Should battery charger be on all the time?

Captn TJ · Feb 11, 2015

I leave mine on all the time since there are some devices that constantly draw on the batteries. Also if there was a leak the bilge pumps wouldn't run down the batteries.

At the same time you should be aware that I have a smart charger that goes from a full to a trickle charge based on battery needs. Additionally I'm checking the water in the batteries on a regular basis.

Steve Dion · Feb 11, 2015

We leave ours on 24 x 7. Have done this for years. We also have a smart charger.

Skipper · Feb 11, 2015

I like this question.

I have an answer based on experience, not expertise.

The boat has a Charles multi bank charger that has the "smart" capabilities. However, when I've left it on 24/7 the batts seem to use their water a little faster. It's easy access to inspect/refill but I'd rather they stayed full longer, so I turn off the breaker when leaving. Leave with batts fully charged. I'm at the boat every weekend. Boat has no DC current leaks. Nor water leaks.

I would approve of leaving on if the boat had any potential for sudden spontaneous and serious water leaks sitting at the dock in So Cal weather (thank you God) with maintained and closed bronze tapered cone seacocks, new cutlass and stuffing box, and no keel bolts, but I don't think it does. When the boat was in Annapolis I would leave the charger on during the cold months. That's when the batts would use water a bit faster. I think the charger tops off every so often during the winter due to natural battery discharge.

I never wanted to let the water get below the plates so it worried me less to have the charger off during the warm months when I was away. A maintenance log would help here but then I would have to remember to update it, and it's easier for me to just remember to maintain stuff. Others are better with logs and have good advise regarding.

Benny17441 · Feb 11, 2015

We leave ours 24/7 in the hands of a smart three stage charger and have not had any problems. I rest on a cursory check of the charger lights to let me know it is receiving power and that it is operating in maintenance mode.

woodster · Feb 12, 2015

i have the sterling 40 amp charger with a temp sensor and it is on all the time ...the thing is trouble free and takes care of my batteries all i ever do is look at the display from time to time to see if the refer is cycling and i can also check and see how much power each light fixture id drawing at any time just by turning the light on and off

Anonymous 121765 · Feb 12, 2015

I use a simple house timer instead of running 24/7. However, the only thing I leave on, is my automatic bilge pump so, my path is simpler.

My smart-charger for the first five minutes is running @ 6 amps for each, while the charger senses the battery state. My timer is set for twenty minutes a day, the charger goes from an initial 6 amp punch & in 15-20 minutes shows both batteries at full.

I've read stories of electrical/safety problems & don't have a warm fuzzy feeling leaving my power running 24/7 unattended. I periodically do a meter check after the batteries are in the relaxed state to verify their charge.

The 24/7 method works fine for many but, this is just my personal preference. I've been doing it this way for years now & get an average of 5 to 7 year battery life. I do only use sealed batteries down here in Florida, because of the summer heat.

In addition, Mainsail is another good source here on electrical & battery info.

CR

Maine Sail · Feb 12, 2015

YVRguy said:
I'm embarrassed not to know the answer to this but here goes:

On my A/C panel there is a breaker for the battery charger. I've been leaving it on all the time when the boat is plugged in. Is this the correct thing to do? Or should it only be on until the batteries show a full charge?

The answer, like most things, is "it depends"... Many chargers that claim to be smart are not in-fact smart at all. Some will bump out of float at the slightest hint of current being drawn and others have higher thresholds or don't simply reset an egg-timer when they do revert to absorption.. Many chargers use an egg-timer approach to determine transitions from absorption to float and this may not be ideal for your bank. Many chargers lack remote temp sensing and you can very easily be over charging a warm battery even at float voltages.
Many chargers have very, very poor low current capabilities which leads to the power supply pulsing on and off so as not to over shoot the voltage sent point however they do with every blip and this causes excess heat. When they "pulse on" they do over shoot then turn off then pulse again. Many chargers also have poor AC ripple which is a complicated subject especially when VRLA batteries are used. The Sterling PCU and ProMariner Pronautic P have some of the lowest ripple out there at just 14mV....

Long and short is that I have seen batteries destroyed in a year or less by poorly designed chargers. If you run refrigeration or any DC loads at the dock it is best to have a charger that allows a setting to lock the charger into float mode to prevent cycling between float and absorption.

