When are you going fully electric?
- Thread starter Ricochet J
- Start date
Can you answer the question rather than deflect ?
I've been reading the posts and it's pretty damn obvious, playing dumb isn't a good look
The 3kwh is a hypothetical figure to highlight the significance of it's proportional imact of energy use to heat a car, in comparison to differing battery capacities. 15% / 2% are figures from my current observations. Perhaps that's a bit inflated - 13% / 3% might be more likely in direct same for same conditions.
Not quite, I expect between 5-6 times. But, it may be that high when it's very cold.
Perhaps you need to explain your actual point it in a less confusing way.
'Going on'? That was entirely what my original posts was about. If it's that obvious why are you continually 'going on' and questioning it?
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Playing dumb? Maybe I'd rather not spend all day arguing on the internet.
There is no arguing. Just trying to help your understanding of physics.
3kW or 3kWh. You have changed units and don’t know if intentional? 13% of a battery to warm the cabin of a leaf?? Are you leaving the windows open ? A typical heater is 3-6kW max. So if you meant 3kWh your leaf takes 30 mins at 6kW to warm up? Again you have just invented numbers. Maybe if you didn’t then we ‘wouldn’t have to waste our time arguing on a forum’. Which is an odd statement anyway as these forums are for discussion and, if the mind allows, education.
The context was the impact of heating on a EV. You seem to think only warm up matters. I believe (on longer trips) warm up is largely irrelevant and cars have no insulation for heat. Only noise (including ‘double glazing’. Which if you actually looked you’d see there is no air gap as the double glazing f is two different thickness panes to deal with different sound frequencies)
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I'm not sure where the confusion is coming from? If a car takes w watts to heat and over the course of t time that drops the range by m miles then it doesn't matter if your battery is 10kWh or 1000kWh, both vehicles have suffered the same drop of m miles. Because the same amount of energy (e) has been used.
or w * t = e
e / efficiency (m/Wh) = m
The battery size isn't part of the equation.
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What I'm confused with is why it's being framed like I've ever disagreed with these over-simplified calculations.
My original point was and still is, what you've got left in your capacity except for what is used by the heating is the bit that matters. The more overall capacity you've got, the less impact an inefficient heater has on your use of the car.
or
89 - (w * t) = m
17 - (w * t) = m
Where m = the thing that matters.
To be honest, I thought the original point was a more simplistic "If you have a bigger battery/longer range, then you're less bothered if you lose say 15 miles of range to heating requirements, as it's proportionally much less of your overall capacity/range" which I don't think is a particularly controversial viewpoint 
Exactly!To be honest, I thought the original point was a more simplistic "If you have a bigger battery/longer range, then you're less bothered if you lose say 15 miles of range to heating requirements, as it's proportionally much less of your overall capacity/range" which I don't think is a particularly controversial viewpoint
I can sort of understand what he means, I only have 14,9KW usable battery and heating the cabin takes ~3kw on mine which you can see on the Zappi, What I noticed is that my range with lots of short trips where the car has been left to cool gets quite an impact from having to reheat (you can watch the miles drop stationary when its warming up) versus what they do in test and have a long run and go oh heat pump makes bugger all difference, as I too get more range on a steady run where the interior heat is maintained, reckon a heatpump probably be more useful in this scenario as when our heater broke, we got another ~7 miles in similar driving, which when you only have on average 30ish miles is a nice bump, when you have a larger battery you EV usage ve heater is less of an impact in miles you can get overall as you have far more energy stored to play with
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Not you lol the other guy
Hardly playing dumb. Just depends on your use case in your heat. On 200mile trip the preheating of the cabin makes no difference if I get there or not without charging (0.5kwh by my maths) Having the heating on 21 or 16 does though. 3 hours of the car just losing the energy you have taken from the battery at around 1.2kW for 3 hours )(3.6kwh In this case the size of the battery is more important anyway
Short trips. Who cares you are charging it every day anyway. Even if we use the massive 3kwh banded about Your leaf range might go from say 80 miles to 20. But on the q8 200 to 180. Doesn’t really matter if you are only driving 30 does it. But the bigger battery is impacted by 20miles still. The only argument for less impact is bout the car efficiency not battery size where 3kwh is maybe more miles in a leaf than a q8 due to… drum roll please.. the size of the car !
To be honest I quickly replied saying a bigger battery isn’t impact by heating less than a smaller one and now we have got here. Both points are probably correct just depends on how you use the car.
But a bigger battery is not ‘less impacted by heating’. If there is a battery heating mechanism in the EV it will need more power to warm it up
There is no playing dumb. This is 101 thermodynamics being confused by a guy with two EVs making correlations similar to Nicolas cages films and shark attacks
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But that's assuming you do exactly the same trip in a vehicle with a 30kWh battery vs a 80kWh battery.To be honest, I thought the original point was a more simplistic "If you have a bigger battery/longer range, then you're less bothered if you lose say 15 miles of range to heating requirements, as it's proportionally much less of your overall capacity/range" which I don't think is a particularly controversial viewpoint
The reality is that many people spec a large battery vehicle because they do long distances. So we aren't looking at a static 15 miles of range loss, we are looking at a proportional loss of efficiency. The longer the trip the more miles you lose. At some point that will be the cross over between making it to your destination or having to charge on route. Or the difference between 1 charge stop or 2.
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Zero
It's not assuming that, it's not assuming anything about any specific circumstances or trips or charging regimes or use cases, it's making a simple generalised point that a larger battery gives you less of a usability impact if you have to spend energy on heating a car and (given the context of the discussion starting with heat pumps) that it's probably less of a worry whether your 100kWh car has a heat pump compared to your 30kWh car.
It may be the case that a specific use case means this is of absolutely zero consequence whatsoever to a particular individual, or it may not, I don't think that was ever really part of @Bug One's original comment.
Most cars won't be heating the battery at 10C. Hell, my Kona wouldn't warm the battery unless it got below -5C.
Maybe my brain is wired back to front but it still seems equally important to me. It's like saying, well it doesn't matter that my car does 20mpg, it's got a big fuel tank.
I do get that with a bigger battery you are going to have less trips that are impacted because the cut off of range is higher but that doesn't offset the efficiency impact.