Electricity 201?

[tbredehoft]

I'm building a 6 volt car (see my signature) I have modern leather motor operated and heated front seats that require 12 volts. I desire to put a 12 volt battery in the trunk and run a wire to a fuse box on the dash for 12 volt service. The seats require a 30 amp fuse. What gage wire do I need between the battery and the fuse box?

Please don't tell me to convert to 12 volts, my head is made up. I have plans to install a trickle charger and plug it in as needed.

[img=left]http://www.alink.com/personal/tbredehoft/Bothcars3.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe
'55 President State Sedan Project
'60 Lark VI (Sold, delivery in two weeks.)
'05 Legacy Ltd Wagon
All Indiana built cars

[JDP]

I can't answer the question without knowing the current draw from the heating elements and motor, but I can guess 8 ga. would do. BTW, be prepared to charge the battery every hour or so if you use the heated seats.

JDP/Maryland
63 R2 SuperHawk (Caesar)
spent to date $54664,75
64 R2 GT (Sid)
spent to date $62,439.30
63 Lark 2 door
51 Commander
39 Coupe express
39 Coupe express (rod)

[tbredehoft]

The car we now use in nasty weather had heated seats, we use them for maybe 10 minutes to break the chill. The seat motors probably wouldn't be used, except for initial settings, old fogies like them just one way, don't seem to change them much.

Tom Bredehoft
'53 Commander Coupe
'55 President State sedan
'60 Lark VI (sold, still on premises)
'05 Legacy Ltd Wagon
All Indiana Built Cars.

[Dick Steinkamp]

quote:Originally posted by Tom B
we use them for maybe 10 minutes to break the chill. The seat motors probably wouldn't be used,

Seems like a lot of work, expense and weight for the benefit.

[JDP]

Why not rig a plug to one of those small, cheap jump start batteries. Plug it in, set it in the back seat when needed for heat, take it out to charge.

JDP/Maryland
63 R2 SuperHawk (Caesar)
spent to date $54664,75
64 R2 GT (Sid)
spent to date $62,439.30
63 Lark 2 door
51 Commander
39 Coupe express
39 Coupe express (rod)

[Dick Steinkamp]

How about one of these...

http://www.antiqueautobattery.com/prod011.htm


Another idea...

http://www.msdignition.com/install_access_1.htm

http://www.pressenter.com/~cmeyer/index.html

http://www.powerstream.com/dc6-12.htm

http://www.radiosforoldcars.com/power.htm

http://www.aaroncake.net/circuits/6-12conv.asp

[tbredehoft]

I'm glad to see the link to 6 - 12 volt batteries. Certainly one of them will solve the problem.

Thanks for the suggestions, I'll work something out.

Tom Bredehoft
'53 Commander Coupe
'55 President State sedan (under construction)
'60 Lark VI (Sold, still on premises)
'05 Legacy Ltd Wagon
All Indiana Cars.

[buddymander]

What happens if you run six volts to the twelve volt heaters? Won't they just operate a little cooler?

[55pres]

quote:Originally posted by buddymander

What happens if you run six volts to the twelve volt heaters? Won't they just operate a little cooler?

Half the output, watts(power)= volts*amps

Randy Wakefield
----------------------
1955 President sedan

"For the future that we wait..."

[Jeff_H]

Its actually 1/4 the power. It would be 1/2 of the power if the current was constant, but its probably not.

Assume that these heaters draw 10A on 12v (just for a number). That means that R (resistance of the heating element) is V/I or 12v/10A =1.2 ohms. Also the power of the heater on 12v will be 10A*12V=120 watts. Also power is V^2/R so 12*12/1.2 = 120 watts again.

If we can assume that the Resistance stays the same then if we run 6V instead of 12v we get 6*6/1.2 = 30 watts which is 1/4 of 120 watts.

I don't know how hot the seat will get with 1/4 of the power, that depends on a lot of things. Maybe still adequate depending on how cold it is...

As for the wiring size; I don't think I would try anything smaller than #10. Put a fuse at the battery end too in case the wire shorts someplace. The fuse won't help much if its on the wrong side of the short!

Jeff in ND

'53 Champion Hardtop

[tbredehoft]

Thanks for the math, Jeff. Also the fuse at the battery idea. However....

I've inquired into the 6 - 12 volt batteries, should know more soon. It looks like you put the 12 volt battery in, hook it up 'so' and away you go with your 6 volt generator and system and the availability of 12 volts, probably for starting/cranking and accessories. Not that this is mentioned, but one of the batteries says it requires a 12 volt generator/alternator. The other one doesn't.

After all, this is for a Driver, might as well have what I want.

[img=left]http://www.alink.com/personal/tbredehoft/Bothcars3.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe
'55 President State Sedan Project
'60 Lark VI (Sold, delivery in two weeks.)
'05 Legacy Ltd Wagon
All Indiana built cars

[mbstude]

Tom, what's happening with the picture of your Lark!?! Is it 'slowly disappearing'?

Matthew Burnette
'59 Scotsman
'63 Daytona
Hazlehurst, GA

[tbredehoft]

Matt, its fading. Sometime after the first of the year it's going to a new home in eastern Pennsylvania. To be replaced by President Ike. Ike now has a solid floor again.

[img=left]http://www.alink.com/personal/tbredehoft/Bothcars3.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe
'55 President State Sedan Project
'60 Lark VI (Sold, delivery in two weeks.)
'05 Legacy Ltd Wagon
All Indiana built cars

[leyrret]

Looks like some type of series-parallel switch spliting the 12 volt battery into two 6 volts to charge it. Used to see these on old
B model Mack using 24v start and 12 volt operating voltage.

[55pres]

Jeff,

Opps, maybe I should recheck my notes from my EE class, I should have figured that 6 volts wouldn't be able to "push" the same amount of amps that 12v would be able to "push".

Randy Wakefield
----------------------
1955 President sedan

"For the future that we wait..."