clean power for elctronics

[furball]

I've had both my depth finder and GPS drop out when I restart my engine. Today the C120 shutdown. The thought of shutting everything down before every restart is a pain in the @$$. Anyone have a recommendation on a power conditioner / backup for marine applications?
Thanks,
John

[RicM]

There are two major reasons that voltage drops occur, when restarting after a shut down, like after a drift, or when using the bow thruster, usually when leaving the dock this time of year. When I leave the dock this time of year my voltage reads very low, 10-11 volts. I was told this is because there is a preheater on the Yanmar 315 that kicks in if the temp is lower that a certain level. If you operate the thruster during that period the voltage will definitely drop below 11.5V where most electronics will kick off. After warming, no problem.

The restart problem can be avoided by using the "both" setting if you have 2 batteries when fishing, starting and stopping the motor etc. The two batteries in parallel should keep the voltage above 11.5V, if not, then one or both of your batteries is probably starting to fail. The foolproof answer is a backup power supply:
http://www.newmarpower.com/DC_Power_Con ... oners.html
This is a rechargable backup battery that is placed into your electronic circuit when the start button is pushed. I do a lot of drift fishing and find this to be a great addition.

[Anthony1013]

Since low voltage issues were brought up, I thought I'd share this about bow thrusters.... something I learned the hard way.

Last winter I had to have my bow thruster motor bebuilt so I went to a local electric shop who had experience with Vetus bow thrusters. I was surprised that my motor had failed so I asked the guy what are the "do's" and "don't's" with bow thruster motors. He said the 2 biggest mistakes people make are engaging the motor with low voltage and running the motor for too long (more than 5 seconds.... pulsing the thruster for shorter bursts is recommenend by this tech). As RicM mentioned, after start up my Yanmar also reads low on the volt meter for several minutes. I try my hardest to not use the thruster until the volt meter creeps back up above 13 volts. It took me a few runs to get used to not using the thruster when departing the slip but I can handle it easily now and my docking skills are that much stronger.

Something else to consider....

Anthony
"MadMoney"

[RicM]

Oh yeah, running the bow thruster with a low battery (low voltage) will definately burn out the motor, also undersized wiring, worn brushes etc. Some owners install a separate battery for the thruster, right in the forward compartment, less wire run, less V drop. The Vetus owner manual for the 55 KGF states that the thruster is not designed to be run more than 4 minutes/hour to allow the motor time to cool off.

[furball]

Ric, I thought it was you who posted the info on the power conditioner but I couldn't find it. Thanks. My pre-heaters run for about 3-5 minutes after startup. I typically don't turn anything on until voltage comes back up. I have 2 4D AGM batteries, this is their third year of service. The Raymarine DSM (depth finder) has dropped a number of times at restart, after drift fishing, and sometimes the autopilot will as well. This was the first time I've ever had the C120 shutdown. I didn't even look at the voltage gauge to see if the pre-heaters came on Engine wasn't shut down for more than 20 minutes. I routinely use my bow thruster with the electronics on and have never had this problem and the battery switch is always in the "Both" position. My batteries may be suspect. Can I load test them in the boat? One will be a nightmare to get out.
I need to do some electronics work this winter like adding a galvanic isolator, power inverter and wiper delay. This and the isolator are at the front of the list. The other two are on the wish list.
Thanks,
John

[RicM]

3 years on 4D AGM batteries does not sound like the end of the line (unless real cheapo's). Check connections to battery terminals, wire brush to remove any corrosion. You could be surprised at what a difference that will make. Put a multimeter on the circuit and test back to the battery to try to find out where the voltage drop occurs. I am not familiar with AGM's, but I have learned one rule that is always applicable in boating, start with the cheapest, simplest answer and work toward the most expensive answer.

[Mariner]

If the batteries aren't properly maintained, they can definitely fail after just a few years. Ours were bad when we bought the boat, just two years after it was comissioned.

Check the water level frequently. You'd be surprised how quickly it will drop.

[Merry Kate]

I've also posted here before that upping the gauge of the short jumper wire from the 12V positive bus to the panel switch running the navigation equipment circuit solved many of my drop-out problems. Going from something like 14 ga to 10 ga on this 10" length of wire made a difference. Track down every bit of both positive & negative (ground) circuit runs with things like sufficient wire gauge, corroded terminations, etc, etc, and it's surprising what you may find.