12V regulator

[(unknown)]

Hello,

I've bought myself a 12V, 250W  immersion heater with the intention that all

the power from my nominal 12V 8ft Hugh Piggot wind generator is used to heat water

in a hot water cylinder.

I was originally thinking that the output from the wind turbine would go directly to

a 12V car battery (as a buffer), and that the immersion heater would be directly

connected to the battery.

But the blurb that comes with the immersion heater says that input voltage must not exceed

13.5V.  So that arrangement isn't going to work, is it, if the output from the wind turbine


goes up to 50V in a gale.

So I've been looking for a 12V, 20A voltage regulator ... but I can't find one anywhere.

Can anyone point me to where I should look. I've googled all over, but found

nothing suitable at any price.

Many thanks for any links...

Moved to the proper section.

[tanner0441]

Hi

You could use a low power regulator driving a current amplifier, remembering to allow for the forward voltage drop in the output stage. I am suprised though that there isn't a OEM chip out there.

Brian.

[ghurd]

That is a tall order.

Normal "12V nominal" is really 13.8V to 14.4V.

The low end of a charging battery is over 13.5V.  Even for SLA batteries.

Meaning the "12V" heater can not be used with any normal "12V" system.

Meaning there is no normal system that would not void the warranty?  You used it, so it is your fault?

Sounds like a loop-hole trick to get out of any warranty.

The regulator is not a problem.  Better regulators can do it.  My kit can do it, with a tweak or 2.

The limits set for the element are the problem.

I expect it will work fine to about 15.5V.  Most all '12V' items do.

The system will need a battery.  The heater is connected to the controller/regulator.

I had an old VW Beetle that called for over 100 octane.  It ran fine on 87.

Pointless, because over 100 was not available.

What brand, and where was the element purchased?

G-

[Ungrounded Lightning Rod]

Don't worry about that overvoltage in high wind.  The battery will clamp it.

You'll need some sort of controller to turn the heater on and off to keep it from sucking the battery down and damaging it.  That should also keep the battery in the normal charge range.  (If you only have a 250 watt heater and your genny puts out more in a high wind you may need some additional load and maybe another controller to keep the battery from overcharging.  You don't want it getting above the equalization voltage - or even into that range for a long time.)

Others have already commented on the 13.5V rating being suspicious.

[Ungrounded Lightning Rod]

You'll need some sort of controller to turn the heater on and off to keep it from sucking the battery down and damaging it.

In other words:  Use a dump load controller with the heater as the first stage dump load.  If your genny is big enough to overcharge your battery in a gale even with the heater turned on, use a two-stage controller (or two single-stage controllers with different set points) and use some other load as your second-stage dump load.

[tecker]

 Put the heater element in series with your charging circuit directly connected to batt

plus You'll go slightly over the tolorence with fullcharge but that's not that bad really .I use 1500 watt 120 volt 10 ohm ( $19 at Homey) that  would  suite a Dump for your stator .

[dnix71]

If the heaters are cheap enough, just buy another. Put the two in series. Individually they won't get as hot as designed, but the water will get just as hot.

[Ungrounded Lightning Rod]

Put the two in series. Individually they won't get as hot as designed, but the water will get just as hot.

Not true for two in series.  Total would only provide about half as much heat.  (A bit more than half, actually.  See below.  But nowhere near the same total.)

Four in 2x2 series-parallel WOULD give you the same heat as one, though each would be cooler.  (Somewhat more, actually, because the resistance rises somewhat with temperature so the set of four will pull a bit more power.)

[laskey]

I'm sure dnix71 meant put two in parallel to achieve what he was talking about.

And I love the whole thing about don't exceed 12V.  It's just a heating element, you could probably put 50 VDC on it for a short time with out damage...  it's not made out of ground up baby, it's a coil of copper for god sakes... give'r!!!

[(unknown)]

Thanks, I like your answer the best!

ie...you could probably put 50 VDC on it for a short time with out damage..

I've got an old car battery lying around, so I think I'll do what I was originally planning ... output of wind turbine into battery.. battery supplies immersion heater.

It does mean that the battery will completely drain when there is no wind, so that won't do it any good,  but it's an old battery anyway.

Maybe I should miss out the battery completely, as I feel it is going to waste energy as it warms up in its charge/ discharge cycle!

The immersion heaters aren't cheap at £50 with postage, so I don't really want to knacker it.

http://www.reuk.co.uk/Immersion-Heater-Elements-for-Wind-Turbines.htm

Thanks for the comments

Richard, Inverness, Scotland

[electrondady1]

forget the battery all together.

 put some big capacitors in line with your heater

http://www.fieldlines.com/story/2006/9/14/17359/1190

http://www.fieldlines.com/story/2006/9/16/225354/917

http://www.fieldlines.com/story/2006/10/29/201016/09

i can't help you with the capacitor size but  check out

our commonwealth brothers at

http://www.thebackshed.com/Windmill/default.asp

those boys are into caps !!

[JamesJackson]

I know this is a bit late - and may be a bit 'yesterday', but didn't the older vehicles - the ones that used generators - instead of alternators - have regulators?

I seem to remember my old 1972 VW beetle using a generator and regulator.

The regulators were relays inside of a metal box, and may not be exactly what you had in mind, but I would think that an automotive junkyard or auto parts store may be a source for one of these.

Regards,

James Jackson

[Flux]

Not as simple as you are hoping.

A battery can't be just left to go flat even if it is knackered. When it sulphates it will not regulate the voltage.

You won't be able to use the heater directly without a battery and just forget the capacitor idea.

Either you need a special controller which you most likely will have to build or you need a battery with simple charge controller and probably a low voltage disconnect unless you have a relay and switch the heater in when the charge is somewhere near to the heater draw.

It would seem more logical to use a battery with shunt regulator and use the heater as the dump load. Unfortunately it will not dump the full turbine power in a good wind so you will need more dump in parallel with it if you do it this way so the full turbine energy will not dump to the heater.

It would work with 2 heaters in parallel if you could furl the turbine down to about 500W but with the stupid cost of those heaters your payback time would be long just to pay for the heaters alone.

There must be cheaper ways to dump 700W into a hot water system but if you want a simple off the shelf option you pay through the nose for it.

Flux

[ghurd]

See what ULR said.

And "the immersion heater says that input voltage must not exceed

13.5V".

Something is very wrong.  

Look for a new retailer.

G-