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Re: Negative Battery Cable Connection

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wcurtis(at)core.com
Guest

Posted: Fri Jan 06, 2006 12:23 pm Post subject: Re: Negative Battery Cable Connection



[quote]#4 would probably be fine unless you spend a lot of time in the >frozen tundra. Might be pushing it then. I, as Tim did, will be >putting in #2 for that exact reason. It gets mighty cold in WI >from time to time. If I never left the warmer climates I wouldn't >bother. Don�t understand this logic. Conductivity INCREASES as temperature decreases. If you are talking about battery performance with temperature, well that�s something else and AFAIK not dependant on the cable attached. That being said however the Van�s ES WH 10 Kit uses #2 positive cable and the airframe as ground per page OP37-12 of the electrical wiring harness instructions. William Curtis http://nerv10.com/

joeb47(at)verizon.net
Guest

Posted: Fri Jan 06, 2006 12:53 pm Post subject: Re: Negative Battery Cable Connection

The situation is thus:

The resistance of the cable, for any given size, does decrease

with decreasing temperature. NOT a large decrease however.

The ability of the battery to deliver full cranking current

decreases with decreasing temperature. This is a BIG

change.

The requirement to crank the engine GREATLY increases

with decreasing temperature.

Therefore the larger wire size WILL help some.

Best method to make a large improvement would be a

larger battery or a gear drive starter motor.

Joe Bienkowski, Bowling Green, OH

William wrote:

 	  Quote: 	
		   >#4 would probably be fine unless you spend a lot of time in the

>frozen tundra. Might be pushing it then. I, as Tim did, will be

>putting in #2 for that exact reason. It gets mighty cold in WI

>from time to time. If I never left the warmer climates I wouldn't

>bother.

Don�t understand this logic. Conductivity INCREASES as temperature

decreases. If you are talking about battery performance with

temperature, well that�s something else and AFAIK not dependant on the

cable attached.

That being said however the Van�s ES WH 10 Kit uses #2 positive cable

and the airframe as ground per page OP37-12 of the electrical wiring

harness instructions.

William Curtis

http://nerv10.com/

rvbuilder(at)sausen.net
Guest

Posted: Fri Jan 06, 2006 2:09 pm Post subject: Re: Negative Battery Cable Connection



That may be true but go outside and try and jump start a car in the winter with WallyMart special jumper cables some time. Then give me a call and I'll bring over my #4 welding cable jumpers and you'll be off. Not an electrician by any stretch of the term but I know what works.  Probably has more to do with getting more electrons out of the cold battery than the conductivity. Just my guess.

dlm46007(at)cox.net
Guest

Posted: Fri Jan 06, 2006 4:32 pm Post subject: Re: Negative Battery Cable Connection



I am using two Odyssey 680s individually or in parallel for starting through

a #2 cable to the starter relay. together they can supply 680 amps each for

the first five seconds and then about 300.

wcurtis(at)core.com
Guest

Posted: Fri Jan 06, 2006 8:20 pm Post subject: Re: Negative Battery Cable Connection



[quote]The requirement to crank the engine GREATLY increases >with decreasing temperature. > >Therefore the larger wire size WILL help some. How so, as it relates to temperature? The original premise was that it may be fine at regular temperature but not so in the cold. I only submit that if the performance is sub-par at a lower temperature it will also be sub-par at normal temperature. Thicker cable is indeed better-there is no debate there. I only suggest that nothing with regard to the cable has any dependency on the temperature. Certainly the lowered temperature has an effect on the battery performance however. William Curtis http://nerv10.com/

kellym(at)aviating.com
Guest

Posted: Fri Jan 06, 2006 8:29 pm Post subject: Re: Negative Battery Cable Connection

You are only looking at the cable and battery performance. The colder it

is, the more force required to turn the engine(thicker oil, reduced

clearances, as well as more friction in the starter itself). More amps

needed to provide that torque, drastically more. If you look at the

stalled rotor draw of the starter you get an idea of what the peak draw

will be. Peak draw is what you are concerned with, not average draw. In

warm weather peak draw will be much lower, hence lighter cable can carry

the say 200 amps needed, where they might not carry the 350+amps drawn

in a cold start at or below freezing.

William wrote:

 	  Quote: 	
		   >The requirement to crank the engine GREATLY increases

>with decreasing temperature.

>

>Therefore the larger wire size WILL help some.

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Tim(at)MyRV10.com
Guest

Posted: Fri Jan 06, 2006 9:00 pm Post subject: Re: Negative Battery Cable Connection

I think he just means that the actual load on the starter to crank

the very cold engine with it's also thicker oil and

everything else requires more battery power...even if you had

a nice warm battery capable of delivering all of it's

summertime current, it would take more to get it to crank

than in the summer.

