Community Forums

Geneandea · 12-14-2015, 12:18 PM

I recently had to do some work I disconnected the negative cable from the chassis battery. completed the work. I started the engine, realizing I had forgotten to reattach the cable. I am somewhat confused as I should not have been able to do or so I thought. single chassis battery and two coach batteries?

Gene

mel s · 12-14-2015, 01:56 PM

Quote:

Originally Posted by Geneandea

I recently had to do some work I disconnected the negative cable from the chassis battery. completed the work. I started the engine, realizing I had forgotten to reattach the cable. I am somewhat confused as I should not have been able to do or so I thought. single chassis battery and two coach batteries?
Gene

Geneandea
If your engine started the negative cable was NOT disconnected from the chassis battery.
Me thinks you may have disconnected the negative cable from the house batteries??
Mel
'96 Safari

twinboat · 12-14-2015, 02:08 PM

If you were plugged in, your BIRD may have been active and you started off your house batteries. They were grounded.

Just like hitting the boost switch.

Geneandea · 12-14-2015, 02:26 PM

I definitely disconnected the chassis battery as for bird?? aux start was not active

HHIDan · 12-14-2015, 02:34 PM

If you are connected to shore then the BIRD (or BIM) might have connected all batteries together. If not on shore the BIRD should have had the batteries disconnected from each other.

When I disconnect one set only I always make sure I tape the ends of cables so sparks don't fly...

twinboat · 12-14-2015, 02:55 PM

BIRD is Bi-directional Isolation Relay with Delay.

It is there to charge your chassis battery when you are plugged in and charging your house bank, so your chassis battery don't run down.

When driving, your alternator will charge your house bank, along with the chassis battery.

It connects both battery banks together with large battery cables. With that, the engine will start from the house bank.

The question is "Did you have the RV plugged in to shore power ? "

Geneandea · 12-15-2015, 07:14 AM

I was plugged in and charging. thanks I will have to get a better understanding of the BIM circuit. I assume the BIM is separate from the aux start switch

twinboat · 12-15-2015, 08:03 AM

Quote:

Originally Posted by Geneandea

I was plugged in and charging. thanks I will have to get a better understanding of the BIM circuit. I assume the BIM is separate from the aux start switch

Many BIMs, IRDs and BIRDs use the same solenoid as the AUX start switch. The AUX switch overrides the auto control.