Equalizing Batteries

[mestrezat]

I want to do my first "equalization" of my battery system and am getting conflicting information from "experts" on how to do it. I'm running a Link 2000 so getting it started shouldn't be a problem but I'm looking for the prep stages to do before I start it.

One "expert" says to just hit the button on the Link 2000 and let her rip. Another says to unscrew all the battery caps(running a bank of 6-6 volt golf cart batteries) after taking off the lid to the battery box and making sure the cabin has good ventilation.

We've got 3 cats living on board. Do I need to get them off the boat or am I safe to just put them in a forward cabin away from the batteries and make sure I have a fan blowing fresh air into the cabin where the batteries are?

Any idea how long it will take to "equalize? It will be the first time I have done it since I installed them in April of 2008. Owning a boat has a steep learning curve.

[David M]

Hopefully this should answer some of your questions.
http://www.xantrex.com/web/id/257/DocServe.aspx

[CharlieJ]

Equalizing batteries is a big deal. It is NOT plug and play. It IS a very labor intensive evolution that greatly stresses the batteries, evolves hydrogen gas and takes a significant amount of time to accomplish correctly. The best advice would be to check with your battery manufacture and follow their recommendations.

Here is a step by step that I developed for a Client:

NOTE:
EQUALIZATION OF A BATTERY BANK WILL PLACE AS MUCH AS 16 VDC ON YOUR BATTERIES AND CAUSE THEM TO BUBBLE AND RELEASE HYDROGEN GAS. THE BATTERY COMPARTMENT MUST BE
VENTILATED. DO NOT ALLOW OR CAUSE SPARKS OR IGNITION
SOURCES AROUND THE BATTERIES THAT ARE BEING EQUALIZED. YOU SHOULD WEAR SAFETY GLASSES AND RUBBER GLOVES WHEN
WORKING AROUND THE BATTERIES WHEN THEY ARE BEING
EQUALIZED. THIS IS NOT A SET AND FORGET PROCESS.


1. Read the instructions for equalizing in the charger or inverter/charger manual.
2. Fully and normally charge the batteries.
3. Remove all loads from the batteries. This is critical as the voltage will go as high as
16.0VDC which can destroy some 12VDC equipment.
4. Loosen the battery caps and ensure the batteries are filled per the Rolls specs. Do not overfill. Put a folded paper towel over the caps to trap any vapor.
5. Start the equalization process. Depending on your charger, the equalization may auto-terminate after six hours. It is important to note that the actual equalization of the batteries may not be completed after as much as eight hours as indicated by the specific gravity readings still increasing with time. If this is the case, start another equalization cycle. It is not uncommon for equalization to take 12-16 hours to accomplish.
6. Monitor the voltage and amperage at least hourly on the Link. Record these values.
Ensure they stay within the limits discussed in the Link manual and Calder's book.
7. Batteries will begin gassing and bubbling vigorously.
8. Take temperature compensated specific gravity readings on each cell every hour.
Record these values.
9. Equalization is complete when specific gravity values remain constant within a point or two in each cell and there are no significant differences between the specific gravity readings between cells.
11. Recovery from the equalization process:
> Remove the paper towels from the battery tops and dispose of them properly.
> Check the electrolyte level in each cell and top up with distilled water in accordance
with the manufacturer's specs.
> Reinstall the cell fill caps.
> Wipe down the battery tops with a solution of baking soda in water to neutralize the acid that inevitably lands on the tops.