[glen]

I’d only equalize if you have noticeable loss of capacity.

The Lifeline manual says this:

—————–

Conditioning/Equalizing Charge: 15.5 volts for 8 hours

Conditioning/equalizing should only be done when the battery is showing symptoms of capacity loss. If conditioning/equalizing is necessary, first go through the normal charge cycle. Once the battery is as fully charged as possible, start the conditioning/equalizing charge.

——————-

You’ll be putting 31V on the batteries for 8 hours. Ideally, you’d disconnect the batteries from the house systems. If you do this in the bus, I’d turn off as many DC consumers as possible. Not all of them will be ready to accept 15.5 / 31V.

Equalization will make sure all cells get a chance to be fully charged. It seems Prius owners have had good success reconditioning older banks using equalization and also replacing single cells that cannot be equalized. They are motivated as a new Prius battery bank can cost $3000 similar to our house banks. This has been an eye opener for me as the common wisdom is to not mix new and old cells. But if you carefully equalize them it seems to work.

[Jim]

Jim,

You
really haven’t hurt the batteries running them down below 12v a
couple times. Deep discharge down into the single digits is another
matter, I’ve seen that and the batteries were toast. Your inverter
probably has a LBCO, low battery cut-off that shuts off at a
pre-determined voltage. The problem is there are so many other 12v or
24v parasitic loads on the coach that even if the inverters shut
down, those other draws could kill the batteries.

As
for equalizing, if it makes you feel good do it, but I doubt you’ll
see any improvment, but if so, it will be short lived. I’ve done it
more than once over the years and gained nothing. Usually when
someone starts thinking equalization, the end result is usually new
batteries.

[glen]

Thanks, for the quick reply.

since it had been a couple of years I could not remember the Pros& cons.

I have reset the Inverter/charger and will wait a while to see what develops/

Jim

[Archived]

Here is an interesting paper on equalization.

http://windandsunpower.com/Download/intelec02.pdf

There is a lot more interest in the subject with the emergence of hybrid cars and wind/solar systems with large serial battery banks. According to the paper the primary failure mode of the battery banks is the undercharging of individual cells as cell voltages drift apart more than a few tens of millivolt. Without equalizaton you only get 30+- full discharge cycles for the bank vs the claimed 400+- cycles for individual cells. They conclude that equalization should be performed every 6-8 weeks.

[Cathy & John]

Are those batteries AGM or Li?

I think the type of battery and the application will be important elements to understand when trying to determine if equalization will be recommended.

[Archived]

The paper covers a broad range of battery chemistries including lead-acid.

No doubt, equalization done right is a good thing. But…there are a few things that can go wrong. Example, if the battery bank is equalized in place with loads connected, some of the loads may not deal with the increased voltage (31V) gracefully. If the equalization current is too high, electrolyte might boil out of the “good” cells before the “bad” cells come up to full charge. Not a good thing for our AGM batteries. Less of an issue for wet cells.

Also, in our application, the Vanner equalizer does help as it ensures that both batteries in the 24V stack see the same voltage within 1% when charging.

It seems we can get 4+ years of service out of good quality batteries without equalization. I wonder if we could double that with regular equalization. I have almost convinced myself to try it ….

Gerald

[Archived]

FWIW I think in general if we rely on auto-start, run heavy loads such as our AC units and allow discharge of our battery bank below 50% we shorten the battery life.

I don’t think it is unreasonable to expect long life from our batteries, given the manufacturer’s own data that suggests the number of charge / discharge cycles goes up significantly when the batteries are recharged at the 50% level compared to letting them get to an 80 or 90% level.

It is no secret I change batteries at 5 years, but so far never when there is a failure. I am getting rid of perfectly good batteries with what I presume is a lot of life left because when they do begin to age and fail to perform they exhibit strange performance via the inverters that I just do not want to deal with. I am doing something wrong if I run my batteries until there is a failure or their ability to hold a charge is compromised.

I do not use auto-start, I monitor my house battery voltages and I run my generator when not on shore power a lot because I believe the generator benefits from use, and I know the batteries are going to benefit from not being deeply dischargd before the generator is run.

I am sure an equalization charge can be beneficial and it is probable the life of a battery can be extended to a degree, but our coaches are supposed to be RECREATION vahicles and to me it is not fun if I have to start nursing a set of batteries. If the anecdotal evidence we all see on the forums is an indication failures seem to be attributable to allowing perfectly good batteries to be discharged to the point where they are “dead”, failure to use the correct charging voltages in the inverters to maintain the batteries, and faIlure to maintain the batteries by keeping the posts clean and tight and recognizing when a bad battery is in a bank, affecting the others.