2015 Ranger Tug R31 CB - Thruster Battery

calcman05

Active member
Joined
Feb 3, 2024
Messages
32
Fluid Motion Model
R-31 CB
Vessel Name
DINGLEHOPPER
I am a fairly new owner of a 2015 Ranger Tug R31 CB. I recently noticed my thruster battery located on the starboard side lazarette is showing 12v on my battery monitor. Even when I'm on shore power, it's showing 12v. I've taken a multimeter to it while plugged into shore power, and it's showing 12v. My engine and house batteries are floating around 13.5v, so those seem to be charging ok. I'm not sure the age of the battery, but if I had to guess it's 5 years old. Could it be a bad battery? More likely just a charger issue? Could use some ideas on where to start troubleshooting.
 
When on shore power the ACRs should open and charge all the batteries and be at the 13.5V float that you see on house/starter. ACRs won't open if the thruster battery is too low, but that limit is 9.5V so 12V is perfectly in range to open up.

If your charger wasn't working then your house/starter wouldn't be showing 13.5V, so I don't think it's a charger issue. I would start by trying to troubleshoot the ACR and make sure all the wiring in tight, including the path from starter battery->ACR->thruster. After that I would look at replacing the ACR, while a 5 year old battery might need to be replaced soon anyways, I don't think that's the issue here.
 
Thanks! When I get some time I'll dive into troubleshooting the ACR. As a quick fix, can I trickle charge the batter directly on the posts using an AC charger? Or does that screw something up?
 
This is for a newer model R31, but you can check the LED light on the ACR to determine it's status


ACR.jpg
 
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