Test for a voltage drop of the DC/DC converter right at the converter with out any load on except for the power it takes to turn on the converter. If the converter is rated for 14.5 volts, it may drop to about 14.3 volts. Then check the voltage at the battery which may read a bit lower like 14.2 volts cause by the resistance of the wire from the converter to the battery.
In my case, I first use a No. 10 copper wire that had a circuit run of about 25 feet. The voltage drop to 13.8 volts with just the controller and three contactors on. I then increase the feeder cable to a No. 6 AWG copper stranded 2-wire cable which brought the voltage up into the 14.3 volt range. Latter I add a electric hydraulic pump for the power steering and Hydro Brake Booster which I had to gang four DC-DC converters together for a total of 180 amps and parallel a pair of three No 6 wires for this circuit and set at 14.5 volts. A total running load of the 12 volt accessories can approach 100 amps at a start up surge when 3 contactors, motor controller, cooling pumps, power brakes, power steering, inverter for heating and A/C and 5 fans. After start up the 12 voltage ampere will drop to 40 to 50 amps. The voltage drop should only be a maximum of 0.5 volts at normal running. Some of these DC-DC power supply are not regulated like a alternator which may start out at 14.5 volts and as the battery is charge, comes down to 13.3 to 13.5 volts as a maintainer voltage. I use a standard auto 12 volt meter and amp meter on my dash to monitor the 12 volt circuits. Roland ----- Original Message ----- From: Danpatgal<mailto:[email protected]> To: [email protected]<mailto:[email protected]> Sent: Saturday, September 21, 2013 6:31 PM Subject: [EVDL] Aux Battery Died - Or was it the DC to DC ?? I have a small 10ah (4 Headways) aux battery and an Elcon DC to DC in my car. I don't even have power brakes, don't normally drive at night, etc ... so for the past 8-9 months, haven't had any issues with running low on aux battery power. Last week, however, after charging up, the car didn't start. When I tested the 12v power, it was 9v ... one of the 4 Headways was at 0v ... dead. I'm not entirely surprised at this, since the cell was one I had revived from the dead. However, I wasn't sure if perhaps the DC to DC failed, and that's why this cell died. So I have a couple questions: Is there a way to ensure that the DC to DC is still working? Will it be "on" just being connected and show a voltage across the outputs? Or do I have to measure it indirectly: the aux battery should show a higher voltage after the main contactor closes? Dan ----- Dan Gallagher http://www.evalbum.com/3854<http://www.evalbum.com/3854> -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Aux-Battery-Died-Or-was-it-the-DC-to-DC-tp4665269.html<http://electric-vehicle-discussion-list.413529.n4.nabble.com/Aux-Battery-Died-Or-was-it-the-DC-to-DC-tp4665269.html> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130921/d59cd668/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
