Battery float charger

oregonrafter · 01-23-2009, 09:25 PM

I just installed a stereo in my Jetcraft, and I've set it up to run from its own deep-cycle battery. My question is, I'm thinking about using a Harbor Freight float charger to keep this battery charged when it's parked in my shop - Will that be sufficient? Do any of you use these float chargers?

Starfish · 01-24-2009, 07:47 AM

Do yourself a favor and install an onboard multi-bank three-stage charger and hook it up to charge both your deep cycle and main batteries. Then you can just plug in the boat when you're at home and it'll charge and maintain both batteries. Your batteries will thank you.

oregonrafter · 01-24-2009, 03:10 PM

Quote:

Originally Posted by Starfish

Do yourself a favor and install an onboard multi-bank three-stage charger and hook it up to charge both your deep cycle and main batteries. Then you can just plug in the boat when you're at home and it'll charge and maintain both batteries. Your batteries will thank you.

Other than having to plug-in one cord instead of two, what is the advantage of this? It looks like multi-bank three-stage chargers start around $250 plus installation. What am I getting that is different than a float charger provides? Float chargers cost around 6 dollars each.

Highmark · 01-24-2009, 03:44 PM

Look at it this way. You get what you payed for. A 6 dollar cheapy over the right stuff. Think about it !!!

HM

Dealmaker · 01-24-2009, 04:49 PM

I have been using a harbor frt. float charger for the last 5 years and never have had a problem starting my 90hp in the spring. But I don't have any drain that I know of on the battery???

Catching Nemo · 01-24-2009, 05:28 PM

Take a look at the ProMariner series from Cabelas. Definitely worth it.

oregonrafter · 01-24-2009, 05:37 PM

Quote:

Originally Posted by Highmark

Look at it this way. You get what you payed for. A 6 dollar cheapy over the right stuff. Think about it !!!

HM

Please stop this. If you don't have answers to my questions, then why bother to post?!? Now I'll divert everyone back to the original question: Will my cheapy, 6 dollar charger be sufficient to keep my battery charged? Is there a reason (besides being the cool-charger guy on my block) that this won't work? I also asked this question: Do any of you use these chargers? ...I don't mind being slapped in the face and told I'm an idiot - I'd just prefer to know why I'm not making the right choice. Why tell me there is something better without telling me the reason I should use it?

oregonrafter · 01-24-2009, 05:54 PM

Quote:

Originally Posted by Catching Nemo

Take a look at the ProMariner series from Cabelas. Definitely worth it.

When looking at the ProMariner chargers at the Cabelas website, I found a couple of pretty informative sections; a marine battery buyer's guide and a marine battery wiring guide. These are good how-to's... thanks for the suggestion.

I don't even know what a "float charger" is, or how it works (or doesn't).

JuneHog · 01-24-2009, 08:41 PM

far more info at the site than i want to post
you'll have to do your own research to learn if the HF charger is actually a float charger or just more Chinese marketing hype junk that can turn a $200 batt. into toast.

http://marine-electronics.net/techar...aq/b_faq.htm#6

6. HOW DO I RECHARGE (OR EQUALIZE) MY BATTERY?

There are up to four phases of battery charging: bulk, absorption, equalization and float. The bulk stage is where the charger current is constant and the battery voltage increases. You can give the battery whatever current it will accept not to exceed 20% of the ampere-hour rating and this will not cause overheating. The absorption phase is where the charger voltage is constant and current decreases until the battery is fully charged. This normally occurs when the charging current drops off to 1% or less of the ampere-hour capacity of the battery. For example, the ending current for a 100 ampere-hour battery is 1.0 amp or less.
The optional equalizing phase is a controlled 5% overcharge, which equalizes and balances the voltage and specific gravity in each cell, the effect of increasing the charge voltage. Equalizing reverses the build-up of chemical effects like stratification, where acid concentration is greater in the bottom of the battery. It also helps remove sulfate crystals that might have built up on the plates. The frequency recommendation varies by manufacturer from once a month to once a year, from 10 to 100 deep cycles, or when a specific gravity difference between cells reaches .03 (or 30 points). To equalize, fully recharge the battery; next, increase the charging voltage to the manufacturer's recommendations (if you cannot find one, add 5%). Heavy gassing should start occurring (be very cardeful about safety precautions). Take specific gravity readings in each cell once per hour. Equalization has occurred once the specific gravity values no longer rise during the gassing stage.
The optional float phase is where the charge voltage is reduced, held constant and used indefinitely to maintain a fully charged battery. Please refer to Section 9 for more information about storing batteries and float charging them. An excellent and easy to understand tutorial on battery charging basics can be found at http://www.batterytender.com/index2.html by drilling down through Charging Tutorials & Charging Basics. The following are multi-stage charging algorithms from Deltran (Battery Tender) for three different types of deep cycle batteries:

