DBMandrake
Posts: 298
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: additional electric heater

Mon Jan 13, 2020 2:01 am

The built in heater in the car actually peaks at 5.5kW during warm up, although it typically settles down to about 3kW once the selected flow temperature is reached. (The temperature knob controls the flow temperature of the water through the heater matrix, not the cabin air temperature - it's up to the driver to manually adjust the heater temperature to regulate the cabin temperature)

Even with this power available it takes about 5 minutes to heat the heater fluid from 0C to 60C (maximum) so it would take an eternity to heat at 1kW, and there's a very strong chance that you simply wouldn't be able to get the heater matrix up to a useful temperature at all with 1kW with cold exterior air blowing through it. If you can't get the flow temperature up to at least 40C you're wasting your time, as this is the lowest setting that will give any useful warmth in winter conditions. (Enough to keep the window clear)

I agree that a 12 volt heater simply isn't up to the job, especially with the added layers of inefficiency of having to heat a loop of water and then heat the mass of the heater matrix itself.

If you really need the extra range and heat in winter a better (although not very PC!) option is a small Diesel/Petrol based heater to heat the heater fluid circuit. A number of people have installed them now and you can get nearly summer range in winter by using one. I was on the verge of installing one myself however the combination of the high up front cost and a recent decision to sell the car this year has nixed that plan.
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

Tiborx8
Posts: 38
Joined: Sat Jun 08, 2019 11:15 pm

Re: additional electric heater

Sun Dec 27, 2020 2:44 pm

So,

for heating while driving: one working solution is the 12v infrared heating film (high temp model) on the floor, in the doors and behind the front seats, plus heated seats and steering wheel.

If someone is after the traditional air heating: all previous posts took it granted that the loop with 2 liters of coolant in it and going under the car and back is granted - nope. There is a possible mod to add a coolant valve used in ice cars to close down the heating matrix while the engine coolant is too cold. With it, it is possible to close down most of the existing coolant loop hence increasing the efficiency of the water heater.... as a water heater, for example, the cabin pre-heater used in the BMW X3 and some bmw minis can be used - I already picked one up together with a ford heater valve - when i build them in, I will make a post about it. as the heater valve is only controlled by a 12v soleaoid, when the HV battery needs heating, it can automatically open the loop.

Don
Site Moderator
Posts: 3030
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: additional electric heater

Mon Dec 28, 2020 5:47 pm

I suppose you may be able to come up with a solution which could slightly improve on the efficiency of the OEM system, but IMO it would be amazing if you could make very much of an improvement - The engineers at Mitsu were certainly concerned with squeezing out the maximum range possible while keeping the occupants at least semi-comfortable and their expertise really shows throughout the car - They're not incompetent by any means so improving on what they came up with won't be easy

Your big problem is - Power. A 1500 watt household heater running on 12.5 amps of 120 volt AC power would not do much to keep the car warm while driving 30 mph through 30 degree outside air . . . . you just need lots more power than 1500 watts to do the job, which is one reason Mitsu chose to get that power from 350 volts DC and not 12 . . . or 24 . . . . or even 36 volts DC. Getting 2Kw from 18650 cells for an hour is gonna take a BUNCH of cells. If you preheat the car at home before you leave, then 2Kw of heat might keep it semi-comfortable until you got to where you're going, but then getting into the cold car an hour later for the trip home . . . . you're still gonna be COLD. Whatever your plans, I would not disable the OEM heating system, that's for sure. If you do, make sure you can easily get it back to a stock configuration

If I lived where it gets cold, I would have bought a little diesel heater long ago. They're cheap, not too hard to install, they use the existing liquid system and OEM pump and they give a TON of heat for very little fuel consumed - A 2 liter fuel tank would probably last for a weeks commuting. Several good threads here on the installation of them from our Canadian friends and a few others

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon
2006 Itasca Navion Sprinter Motor Home

jray3
Posts: 1715
Joined: Tue Dec 06, 2011 1:05 am
Location: Tacoma area, WA
Contact: Website

Re: additional electric heater

Tue Dec 29, 2020 1:33 pm

I'll echo Don's comments, adding that I ran the numbers a few years back and concluded that a preheated hot water bottle carries more Btu/lb than even fully charged LiFePO4 batteries can. That water bottle could be in your lap, a lumbar support, or as advanced as a custom metal tank on the floorboards. I used an old steel outboard motor fuel tank as a hot water bottle a few times in experimentation, but didn't need it on my short commute at the time. Now my commute is too long for the i-MiEV, so my wife uses the car daily in local errands- allowing full heater use without stressing over range or battery life.

