Battery Charger

[jorgefife]

Just read the latest Cruising World magazine, and now I am more confused
I have a battery charger, from a car I think: I have it on low amps to re-charge battery, all I have is a VHF and a fridge, and 2 normal batteries that came from a V8 motorcar
So I don't need anything fancy.
My question: is there something that will give a trickle charge and not let the batteries overheat?
Should I get a solar panel ?

 

[Stu Jackson]

I don't have that issue yet, but I'm guessing it discusses three stage chargers.

If what you have is working for you without boiling off your battery acid, then that's fine. You would do well to get a solar panel instead of leaving a "dumb" charger plugged in all week when you're away from the boat.

To size any kind of charging and storage system you need to do an energy budget and do the math.

The West Marine Advisors in the catalogs and online have all the information you need to do that.

www.amplepower.com has good battery info. Download the Primer on the tech tab.

 

[rardiH36]

Hi Jorge:

There are many on the forum that know a lot more than me about battery management. But as a fellow "keep it simple as possible because my energy demand is minimal", here are my thoughts.

I think not enough info in your opening query. Is that fridge powered up when you are away from the boat? If so you need more than a trickle charger.

If everything is off when you leave your boat (which is my situation) then give consideration to Stu's thought that a solar system is best. I have only a 20W panel that feeds into a dual battery charge controller which apportions the solar panel voltage/current between the two batteries as necessary to keep each one fully charged. If I check the voltage of my batteries early in the morning, I see the charger allows each battery to get to 14.x volts. Then reduces to 13.6V (or thereabouts) float for the balance of the day. Everything I've read suggests that the best charging regime will allow the battery to return to its natural voltage state periodically. A solar system does this by default because the sun goes down on a pretty regular schedule. Another advantage of solar is you can leave you boat unplugged from shore AC. This can greatly reduce galvanic issues such as excessive zincs depletion.

If you really do want just a 110v maintenance charger, check out these two as an option.

http://www.amazon.com/NOCO-G3500-Au...VEKS/ref=sr_1_5?ie=UTF8&qid=1329354470&sr=8-5

http://www.amazon.com/NOCO-G750-Aut...S6/ref=sr_1_10?ie=UTF8&qid=1329354470&sr=8-10

More detail about these chargers is further down on each page. Or google for the manufacturer's website.

Do your own diligence if suitable for your needs. Both will suspend the charging and let the battery "decompress" once in a while. Do you need/want the two batteries to be independent of each other? Then a dual charger (or two chargers) are necessary. Or a battery combiner.

You mention that your batteries are car type. Probably you know that these can't deep cycle into the 11V range very often and then recharge to normal capacity very many times. So important not to let them run down -- ever. The fridge is probably the largest power grabber on most boats. I would think it would draw down your batteries into the 11v range in pretty short order when you are not plugged into your main high amp shore charger.

Have fun!

 

[jorgefife]

Hi Jorge:

There are many on the forum that know a lot more than me about battery management. But as a fellow "keep it simple as possible because my energy demand is minimal", here are my thoughts.

I think not enough info in your opening query. Is that fridge powered up when you are away from the boat? If so you need more than a trickle charger.

If everything is off when you leave your boat (which is my situation) then give consideration to Stu's thought that a solar system is best. I have only a 20W panel that feeds into a dual battery charge controller which apportions the solar panel voltage/current between the two batteries as necessary to keep each one fully charged. If I check the voltage of my batteries early in the morning, I see the charger allows each battery to get to 14.x volts. Then reduces to 13.6V (or thereabouts) float for the balance of the day. Everything I've read suggests that the best charging regime will allow the battery to return to its natural voltage state periodically. A solar system does this by default because the sun goes down on a pretty regular schedule. Another advantage of solar is you can leave you boat unplugged from shore AC. This can greatly reduce galvanic issues such as excessive zincs depletion.

If you really do want just a 110v maintenance charger, check out these two as an option.

http://www.amazon.com/NOCO-G3500-Au...VEKS/ref=sr_1_5?ie=UTF8&qid=1329354470&sr=8-5

http://www.amazon.com/NOCO-G750-Aut...S6/ref=sr_1_10?ie=UTF8&qid=1329354470&sr=8-10

More detail about these chargers is further down on each page. Or google for the manufacturer's website.