9. HOW CAN I STORE BATTERIES?

Batteries naturally self-discharge 1% to 15% per month while in storage, and lead sulfation will start occurring when the state-of-charge drops below 80%. If left in a vehicle, disconnecting the negative cable will reduce the level of discharge by eliminating the parasitic load. Cold will slow the self-discharge process down and heat will speed it up. Use the following six simple steps to store your batteries:
9.1. Physically inspect for damaged cases, remove any corrosion, and clean and dry the battery tops.
9.2. Fully recharge the batteries.
9.3. Check the electrolyte levels and add distilled water as required, but avoid overfilling.
9.4. Store in a cold dry place, but not below 32� F (0� C).
9.5. Depending on the ambient temperature and self-discharge rate, periodically test the state-of-charge using the procedure in Section 4. When the state-of-charge drops below 80%, recharge the batteries using the procedures in Section 6. An alternative would be to connect an automatic voltage regulated, solar panel or smart trickle charger to float batteries. Based on the manufacturer's recommendations, use an automatic or smart charger that has been manufactured for this purpose and battery type. You may also use a setting of 13.02 to 13.8 volts for wet batteries and 13.2 to 14.1 volts for VRLA batteries, compensated for temperature, and the correct automatic or smart charger that has been designed not to overcharge the batteries.
The following graph from Concorde demonstrates the effect of temperature on float voltage requirements.

sure wish someone could recommend a top gun Merc OB tech in the Vanc Wa area

Highmark · 01-24-2009, 09:20 PM

Mike I just asked you to think about it.
I have used the cheap model units in the past. what I got was Over charged and burned up batteries from it. If you desire to use a float charger go buy the 50 dollar unit. it will hold up and last. I'm vary carefull as to what I buy from H/F. there product standards are a little less than what I would use on my boat. Perhaps out in my shop, but not in my boat. My 2 cents.

Herman

Quote:

Originally Posted by oregonrafter

Please stop this. If you don't have answers to my questions, then why bother to post?!? Now I'll divert everyone back to the original question: Will my cheapy, 6 dollar charger be sufficient to keep my battery charged? Is there a reason (besides being the cool-charger guy on my block) that this won't work? I also asked this question: Do any of you use these chargers? ...I don't mind being slapped in the face and told I'm an idiot - I'd just prefer to know why I'm not making the right choice. Why tell me there is something better without telling me the reason I should use it?

Smj · 01-25-2009, 08:57 AM

A float charger will work fine as long as it is delivering 14.4 volts, AND you're not discharging the deep cycle battery more than (just a guess here) 10%-15% percent.

If you give deep cycle batteries much less than 14.4 volts, and/or recahrge them with less than 6 or 8 amps, you will kill the deep cycle battery sooner than need be.

You'll hear all kind of stories on this board about batteries and charging, some good info some not so good info. Rather than get so snippy, call Trojan Batteries and talk to a REAL battery tech! Or, if your using an AGM or gel deep cycle call their manufacturer.

Smj

Jeb · 01-26-2009, 07:55 AM

If you're talking about the mounted - small float chargers, the biggest difference (beyond quality) is that the marine grade are sealed, while the Harbor Freight ones are not. The moisture will kill them in a short period of time. In salt water they won't last a season. When you plug them in, you can end up frying your batteries because the corrosion from the salt can cause the charge/control circuits to malfunction.

jfa686 · 01-26-2009, 11:43 AM

also check the Guest chargers as well as the Minkotas..both are marinized units. i think I got my dual bank Guest for like a little over a hunderd bucks. Money well spent and i never worry at the dock.

