Thruster Batteryy

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ethanbarnett

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Fluid Motion Model
C-30 S
Vessel Name
LIBERTY
After being underway for 5 hours we opted to utilize the thrusters briefly, a few short bursts. We than saw Low Voltage Warnings. What is this a sign of? Additionally while running the generator when anchored I turned the Thruster Battery switches to the off position. I did the stern one first, and then when I did the bow thruster switch the generator shut down. Is this the correct function/wiring for both the thrusters and the generator?

Thank you,

Ethan
 
Ethan, the thruster draws a considerable amount and can lower voltage to 9.5V on initial draw. More detail about the situation is needed. If the engine was turned off then you had no power from the alternator, so low voltage can very well pop up. The thrusters operating with engine off and the generator on sounds like a similar situation. The thrusters draw a considerable amount of amperage. The generator probably could not take the increased load to charge the batteries and shut down. If you have the engine on and use the thruster you should not get a low voltage warning. If you get a warning it is quite possible that the thruster battery is weak. A load test may be in order. How old are the batteries?
 
ethanbarnett":3pssejt4 said:
After being underway for 5 hours we opted to utilize the thrusters briefly, a few short bursts. We than saw Low Voltage Warnings. What is this a sign of? Additionally while running the generator when anchored I turned the Thruster Battery switches to the off position. I did the stern one first, and then when I did the bow thruster switch the generator shut down. Is this the correct function/wiring for both the thrusters and the generator?

Thank you,

Ethan

Ethan,

With the generator you need to have the bow thruster switch on as that is directly linked to the generator. If it is off the generator will not start, if you turn it off while generator is on it will shut down like it did on you. On the low voltage warning I would look at the batteries depending on the age of the boat/battery, I would need more info on this to help understand what is going on here. Let me know if I can help you.

Thank you,
Kevin Lamont
 
Kevin thanks for the timely reply. Yes the engine was running, and those thruster batteries (and evidently generator starting battery as well) are approx 3 years old. This boat was delivered in April 2015. Time for a load test it seems.
 
and to you too Mr. Rizzo. Been a long day traveling up from Lorellei to Angelfish Creek for our jump off to Bimini tomorrow. First goood weather window.
 
where is the low batt volts error showing? on the blueseas panel? or on Garmin? elsewhere?
 
great question. On the Garmin Chartplotter.
 
I'm not sure how a low voltage of thruster battery would effect the Garmin low voltage alarm. Are your boat thruster batteries parralled with your house batteries? You should have 3 different battery circuits House/engine/ thruster. It appears that you may actually have 4, House/engine/thruster stern/ thruster bow/generator. Each system should be isolated by a isolating relay and possibly a parallel battery switch. How does the Garmin monitor your thruster batteries? I know I can monitor engine batteries thru the Volvo EVC link , and the house because that is what powers the Garmin. I didn't know the thruster batteries could also be linked to the Garmin. Do you also have a parallel battery switch that will link battery bank to battery bank ? If so do you keep it on or off ? It should be off for normal operation. When you are running the engine and under way what does the battery Voltage register? Engine should be approx. 14V, Thruster batteries should be approx 14V unless you are using the thruster. House should be a minimum of 13V. The house voltage changes from amperage draw but the alternator should be able to maintain 13V with a good battery bank and its amperage output capacity. If everything is wired correctly, and parallel switch are off I would suspect a bad battery somewhere in your battery circuits.

If the thruster batteries can be monitored by the Garmin how is that done? My only way of monitoring the thruster is Blue Sea panel.
 
Brian,

At some point all the batteries are connected via the relays. I would assume for the low voltage alarm to go on the thruster battery may be weak, but had a surface charge enough to keep the relay connected. It is possible that the large draw then lowered the voltage on the house, which the Garmin is connected to. To many variable to start troubleshooting without all the information and the exact configuration at the time of the alarm.
 
I thought the low voltage on the garmin was only the house batteries - as the garmin runs off the house and not thruster batteries (in my boat but I thought all?)

how would the garmin know that its the thruster battery thats low? mine just says "low volts" and doesnt say which battery bank is low as its not that smart?

if the house battery was low and the ACR relays are closed to include the thruster that would still be a low house battery volts issue that caused it no?

of course this assumption changes if you have made the modification to connect thruster and house batteries with a new switch to get more battery power out of your house batteries when on the hook. (quite a few owners have done this)
my thinking
1. this is either coincidence
2. house battery is weak; and thruster and house are somehow connected beyond the use of the ACR relay with a switch and you have pulled down all the batteries in the bank to low volts - causing the error.
3. strangely your Garmin is wired to the thruster battery?

I would check wiring and then load test batteries. If they are old I would just replace and save the hassle of the load testing.

separately I was told you should not move the battery switches with engine on; is this the case with the generator too?
 
Along this same line... It sounds like the thruster is best used only when the engine is running, correct? Also, should the circuit settings always be in "charge" mode - both when plugged into shore power and when the engine is running away from external power?
 
I only use thruster when engine running as its such a high amp item.

i leave charger on on the panel all the time. not sure if turning charger off when on shore power stops charging. or if that only applies to when charging on generator or engine alternator.

I think solar charger bypasses all this anyway
 
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