That said if your boat has parasitic loads at the dock then running the charger will nearly be a requirement. If you eliminate parasitic loads and turn everything off then charging to full and turning off the charger can sometimes be a healthier approach, if your charger is not up to snuff. Unplugging from the dock entirely and using solar is by far the best choice in terms of corrosion potential...

Not an easy answer...

Anonymous 121765 · Feb 12, 2015

Main

Too funny man, I just finished doing an edit in my post & your reply notice just showed up in my email.

CR

kloudie1 · Feb 12, 2015

I had an old ferro-resonant charger that had a high float voltage and would boil the electrolyte out if left on constantly.. I talked to the manufacturer who told me that the float was high because they'd designed it for low volts at dockside..and I don't have low dockside voltage. I was a little amazed.. I replaced it with a Xantrex (temperature compensated) over ten years ago and have been happy leaving it on all the time.. I have noticed a big difference in the water not boiling out compared to the old charger. Battery life is MUCH better.

BigEasy · Feb 12, 2015

Probably better if the charger is off if the boat is unattended for weeks at a time.

Having said that, I do leave my smart charger on (Xantrex + remote monitor + temp
sensor), primarily to keep batteries charged with the 12 volt refer remaining on. That's price that you gotta pay for a cold beer! Also, I am usually on the boat 1-2 times a week.

Doug4bass · Feb 12, 2015

Our new Catalina has a supposedly Charles 3 stage "smart" charger. I have to leave it on all of the time at the slip because of the refrigeration....which I dont particularly like. Always turned my old boat's charger off when I left the boat for more than a few days.....

Ron20324 · Feb 12, 2015

My solar keeps the batteries in good charge. When I have to leave the fridge on during the week, though, I turn on the battery charger set to the constant 13.2 setting. All's well after 5 years.

Maine Sail · Feb 13, 2015

Doug4bass said:
Our new Catalina has a supposedly Charles 3 stage "smart" charger. I have to leave it on all of the time at the slip because of the refrigeration....which I dont particularly like. Always turned my old boat's charger off when I left the boat for more than a few days.....

You flip on the battery charger breaker which now starts a 4 hour egg-timer.

4 hours later, regardless of the banks SOC, or how long it was actually at absorption voltage, the charger drops to float voltage...

Smart....?

Hint the egg-timer should not start its countdown at charger turn on, At a bare minimum it should start when the transition from bulk (constant current) to absorption (constant voltage) has been achieved. Egg-timers are not smart.......

"When power is applied, the Charger will enter a bulk or “quick-charge” mode, during which a higher rate of charge is achieved to replenish the batteries. After four (4) hours in the quick-charge mode, the output will drop to a float rate to maintain the batteries at the selected finishing voltage."

Smarter chargers don't simply rely on an egg-timer model for charging....

Stu Jackson · Feb 13, 2015

Maine Sail said:
The answer, like most things, is "it depends"... ................

If you run refrigeration or any DC loads at the dock it is best to have a charger that allows a setting to lock the charger into float mode to prevent cycling between float and absorption.

Not an easy answer...

If you run refrigeration...

Why?

Buy a cold six pack at 7-11 on the way to the boat, and leave your mayo at home.

McIntoshUSA · Feb 13, 2015

Very interesting topic. Thank you for all the good info.

Mike

VF84Sluggo · Feb 18, 2015

Wow...as I prepare to close on my new-to-me 1995 C30 MkIII, the more I read, the more I realize I don't know.

I've never given much thought to the yellow AC cords I've seen plugged into boats at the marina. Now I'm reading about all kinds of horrors regarding leaving your boat plugged in. I always figured you needed to keep AC applied, to at least keep the batteries charged up, power the automatic bilge pump, and maybe run a dehumidifier. Guess I'm just confused on how I'm supposed to do this, but then not leave the boat plugged in.

Man....makes me wonder if I ought to just keep renting and only have to worry about being a sailor...no kidding

gettinthere · Feb 19, 2015

Been running charger full time for 5 years when at the dock. Full frig/freezer so we run AC powered charger, a zantrax truecharge 40+. No problems.

VF84Sluggo · Feb 19, 2015

Ok good, thanks.

Been looking at galvanic isolators, isolation transformers, "GalvanAlert" connector, extra zincs on a line hanging over the side with a wire connected to it and clipped to the engine block...man.

Seems like every thread, link, forum I go to, there's another booger lurking there just waiting to wreak all kinds of mayhem...like in the insurance commercial