Nav station chartplotter doesn't work when Sailing?!?

[inspectr]

My Lowrance plotter would often shut down when the anchor winch was working due to voltage drop
We had to remember to raise the engine idle above 1500RPM
Our house batteries recently died
One of the symptoms of impending battery death was that the whole Raymarine system, autopilot, wind, depth and all other instruments shut down also due to voltage drop even when under way engine powered.
I second other opinions above about dead or dying house batteries as a first point of investigation

[skipgundlach]

Your system issues are reminiscent of our radar problem: Unless the engine was running, we could not use it.

I complained to the installing/sales company that I needed the 4-wire power line (too long a run) and not the 2-wire they'd provided as an extension.

The 4-wire cured the issue.

But it was a voltage/amperage issue; once it got more power it worked.

I'd start with metering the output at the plotter(s - one can be connected while the other's being tested for voltage) - and for that matter, you might find that taking one out of the system would make the other operate.

I'd also inspect the connections from the breaker or however it is you control power to the unit/s, as, at least on our boat, nearly always if something unexpectedly - or in some instances but not others - doesn't work, there's a crummy ground (why that? I dunno) connection at fault.

And, of course, the battery bank may be the culprit as ID'd by others - but while you're at THAT, checking the above stuff wouldn't hurt...

[MerSea]

Thank you all!! Yesterday we disconnected from shore power and turned all the electronics on, along with tv, 2 computers, 2 small frig's and two 8 qt freezers. We have a great battery bank, 800 watts but our solar power is lacking (maybe 300w). We were not able to go 24 hours (just 20) without hooking back up to shore power. Everytime one of the freezers came on the amp's jumped up in the 20's. We had someone check our batteries and he thought they were fine. Does this seem like a normal amount of time before starting engine/generator/shore power? It's a 'new to us' boat so we aren't aware of all the wiring - been trying to figure it out.

We have 3 electric winches and when we use the winches we get a low voltage (<11) alarm on the chart plotter. It goes back up but we get the alarm often. I think the batteries AGM are 3 years old (boat is 5 yrs old). The system is b&g navionics zeus2 chartplotters. We have a midnite battery charging unit connect to the solar and inverter (2000wt I think).

And yes the chartplotters work when the engine is running. We hate to change the batteries if they are ok but don't want to get to the bahamas and then realize we should have changed them!

Thank you all!!!!!!!!!

[skipgundlach]

there are some ways you could check your capacity, particularly if you have any amp measuring gear or instruments.

The total amp hours you likely will use, vs the ability to replace those AH, is your real issue. A massive load like an electric winch or windlass will pull down the voltage and take much of the available amperage; likely, as you've discovered, that's what's at work about your plotters.

The amount of time should be a direct relation to the number of amps and the time those amp-eaters run (AH consumed). A higher draw than, say, 5% of capacity, is harder on the battery, of course, if done for extended periods of time...

If you are going to stay in the Bahamas for years versus weeks or a few months, then likely you'll be happier with new batteries. On the other hand, if you have charging sources available, and, as is frequently the case, you motor a lot from here to there, your navigation issues might be moot. So, were it I in your position, and didn't want to run the engine if I could manage without it, but still have the plotters, I'd shut down everything not essential to navigation and maneuvering, and see if your plotters stayed working. If not, likely new batteries are needed. If yes, then you can deal with it like that and wait until you get back to US pricing and freshness-of-battery...

[Snore]

Originally Posted by MerSea

Thank you all!! Yesterday we disconnected from shore power and turned all the electronics on, along with tv, 2 computers, 2 small frig's and two 8 qt freezers. We have a great battery bank, 800 watts but our solar power is lacking (maybe 300w). We were not able to go 24 hours (just 20) without hooking back up to shore power. Everytime one of the freezers came on the amp's jumped up in the 20's. We had someone check our batteries and he thought they were fine. Does this seem like a normal amount of time before starting engine/generator/shore power? It's a 'new to us' boat so we aren't aware of all the wiring - been trying to figure it out.

We have 3 electric winches and when we use the winches we get a low voltage (<11) alarm on the chart plotter. It goes back up but we get the alarm often. I think the batteries AGM are 3 years old (boat is 5 yrs old). The system is b&g navionics zeus2 chartplotters. We have a midnite battery charging unit connect to the solar and inverter (2000wt I think).

And yes the chartplotters work when the engine is running. We hate to change the batteries if they are ok but don't want to get to the bahamas and then realize we should have changed them!

Thank you all!!!!!!!!!

There is a learning curve on battery and load management. MaineSail is IMHO the smartest guy around on battery management. You can read our opinions, or go to the source https://marinehowto.com/category/electrical/


My personal boat was set up based on his articles. If you find them useful, be sure to contribute something- there is a link in the bottom of his pages.

I would suggest learning what each item draws. Also checking the winches, as they should not cause a low voltage. I am not sure if under-size cables to the winches would cause them to draw more amps. But couldn’t hurt to check that also.

[wingssail]

Originally Posted by MerSea

Thank you all!! Yesterday we disconnected from shore power and turned all the electronics on, along with tv, 2 computers, 2 small frig's and two 8 qt freezers. We have a great battery bank, 800 watts but our solar power is lacking (maybe 300w). We were not able to go 24 hours (just 20) without hooking back up to shore power. Everytime one of the freezers came on the amp's jumped up in the 20's. We had someone check our batteries and he thought they were fine. Does this seem like a normal amount of time before starting engine/generator/shore power? It's a 'new to us' boat so we aren't aware of all the wiring - been trying to figure it out.

We have 3 electric winches and when we use the winches we get a low voltage (<11) alarm on the chart plotter. It goes back up but we get the alarm often. I think the batteries AGM are 3 years old (boat is 5 yrs old). The system is b&g navionics zeus2 chartplotters. We have a midnite battery charging unit connect to the solar and inverter (2000wt I think).

And yes the chartplotters work when the engine is running. We hate to change the batteries if they are ok but don't want to get to the bahamas and then realize we should have changed them!

Thank you all!!!!!!!!!

You are seeing that the electrical usage you have can exhaust the battery capacity in 20 hours. You must be using close to 20 amps continuously, in your test.

Possibly the batteries (at 3 years old) are already seeing a reduction in capacity.

As stated above, you need to measure the amp usage of each of your electrical items and compute the expected daily load. That is what you need to have battery capacity to serve and the amount you need to replace each day from charging sources. Reducing the load by restricting the use of certain devices may be needed.

More battery capacity, more charging capability, or less usage will be required to keep voltage high enough to run the electronics.