batteries for 24v thruster

[Ski in NC]

24V gets spec'd when the thrust requirements exceed those available in 12V. If on your boat you can spec an appropriate 12V unit and your boat is 12V, I'd go 12V. Higher volts make sense on larger units as the 24V allows physically smaller cables and physically smaller motors.

 

[Greatlaker221]

I used two 12V AGM batteries wired for 24V for SE80 Side Power 24V thruster. I use a Sterling 12V to 24V charger for re charging when underway pulling from house bank charged by alternator on FL120. 12V house bank charger maintains and tops off at the dock. Works great.

 

[Willo B]

So at this point i'm going with the two NorthStar group 31, I can get a better price on them then the Odesseys for my SE120 side power. Then I think i'll be going with a Parallel / Series relay and recharge off House or Start bank. Each has its own alternator.

 

[RickyD]

I am in the process of installing a Side Power SEP170-250 24v in my Californian 55. I have ordered 2 Odyssey PC2150 group 31 AGM batts. Also, a ProMariner 20 Plus. I looked at more expensive chargers but could not justify them. Now I read this thread and wonder about the wiring. Maybe I should return the charger and go with the 12v to 24v switch for $60 bucks. I would like everything to charge off of the alternators and the generator not just at the dock. I don't know much if anything about this stuff so i need some help here.


I'll want of course to charge off of the shore power.
I have a 4kw generator and a 16kw generator so I want to charge off of them.
I'd like to keep the charge up from the alternators but since I run lots of power, I do need to run a generator daily so maybe I don't need the alternator source.


I have two 8Ds as starters for my Cat 3208s. The Port is isolated from the house bank, the Stb is included in the house bank. House bank is 2 8Ds. So should I drain the house I can always start the port engine. I also have a small start batt for my 4kw gen. Not sure where the 16kw gets its start energy. The boat is still new to me.


I have the charger and batteries on order. Now is the time to make any changes. Sounds like I did ok with the batteries. What about the charging system? Any suggestions would be welcomed.

 

[ranger58sb]

24V gets spec'd when the thrust requirements exceed those available in 12V. If on your boat you can spec an appropriate 12V unit and your boat is 12V, I'd go 12V. Higher volts make sense on larger units as the 24V allows physically smaller cables and physically smaller motors.

Thanks! I'm translating that to mean since the SE100/185 (185mm tube) is good for the boat, and since we'd mount batteries adjacent to the thruster, there'd be no advantage to the 24V unit versus the 12V unit. Yes?

Given a 12V boat, I'm seeing it being a lot easier to deal with charging with the 12V thruster...

-Chris

 

[JDCAVE]

I’m going to bump this thread as I’m looking for input. The existing batteries for my Wesmar 24VDC bow thruster (unknown hp) are Northstar NSB M12-210. They are a very expensive AGM, and are basically a 4D at 132 lbs a piece. The maintenance logbook indicates they were installed February 2010, so they have 9 seasons. Realistically they are nearing end of life. So I did some tests:

With the charger just turned off for the test. Batteries are at 13.27 Volts, measured at the battery with digital meter.
5 second thruster test: drops down to 9.2. Volts during the test. After the test, recovers to 12.94 volts quite quickly.

It did this 4-5 times. The thruster seems ok, perhaps a little less jump than I remember. Is the voltage drop to 9 volts excessively low?

Jim

 

[JDCAVE]

A further update: I used the clamp meter and measured a peak draw of 368 amps @ 24 VDC = 8832 watts / 745 = 11.8 electrical hp.

However I had measured 9.3 VDC at the batteries during operation, which would suggest a possible correction of:

2*9.3/24*11.8= 9.2 effective hp.

Does this make sense?

Jim

 

[Ski in NC]

9V when running sounds a bit low, but if thruster is providing enough thrust, it is good enough. What happens if you run it like 10-15sec? When my flooded batt gets tired, not only do volts go low, but an extended run you can hear rpms dropping.

 

[JDCAVE]

I’ve not noticed a change in RPM on longer tests. I realize now, when I did the test at the dock, the 40 amp charger was on, and able to contribute 40 amps @ 12 VDC. Probably should have done this test with the charger off, so I should probably repeat the test with the charger off and also for a longer period.

Jim

 

[Xsbank]

Fully charge the batteries to float, then disconnect them. Wait 24 hours and then test them.

Nigel Calder is the best source of this sort of information - buy his book!

How long do you use your thruster for? 60 seconds? I think you need a starter-type battery, one that produces a large rush of amps for a short period of time, then is recharged. A CCA rating of 1100 amps is a good size to take care of the inrush current; take 370 amps out for a minute, you have used about 6 amps of your battery capacity which means a rapid recharge to full specs. If you use short bursts of thruster rather than steady on, you have two considerations - the starter-type battery will recover a lot between bursts but the inrush current is largest at the initiation of starting the motor and will also stress the relays more, causing a shorter time-between-fail for them (so keep spares).

Start batteries are designed for multiple high-load "bursts" and immediate recharging but deep cycles are NOT designed for that kind of loading.

 

[JDCAVE]

Yes. I have his book. Twice. The kindle version and the recent hard copy. I have concluded I’m fine for now. Different thrusters will have different demands.

2350 MCA and 1850 CCA SHOULD be more than sufficient. The issue is age, and I’ve decided they are fine for now.

Jim

 

[FF]

"Start batteries are designed for multiple high-load "bursts" and immediate recharging but deep cycles are NOT designed for that kind of loading"

While this may be true some docking endeavors seem to involve long term operation of the thruster , a 180 in a tiny channel for example.

The problem with start batts is they save themselves by covering the many thin plates with gas.


This solves the problem of attempting to start an engine with non stop cranking , but could be a danger to a boater that actually needs the thruster to operate , even at reduced thrust.

Waiting a few min as one would do roadside , for the start batt to recover might be very exciting.

Of course the motors in DC thrusters are frequently very time limited , so the starts not working might be a positive long term.

 

[Xsbank]

If you have an emergency and you are relying on a thruster to save you, your boat-handling skills need work.

We had a 50' canal barge in France and the bow thruster failed on the second day. I just used experience with a single here on the coast and we didn't break anything. It was a lot more work to reverse or lock but it worked there just like it does here.

Instead of loading up Friday night and zooming off to an anchorage to drink your face off, try practicing some maneuvering. And while I'm being obnoxious, when was the last time you did a "man overboard" drill? Its a little more complicated than an RV.

 

[FF]

If you have an emergency and you are relying on a thruster to save you, your boat-handling skills need work

."try practicing some maneuvering"

Emergencies for folks that have bow thrusters are emergencies , not normal operations ,after the thrusters fail.

Our 50 ft single engine has no bow thruster , although it still has a backing rudder.

With a 27 inch prop replaced by a 32 diameter unit ,and tiny rudder, our 90 ft wide canal is always a fun 180 to dock.

Practice does make perfection .

Then I pop my one Becks for the day.