as to the loads that each appliance will need.

I was more thinking about using an invertor for something else, seeing it it would power things in emergencies. If I wanted to actually power things regularly I'd do it properly.

A friend of mine spent $13K on a solar setup recently, with no storage. I'm getting similar savings to him simply by switching to Flick Electric.

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#1419762 3-Nov-2015 13:03

Ok, I'd like to refocus the question. Ignore the fridge thing. Could a cheap inverter like the "unspecified" modified sine wave one above power a couple of desk fans? They're typically low current. I'm thinking, yes, they probably can.

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