Llecentaur
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Re: Practical solutions for extending cold weather range

Sun Sep 29, 2013 9:41 pm

Hi Don, thank you for information.

Re Webasto, it goes below drivers feet, rather around the arch of the drivers wheel. TestO had kindly given thennorwegian manual which I translated with difficulty Witt the assistance of a Swedish student :).

Let me put my hand on it and scan it with the hand written add ons. I am sure forum has Ressources to rework it.

Llecentaur
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Re: Practical solutions for extending cold weather range

Mon Sep 30, 2013 1:54 pm

Just ordered two of these as an infrared alternative.

http://www.ebay.com/itm/New-Infrared-He ... 53fc7336b0

Voltage is 277V which might not be high enough for the 16kw battery that runs nominal at 330v but I hope it would work for my 14.5 KW running at 298V (80 cells vs 88).

Wondering if they would fit under dash to warm up feet ? Or alternatively I was thinking of installing one on top of the back window, aiming forward...

Any idea how I could safely feed them from main battery ?

Don
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Re: Practical solutions for extending cold weather range

Mon Sep 30, 2013 4:51 pm

Llecentaur wrote:Any idea how I could safely feed them from main battery ?
That's going to be a real challenge. Doing it at all will be difficult and getting 330 volts *safely* into the cabin is probably beyond the scope of most experienced DIY'ers

If you try it yourself, I'd use quality wire and put it inside code rated conduit, especially where it comes through the firewall. Make sure you install a 2 or 3 amp fuse as close as possible to where you pick off the pack voltage. I'm a pretty experienced electronics installer (I installed radar systems and ILS equipment for the Air Force for 30 years) and this is one of very few things I would not try to do myself - I just don't think you want full traction pack voltage inside the car

Don
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FiddlerJohn
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Re: Practical solutions for extending cold weather range

Mon Sep 30, 2013 6:47 pm

Don wrote: I just don't think you want full traction pack voltage inside the car...Don

+1

Llecentaur
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Re: Practical solutions for extending cold weather range

Mon Sep 30, 2013 9:24 pm

Oops, I understand your warning. Some Canadian forum members were discussing last year about the idea of installing two 120V IR bulbs in series under dashboard and I followed their idea without further analysis.

Indeed a fuse is a must. But finally 300V DC or 240V AC have the same danger, I guess your worry is to have a cutoff circuit to avoid shorts due to high amps ?

Isn't there some super fast cutting circuits like the ones at home ? I think it monitors current that goes vs current that comes back and if there is a difference, it cuts off.

A combination of such circuit and 2 amp fuse should give some degree of protection?

peterdambier
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Re: Practical solutions for extending cold weather range

Tue Oct 01, 2013 1:21 am

And beware of fuses in series.

This used to be my charging socket for more than a year. I was always lamenting about Schuko plugs and sockets and ruined many of them. I have long since modified everything to CEE 230V/16A and adapters for CEE 400V/16A and 32A.

This one was smelling loud enough for my landlord to agree in replacing the final Schuko with a CEE 230V/16A or Blue Command Socket.

This used to be in a circuit with a fuse tripping at 16A and trip it did never. The line to our car is some 25 meters 2.5 mm squared. In the house there is another 10 meters looking like 1.5 mm squared.

Bad thing about Schukos they love to tilt when the cord pulls down. That gets a smaller surface, that gets hotter because it has more resitance. That gets even more resitance because of the heat ... and the case melts and allows for more tilting.

A rat race that will never trip the fuse except for a very unlikely short and even that short has too much of a resitance most of the time.

Shunts and fuses are working mostly the same way. Shunt: current through a resistor results in voltage that keeps telling the BMU how much current flows. Side effect voltage times amperes gives heat radiated from the resistor and of coarse a voltage drop over the resistor.

Fuse: current through a resistor drops voltage. Voltage times current gives heat and the fuse melts. Side effect voltage drop over the resistor.

Putting two fuses in series might result in half the current and none of them blowing. There may be reasons for splitting circuits and putting fuses in every branch but think twice and never put fuses of the same size in series. Before putting three fuses in series in a rats nest of wires send an invitation the the fire brigade. You might need them. Fuses do produce heat. Never put them on wood.

In our car things are even more tricky with stuff that can burn and circuits of high and not so high voltages. In a house you always have yet another fuse just in case and mostly you wont see more than some 20 amperes but in our car with a motor that needs some 500 amperes there is no more fuse. That is why the mitsu people are wearing a divers suit with googles and all before touching our main battery.

Cheers
Peter and Karin

Image
Peter and Karin Dambier, DL2FBA, www.piraten-fraktion-bergstrasse.de

Don
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Re: Practical solutions for extending cold weather range

Tue Oct 01, 2013 6:46 am

Llecentaur wrote:Indeed a fuse is a must. But finally 300V DC or 240V AC have the same danger, I guess your worry is to have a cutoff circuit to avoid shorts due to high amps ?
Yes, but . . . . the car is subject to all sorts of movement and vibration that home wiring doesn't get and your heater isn't designed for any of that. Pretty sure it wasn't intended for any mobile application. Then there's the fact that the foot-well area is likely to get wet in the wintertime and a 300 volt heater in the proximity of someone's wet feet is just . . . . scary

A combination of such circuit and 2 amp fuse should give some degree of protection?
Yes, it would keep you from having a fire, but it won't prevent someone from getting seriously shocked

Don
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Llecentaur
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Re: Practical solutions for extending cold weather range

Tue Oct 01, 2013 12:05 pm

Thank you for the information. Anyway I will have to test the heaters on 240v to see how much they heat, as they will be even hotter at 298 v.

If they get to near burning. Temperature, then problem is solved, they have no place in a car, I was expecting them to be almost touchable like 60 or 70 c.

A friend works in a company producing high grade industrial thermometers and will provide me with shielded (with iron and fiberglass) and silicon insulation wire. These would be the safest things to attempt such project.

Then the 2A fuse will have to be probably near existing heater were I guess I could hook the juice.

First step: testing the heaters when they arrive, hopefully by week-end, at worse, I can install them in our SPA ;)

Don
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Re: Practical solutions for extending cold weather range

Tue Oct 01, 2013 4:57 pm

Harbor Freight has their little $20 cigarette lighter heater/defroster on sale for half price. For just ten bucks I think I'll grab one of those and sit it up on the dashboard with some Velcro and see if that doesn't solve my winter fogging problems. It's only 100 watts so it will use way less juice than running the heater to defrost . . . . assuming it's powerful enough to do anything

http://www.harborfreight.com/12-volt-au ... 60525.html

The link shows it's $15, but if you're on their mailing list, they sent me a coupon for $9.99

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Re: Practical solutions for extending cold weather range

Wed Oct 02, 2013 2:41 pm

Llecentaur wrote:Thank you for the information. Anyway I will have to test the heaters on 240v to see how much they heat, as they will be even hotter at 298 v.

If they get to near burning. Temperature, then problem is solved, they have no place in a car, I was expecting them to be almost touchable like 60 or 70 c.


I'll bet that these puppies glow bright red- also known as quartz heaters, like the glass tubes in a toaster oven. The other big safety factor on DC voltage is that it's much harder to break a DC arc than an AC arc, which changes direction 60 times per second (50 in Japan). A fuse that is only AC rated can't be relied on for a DC circuit of anywhere near as much voltage.
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