-Jay
2012 i-SE "MR BEAN" 110,300 miles
2016 KIA SOUL EV, 90 kW, 27 kWh, 34k miles
2000 Mazda Miata EV, 78 kW, 17 kWh
1983 Grumman Kurbwatt EV,170 kW, 32 kWh
1983 Mazda RX-7 EV 43 kW 10 kWh
1971 "Karmann Eclectric" EV 240 kW 19 kWh

drcat
Posts: 9
Joined: Tue Dec 08, 2020 3:21 am

Re: additional electric heater

Wed Dec 30, 2020 10:57 am

That's not an awesome solution but I have a 150W 12V made-in-china heater aiming my wind glass. It defogs the glass from inside pretty well combined with the main fan at slow speed but its still cold in the car. With a heated seat its less or more acceptable for driving but no comfort still.
My c-zero has also a 900W / 220V heater installed by previous owner with a plug on the rear bumper. I think what if I'll connect it to H/V lines and re-wire inside to deal with 360 volts instead of 220.
It produces a decent amount of heat for comfortable driving and won't affect mileage significantly. Except for the fan type - it seems needs AC not DC but its not a big deal

Tiborx8
Posts: 38
Joined: Sat Jun 08, 2019 11:15 pm

Re: additional electric heater

Sun Jan 03, 2021 1:20 pm

Don wrote:I suppose you may be able to come up with a solution which could slightly improve on the efficiency of the OEM system, but IMO it would be amazing if you could make very much of an improvement - The engineers at Mitsu were certainly concerned with squeezing out the maximum range possible while keeping the occupants at least semi-comfortable and their expertise really shows throughout the car - They're not incompetent by any means so improving on what they came up with won't be easy

Your big problem is - Power. A 1500 watt household heater running on 12.5 amps of 120 volt AC power would not do much to keep the car warm while driving 30 mph through 30 degree outside air . . . . you just need lots more power than 1500 watts to do the job, which is one reason Mitsu chose to get that power from 350 volts DC and not 12 . . . or 24 . . . . or even 36 volts DC. Getting 2Kw from 18650 cells for an hour is gonna take a BUNCH of cells. If you preheat the car at home before you leave, then 2Kw of heat might keep it semi-comfortable until you got to where you're going, but then getting into the cold car an hour later for the trip home . . . . you're still gonna be COLD. Whatever your plans, I would not disable the OEM heating system, that's for sure. If you do, make sure you can easily get it back to a stock configuration

If I lived where it gets cold, I would have bought a little diesel heater long ago. They're cheap, not too hard to install, they use the existing liquid system and OEM pump and they give a TON of heat for very little fuel consumed - A 2 liter fuel tank would probably last for a weeks commuting. Several good threads here on the installation of them from our Canadian friends and a few others

Don



Don, I think it is time to change paradigm of car cabin heating as the ice power is over. What i am talking - and doing - about is not new - see the post here, for exmple:

https://chargedevs.com/newswire/new-hea ... Zw1hXV-8EE

Mitsu engineers actually made not such a brilliant job in my view - at least in some way. One clear shortcoming is heat insulation of the cabin, the other is - but it may be due to the time the design was - clearly the heating solution. Infrared heating in the past years are well proven in all areas - from homes through stadiums to churches - that they can solve a heating problem where heating the air takes too much of energy. It is not just me saying that - it is a fact.

As for the high power need of a close-circuit water heater - it is clearly not a parking heating solution. The dc-to-dc converter in the car can charge the 12v battery by 1.5kwh max, so 0.5 kwh can be easily covered by the Dc-to-Dc converter during travel. As I wrote, I don`t believe it would heat up the air in the cabin - why would it be needed as the infrared film does this job - but could defog the windscreen and the front side windows.
This combined heating could work indeed in my opinion - the infrared part of it I don`t think so, I know so.
Best regards.

GarryIno
Posts: 1
Joined: Wed Feb 24, 2021 9:28 am

Re: additional electric heater

Wed Feb 24, 2021 9:48 am

Hi...the more up to date electric vehicles can be modified to warm the lodge prior to moving off. This should just be done while the vehicle is as yet connected as clearly the warming will utilize battery power. On the off chance that you are just utilizing the vehicle for a short excursion, you will most likely be OK, in the event that it isnt connected, yet you do need to utilize an electric vehicle in an alternate manner.

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