X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 02 Jan 2008 16:55:19 -0500 Message-ID: X-Original-Return-Path: Received: from imo-d04.mx.aol.com ([205.188.157.36] verified) by logan.com (CommuniGate Pro SMTP 5.2c4) with ESMTP id 2627209 for lml@lancaironline.net; Tue, 01 Jan 2008 17:35:09 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.36; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d04.mx.aol.com (mail_out_v38_r9.3.) id q.c62.222236a9 (65097) for ; Tue, 1 Jan 2008 17:34:24 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Tue, 1 Jan 2008 17:34:24 EST Subject: Re: [LML] Ammeter Installation X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1199226864" X-Mailer: AOL 9.0 VR sub 5006 X-Spam-Flag: NO -------------------------------1199226864 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 1/1/2008 2:50:22 P.M. Central Standard Time, rwolf99@aol.com writes: Now let's talk about sensor polarity. The manual tells me to run the wire from the alternator thru the back side of the sensor (the PC board) and out the front. So presumably positive is when current is flowing from the PC board side to the sensor side. If I put this in the line from the battery, I want a positive number to indicate battery charging, don't I? That would mean the wire should go thru the sensor in the other direction. Rob, Do not flip the logic. A positive indication still will indicate the alternator is charging the battery. A negative indication should indicate the ampere load discharging the battery. I.E. As soon as the master switch is engaged (and the unit boots), you should see the battery discharge rate as a negative number, maybe -7 to -12 amps depending on how many basic things come to life (relay, engine monitor, turn coordinator, landing gear locked lights, etc.). After engine start (and re-boot of the EPI), the main bus voltage should got to around 14.3 to 14.6 (SLA battery) and the ammeter indication should soon drop to fractions of an amp although mine is quite variable by jumping between charge and discharge (needle neutral). You also said: <<<<< How would I use this device to determine whether the battery is charging or discharging? To accomplish this goal, the current sensor would have to be on the wire from the battery (actually the downstream side of the battery contactor) to the main bus, and the alternator output wire would be connected to the main bus without passing through the current sensor. Sound good so far? >>>>>> Nope. I have the PC board mounted between the battery and the master relay. Thus I can see the load from the master relay included on the display (one side of the coil is internally wired to the "bat" side of the relay). If the alternator is capable of handling the electric load there may be a small positive charge going to the battery with the bus voltage at 14.3 to 14.6 (SLA battery). BTW, my original sensor is still mounted on the firewall since I didn't want to cut and rebuild the line from the main bus to the plus side terminal of the starter relay - the same terminal to which the B-lead from the alternator is connected. If I would have put a multi poled switch on the sensor to EPI lines, I could have monitored both the battery and the alternator load with a twist of the wrist. I already monitor the voltage of the main bus, essential buss and EI battery with a rotary switch. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Darwinian culling phrase: Watch This! **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) -------------------------------1199226864 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 1/1/2008 2:50:22 P.M. Central Standard Time,=20 rwolf99@aol.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Now=20 let's talk about sensor polarity.  The manual tells me to run the wir= e=20 from the alternator thru the back side of the sensor (the PC board) and ou= t=20 the front.  So presumably positive is when current is flowing from th= e PC=20 board side to the sensor side.  If I put this in the line from the=20 battery, I want a positive number to indicate battery charging, don't I?&n= bsp;=20 That would mean the wire should go thru the sensor in the other=20 direction.
Rob,
 
Do not flip the logic.  A positive indication still will indi= cate=20 the alternator is charging the battery.  A negative indication should=20 indicate the ampere load discharging the battery.  I.E. As soon as the=20 master switch is engaged (and the unit boots), you should see the battery=20 discharge rate as a negative number, maybe -7 to -12 amps depending on=20= how=20 many basic things come to life (relay, engine monitor, turn coordinator= ,=20 landing gear locked lights, etc.).  After engine start (and re-boot of=20= the=20 EPI), the main bus voltage should got to around 14.3 to 14.6 (SLA=20 battery) and the ammeter indication should soon drop to fractions of an= amp=20 although mine is quite variable by jumping between charge and discharge= =20 (needle neutral).
 
You also said:
<<<<<
How would I use this device to determine whether the battery is chargin= g or=20 discharging?  To accomplish this goal, the current sensor would have to= be=20 on the wire from the battery (actually the downstream side of the battery=20 contactor) to the main bus, and the alternator output wire would be connecte= d to=20 the main bus without passing through the current sensor.

Sound good s= o=20 far?
>>>>>>
 
Nope.

I have the PC board mounted between the battery and the master=20 relay.  Thus I can see the load from the master relay included on the=20 display (one side of the coil is internally wired to the "bat" side of=20= the=20 relay).  If the alternator is capable of handling the electric load=20 there may be a small positive charge going to the battery with the= bus=20 voltage at 14.3 to 14.6 (SLA battery).
 
BTW, my original sensor is still mounted on the firewall since I=20 didn't want to cut and rebuild the line from the main bus to the p= lus=20 side terminal of the starter relay - the same terminal to which the B-l= ead=20 from the alternator is connected.  If I would have put a multi poled=20 switch on the sensor to EPI lines, I could have monitored bot= h=20 the battery and the alternator load with a twist of the wrist. I alread= y=20 monitor the voltage of the main bus, essential buss and EI battery with a ro= tary=20 switch.
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

Darwinian culling phrase: Watch=20 This!



See AOL's top rated recipes and e= asy ways to stay in shape for winter.
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