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A better defender heater - a new project!


simonr

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The original heater matrix is still there, only the on/off flap is gone. The cable broke on mine about 6 years ago anyway, so I don't suppose I'll miss it.

I got a bit carried away in fitting the whole thing together, so I forgot to take any photos of the element inside the heater box.

The idea of the PTC is just to provide demisting for the first few miles while waiting for the tdi to make some heat.

http://www.dbk-usa.com/ptc-heaters/about-ptcs

I have a webasto anyway, so don't really need it, but it's an interesting experiment.

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I had the same thought... tried a 20W Cabinet Heater last year stuck to the dashboard. Despite being only 20W, my theory was that it was small enough to put in the flexi between the dashboard and vent, then force air through it with the main fan. You'd need 2 of course, otherwise the air would just take the easy route out of the unrestricted vent.

Astoundingly it did actually have a noticeable effect, despite its tiny little fan. It demisted about a 2" circle on the screen :wacko:

That's more than I thought it would achieve, and sadly in a Defender sometimes you'd really kill for even a 2" bit of screen that didn't mist over every few seconds!

Overcooling it with the main fan running full chat would push it's real power limit up a bit, but I don't think even 30W would have been enough to be worth the hassle.

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The original heater matrix is still there, only the on/off flap is gone. The cable broke on mine about 6 years ago anyway, so I don't suppose I'll miss it.

I got a bit carried away in fitting the whole thing together, so I forgot to take any photos of the element inside the heater box.

The idea of the PTC is just to provide demisting for the first few miles while waiting for the tdi to make some heat.

http://www.dbk-usa.c...ters/about-ptcs

I have a webasto anyway, so don't really need it, but it's an interesting experiment.

If the cable has gone... do you have a need for the cable clamping bits on the heaterbox end?

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I like the PTC idea!

Another thing I added to a previous Land Rover - but got rid of the truck before I had a chance to try it out in proper cold weather.

I connected the chamber under the heater intake vent via a bit of drain pipe to a vent in the passanger footwell. Then I fabricated a hinged flap on top of the intake vent. The flap was spring open and closed via a choke cable. In the open position it acted as an air scoop (though I'm not convinced it made much difference to the air flow.

In the closed position, the heater sucked air from the passanger foorwell instead of the outside. It made a big difference to the temperature of the air coming out the vents - and was very simple plumbing wise! If I did it again I'd use a bit of flexible pipe, about 3" bore which would be even easier!

Interestingly, it set up a circulation pattern that heated the rear of the vehicle more effectively than before. Closing the flap also meant that the heater did not fill up with water while wading with the bow wave washing over the wings. I wondered to myself why Land Rover didn't do something like this as standard and use a butterfly valve to close the intake.

Si

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Should be interesting Si!

One idea I have seen floating around is using a PWM controller to get rid of the stupid selector switch from the equation altogether...

If someone is thinking of buying one, I have a tip - don't! I did and installed it only to find that the blower could only go up to less than half speed when the thingie was turned on full. :angry:

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If someone is thinking of buying one, I have a tip - don't! I did and installed it only to find that the blower could only go up to less than half speed when the thingie was turned on full. :angry:

That being the case, since the switch on the dash is intended for two speed operation, use the first position to give you 0 to 50% via the PWM (fed with 12v, not through the half speed ballast resistor) and the second position to bypass the PWM to give you full speed.

Are you sure you were feeding the power into the right wires on the motor? It seems unlikely that a PWM controller, even from China, would only give 0 to 50%. Could it be that you were feeding it in to the half speed motor connection - so you were getting 0 to 100% of half speed?

Simpler just to use one of the heater controllers from a car with a ballast resistor pack and run it on 24v to give 50%, 100% (same as 12v), 150% & 200% (running on 24v).

Si

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I like the PTC idea!

Another thing I added to a previous Land Rover - but got rid of the truck before I had a chance to try it out in proper cold weather.

I connected the chamber under the heater intake vent via a bit of drain pipe to a vent in the passanger footwell. Then I fabricated a hinged flap on top of the intake vent. The flap was spring open and closed via a choke cable. In the open position it acted as an air scoop (though I'm not convinced it made much difference to the air flow.

In the closed position, the heater sucked air from the passanger foorwell instead of the outside. It made a big difference to the temperature of the air coming out the vents - and was very simple plumbing wise! If I did it again I'd use a bit of flexible pipe, about 3" bore which would be even easier!

Interestingly, it set up a circulation pattern that heated the rear of the vehicle more effectively than before. Closing the flap also meant that the heater did not fill up with water while wading with the bow wave washing over the wings. I wondered to myself why Land Rover didn't do something like this as standard and use a butterfly valve to close the intake.

Si

I don't suppose you could sketch this out?

Cheers,

Mike

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That being the case, since the switch on the dash is intended for two speed operation, use the first position to give you 0 to 50% via the PWM (fed with 12v, not through the half speed ballast resistor) and the second position to bypass the PWM to give you full speed.

Are you sure you were feeding the power into the right wires on the motor? It seems unlikely that a PWM controller, even from China, would only give 0 to 50%. Could it be that you were feeding it in to the half speed motor connection - so you were getting 0 to 100% of half speed?

Simpler just to use one of the heater controllers from a car with a ballast resistor pack and run it on 24v to give 50%, 100% (same as 12v), 150% & 200% (running on 24v).

Si

The bit of this that caught my eye is the "two speed" comment, at the moment I have nothing, nothing and light breeze!

Cheers,

Mike

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I don't suppose you could sketch this out?

