Battery Equalization for Dummies!

[Sleepy]

I got the battery tray all cleaned and repainted and had all the batteries checked at auto-supply store. All batteries checked good, but they are 5 y/o 6V batteries. First,how do I know if they should be equalized, and just how do you equalize batteries? My system on my RV doesn't have any such settings. I have looked at many battery chargers in stores etc. and none of them have an "equalizer" setting. Many posts have talked about periodic equalizing but I bet 99% of RV owners don't have a clue what to do or how to recognize it. Are there places or special euipment needed to equalize? By the way, POR-15 rust-preventive paint (recommended on this site) is incredible product for cleaning up those corroded battery trays. As always, thanks to you all for your help.

[RV Wizard]

Here are some links that will help:
http://www.usbattery.com
Frequently Asked Questions (FAQ) - DC Battery Specialists
Deep Cycle Battery FAQ
http://www.rvsolarelectric.com/sources.htm
http://www.batteryfaq.org

[BryanL]

In general, RV batteries do not need an equalization charge unless your battery charging and maintenance equipment is inadequate and you don't really use the batteries much if at all.

That is because RV batteries that get occasional discharges followed by a full, prompt, and complete charge that is done over enough time to make sure all cells in the battery bank are fully charged.

At 5 years, your batteries are showing a reasonable life. The problem you face is reduced capacity because of sulfation due to age, not imbalanced charge in cells.

An equalization charge, which is an intentional overcharging to assure complete and even charge in all cells in a battery bank, can be harmful to batteries.

[Bob (WA0MQE)]

Equalization of batteries is not harmful when done properly.

I worked in the Telecommunications Industry for years. We had hundreds of remote communications facilities which we maintained. All of these facilities had large battery banks and four level regulated battery chargers. They had emergency backup generators for when the commercial power failed. The chargers had Bulk, Normal, Float and Equalization. Each year during annual maintenance trips to the sites we'd check the batteries, by specific gravity, voltage tests and load-test. If there was signs of problems we'd equalize the battery bank. These batteries would last better then 10 years, some even 20 years without replacement.

[BryanL]

re: "We had hundreds of remote communications facilities which we maintained." -- this is not your typical RV battery situation. The 10 or 20 year lifespan indicates that you weren't using lead acid batteries. See the NAWS FAQ.

It could be interesting to get into the differences in use profiles, battery size and type, and more. What needs to be realized though, is that telecom standby and UPS service is an entirely different thing than RV use.

re: "Equalization of batteries is not harmful when done properly." -- the key words here may be "done properly." For typical RV use, equalization is not needed and a battery overcharge can easily stimulate plate corrosion and electrolyte loss. (You don't need specific gravity testing either for RV batteries in nominal use).

I don't know what it is about batteries that brings out the contrarians. Folks gotta' bring in submarines, massive standby systems, or grandad's batteries and such things to try to refute and contradict what is offered for the RV crowd with modern batteries.

What I offer is gleaned from critical reading of very many sources. I can provide links. I do suggest folks go find out for themselves but be very careful about taking what they read without careful consideration of application, pertinence, context, and assessment of measure.

[wa8yxm]

Equalization serves several functions in a battery..

In another thread someone mentioned that one of the D-cell batteries in his battery operated fan was "Backwards" That is the center pin was negative and the case positive.

It is nearly impossible to make two batteries absolutely identical. there are always minor differences and because of this over time you might have one battery, or to be more precise, one cell, that is slightly overcharged and one undercharged.

ONE job of Equlization is to bring all cells up full

Another .. Liquid filled cells... The acid water mix can "Stratify" that is mostly water on top, acid on bottom.. Equilazition somewhat boils the cell and stirs up the mix making it more "Equal" shall we say.

It may aid in desulfation

How to do it: Normally a good converter (NOT a Magnatek 6300 or equal) will have that as an option.. Often initiated by the operator (you) at the push of one or more buttons.. Alas as to exactly how you are going to have to RTFM for your converter.

Progressive Dynamics 9200 or any PDI with the charge wizard.. Just plug it in for a week, it's automatic.

[BryanL]

re: "ONE job of Equlization is to bring all cells up full" -- this happens when you properly charge the batteries and provide sufficient charging time. RV batteries tend to get infrequent moderate discharge use followed by a reasonable or prompt charge followed by a storage charge. This process tends to even out the batteries making equalization unnecessary. Where equalization becomes more useful is when you have standby service or when you have habitual inadequate charging (many RV solar systems) coupled with poor maintenance charging.

re: "Equilazition somewhat boils the cell and stirs up the mix" -- this can be important in maintenance but it is not a classic equalization charge. It is a technique the ChargeWizard and WFCO converters use for battery maintenance but it is a short burst that does not do the classic equalization overcharge (or present the risks of a proper equalization charge). Their use of the term is misleading (see progressive dynamics battery basics) and is a lesson to be careful in what you can find out there.

The tech note at Xantrex (PDF has some good information about the caveats and considerations. What you have to watch with this one is the battery use descriptions and the implied use profile. Another good paper is Krien and Ballog (PDF). Again care is needed to read what the paper is saying. Here's something I think that distills the issue a bit.

Quote:

The conventional equalization method is to provide a _forced overcharge_ interval after the main charge sequence. The objective is to deliver full charge into the lowest cells. The process can be termed _passive equalization,_ since it relies on the properties of the battery cells to restore matching. Unfortunately, passive equalization works at the expense of gassing and dryout of the highest cells. In addition, it is a slow process. The forced overcharge equalization process is routinely used with lead-acid batteries.

(note: one of the features of the ChargeWizard is that it doesn't cause electrolyte loss yet still maintains a full charge with electrolyte stratification prevention -- that full charge will, over time, bring all cells up to equal status, kinda' like a gentle long term replacement for the true equalization charge)

The key I am pushing is that equalization charges are (IMHO) overemphasized in the RV application. Equalizing charges risk putting too high a voltage on your RV circuits possibly damaging appliances. They enhance risks to the battery. There is an inherent exposure to sulfuric acid that risks personal safety.

In typical RV applications, an equalization will not gain the user anything that can't be obtained by safer practices with proper equipment.

Quote:

Progressive Dynamics 9200 or any PDI with the charge wizard.. Just plug it in for a week, it's automatic.

Excellent advice. I'd just suggest to leave it plugged in as it will keep your batteries well maintained.

[wa8yxm]

I"m glad you agreed with my bottom line

By the way. Damon gifted me with a PDI 9800 PLUS Charge Wizard.. I do leave it plugged in nearly 100% of the time and I do have to add water to the batteries.. Every Mother's Day.. Yup, once a year.