batteries need replacing?

[A Fishin C]

Garmin 740 radar/chartplotter shuts off when I use my electric trims tabs.
Worked well for 5 year till this year.

Could it be my batteries do not hold enough volts to power both?

Chartplotter shows 11.1 Volts on one battery and 11.3 volts on other battery.

batteries are probably at least 6 years old.

[DayBreak]

If you have flooded cell batteries, check the water level and top off with distilled water if necessary. 11.1 and 11.3 volts is pretty low which may be the culprit. A new battery on a good smart type trickle charger should show a battery voltage state of about 12.9 or 13 volts. If a battery goes below 12 volts too many times, its expected life is shortened.

[tsturm]

[Foggy]

My experience is most flooded lead-acid batteries are shot after 4 - 5 years.
If yours are 6, it's time...

Aye.

[thataway]

Measure battery voltage at the battery, and load test the battery . (any auto parts store should have a load tester--and do it for no charge.)

What the chart plotter is seeing is the. voltage it is receiving. As mentioned there is often a voltage drop due to corrosion. Remember that the ground system is just as important as the positive system. Every year, go over all of the connections, check for corrosion-put on non corrosive dielectric grease and tighten up the fittings.

Also often C Dory did not put large enough wire running from the batteries to the console. When I buy another C Dory, I double the size of the wiring--I also put in a large fuse block--and then run each item off its own circuit.

If the battery voltage is 11.1 or 11.3, at the battery it is shot. Generally you should not discharge a flooded lead acid battery to less than 12.2 volts, resting steady state. (nothing running off the battery for at least 30 minutes).

Unless you have one of the newest "smart chargers", leaving a trickle charger is probably not the best practice. Electrolyte needs to be checked regularly in any flooded lead acid battery.

If you take care of batteries they can last a long time. I got over eight years out of the starting batteries on my last large RV (Starting an 8.3 Liter Cummins Diesel). However most small boat batteries don't last more than 3 to 4 years. Although many don't bring batteries up to full charge after using the boat--relying own the engine to charge the batteries, this is not necessarily best practice. The battery needs to be topped off after your use the boat.

[ssobol]

[BrentB]

m2cw You got your money worth and buy new ones.

[A Fishin C]

thanks everyone,

I will be replacing the batteries asap.

[A Fishin C]

charged up battery 2 last night, says 12.5 volts

checked it out and traced the fault to the port side electric trim tab.

checked the deutsch connectors and the fuse. even switched the wiring to another accessory panel. It still causes the use of the trim tab to shutt offt the other accessory (vhf).

Opened up the top of the trim tab and looks dry in there. (now i dont know which wire went where)

any ideas? the trim tab still works...

[BrentB]

I would start looking at the tabs wiring from helm to tabs

tabs should be one circuit with no other items.

then check each tab

maybe some creative wiring between 2 items

I just 3 months redoing, updating and replacing items on our Parker. I sure like Blue Seas components esp bus bars and power posts. I removed a lot of poor wiring and tinkering to make it right

[ssobol]

Could be a bad motor or mechanism is requiring lots of current to move the tab which is causing the electrical system voltage to sag too much. Does the same thing happen when the motor is running, or just when the tabs are moved using the battery?

I'd get a current meter and check the current draw for each actuator. In theory they should be the same.

[thataway]

a fully charged battery should be higher than 12.5 volts--especially if just charged over night. I would want to see at least 12.6 to 12.7 volts for a flooded lead acid battery.

There could be corrosion or bad fittings in the trim tab circuit.

Agree that you should check out the entire trim tab circuit, since there is evidence that it is drawing excess current.

The usual digital volt meter may not be able to be used. Generally if over 250 to 500 milli amps, one has to change the positive lead to the fused circuit--which usually only measures up to 10 amps. Beyond that, you have to have a clamp on multi meter or a specific meter with a shunt designed for higher amperage. If there is a short or bad motor, the current draw may be in excess of 10 amps, and it will blow the fuse in the multimeter.

No matter, you have to both check out the circuit and at least have the battery load tested. (Or buy a load tester at Harbor Freight).

[DayBreak]

Correction on my earlier post!

Earlier when I said that one should use a smart type trickle charger, I should have used the term smart charger. Smart chargers use a 3 stage charge. They are safe, easy to use and will not overcharge your battery. The first stage is a bulk charge. There is no risk of overcharging your battery with this stage because your battery has not reached a full charge yet. At about 85% charge, the battery has reached absorption stage. At this point most chargers will maintain a steady voltage while the amperage declines. The lower current going into the battery slowly brings up the charge on the battery without overheating it. The last stage is the float charge. This stage brings up the battery up to 100% and maintains that state of charge. The current decreases to the point where it is considered a trickle.

It's the healthiest thing for a battery is to remain at 100% state of charge.

We use a Deltran Battery Tender 3 amp. battery charger and maintainer year-round on our C-Dory and are happy with the product.

[BrentB]

I have 2 Noco Genius battery chargers on our boat and a portable Battery Minder charger recommended by Thataway

[thataway]

Daybreak, you are correct--but where I may differ is your use of the: