Every year when the ice comes I make a solemn promise to myself to buy a car that has a heated washer system.

These are few in number. You can have it as an option on some Volvo models, BMW in some markets has a Cold Weather Package that includes them and Tesla has a Subzero Package. But from reading about these, the system is limited to heated nozzles that of course does not mitigate the possibility of the liquid freezing further back. Pretty useless really.

It occurred after a trip to the office on Tuesday that EVs are more in need of such an option than their petrol or diesel counterparts for the simple reason that on my commute the heat from an ICE has been sufficient to thaw out the tubes before reaching the office. In the Fluence it stays iced up permanently; there is no thawing while it is parked, and if it gets bunged up in the cold then it stays bunged up in the cold.

Any thoughts? Other than making the mix in the reservoir 1:1 with the deicer/washer fluid is there any other e.g. third party solution available?

- why not make the mix 1:1?
- maybe you can find a better (lower temp. capable) winter washing fluid?
- add some industrial alcohol, helps to lower the freezing point and improves cleaning as well
- there are (electric energy wasting) PTC heater sleeves for domestic water tubes, maybe there is something that works from 12V?

Just a few thoughts...

I buy the -30c washer fluid. Bit of a bu**ger to find, and expensive when you do, but it never freezes. Watch out for the nonsense -5c stuff at petrol stations though.

I understand the Russians use cheap vodka, but I don't think it would do your paintwork much good.

Thanks both.

My first reaction as stated was to simply up the mixture concentration, but if there were an alternative option I'd have been open to a little exploration. The (albeit minor) problem these days is that so much of the de-icer fluid you see at supermarkets and in garages is pre-mixed garbage and the proper industrial stuff is much harder to source.

Such details are obvious if you sit down and think about it, but it seems EV makers were in such a hurry to get these cars out they overlooked detail.

You should use concentrated screen wash neat. 'Fraid there is only one solution if you find that doesn't work, and that is to 'undo' what was done some decades ago - add back into your washer mix a bit of methanol (which was taken out many years ago for fear of people drinking it. Doh!).

You need only a teeny amount of the stuff added to a regular screen wash mixture, so if you have any access to a wet lab or any other industrial stores you only need 5 to 10% in the mix and your mix will simply not freeze up in a UK winter. It is the combination of several low freezing point solvents that really lowers the overall freezing point. It's all about the entropy.

Are you sure it needs to be Methanol (cause that's really toxic)? Ethanol is much easier to obtain, it's the common industrial cleaning alcohol. Ethanol is in fact the stuff that makes beer and whiskey desirable, the industrial flavour is just fully concentrated and made undrinkable by a stinky additive. Afaik, Ethanol does the job as well.

Yes, methanol is highly toxic and I agree you should use something like ethanol if you have any concerns or any fears it could be misused or confused with any other liquid that someone could drink. I aim to keep nothing on the shelf, just add 10ml or so to each washer bottle.

I don't like having nasty chemicals around, but we tend to do so anyway, especially bleaches and such. I'll trust that no-one will syphon off my washer bottles and then proceed to drink the whole lot to get a lethal dose, I'm guessing the probably of that being no greater than someone drinking from a bleach bottle.

What do you think? Maybe you're right, I should stick to ethanol, though I struggle to see the risk if properly handled.

I'm sure you can handle the risk. My question rather points in the direction whether methanol is a (much) more efficient anti-freeze than ethanol. Is it?

I think it is, for the simple reason that regular screen wash will already contain some ethanol. For thermodynamic reasons, having a mixture of different liquids will drop the melting point. Think of 'cooling mixtures'. So adding ethanol will simply increase the fraction of ethanol already in the wash fluid. Add methanol (which, yes, has a significantly greater effect of lowering the freezing point at small % volumes than ethanol) and you get that added effect. I have found that, literally, just a few 10's ml of methanol is enough to turn a frozen washer bottle into free flowing viable washer fluid. It is really very little that is needed. You really want small %ages anyway, as the flash point is lowered significantly in higher concentrations with water.[hr]
One other observation of merit with EVs in the cold:-

Using ICE cars in cold weather I always found/find the window fogged up on the outside for the first few 100 yards, requiring a nudge on the wipers to clear them a few times before it stopped happening. I always presumed this was, perhaps, the air content being at dew point so as you drive through it so condensation appeared on the cold window.

Post-EV ownership, I now know better!

This never happened with the Fluence and I deduce the reason is that that condensate on the outside of the window in an ICE is actually condensate being evaporated quickly off the exhaust system under the bonnet, and releasing warm humid air over the cold windscreen in the first flush of heating of that exhaust manifold.

It never occurred to me before, but was instantly obvious when I realised it did not happen with an EV.

OK, must be significant then.

Now that you mention it: Indeed, I noticed the same difference between ICE and Fluence - Good explanation