overcharging of batteries

B. Sitton Posted 2015-12-04 8:26 AM (#3237) Subject: overcharging of batteries Location: Ignacio Colorado (72.161.124.76) I was looking at the new Duramax conversion going on. Pictures of swelled/cooked batteries. When I got #902 the charging system was not charging in the proper voltage range. The original voltage regulator is adjustable but the problem turned out to be the engine relay. This is the one that powers the ignition system. A bad connection in the relay was causing lower voltage to the ignition/charging control systems. This in turn was causing the charging system to overcharge the batteries to get the system control voltage into the target range. The battery voltage to the relay was getting knocked down to 8-9 volts on the output side of the relay. The regulator was full fielding the alternator to try to get the voltage up to 14 volts. The battery voltage was in the 16-18 volt range while the voltage to the regulator/ignition was just getting up to it's target voltage. What I found wrong with the relay was one of the rivets that holds one of the spade terminals to the relay was loose. I soldered the connection and the system worked as designed. FYI Bill byegorge Posted 2015-12-04 2:30 PM (#3238 - in reply to #3237) Subject: Re: overcharging of batteries Location: Olympia, Washington (174.61.212.92) Now that's cheating Bill, you are supposed to try and source an obsolete relay. When you do find one it's been superceded by a modern 'piece' that will never be as good as the one you are throwing away. Oh, and since it's 'vintage' as well as 'RV' the cheap new part is anything but.