I know what Michael means when he talks about his 4ga jumper cables.

We have consistent periods of 10 to 20 day in a row each winter where

every day is below zero. I've used cheap jumper cables to try to

start cars with weak batteries, but eventually I got a nice pair

of thick ones as a gift. They'll crank a car over much better than

the smaller wired ones. I've also actually seen with my own eyes,

battery cables with the insulation melted and sliding off because

the person cranked too long on the starter during times trying

to start the engine.

I just know that whenever I've tried to go flying and it's between

10 below and 10 above zero (yes, I keep a preheater plugged in

all winter long) it definitely doesn't start as easily and

having a well charged battery, with a battery blanket

attached can help get things started much easier. The 2GA wire

won't hurt. Nothing against the 4 for those who are lucky

enough to have that as a viable option.

Yeah, you may not want to move up here. 

Tim Olson -- RV-10 #40170

Current section: Panel Wiring

DO NOT ARCHIVE

William wrote:

 	  Quote: 	
		   >The requirement to crank the engine GREATLY increases

>with decreasing temperature.

>

>Therefore the larger wire size WILL help some.

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Tim(at)MyRV10.com
Guest

Posted: Fri Jan 06, 2006 9:02 pm Post subject: Re: Negative Battery Cable Connection



Forgot to mention...hence the reason I buy 1000+ CCA batteries

for my truck. You need it in the winter. The coldness

of the battery just adds to the need.

Tim Olson -- RV-10 #40170

Current section: Panel Wiring

DO NOT ARCHIVE

Kelly McMullen wrote:

dlm46007(at)cox.net
Guest

Posted: Fri Jan 06, 2006 9:45 pm Post subject: Re: Negative Battery Cable Connection



For those looking for batteries; check out

http://www.enersysreservepower.com/ody b.asp?routine=ody spec&brandID=5 . I

am using dual 680s but a 925 mounted on a side will fit the kit battery

configuration.

ddddsp1(at)juno.com
Guest

Posted: Fri Jan 06, 2006 10:31 pm Post subject: Re: Negative Battery Cable Connection



Anyone using the FATWIRE battery cable from Periheliondesigns.com?� Suppose to be 45% lighter and more flexible?�Twice tha cost though!!!�Also, was looking to do an Odessey 925 with a small SLA motorcycle battery as a backup in case of ALT/BAT failure. Anyone done this.....if so what does your wiring diagram look like and where did you mount the backup battery?.� I would want the backup battery on a separate circuit just to switch on in case alt or main battery failed..........would like it to be charged while flying�too.

Thanks,

DEAN

dav1111(at)cox.net
Guest

Posted: Sat Jan 07, 2006 2:32 am Post subject: Re: Negative Battery Cable Connection



I have installed the Pedriheliondesigns Fat Wire and although yet to start the engine I am real happy with the purchase and install. I installed as per Van's Wiring Harness design with a Concord Battery. The Fat Wire is really lite weight and everybody who has seen mine likes it.

I also am using the Fat Wire connection lugs and like them as well.

Russ Daves

N710RV Reserved - Flying to OSH 2006

 	  Quote: 	
		  

From: "ddddsp1(at)juno.com" <ddddsp1(at)juno.com>

Date: 2006/01/07 Sat AM 01:29:53 EST

To: rv10-list(at)matronics.com

Subject: Re: RV10-List: Re: Negative Battery Cable Connection

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Tim(at)MyRV10.com
Guest

Posted: Sat Jan 07, 2006 6:27 am Post subject: Re: Negative Battery Cable Connection



Sounds real close to what I did (the Battery stuff). I didn't use

Fatwire just because of cost, but I would think it would be

an excellent option for those so inclined.

My Batteries are an Odyssey 925 in the back (I didn't put it on it's

side, but enlarged the tray...either way works fine) and I wanted

a bit more juice from the Aux, so I have 4 thin SLA's that

just make it tucked into some wasted space.

http://www.myrv10.com/N104CD/panel/20051228/index.html

At present, I have it all wired up and working, but I don't have

photos yet.

My diagram is available too.

Today's is

http://www.myrv10.com/N104CD/electrical/N104CD Electrical Schematic Rev5.pdf

But I change it as I find small things as I'm currently wiring it.

It might be a bit different than what some people would do, but

I'm happy with it.

Tim Olson -- RV-10 #40170

Current section: Panel Wiring

DO NOT ARCHIVE

ddddsp1(at)juno.com wrote:

 	  Quote: 	
		   Anyone using the FATWIRE battery cable from Periheliondesigns.com?

