Bow thruster voltage drop

[DrNickS]

I have a Vetus 55 on my A-28 year 2001 and noticed a problem when docking at the end of this weekend. The voltage drops way down and I get a error message on my VHF screen that reads "low battery." My GPS turns off due to the voltage drop and volt meter goes all the way down. I have never had this problem before so I assume the power cable to the thruster is the right size. I did not have chance to check it out since we shut her down for the weekend. I will investigate this all next weekend.

Some thoughts I had were - 1 or 2 bad batteries? (house is 8D and starting is 27). Possible corrosion at ends of power cable? Should I test with shore power plugged in and engine off to see if I get the same symptoms?

Has anyone had a similar problem? Thruster operates fine but I do not want to burn it out due to low voltage.

Thanks for any assistance.

[RicM]

The Albin 28 was designed at a point in time before big screen electronics. As we add the goodies like 10" screens, autopilots and Hi Def Radar we have to remember that all that stuff needs more amps, and when you crank the engine the amps drop, sometimes below what the GPS or Radar needs. There are several ways to supply the needed amperage to avoid brownouts. Upgrade the batteries...expensive and might be overkill....add a momentary powersource.....less money but more hassle, or remember that when you are using the electronics for fishing keep the battrey switch on BOTH. That supplies more amps when you crank.

[JackK]

I was having the same problem this spring. It turned out to be dirty terminals on the batteries. I took a wire brush to the terminals and then a little steel wool.

I wouldn't have guessed this to be the solution but a savvy electronics friend suggested I start there. I didn't need to look further!

Jack

[chiefrcd]

Had same issue...mine is a Side Power thruster. You also need to be careful running the bow thrusters with a low battery as it can cause damage to the bow thruster. Check the amps and if it's a battery, replace it before you do serious damage.

[Mariner]

Yeah, make sure the battery is fully charged, and that the terminals are making a good connection. It's not uncommon for those terminals to work loose or corrode up over the winter or the course of a season. Just because you checked them in September before layup, does not mean they're good now.

If the problem persists, you will want to have the battery tested. Replace if necessary. If you want to get fancy, you can add a group 27 up front on an isolator that is dedicated for running the thruster and windlass. Heck, you could also do a dedicated electronics battery located close to the helm. That would isolate the two and ensure that neither interfered with the other.

[DrNickS]

Thank you all for your suggestions. I hope it is as simple as a loose terminal.

Regarding testing the batteries, what is the protocol you all recommend? I can easily remove the 27 and take it to a shop to test but the 8D is a bit heay to transport. Should I buy a load tester or just use my multimeter and test the amps? I think the load tester is what I should use.

[Mariner]

Use a load tester. If there's a small marine supply store that has one, they'll often let you borrow it if you promise to buy the batteries from them. Ignore the color coded "good" and "bad' indicators. Instead, pay attention to what it says the CCA's are, and compare that to what your battery is supposed to put out. If you don't know what your battery is supposed to put out, look at what a new one just like it is rated for. Also, look for discrepencies between batteries if you have mulitple of the same size/type. One battery with lower CCA's in a bank of multiple, will draw the others down, "leaking" valuable power". Obviously, test the batteries with the terminals disconnected to avoid any outside influence.

A multimeter is of no use to you when testing the batteries.

[JoeH]

See my post of May 20, 2008. I have a 2004 flush deck with similar problem. Dave at Vetus indicated my problem may be the result of a bad solenoid or brushes. Quoted me $282.99 for the brushes and $322.40 for the solenoid. (outrageous !!!) That's why some of Vetus' distributors are dumping the line. My mechanic fixed the problem today. Turns out the brushes were corroded and (fused to the motor). He cleaned off the corrosion on the brushes, sprayed on some WD 40 on the brushes and windings and voila. the thruster is working fine. He indicated the motor was quite corroded mainly because of the bilge water that sits in the forward bilge under the thrusterand gives off moisture. He suggested I place some king of moisture absorber in that area and to check for excessive moisture periodically.

He saved me a ton of money.

Joe H

[DrNickS]

Problem solved. It can't believe it was so easy. I had my only my starting battery on. The 8D house battery had not been charging. After charging all was well.

I question why the starting battery did not supply enough juice to the thruster after cruising for 2 hours. Should the 27 starting battery be able to power the thruster? I will test it with the load tester tomorrow.

I usually run with my battery selector set to "both" and spend very little time on the hook. I will start a new thread on this forum to ask what others do.

And...thank you all for your valuable feedback. What a great forum.

[AlanD]

I believe what you are seeing is the large current draw from the bow thruster, and if you have only one battery feeding that current, it will impact what it can send to your electronics and give you that brown out. Has nothing to do with the charge, but number of batteries feeding your boat. Two batteries and you get more VA (Volt Amperes) to spread around. Personally, I turn off the electronics when docking, not that I have too, but with all the draw on current and possible spikes in voltage, don't want to risk it.

[DrNickS]

Personally, I turn off the electronics when docking, not that I have too, but with all the draw on current and possible spikes in voltage, don't want to risk it.

AlanD - That is what I have started doing after experiencing the low VA rebooting my GPS. I do not want my electronics to experience brown outs. Thanks for your response.

[johnmurray]

An earlier post mentioned the option of a separate bow thruster battery to avoid running down the main batteries and risking a no-start or electronics brown out. Would the bow thruster battery get charged from from the same sources as the main batteries (engine underway or battery charger when on shore power)? How complicated is it to set this up?

[RicM]

If you are sure that the bow thruster, cables and connections are all in good shape, the battery is healthy and you still get the brown-out this is an alternative for about $155.
http://www.newmarpower.com/DC_Power_Con ... oners.html
Adding this to your electronics power source is easy and the unit is compact and much lighter and cheaper than adding a whole new battery, charging arrangements etc. While it is usually wired to the starting switch, I see no reason you could not wire the trigger to the bow thruster circuit as well. This little unit contains a sealled rechargeble battery that kicks in when the engine is cranked or the thuster is run and replaces power to the electronics, avoiding the shut downs. I had one of these on my last boat and it was great, installing one this weekend on Time after Time due to shutdowns after drifting with the engine off, then losing power on restart.