Low voltage starboard side

YYZRC

Isolator is new ProIsoCharge. Batteries are two year old AGM group 29. 

VV reads 14.2v port, 11.8 starboard when engines running. Voltmeter on starboard battery (disconnected) reads 12.6v. I swapped batteries port to starboard, no change. I swapped alternators port to starboard, no change. 

Now stumped. Thoughts?

Grahamu

What are the voltages at the isolator alternator input terminals

davidbrooks

I would be checking each wire then. Test the wires and terminals.

GMSLITHO

behind the panel where you switch from battery 1 or 2 or both there are 2 big 30 amp fuses .I had the same issue last year 

YYZRC

Thanks @GMSLITHO - my boat has the remote battery switches like this:

I will check the breakers!

GMSLITHO

Ok I didn't have those  mine was a manual switch 

YYZRC

More testing. 

Engine running, starboard alternator 16.4v, port 14.6v

Engine and battery charger off, starboard battery 12.4v, port 13.4v

At the isolator, starboard battery 1.8v, port 12.7v

Will now swap the charging breakers to see if that’s the issue. 

YYZRC

Found it. Loose nut on the starboard breaker. 

Check your nuts!! 7/16”

aero3113

Nice find @YYZRC !!

pcmpete

Good find, where is the breaker located?  I need to check my nuts too.
I have the same remote battery switch setup.

YYZRC

They’re in the panel behind the transom door. 

pcmpete

YYZRC said:

They’re in the panel behind the transom door. 

Did you open the panel, or gain access from bilge?

Thanks

YYZRC

I just removed the 8 or so screws that hold the entire panel in place. 

pcmpete

Is that your normal voltage at idle. Mine always sits around 12.9v-13.1v which always 'feels' low to me.

kordo

Anyone know the part number for the emergency start switch shown in the pic posted earlier in this thread (from YYZRC)?  Thanks.

YYZRC

Pretty sure they are discontinued but here is an example with product number:

https://maxmarineoutlet.com/product/bep-marine-electric-battery-switch-300a-722-ne-300a-oem/

kordo

Thanks YYZRC, but it's the switch by the portside door that you press to combine the starting batteries when one battery is dead.  It's between the remote port and starboard battery switch.  Your pic from July 2021 in this thread shows it clearly.  Thanks.

YYZRC

Oh just the rocker switch? It’s just a Carling momentary on. Push it out from the back and see how many posts are on it. 

It’s probably this one:
https://rockerswitchpros.com/product/v2d1-s00b/