Suppose to be 45% lighter and more flexible? Twice tha cost

though!!! Also, was looking to do an Odessey 925 with a small SLA

motorcycle battery as a backup in case of ALT/BAT failure. Anyone done

this.....if so what does your wiring diagram look like and where did you

mount the backup battery?. I would want the backup battery on a

separate circuit just to switch on in case alt or main battery

failed..........would like it to be charged while flying too.

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rvbuilder(at)sausen.net
Guest

Posted: Sat Jan 07, 2006 7:40 am Post subject: Re: Negative Battery Cable Connection



Neat stuff and I am considering it.� Much lighter and it is actually #2+ as it is really a little better than #2.� Send Eric an email with your address and he will send you a short sample of the different wires.� And you can always use the sample as a short run. 

�

Michael

do not archive

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of ddddsp1(at)juno.com

Sent: Saturday, January 07, 2006 12:30 AM

To: rv10-list(at)matronics.com

Subject: Re: RV10-List: Re: Negative Battery Cable Connection

bob.condrey(at)baesystems
Guest

Posted: Sat Jan 07, 2006 9:39 am Post subject: Re: Negative Battery Cable Connection



I considered it but the wire, although lighter, is much larger diameter than standard. Space in my conduit is at a premium.

Bob

--------------------------

Sent from my BlackBerry Wireless Handheld

jerry(at)mc.net
Guest

Posted: Sat Jan 07, 2006 10:43 am Post subject: Re: Negative Battery Cable Connection



Tim ...

Your batt install is the best use of airframe space I've seen. I also like

your strap hold-down idea. I'm using a nylon strap as well ... secured with

velcro on top of batt plus velcro between the strap on the return fold.

Question:

What program did you use to to draw your wiring diagram? Did you down load

the symbols from Aeroelectric? I just ordered TurboCAD from ebay V9.2 ...

Thanks ...

Jerry Grimmonpre'

RV8A

Tim(at)MyRV10.com
Guest

Posted: Sat Jan 07, 2006 11:01 am Post subject: Re: Negative Battery Cable Connection



Thanks Jerry. I used Autocad 2000, I think it is. I just loaded

up one of Bob's existing drawings and then moved things around.

I didn't use any symbol libraries until today when I finally

decided to replace the symbol for the ammeter shunt for something

more like a Hall Effect sensor.

I too was thinking of ordering TurbCAD from Ebay just because it's

so cheap and it might be a nice long-term program to use. The

Autocad I have is kind of a "loaner".

Tim Olson -- RV-10 #40170

DO NOT ARCHIVE

Jerry Grimmonpre wrote:

lwalters2(at)cfl.rr.com
Guest

Posted: Sat Jan 07, 2006 11:06 am Post subject: Re: Negative Battery Cable Connection

William wrote:

 	  Quote: 	
		   >The requirement to crank the engine GREATLY increases

>with decreasing temperature.

>

>Therefore the larger wire size WILL help some.

How so, as it relates to temperature?

The original premise was that it may be fine at regular temperature

but not so in the cold. I only submit that if the performance is

sub-par at a lower temperature it will also be sub-par at normal

temperature. Thicker cable is indeed better-there is no debate there.

I only suggest that nothing with regard to the cable has any

dependency on the temperature. Certainly the lowered temperature has

an effect on the battery performance however.

William Curtis

http://nerv10.com/

Guys, Guys. William finally go to the point. The difference between #2

and #4 and down into the 00s boils down to resistance. The resistance

change with the temps we live in don't amount to a hill of beans ....

old electrical term, believe me ..... but the battery does suffer due to

low temperatures. When you're trying to push 200 or 250 or whatever

cold cranking amps down that starter wire, that insignificant difference

in resistance results in a major voltage drop change by the time you get

to the starter.

Having said that, if someone wants to plumb their bird with #10 house

wire .... well, just have at it. Think of it as an experiment. Also,

get some training on how to properly prop an airplane. (OSHA warning

goes here  )

For myself, I like to use welding cable ..... far more flexible, less

prone to vibration failures, and it's able to handle the current just

fine. So what if I suffer a small weight penalty ..... I don't have to

worry about starving my starter when I need it.

JMHO

Linn

do not archive

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bcondrey(at)cox.net
Guest

Posted: Sat Jan 07, 2006 12:54 pm Post subject: Re: Negative Battery Cable Connection



The real issue with increased wire size is decreased resistance.� #4 copper wire has a resistance of .000249 ohms per foot, #2 has .000156 ohms per foot.� These numbers are small, however with a high current draw (starter for example) it makes a huge difference.� There's also internal battery resistance to take into account (.004 ohms is a typical value).� Bottom line is that you WILL have voltage drop across the wire, how much is dependent on total resistance and current draw.� When the temperature is really cold the battery has less capacity AND the engine is harder to turn.

�

An excellent tutorial on the above is located at http://www.aeroelectric.com/articles/wiresize.pdf

�

Bob #40105

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