My first winter in my Meepster... so far!

[RobbW]

I just keep thinking of the fuel costs and CO2 I'm saving. Plus, after driving the Meepster for several months, my minivan now feels like a unwieldy tank whenever I'm forced to drive it.

 

[PV1]

Anything warm to report?

The heater works really good on MAX. :mrgreen:

I'm still thinking of that Enerlogic film. The majority of the heat loss is through the windows. I had a space heater in the car the day after Christmas when I was installing the OVMS module. The heater was in the back and the first glass to shed it's snow was the windshield. Although, I tried driving an ICE Focus without heat and saw similar heat loss. The floor in the i-MiEV gets cold quicker because the air hitting the firewall isn't heated by an ICE.

Robb and PV- you have my respect. To still prefer the i over an AWD SUV with nearly unlimited heat output in that kind of weather would strike anybody who hasn't spent time in an i as just plain crazy!

I've driven SUVs, and they are just too top-heavy and rough with power output for snow. I went to avoid a tarp strap cartwheeling down the road last summer in an Escape, and it felt like trying to steer a boat, dipping and leaning before finally moving to miss it, and that was on a warm, dry road. I also had a guy on a lawn mower pop out from behind a hedge on a skinny road and the i-MiEV moved instantly. I'll take my i-MiEV any day over an SUV, just because it behaves much better than many other vehicles. Going down a snow-covered road up to three inches deep (all the more we've had at one time) in the i-MiEV would convince just about anybody that it rides on rails. The roads this morning were garbage (still are), and I still had to purposely screw around to get the i-MiEV to break loose.

 

[jray3]

Back to the hot water storage idea... I see from the service manual that the hot water heater loop circulates everywhere in the system; the entire volume even passes through the reservoir. So, adding additional storage capacity could be done at any point in the loop, though a small benefit would be had from putting the storage right in front of the heater. That would keep the loop at max temp while keeping load off of the heater for as long as possible.

This is one modification that could substantially increase heating effectiveness without doing anything more than adding some hot water hose and a reservoir (or bladder). No electrical mods, no second heater to plug in. The preheat function would be more fully utilized by keeping it at full load for the full 30 minute preheat, and that should happen regardless of other settings (defrost vs interior, etc..). It could also be uninstalled for the other three seasons, deleting weight and adding back space.

So, the quest is to
1: find places to squeeze in more water storage (preferably in the cabin to capture radiation from the tank).
2: identify the optimal added water volume (one gallon of water requires .0199 kWh to rise one degree F, and the stock heater 'appears' to set back around 140 deg F, so during a 30 minute preheat (5 kW * 0.5 hr = 2.5 kWh) there's enough energy to raise 2.58 gallons from 32 degrees to 140 degrees. That's without dumping any heat into the cabin or accounting for the system's original water capacity, so (switching to guesstimation mode) at most, a two gallon reservoir would be useful, and one gallon would probably harvest the lion's share of heat.

Storing 2.5 kWh worth of heat, or actually only 1.65 kWh if you consider that full 5 kW preheat for 30 minutes while recharging at 3.3 kW would leave us with an 0.85 kWh deficit, would 'add back' about 6.4 miles of winter range, figured at 258 Watthrs per mile.
:|
Alternatively, I'm considering using an old 6 gallon outboard motor fuel tank (flat bottom steel tank, won't roll around) with a supplemental electric heating element on it's own plug. That six gallons heated to 180 degrees in freezing weather would store a whopping 17.6 kWh worth of energy in about 55 lbs, which would be 100% recoverable as the tank radiates heat all the way down to ambient temperature. Or use a 5 gallon domestic hot water tank that would be an uglier but arguably safer and more straightforward option, strapped on a cradle in the back cargo area...

 

[Don]

You'll still need an electrical mod to allow you to continue pumping all your hot water through the heater core in the cars interior *without* having the heater turned on . . . . won't you?

Don

 

[jray3]

With the preheater activated or the car running, it would heat and circulate hot water from the secondary holding tank. Come to think of it, the only useful heat would be the Delta T between holding tank and normal heater discharge temperature. As long as the supplemental tank was pre-heated, the demand on the battery would max out at equal to stock or less, as long as the secondary tank is inside. A downside would be if the secondary tank got chilled down after a long day unplugged at work, then the built-in heater would have a very difficult time reheating the larger volume of water.

Otherwise, the supplemental storage tank would passively radiate to the interior, whether spliced into the heating loop or standalone. As a standalone, it could have a small fan of it's own. The standby losses would be about as bad as locking up a space heater in the car while garaged, the main purpose would be to have a reservoir of heat to take with you after unplugging (whether integrated or standalone).

The thought experiment continues... benefits of a larger reservoir of hot water for the original heating loop may me exaggerated.