It's not that hard to imagine without a sketch. I can't remember where the pipe was routed - but you just need a pipe that connects the footwell (via a big hole) to the plastic chamber underneath the wing (via another big hole). Mastic to seal - then something to block off the inlet vent.

Another option would be to use a Freelander2 PTC Aux water heater (Part Number LR004074) which just sits in line with the heater hoses.

Si

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It's not that hard to imagine without a sketch. I can't remember where the pipe was routed - but you just need a pipe that connects the footwell (via a big hole) to the plastic chamber underneath the wing (via another big hole). Mastic to seal - then something to block off the inlet vent.

I was wondering but I just realised, you mean the air intake for the heater that goes from wing to blower. :)

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It's not that hard to imagine without a sketch. I can't remember where the pipe was routed - but you just need a pipe that connects the footwell (via a big hole) to the plastic chamber underneath the wing (via another big hole). Mastic to seal - then something to block off the inlet vent.

Another option would be to use a Freelander2 PTC Aux water heater (Part Number LR004074) which just sits in line with the heater hoses.

Si

I was more interested in the inlet valve bit, but that's okay, I can work it out!

Cheers,

Mike

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Are you sure you were feeding the power into the right wires on the motor? It seems unlikely that a PWM controller, even from China, would only give 0 to 50%. Could it be that you were feeding it in to the half speed motor connection - so you were getting 0 to 100% of half speed?

Si

Not 100% sure... I followed the wiring diagram and used the green/slate wire which is supposed to go directly to the blower motor. The wires can of course be connected otherwise IRL. Something I didn't check. :blush::unsure:

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I was more interested in the inlet valve bit, but that's okay, I can work it out!

OK, imagine I'm a Blue Peter (or Viz) Presenter........

* OK Children, take a piece of scrap paper and lay it on the wing of a grown-ups Land Rover on top of the black plastic bit. Run your finger round the rim of the plastic to leave a dirty mark on the paper. You could use a felt tip pen for this if you don't have dirty fingers.

* Ask a grown up to help you cut along the line with dangerous jaggy scissors.

* Lay the cut out shape on a sheet of Aluminium - you will probably have to steal this from your neighbours shed. Then draw around the edge of the paper with a marker pen (the kind you use for writing your girlfriend's name on the bus stop).

* Using the band saw in your neighbours shed (it might be worth waiting until all the grown ups are drunk before you do this), cut around the inside of the line on the Aluminium. Have a roll of sticky tape handy to repair any severed fingers.

* Call NHS Direct who will give you some helpful if not all that useful advice on finger re-attachment.

* Steal a small hinge from somewhere. The medicine cabinate in the Bathroom is a favorite place to look. Always steal the top hinge so the door falls off in a comedy way when opened. Then the grown ups will be laughing so much they will forget to blame you.

* Stick the hinge to the narrowest edge of the aluminium with double sided sticky tape. If it falls off find some pop rivets and a drill in the shed.

* Stick the other side of the hinge to the wing using double sided sticky tape or the screws from the medicine cabinate. If your neighbour has now padlocked the shed because he thinks the pikeys have been stealing stuff - you can start the screws by hammering a small nail through the wing (maybe get a grown up to help you hold the nail while you clout it with a hammer)

* You need a rubber lip seal around the outside of the aluminium plate on the side where it contacts the heater intake. Open your mum & dads bedroom window and carefully peel off the window sealing strip. stick this to the plate with double sided sticky tape. Old people don't feel the cold so they will not notice the seal is missing.

* Next you need to be able to open & close the flap from inside the cab. there are two options for this depending on whether your dad has a bicycle.

* If not, join several garden canes together with sticky tape. Glue one end of a cane to the top of the flap. Remember to smell the glue to make sure it is not solvent based.

* You can either poke the other end of the canes through the top of the drivers side window at eye level. This will make it easily seen and avoid painful poking incidents. Or using the nail you used previously make a small hole in the middle of the windscreen to operate the flap.

* If your dad does have a bicycle, remove the gear lever and cable. Your dad only uses his bike for going to the pub - so he won't remember whether it has gears or not. If you leave it in the most difficult gear - he will just think he's too unfit and walk instead and he will forget about the whole gear thing.

* Poke a small hole in the underside of the heater plenum chamber underneath the flap and pass the wirey bit of the end of the cable through the hole, through the intake vent and through a similar hole in the flap. Tie a knot in the end of the wire to stop it pulling through.

* Un-tie the knot because you have forgotten to add a spring to open the flap. You need a compression spring. Since the shed is now out of bounds, the next best place to look is inside the sofa. Lift one of the cushions, ideally where Dad sits, and cut a hole so you can see inside. remove a spring from somewhere in the middle. Your dad will think it has sagged and the covering has ripped because he's so fat.

* Pass the wire end through the spring and through the flap. re-tie the knot.

* If you have forgotten to attach the lever inside the cab and route the cable neatly, you will have to un-tie the knot again and repeat the above.

* Now, when you move the gear lever, the flap should magically open and close!

* If it does not work quite like that, phone Hybrid from Hell aka Nigel Barker who is a dab hand at DIY - he should be able to help. Before ringing, it might be worth having NHS Direct on the other line to help him with his more immediate problem - then he will be delighted to assist!

:ph34r:;):o

Si

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I think adding recirc like that is a brilliant idea (although I'd probably use Si's other suggestion of a butterfly valve). I'm still surprised that the heater system doesn't have recirculate as standard, it's not like it's a complicated thing ...... I bet tractors have it ! :)

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