Originally Posted by
redprevost
Getting the bus ready for I trip,I realized that I may have a problem.I have a 97 h45/98 vantare/when I purchased the coach the top post on the blue round multi battery isolator mod 3002,had no cable on it,and the center post had 3 cables/bringing the coach home,over 2000 miles I had both high and unbalanced lights on the dash/I didconnected the 3rd cable from the center post and drove home/with the disconnected cable that appears to go to the house batteries reading 15.5 volts/the house batteries read 13.5 in float mode/the bus batteries read 12.5 as do the center and lower post on the surepower ind. isolator/where am I getting 15.5 volts from?If I hook up the cable with 15.5 to the top terminal,will that cook the batteries?Is there any way to test the battery isolator?with nothing attached to the isolator top post it reads 12.0 when the bus batts read 12.5 as do both the center and bottom posts on the isolator,which are hooked up currently/hope someone out there can help/thanks in advance/joe
There is, with all cables disconnected from the isolator to test...basically just like a huge diode. From the center post with neg (black) lead of a digital multimeter, you should get approx .707kohms on the diode/2k ohmmeter scale. Then reverse the leads, put red on the center and the black lead on each top, then bottom post, it should give you a reading of infinity/open if the diodes are all good. Also, from outside post to the other outside post, in both directions the meter should read infinity/open circuit as well. Just like any diode, there is a voltage drop across the PN junction with current flow, so in a normally working system the alternator post/alternator output is 1-2 volts higher than each of the output posts that go to each battery bank to compensate (remember, the voltage regulator is "seeing what the actual chassis battery voltage is, not alternator output, and adjusting the alternator field to maintain the batteries at it's setpoint level). What is the 8th digit from the right and the last four numbers of your VIN, if you don't mind my asking? All Vantare H3's in this vintage should have 24-volt house batteries. Just curious.
Ben Cummings
U.S.A. Luxury Coaches, LLC
Clearwater, FL