12 volt battery charger recommendations

[mheichelbech]

Just about have the job boat project done. Looking for recommendations for a battery charger.  Don’t need an on board charger.  In fact I’m looking for something to use for other than my deep cycle battery as well (riding mower battery, car start if needed, etc).  I saw a Stanley 25 amp charger for $81 on Amazon ($50 for 15 amp) but not sure if there may be better deals around.  This one is a battery maintained as well.

[Tennessee Boy]

I'll share my experience with battery chargers.  I've used three different chargers in my 30+ years as a boat owner.  The first was a cheap one from Walmart.  The second is a fancy digital one with lots of bells and whistles.  The third is a an onboard charger.  They all charge my batteries as expected.  They all still work, including the cheap one I bought 30 years ago.  The onboard charger is very convenient and worth the money IMO.  The newer ones charge the batteries faster than the older one but all of them charge the batteries before I'm recharged and ready to go out again.

[mheichelbech]

31 minutes ago, Tennessee Boy said:

I'll share my experience with battery chargers.  I've used three different chargers in my 30+ years as a boat owner.  The first was a cheap one from Walmart.  The second is a fancy digital one with lots of bells and whistles.  The third is a an onboard charger.  They all charge my batteries as expected.  They all still work, including the cheap one I bought 30 years ago.  The onboard charger is very convenient and worth the money IMO.  The newer ones charge the batteries faster than the older one but all of them charge the batteries before I'm recharged and ready to go out again.

Thanks.  So if your experience is the most common I’m guessing that besides bells and whistles, from a pure charging standpoint, the only material difference is how fast it charges, ie amps?

[Alex from GA]

I have been using the older version of this for a couple of years with no problems.  Amazon for $58.  Schumacher SC1303 6/12V Fully Automatic Battery Charger and 10A Maintainer

[70diesel]

I have a NoCo Genius G7200. It works great. It can do multiple types of batteries and can also charge 24v. There is no thinking, plug it in, put it on battery and let it do what it does. When battery is charged it goes to a trickle. About $100

[Bankc]

On 5/26/2020 at 8:02 PM, mheichelbech said:

Thanks.  So if your experience is the most common I’m guessing that besides bells and whistles, from a pure charging standpoint, the only material difference is how fast it charges, ie amps?

Not necessarily.  There's some science behind how to charge a battery.  The cheapest ones use what's called a "trickle charge".  This is just a low voltage charge that slowly charges the battery.  It doesn't require any special circuitry, and it's relatively safe, as it doesn't tend to overheat the battery too badly.  A battery maintainer is basically an advanced trickle charge, that can cycle on and off.  It prevents the battery from generating unnecessary heat, which will shorten the batteries lifespan and generate heat and waste electricity, yet maintains a steady charged state.

The more fancy chargers, often called "smart" chargers, will run a 3 stage system where they'll run a high voltage at first and then gradually lower the voltage until it reaches the trickle charge state.  What this does is it not only charges your battery faster, but it can put a deeper charge into your battery, making it last longer, while also extending the overall lifespan of the battery (because it prevents he battery from overheating).  Now when I say it puts a deeper charge into the battery, it's not a night and day difference.  It's a difference for sure, but it's not going to perform miracles.  

 

They used to make "fast chargers" which just did the high voltage stage charging on a timer, and then dropped to a trickle when the timer ran up.  You don't see these as often, as the smart chargers cost about the same or less to make, and offer better performance and safety.

 

Now in practice, does any of that mean anything to you?  It all depends on how you plan on using the charger.  I'd get a trickle charger with a battery maintainer if you plan on just leaving it hooked up all of the time when not in use.  I'd get a cheap trickle charger if you're okay with hooking the battery up a few days (give or take depending on the current state of the battery) before going out on the water.  If you need it charged faster, or will be pushing the limits of your battery (i.e. if you have completely drained your battery before), then a more advanced smart charger might be worth your money.

 

So they're all different.  And different chargers may have a mix of these features.  But to be honest, I think most people could probably get by fine with any of them.  As long as you follow the directions and don't overheat your batteries, yet give them enough time to reach a full charge, they'll likely all work well enough.  Just make sure to remove your battery from any small, confined areas before charging so any gasses it releases and heat it generates can escape.