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Windshield Wiper Warmers like the rear window defrosters?

A few years ago, someone asked about windshield wiper warmers.  No real responses.  I'm asking again.  The issue is that in the northern states, the wipers get iced up, and it happens even while you're driving.  We know how to do this for the back window, which won't save anyone's life if the front one is iced over.  We know how to use a hot wire to cut foam. So we know how to heat wire. Some of the newer cars hide the wipers below the glass, so defrosters don't help much.  And washer fluid doesn't work nearly as well as you might think.  Hot liquids freeze faster than cold liquids, but the goal here is to warm up the wiper blades.  How would we go about making a warm wire setup that can be connected to the battery for slow warming and lay under the wiper blade area?  Any guesses?  It's getting cold here in Michigan!  You'd think one of the automotive companies would figure this out, but they clearly think we all have garages and live in warm states.  I'd like to see some responses that wouldn't be too difficult for a novice - I don't care about technical terms, I just want to know how to wire it up so it works.

Libahunt2 years ago
I have had an idea for a while that I am planning to implement myself soon. My problem is more about melting the ice on the inside of the window before driving off (warming up diesel engine takes looong). But it might help with the wiper blades too, assuming they lay normally on the bottom part of the windshield, but not too low.

I am planning to install a resistance wire over the ventilation holes that blow onto the windshield. And connect that to the cigaret lighter power. For safety reasons I plan to install button that's closed only while someone keeps pressing it, so it can't be left unattended. My VW vento '95 has a 10A fuse for cigaret lighter. So under 12V*10A = 120W > ~100 W heating only. Not much. Desirable resistance would be between 1.3 and 1.5 R. I want to run a thick insulated wire from the lighter to the center top of the dashboard and from there resistance wire to one side, back and straight to the other side and back to center, or so that each side loop would be separate - two parallel lines. I haven't yet figured out what would hold the hot wires higher from the plastic dashboard (PCB material maybe, maybe combined with usual hard wire for some heat dissipation). Electrical connections might be problematic too (I hope screw terminals can be stripped from plastic leaving only metal part, then I could attach piece of bare but thick low resistance wire between the hot part and insulated wire).

My case is more safe because I will probably be using this heater while vents are running to distribute the heat. For more local heating you might need to make some heat screen under the wire if you place it to the inside of windscreen.
whisperonthewind (author)  Libahunt2 years ago
Great idea, but my wiper blades rest below the windshield (and don't even have one of those quick flick stops so the blade could be at a windshield level), tucked into a neat little wiper blade home. Great for them, good for ice to enclose them, too.
Well, then You have two more problems - it's wet where the heating element must be and you can't too easily put a switch inside the car or take the power from cigaretlighter.

Floor heating cabels should be waterproof themselves, but connections must be made good waterproof also. And they give very low heat, I found ones that are meant to give 10-40W/m on 220V. Connecting it to 12V leaves 0.5-2.2W/m. American 120V equipment should give almost twice that, but it still seems low. But I think this wattage must be maintained by the control box, I doubt it would be derived from the resistance of the cable because you can use the cable in different lengths in different rooms. Too much things I don't know about this cable, but someone more knowledgeable might get further with this idea.

Stupid designers that hid the wipers - on old cars one can at least twist them up, out from the snow pointing towards the sky, while parking.
whisperonthewind (author)  Libahunt2 years ago
I could twist mine up to a point, but then I run the risk of kids or vandals tearing them off. I wonder if those floor heating cables could be connected to the car lighter with an adapter rig? I usually only worry about ice on the wipers when I'm in the car, mostly before work, or on the way home. If I had something that could do the job, I could take the time to do it. Defrosters on my car will defrost the whole window but not touch the wiper blades. What about heat tape? Would that work if I laid it down under the blades? How hot does that get? Anyone know?
Heat tape seems to be similar to the floor heating cable, maybe even better suited for damp outside environment. But I'm not able to comment on the nuances. Regarding the voltage it is meant to, it will not get too hot on 12V, problem may be the opposite.

Could you simply try that out? Buy most powerful short cable. Make an extension cord with cigaretlighter plug on one end and wall outlet on the other, so long that reaches out from car front door, lay the heat tape onto the frozen wiper. No permanent installation. Be ready to change the fuse if that burns out, but that's low probability. You can measure the resistance beforehand and calculate instead.

Or you could post new, more specific question.

rickharris2 years ago
There are several cars here in the UK that have a heated front screen - Ours works fine - Ford Fiesta,
whisperonthewind (author)  rickharris2 years ago
Maybe I'll move there. Here, they think heated seats are more important, although I don't recall my 'seat' ever being cold while I was driving.
If I wanted to clear the screen I would buy one of the many 12 volt hot air blowers on the market.
iceng2 years ago
My 2010 Subaru has hidden windshield wiper defroster warmers.
They function exceedingly well but the really suberb feature in winter
are the very excellent side by side adjustable tush heaters :-)

A
CameronSS2 years ago
What about bleeding hot air from the engine compartment to blow onto the blades? It could either be a completely independent system, or you could tap a duct off the heater that goes into the passenger compartment. Throw a lever on the dash, moves a vane to redirect hot air to blast onto the wipers.

Not sure exactly what your question is about the wire.You'd need to experiment with wire sizes and lengths to find a setup that gets warm enough to melt ice buildup, but won't burn the rubber blades or run down your battery (which is already cold and reduced-capacity). Or set it so that it'll get very hot but very briefly.

Check hardware stores for "nichrome wire".
whisperonthewind (author)  CameronSS2 years ago
The reason I was wondering about the wire was because I figured it was possible already (as in the rear window) to run low grade heat through it to warm the wiper blades. My wipers rest below the windshield, but pretty high up anyway. The defroster doesn't seem to do a very good job, takes forever, even though the heat is working. And here in Michigan we also deal with freezing rain, sleet, etc. I don't have to worry about the passenger compartment - my kids all moved south anyway... I don't know enough about electricity and electrical gizmos or what to do with nichrome wire - although I've heard a bit about it. I don't want to melt rubber, or run down the battery, just melt ice until the blades can clear the windshield more efficiently.
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