The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
Subject: Re: Charging a battery from a car battery
X-Newsreader: Forte Agent 1.92/32.572
Date: Tue, 03 Dec 2002 12:37:57 -0500
NNTP-Posting-Date: Tue, 03 Dec 2002 12:38:02 EST
Organization: Bell Sympatico
I am not discussing the full system that I am not familiar with , but
if one connects a dc source to two batteries through a diode in
series with each battery , one battery will never get power from the
On Tue, 3 Dec 2002 09:41:15 -0000, "Kijoma"
>diodes = baad ..
>most of these units wire to the alternator warning light circuit.
>if there is no power on the alternator light (engine stopped or off) the
>second battery is switched off.
>when the engine is running, the relay energises and parallels the batteries.
>dont do this with a sealed battery tho as if its flat the inrush current
>from the other battery/alternator will probably do it damage.
>you basically need a small boost switching regulator that can give a current
>limited output which is essentially constant regardless of source battery
>oh and hook it to a relay/transistor to the ignition circuit so its off when
>the engine is off.
>"Vlad" wrote in message
>> Just 1 diode in series with each battery
>> On Tue, 03 Dec 2002 03:26:56 GMT, firstname.lastname@example.org (klmok) wrote:
>> >On Tue, 03 Dec 2002 00:22:15 -0200, Bruce Douglas
>> > wrote:
>> >>I am trying to make a battery charger for charging my sealed lead
>> >>batteries from a car on occasions when I am away from mains power.
>> >In RV camper shops they have a battery charger isolator for charging
>> >the second battery. It allows the alternator to charge both the main
>> >battery and the second battery but won't let the second battery draw
>> >juice from the main battery when to alternator is not running.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup