slowbutsteady
Member
- Joined
- Nov 25, 2020
- Messages
- 18
- Vessel Name
- Makeleah
- Vessel Make
- 34' 1981 CHB Tri Cabin
I have a bow thruster with a dedicated group 31 115 AH full river AGM battery. The dedicated battery is recharged via a connection to the house batteries (600 AH of AGM northstar Batts) about 7 feet away via a blue seas ACR/Combiner with 80 amp thermal breakers at both ends.
Ive noticed when underway and the combiner engaged the engine will lug and voltage will drop when the thruster is used. My interim solution to reduce strain on my alternator from those momentary load spikes is to manually trip the breaker while docking/maneuvering thus severing the combiner from my house bank and then rearming the breaker while underway or back at the dock and connected to shore power to keep the thruster battery charged. The thruster seems to operate with the same force whether the combiner is activated or not. The house bank is brand new and I did a simple test (not a load test) on the dedicated thruster battery to find that its still reading around 650 CCA (Its rated for 720). The thruster battery is getting close to 6 years old so Im inclined to replace it but just want to understand if there are any other flaws with the installation I should look at too.
The thruster is a 12 v 10 HP thruster. I dont know its precise amp draw during operation (i'll test this with a ammeter next time I have a buddy on board) but if pressed to guess I would say somewhere in the 250-300 amp range in short bursts. I'm conservative with the thruster when docking too but do use it in short bursts when getting in to the slip. On a few occasions the breakers have tripped themselves even with relatively light use.
I know there are a variety of ways to wire in a thruster but my understanding is that having a large battery directly adjacent to the thruster itself with heavy cable is ideal.
Ive noticed when underway and the combiner engaged the engine will lug and voltage will drop when the thruster is used. My interim solution to reduce strain on my alternator from those momentary load spikes is to manually trip the breaker while docking/maneuvering thus severing the combiner from my house bank and then rearming the breaker while underway or back at the dock and connected to shore power to keep the thruster battery charged. The thruster seems to operate with the same force whether the combiner is activated or not. The house bank is brand new and I did a simple test (not a load test) on the dedicated thruster battery to find that its still reading around 650 CCA (Its rated for 720). The thruster battery is getting close to 6 years old so Im inclined to replace it but just want to understand if there are any other flaws with the installation I should look at too.
The thruster is a 12 v 10 HP thruster. I dont know its precise amp draw during operation (i'll test this with a ammeter next time I have a buddy on board) but if pressed to guess I would say somewhere in the 250-300 amp range in short bursts. I'm conservative with the thruster when docking too but do use it in short bursts when getting in to the slip. On a few occasions the breakers have tripped themselves even with relatively light use.
I know there are a variety of ways to wire in a thruster but my understanding is that having a large battery directly adjacent to the thruster itself with heavy cable is ideal.