Return-Path: Received: from email2k3.itlnet.net ([64.19.112.12] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 741661 for flyrotary@lancaironline.net; Wed, 16 Feb 2005 13:36:03 -0500 Received-SPF: none receiver=logan.com; client-ip=64.19.112.12; envelope-from=jwvoto@itlnet.net Received: from rav.itlnet.net (unverified [192.168.10.149]) by itlnet.net (Rockliffe SMTPRA 6.1.17) with SMTP id for ; Wed, 16 Feb 2005 12:35:18 -0600 Received: from JWVOTO (unverified [64.19.116.129]) by itlnet.net (Rockliffe SMTPRA 6.1.17) with SMTP id for ; Wed, 16 Feb 2005 12:35:17 -0600 Message-ID: <00a101c51456$b8097e20$77741340@JWVOTO> From: "Wendell Voto" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Battery voltage (was: Racetech RV6A Forced Landing) Date: Wed, 16 Feb 2005 12:36:29 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0092_01C51424.23B57580" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 This is a multi-part message in MIME format. ------=_NextPart_000_0092_01C51424.23B57580 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable > At 05:11 PM 2/16/2005 +1000, you wrote: > >Bill, > >What would you expect the battery to show under starting load. > >George ( down under) >=20 > The Hawker Odyssey PC 680 that most folks use has an internal = > resistance of 0.007 Ohms. A typical starter draws perhaps 200 amps in = cold=20 > weather. This means that the battery voltage will drop 200 x 0.007 =3D = 1.4=20 > volt initially. If the battery is fully charged,the voltage will be=20 > about 12.8 - 1.4 =3D 11.4 volts for the first few of blades. As you=20 > continue to crank, the voltage will continue to decline. If you = continue to=20 > draw 200 amps for 60 seconds (at 77 degrees F) the battery voltage = will sag=20 > down to 7.2 volts. >=20 > If you do crank for this long, it might take as long as ten=20 > minutes for the battery to charge back up to 13 volts. (Of course this = > depends on the size of your alternator and the draw from other loads = on the=20 > system.) >=20 > There are nifty charts and graphs at: >=20 > http://www.batterymart.com/pdf_files/odyssey_guide.pdf >=20 > Went to this site and is good, however no weights are given. One = curious thing, the 625 seems to outperform the 680 in CCA, CA, HCA, and = reserve but not in PHCA. Looks to me if you don't need to few extra = cranking amps, the 625 would be the battery of choice (it should be = lighter?) Wendell > >=20 > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0092_01C51424.23B57580 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

> At 05:11 PM 2/16/2005 +1000, you wrote:
> = >Bill,
>=20 >What would you expect the battery to show under starting = load.
>=20 >George ( down under)
>
>=20          The Hawker Odyssey PC = 680 that=20 most folks use has an internal
> resistance of 0.007 Ohms. A = typical=20 starter draws perhaps 200 amps in cold
> weather. This means that = the=20 battery voltage will drop 200 x 0.007 =3D 1.4
> volt initially. = If the=20 battery is fully charged,the voltage will be
> about 12.8 - = 1.4=20 =3D 11.4 volts for the first few of blades. As you
> = continue to=20 crank, the voltage will continue to decline. If you continue to
> = draw=20 200 amps for 60 seconds (at 77 degrees F) the battery voltage will sag =
>=20 down to 7.2 volts.
>
>=20          If you do crank for = this long,=20 it might take as long as ten
> minutes for the battery to charge = back up=20 to 13 volts. (Of course this
> depends on the size of your = alternator and=20 the draw from other loads on the
> system.)
>
>=20          There are nifty charts = and=20 graphs at:
>
> http://ww= w.batterymart.com/pdf_files/odyssey_guide.pdf
>=20
> Went to this site and is good, however no = weights=20 are given. One curious thing, the 625 seems to outperform the 680 in = CCA, CA,=20 HCA, and reserve but not in PHCA. Looks to me if you don't need to few = extra=20 cranking amps, the 625 would be the battery of choice (it should be=20 lighter?)

Wendell
>
>
> = >> =20 Homepage: http://www.flyrotary.com/
> = >> Archive: http://lancai= ronline.net/lists/flyrotary/List.html

------=_NextPart_000_0092_01C51424.23B57580--