Do your own diligence if suitable for your needs. Both will suspend the charging and let the battery "decompress" once in a while. Do you need/want the two batteries to be independent of each other? Then a dual charger (or two chargers) are necessary. Or a battery combiner.

You mention that your batteries are car type. Probably you know that these can't deep cycle into the 11V range very often and then recharge to normal capacity very many times. So important not to let them run down -- ever. The fridge is probably the largest power grabber on most boats. I would think it would draw down your batteries into the 11v range in pretty short order when you are not plugged into your main high amp shore charger.

Have fun!

Hello there!
Yes, the fridge stays connected all the time, it is only a small one
And I am permanently connected to shore power
Does it mean all is OK?

 

[jorgefife]

Hello there!
Yes, the fridge stays connected all the time, it is only a small one
And I am permanently connected to shore power
Does it mean all is OK?

Please educate me here: my set-up is very simple: the small fridge is beeing powered by the shore power: so nothing is draininbg the batteries, because nothing else is connected to it
In my simple mind, is there not some kind of device that will keep the batteries at a certain level of charge at all times, besides over charging?
In my mind it is all very simple, so what do you say?

 

[Jim Legere]

Hi Jorgé,

What kind of batteries do you use: old fashioned vented lead acid, AGM, Gel-cells? Because the type of battery determines what kind of charger is best.

If you are using old fashioned lead acid, you can probably get away with an automotive-type battery charger set to trickle charge. There are also marine versions of simple chargers available that will be more expensive but may last longer. A small solar cell (~15 watts) will also keep your lead acid battery charged up and may not require a fancy regulator. You will have to check the liquid level in the battery from time to time as, even on trickle charge, you may boil off some of the water from the electrolyte. Use distilled water to top up.

If you have the more expensive AGM or gel-cell batteries, you should probably use a 'smart charger' with multi-stage charging that can be set up for the specific type of battery.

And you are correct - if your fridge is plugged in to the shore power, it has no effect on battery charging. However, there are some things to watch for with shore power. Not all marinas have top notch wiring and stray currents can cause damage to underwater metal on your boat (like your prop and shaft). If your zinc anodes on the shaft are getting eaten up in a month or two, you definitely have a problem with shore power.

 

[Ed Schenck]

You are confusing me Jorge. In an earlier post you asked about anchoring at sea. So you must be planning on being away from the dock for extended periods. When were you going to build a battery system for serious cruising? Maybe this battery charger is just a temporary measure. In which case what you have should be fine.

Like you I have always kept the boat plugged in because of the refer, also the bilge pump. This year I hope to install a small solar panel. Then I will leave the refer off and the boat unplugged.

 

[jorgefife]

You are confusing me Jorge. In an earlier post you asked about anchoring at sea. So you must be planning on being away from the dock for extended periods. When were you going to build a battery system for serious cruising? Maybe this battery charger is just a temporary measure. In which case what you have should be fine.

Like you I have always kept the boat plugged in because of the refer, also the bilge pump. This year I hope to install a small solar panel. Then I will leave the refer off and the boat unplugged.

Ed,
No, I am not planning on going to sea: I just don't want to overcharge or put strain on the 2 batteries I have: twice I had to top up with water on the cells because some were dried up
I like the idea of a small solar panel, and not this continuos charger that , in my mind, just keeps charging the batteries, regardless.
Sometimes I forget to start the motor, but 2 weeks later, it starts right away. Like I said, don't want to destroy 2 perfectly good batteries because they were pressured into accepting more charge than they wanted!
I will investigate about a small solar panel, any ideas where to go? I am sure there are hundreds of sites out there, you lift up a stone nowadays and there is a solar panel under the stone!

 

[Ed Schenck]

The problem on our narrow stern Cherubinis is where to put a solar panel. I don't have an arch nor davits and no plans to add them. I do have an idea for my radar pole.

As far as where to buy I like to follow the threads here on SBO. Like this one: http://forums.hunter.sailboatowners.com/showthread.php?t=137021 . I've been watching for a couple of years. But E-Bay is another good source as long as the brand is one that you have read about. I plan to go with something around 40 watts which will require a regulator. I am going with fewer amp-hours this year, just 225. A bigger panel might allow me a longer weekend without the diesel or generator.

 

[kloudie1]

I agree with Jim.. If you have plain old lead-acid batteries, an auto charger set to trickle charge will be OK, especially if you leave the refrigerator running off the batteries. If the refrigerator is off, you can put the charger on a plain old heavy duty household timer and set it to charge for an hour (or two, or whatever) in the morning when it is cooler.

