X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 04 Nov 2009 17:38:33 -0500 Message-ID: X-Original-Return-Path: Received: from mailrelay.embarq.synacor.com ([208.47.184.3] verified) by logan.com (CommuniGate Pro SMTP 5.2.17) with ESMTP id 3930617 for lml@lancaironline.net; Wed, 04 Nov 2009 12:37:19 -0500 Received-SPF: pass receiver=logan.com; client-ip=208.47.184.3; envelope-from=liegner@embarqmail.com X-Original-Return-Path: X-BINDING: X-Spam-Rating: None X_CMAE_Category: 0,0 Undefined,Undefined X-CNFS-Analysis: v=1.0 c=1 a=o1d4Y2oB5JEgl2cPm7IA:9 a=Fmg_X841ei4l93fGfj6ycETUl2UA:4 a=ZeldRdrFSqE8NmeuXrMA:9 a=xSwJlWJ6iUCriBdf0AoA:7 a=8iJJT3Du0Q-NRuVKEfOpRCLBGYoA:4 X-CM-Score: 0 X-Scanned-by: Cloudmark Authority Engine Authentication-Results: smtp03.embarq.synacor.com smtp.user=liegner@embarqmail.com; auth=pass (LOGIN) Received: from [66.152.128.69] ([66.152.128.69:45283] helo=[10.0.1.150]) by mailrelay.embarq.synacor.com (envelope-from ) (ecelerity 2.2.2.40 r(29895/29896)) with ESMTPA id 4A/92-01774-9ABB1FA4; Wed, 04 Nov 2009 12:36:43 -0500 Mime-Version: 1.0 X-Sender: liegner@embarqmail.com@pop.embarqmail.com X-Original-Message-Id: In-Reply-To: References: X-Original-Date: Wed, 4 Nov 2009 06:40:19 -0500 X-Original-To: "Lancair Mailing List" From: "Jeffrey Liegner, MD" Subject: Re: L-IVP Battery Cooling X-Original-Cc: "Colyn Case at earthlink" Content-Type: multipart/alternative; boundary="============_-954766276==_ma============" --============_-954766276==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" Also, a remote location causes more voltage drop due to the longer cable. I have one battery in the back and tried copper wire (very heavy) and had almost no voltage drop, but when I checked aluminum wires (very light), I had nearly 1.0v drop from the terminals to the Buss. Aluminum is OK for avionics Buss, but not cranking or hydralic pump amp (too much heat and volt loss), if drawing off a battery behind the rear bulkhead. My humble opinion. Voltage drop per foot is part of the specification of the cable wire guage and material. Jeff L LIVP >Bill said, >I think the only drawback to a remote >> location is the extra weight of the longer cables and perhaps W&B >> oncerns. -Bill Wade > >Probably most people would agree. However, I would want a very positive >way to disconnect the battery from a) the starter and b) whatever >else might short. >Burning insulation in the cabin is seriously no fun. We had a post >recently of a guy >with a stuck starter contactor that couldn't get it to let go. >Your next line of defense would >be the main battery contactor itself in that situation. For those >two situations you want >a really high quality, high break current, contactor at the starter >and main battery. If it were me I wouldn't accept anything >less than a wr582 but actually I went with kilovac ev200s. > >....but being a little imaginative with the other scenarios, suppose >you somehow stressed one >of the biggish ring terminals on your grid or ground bus and that >wire was just wondering around >looking for something to connect with. Good workmanship is the >best defense, but for that particular >situation, if you had the batteries in the back, wouldn't you want >something near the front that would >take the battery out of the loop? > >It is really amazing how long a big battery can keep an electrical >fire going if you can't get the thing off line. > >My plan therefore is to make sure something else opens or fuses >before the wire melts down. > --============_-954766276==_ma============ Content-Type: text/html; charset="us-ascii" Re: L-IVP Battery Cooling
Also, a remote location causes more voltage drop due to the longer cable.  I have one battery in the back and tried copper wire (very heavy) and had almost no voltage drop, but when I checked aluminum wires (very light), I had nearly 1.0v drop from the terminals to the Buss.  Aluminum is OK for avionics Buss, but not cranking or hydralic pump amp (too much heat and volt loss), if drawing off a battery behind the rear bulkhead.  My humble opinion.

Voltage drop per foot is part of the specification of the cable wire guage and material.

Jeff L
LIVP


Bill said,
I think the only drawback to a remote
> location is the extra weight of the longer cables and perhaps W&B
> oncerns.  -Bill Wade
Probably most people would agree.  However, I would want a very positive
way to disconnect the battery from a) the starter and b) whatever else might short.
Burning insulation in the cabin is seriously no fun.   We had a post recently of a guy
with a stuck starter contactor that couldn't get it to let go.   Your next line of defense would
be the main battery contactor itself in that situation.  For those two situations you want
a really high quality, high break current, contactor at the starter and main battery.  If it were me I wouldn't accept anything
less than a wr582 but actually I went with kilovac ev200s.
 
....but being a little imaginative with the other scenarios, suppose you somehow stressed one
of the biggish ring terminals on your grid or ground bus and that wire was just wondering around
looking for something to connect with.     Good workmanship is the best defense, but for that particular
situation, if you had the batteries in the back, wouldn't you want something near the front that would
take the battery out of the loop?  
 
It is really amazing how long a big battery can keep an electrical fire going if you can't get the thing off line.
 
My plan therefore is to make sure something else opens or fuses before the wire melts down.
 

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