Barviewrocks · 01-27-2009, 03:33 PM

I used two last winter to keep my boat batteries charged. They apparently over charged the batteries as they would not hold a charge in summer.

I have switched to an Optima blue battery and disconnect the negative terminal in the winter on a fully charged battery. We will see how this works out.

I threw mine away. I would suggest you look elsewhere.

kscheffler · 01-27-2009, 03:50 PM

As the charge diagram above shows float charge should not be greater than 13.2 volts for lead acid battery. If you are holding 14.4 volts like most battery charges will do you will cook the battery; which happens to most. The battery charger must have a battery float function. Based on experience trust no charger check the voltage; most chargers are not properly set from the factory. Return the charger if it charges more than 14.4 during the bulk charge or more than 13.2 during the float maintenance. All of these parameters are different for the AGM glass matt batteries. Proper charging is critical to extend the life of a battery. A great book is "Living on 12 volts" buy it if you want to understand batteries and charging system.

oregonrafter · 01-31-2009, 08:52 AM

Quote:

Originally Posted by kscheffler

As the charge diagram above shows float charge should not be greater than 13.2 volts for lead acid battery. If you are holding 14.4 volts like most battery charges will do you will cook the battery; which happens to most. The battery charger must have a battery float function. Based on experience trust no charger check the voltage; most chargers are not properly set from the factory. Return the charger if it charges more than 14.4 during the bulk charge or more than 13.2 during the float maintenance. All of these parameters are different for the AGM glass matt batteries. Proper charging is critical to extend the life of a battery. A great book is "Living on 12 volts" buy it if you want to understand batteries and charging system.

Great advice, thanks.

Starfish · 01-31-2009, 12:21 PM

Quote:

Originally Posted by kscheffler

As the charge diagram above shows float charge should not be greater than 13.2 volts for lead acid battery. If you are holding 14.4 volts like most battery charges will do you will cook the battery; which happens to most. The battery charger must have a battery float function. Based on experience trust no charger check the voltage; most chargers are not properly set from the factory. Return the charger if it charges more than 14.4 during the bulk charge or more than 13.2 during the float maintenance. All of these parameters are different for the AGM glass matt batteries. Proper charging is critical to extend the life of a battery. A great book is "Living on 12 volts" buy it if you want to understand batteries and charging system.

That's why I personally opt for the multistage onboard chargers... there's a separate bulk charge, trickle charge, and then float cycle that periodically checks battery voltage and then engages the charger to float it. When the battery is fully charged there's no charging applied and therefore it won't cook the battery when left plugged in for an extended period.

oregonrafter · 01-31-2009, 01:50 PM

I just tested the voltage output of the float charger, as well as the voltage output of my Sears portable battery charger... they are both hovering around 16.5 to 16.6 volts, according to my multi-tester. ...I'm not sure what to make of these readings... both seem a little high, if we are to go by that scale.

fishkisser · 01-31-2009, 05:27 PM

I would surmise that your chargers are putting out 1.5 amps or so ... Tight Lines ... Barney

oregonrafter · 01-31-2009, 06:06 PM

Quote:

Originally Posted by fishkisser

I would surmise that your chargers are putting out 1.5 amps or so ... Tight Lines ... Barney

Thanks Barney... but what does that tell me? Is that normal for these chargers?

JuneHog · 01-31-2009, 06:08 PM

another technique is to put the questionable "cheapy float charger" on a 120v timer and only let it run a couple hours a day.
prevents cooking warping and drying out an expensive batt.

fishkisser · 02-01-2009, 05:19 AM

Quote:

Originally Posted by oregonrafter

Thanks Barney... but what does that tell me? Is that normal for these chargers?

Yep they will maintain a charge but usually do not recharge a really low battery very well ...
Most inexpensive models do not shut off when they are supposed to , the timer is a good idea ...

kscheffler · 02-02-2009, 07:33 AM

16.5 is WAY TOO HIGH of voltage output no matter what the amperage. Get that charger off those batteries. If they are lead acid batteries they will need a shot of RO water. High voltage basically boils off the water from the battery. Like I said earlier most battery chargers that I check are off on the correct voltage; make sure to check new chargers and keep taking them back until you get one that is working properly. Best case is to get a charger that you can adjust output voltage and amerage but they are expensive.