 

[MLampner]

Jorge if as I suspect this is an interim rig and the question is how to keep these batteries alive as you work on the boat and there are no real demands on the batteries other than an occasional start the small plugs in through the cigarette lighter is a cheap way forward. Most automotive catalogs have them and and with a little shopping you can pick one up ready to go under 50 dollars.

I use one in the winter or did till it drowned. They were designed to sit on the dashboard top in the window since my boat has no protected area for it it sat in a plastic box on the cabin top. Unfortunately the wind flipped and two weeks ago I came over to work and found out the boxes bottom which had vents was face up and it was full of water.

Left it to try out but they are good maintence devices for lead acid batteries if you can protect them.

 

[Maine Sail]

You will want a charger that does FLOAT charging and is intended for marine applications.

The charger should ideally be built to ABYC / UL 1236 standards. These standards are specific to the marine industry, though I think the emergency market such as rescue and ambulance are also required to use UL 1236 chargers.

This standard is created around safety and isolation of AC & DC. A UL 1236 charger has undergone a 1500 volt test to ensure there is adequate AC/DC isolation inside the charger. 1500 VOLTS !

While there are some non-marine chargers that can do quite well in the marine environment the UL 1236 or "ABYC" compliant statement or logo will be a good guide and won't leave you guessing if the charger you chose can handle the environment or is well suited to a marine application.

Cheap auto chargers can be horribly "leaky" and can lead to corrosion potential.

You could look at products by ProMariner they have some reasonable prices on marine UL 1236 chargers.. They make decent quality, inexpensive chargers that will not cook your batteries.

If you want really inexpensive check out The Charger Guy on eBay he sells refurbished ProMariner products.

 

[MLampner]

Sorry wasn't clear Maine Sail IMHO is right if we are talking an AC to DC charger don't mess with an auto charger. They were designed for vehicles that sit on nice rubber tires.

I wasn't clear I was talking about the little 15 or 18 watt solar panels that come with alligator clips or a lighter plug. These are great for atop up and their limited output will not overcharge a battery. Better yet at night the internal resistance of the cell prevents the battery from bleeding current back through them.

Wouldn't want to rely on one to replenish a dead battery but will hold batteries over the winter or when you can't run the engine for a few weeks.

 

[tomgrigsby]

Jorge I have had the same problem of batteries going dry on the charger. Another low cost solution to keep your batteries topped up without ruining them is a Battery Tender. It is a very small unit sold by most automotive stores that is basically a trickle charger. It takes a couple of days for it to bring up a battery that is really low, but it also can be left on the batteries without boiling them dry.

 

[jorgefife]

Jorge I have had the same problem of batteries going dry on the charger. Another low cost solution to keep your batteries topped up without ruining them is a Battery Tender. It is a very small unit sold by most automotive stores that is basically a trickle charger. It takes a couple of days for it to bring up a battery that is really low, but it also can be left on the batteries without boiling them dry.

Tom Gribsgy
That's exactly it: a battery tender, that will stay permanently on and will not overcharge the batteries
Thanks everybody

 

[Steve Dion]

Jorge:

Your batteries "probably" do not have a lot of life let in them. Automotive batteries are not intended for deep discharge so what you have today, may not be what you will have in the future.

If/when the time comes you may want to consider some deep cycle batteries and a nice inexpensive smart charger.

I am not sure what type of refrigeration you have. Does it run off of this battery bank? If it does it may be sooner than later that you will need to refresh this system.

I would also suggest that you have your refrigeration on a seperate bank from your starting/reserve battery. It is nice to be able to start your engine in an emergency.

 

[jorgefife]

Jorge:

Your batteries "probably" do not have a lot of life let in them. Automotive batteries are not intended for deep discharge so what you have today, may not be what you will have in the future.

If/when the time comes you may want to consider some deep cycle batteries and a nice inexpensive smart charger.

I am not sure what type of refrigeration you have. Does it run off of this battery bank? If it does it may be sooner than later that you will need to refresh this system.

I would also suggest that you have your refrigeration on a seperate bank from your starting/reserve battery. It is nice to be able to start your engine in an emergency.

Steve,
My small fridge is powered by the off shore power, so it puts no strain on the batteries