Thruster Battery

[gswearin]

Hi All. I’m assuming I have a bad battery but it’s odd enough I thought I’d ask the group. We’ve been cruising without shore power but motoring enough to keep the batteries at 100 percent a fair amount. After sitting the night the thrusters don’t have enough juice to work. If I run the boat for as little as 7-10 minutes they are fine, which isn’t enough to actually charge a low battery. Appreciate your thoughts. Thanks!

 

[Rode Trip]

Charge them up fully, wait about an hour after you stop and check battery voltage directly with a meter. It should be around 12.8 volts. If you're seeing 12.5 or lower you probably have a bad battery. Without knowing the age or type, lead acid usually last 3-5 years, agm usually last 5-7.

 

[scross]

If you need to replace the thruster battery I’d suggest you go with a starter type battery rather than a dedicated deep cycle type. Same if you need to replace the engine battery.
FM saves $$ by buying only AGM or lead acid deep cycle batteries rather than batteries specifically designed for their intended use.

 

[gswearin]

Thanks. On my boat (2021 R29) both the engine and thruster batteries are starting-type batteries. I’ll replace it with the same.

 

[Cutwater28GG]

Two things could be at play


1. You are not actually charging them up properly. The volts need to be high for the acr to close. And it takes a long time for agms to get to high soc.

2. Your batteries are dead and not holding a charge.

I’d make sure 1 is not true first.