How do you Equalize a Battery?

[syoun10]

I know you are meant to equalize a battery every now and then. That gets sulfation off the plates, and rejuvenates them.

I also know that you achieve equalization by over-charging at 15.6 volts for a few hours.

But HOW to do it?

The charger on my 2006 Hunter 33 doesn't have any switch settings that allow you to do it (at least to my knowledge), and even if it did, the charger is completely inaccessable.

SO ... how do people equalize their batteries?

 

[wetass]

There a a bunch of different ways, like using your solar panels, or smart regulators, etc. Some dedicated/permanently installed marine chargers have the option - mine doesn't. So, what I use is a simple portable charger that has the option for equalizing. Its not the best system and I can only do a single battery at a time since its not powerful enough to do multiple batteries, but it works.

http://www.westmarine.com/webapp/wc...gclid=CNH537XtlbUCFUfhQgodPGAAEw#.UQwY5uh4UTg

 

[seadaddler]

Charger

Yes my Blue Sea charge controller does it but I use my 2000 freedom charger/inverter has the option with the optional remote and other special chargers are able to do it also.
Nick

 

[Maine Sail]

You need a battery charger or bench top DC switch mode power supply capable of doing 15.5V - 16V (depending upon your batteries). I would not advise trying to equalize any battery with an alternator or solar. These are fairly useless features intended as "selling tools".. You really need a steady constant voltage, and low current, for 2-8 hours.

I prefer using a bench top power supply that allows you to control both current and voltage. Something between 5A and 10A will work. Usually they are sold as 30V x 5A or 30V X 10A etc.. They run about the same price as a charger that does equalization but have many more uses...

#1 Check specific gravity of the batteries note on paper what the readings are.

#2 Charge batteries to full at 14.4V and wait until the current falls to less than 1.5% of capacity or less. So for a 100Ah battery charge at 14.4V until the battery is taking less than or equal to 1.5A of current.

#3 Fill with distilled water, if necessary, to approx 1/8" below the fill well. Be careful not to allow any dirt or contamination into the cells and to not over fill. The water should not be touching the plastic fill well. Contamination is the destroyer of batteries.

#3 With a power supply, adjust the voltage to 15.5V without the batteries connected. Cross check it with a DVM.

#4 Connect battery and adjust/limit the current so that you can maintain 15.5V. too little current and you won't get to 15.5V, too much current is unnecessary.

#5 Stop equalizing at 2 hours, let batteries rest for 40 minutes to an hour, and check specific gravity of the cells. If all cells are equal continue for another two hours.

#6 If all cells were not equal continue for another 2 hours then check again. When the cells get close to equal stop any time before 6-8 hours. You don't want to over equalize but do want the cells to be in balance.

#7 This is all based on temps of 70-80F.. If the batteries are warmer than 80F you'll want a lower temp compensated EQ voltage.


With a battery charger follow the instructions for your charger but many of the steps above apply.

 

[Bill Roosa]

My charger does this every 28 days of operation automatically. The timer resets every time you turn it off though so the bats don't get equalized during the sailing season, course they get exercised during that time so I'm not thinking it is all that important.
I leave the battery charger on all the time when away from the boat and am working on 7 years on the original (PO may have replaced them but don't know (1993 model so 20 years??? not likely)) batteries and they seem to be fine.

 

[marian]

How do you know your batteris needs to be EQ?

 

[Paul Mermelstein]

IMPORTANT: I did not see it above, and it may be obvious to some, but equalization is only recommended for lead acid batteries, not AGMs or gels.

 

[Maine Sail]

How do you know your batteris needs to be EQ?

Usually a loss in capacity, voltages lower than normal for the applied load, you've not topped them up to full very often, the cells specific gravity is out of balance, they come up to absorption voltage quickly and don't take the same charge current they used to.

 

[Blitz]

bench top power supply

I prefer using a bench top power supply that allows you to control both current and voltage. Something between 5A and 10A will work. Usually they are sold as 30V x 5A or 30V X 10A etc.. They run about the same price as a charger that does equalization but have many more uses...

Maine Sail - This is a great winter project. You noted previously that you often use the Extech power supplies and one of the ones you use is the model 382260 (I assume for a greater range of uses such as 24 volt systems). Since I'm only concerned with 12 volt systems and equalization of my 12 volts batteries would you think that a Unit such as the ExTech 382202 would be adequate?

http://www.extech.com/instruments/product.asp?catid=39&prodid=211

 

[Bob S]

Timely post. I set myself up to do it in the spring just before launching.
I bought a refractometer and a Mastech 3A 30V power supply.

http://www.amazon.com/Mastech-Singl...id=1360950896&sr=1-5&keywords=dc+power+supply

Thanks for the procedure!