Isolator not charging chassis batteries

[Bryan Beamon]

When we are plugged in to AC our isolator or bi-directional relay (bird) inconsistently stops charging our chassis batteries. I have replaced both the isolator and the bird but still experiencing the inconsistent chassis battery charging. I can bring on line the isolator and bird by using our battery  boost switch. Any ideas why this is happening?

[Edward Buker]

Bryan,

I do not own a coach with a Bird and have not worked on one. If both Bird units are acting the same then you would have to assume they are doing what they are designed to do. There must be a trouble shooting guide that tells you the voltage/operating conditions vs whether or not the Bird should connect or not. For instance I read one time that if a Genset is running there is a sense line that disconnects the Bird from charging so that two sources are not charging. I think the threshold voltage for connecting was a little high also, 13.5V possibly if I remember and if what I read was right. Much of the time my Xantrex charger runs a lower charge voltage then that threshold when my house batteries are fully charged. I think some voltage measurements on the house and starting bank when both the Bird is conducting or not vs what the manual says may help. Others with more Bird knowledge may be able to shed some added light here..

Later Ed

[Bryan Beamon]

Thanks Ed for your insight I will investigate your line of thinking.

[Steve Huber Co-Admin]

Brian,
When the BIRD senses either house or chassis battery voltage above 13.3 V, it closes the Isolator Relay, which parallels the batteries, charging both sets. Since you’ve replaced both the isolator and the BIRD, and the system “works” when applying the Boost Switch, I’d consider either a bad chassis battery or a bad battery cable connection.
Steve

[Bryan Beamon]

Steve we are going into Monaco at Coburg tomorrow and will let you know what they say . Thanks for the imput.