Equalizing 6 volts.....

[NYSail]

Hello all!
Meant to call Trojan Friday but forgot....... I have 4 6volt t125 / series parallel. When I equalize, can I do as a single 12 volt bank, all 4, or should I do 2 at a time (still connected in series). Also again I meant to call so pardon my ignorance with flooded a I have only had agms for past 13 years. When isolating the bank form any loads do I also isolate the neg so the only connection is the battery charger.
Thanks
Greg

 

[Rich Stidger]

I have four 6V house golf cart batteries in the usual series-parallel connection. I equalize all four at once. I loosen the caps on the cells but leave them loosely in place so that the cells can't spray electrolyte onto the top of the batteries. When done, I tighten the caps and wipe the top of the batteries with a solution of baking soda and water and then dry.

Then to isolate all of the batteries for the winter storage, I simply disconnect one end of the series connection on the two sets of batteries. All four batteries are then disconnected on one connection. I shut off the main battery switch as well. I make sure that the tops of the batteries are clean and dry and without any electrolyte on the surface.

 

[NYSail]

I have four 6V house golf cart batteries in the usual series-parallel connection. I equalize all four at once. I loosen the caps on the cells but leave them loosely in place so that the cells can't spray electrolyte onto the top of the batteries. When done, I tighten the caps and wipe the top of the batteries with a solution of baking soda and water and then dry.

Then to isolate all of the batteries for the winter storage, I simply disconnect one end of the series connection on the two sets of batteries. All four batteries are then disconnected on one connection. I shut off the main battery switch as well. I make sure that the tops of the batteries are clean and dry and without any electrolyte on the surface.

thanks...... do you isolate the bank before equalizing..... positive and negative so the only attaching wire is the charger?

again thanks!
Greg

 

[Stu Jackson]

thanks...... do you isolate the bank before equalizing..... positive and negative so the only attaching wire is the charger?

again thanks!
Greg

Why do you think you need to do this? All an equalizing charge is is basic charging with higher voltage and limited amperage. What charger do you have? My Freedom 15, with a 75A charger, limits current to around 15A when equalizing. No need to do any separation.

 

[Rich Stidger]

thanks...... do you isolate the bank before equalizing..... positive and negative so the only attaching wire is the charger?

again thanks!
Greg

I don't remember isolating the bank before equalizing. But at the time I do that at the end of the season, everything is shut off at the breaker panel. Besides that, most marine equipment will withstand 17V and my equalization gets up to about 16.3-16.5V.

 

[Stu Jackson]

Greg, also make sure to fully charge the bank before equalizing.

 

[NYSail]

Thanks all!

 

[Maine Sail]

You'll want to ensure all batteries have a very well rested matching SG or open circuit voltage before EQing in series. If the batteries are not well balanced, it happens, you can easily wind up with one 6V battery at over 17V.. Here in the shop we EQ them as a 6V battery

 

[dLj]

The numbers I'm reading above seem off - Equalization takes place between 15.8 and 16.2 volts. Current must be controlled, and 15 amps would be a lot - are you controlling for temperature? Your equalization step should not heat up your batteries. I don't recall numbers for temps, but warm is not good... I am typically equalizing using from 1 to 5 amps, depending upon battery capacity. I also equalize one battery at a time. But I don't know anything about doing multiple batteries - that was just how I was taught to do this step....

dj

 

[NYSail]

You'll want to ensure all batteries have a very well rested matching SG or open circuit voltage before EQing in series. If the batteries are not well balanced, it happens, you can easily wind up with one 6V battery at over 17V.. Here in the shop we EQ them as a 6V battery

i would assume my 15 year old Xantrex 40 amp will not do 6 volt. What type charger do you use in your shop? Thanks as always!
Greg

 

[rschuss]

Good info at, A detailed discussion about battery equalization, when why and how to do it.

 

[Hello Below]

Good info at, A detailed discussion about battery equalization, when why and how to do it.

For Trojan owners, this is an excellent read, Trojan Battery Maintenance.

Note: "Trojan only recommends equalizing when low or wide ranging specific gravity (>0.030) are detected after fully charging a battery." and the equalization charge is 16.2V.

 

[dLj]

Wish I had a spare $172 to buy IEEE 450 "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and Substations" As far as I'm aware, that is the standard that we should all learn about and be following to maintain our lead acid batteries. It's written for the power industry, but would be very applicable to our batteries.

There is a nice document that is free:

https://sites.ntc.doe.gov/partners/tr/Training%20Textbooks/02-Batteries/0-Lead%20Acid%20Storage%20Batteries.pdf

The above has a lot of good information, but the details needed are really in IEEE 450 as I understand it.

I was taught how to maintain lead acid batteries by a retired electrical engineer who had been the head electrical engineer for the Hoover dam. I met him many years ago in Tampa Florida where he was living on his sailboat with his wife shortly after retiring. He taught me how to perform equalization and he cited this IEEE 450 standard as his reference.

Note in the DOE document in the provided link the following:

"General
In general, a good maintenance and inspection program should be based on the recommendations in ANSI/IEEE Std 450, IEEE Recommended Practice for Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and Substations; and in DOE-STD-3003-94, Backup Power Sources for DOE Facilities. Some of the recommended practices from these and other references are presented in the following paragraphs. Flooded lead-acid batteries can function for 10 years or longer if properly maintained.
The six general rules of proper maintenance are
1. Match the charger to the battery requirements.
2. Avoid overdischarging the battery.
3. Maintain the electrolyte at the appropriate level (add water as required).
4. Keep the battery clean.
5. Avoid overheating the battery.
6. Provide an equalizing charge periodically to weak batteries/cells."

I would love to hear a technically in-depth discussion of each of the above points rather then listening to marketing hype.

I know that since following the instruction I got from the Hoover engineer, I've typically found that 10+ years on a flooded lead acid battery is correct. When I have screwed up and not followed that advice, I've killed batteries in short order. But here, we are always talking about how great it is when our batteries last 6 to 8 years. What are we doing wrong?

dj

 

[Davidasailor26]

But here, we are always talking about how great it is when our batteries last 6 to 8 years. What are we doing wrong

The types of battery applications IEEE and DOE are talking about are probably different than what sailboats need. For example, batteries used for “Backup Power Sources for DOE Facilities” probably don’t get cycled very often, but rather sit on a maintenance charger for months or years before being called into service. To be effective in our use case requires all of the same considerations as the DOE case, but deep cycling itself puts additional wear on the batteries. The effects of that additional wear will be greater or less depending on how effectively the boat’s systems address additional considerations that the DOE might not list, like depth of discharge, recharge rates, and time spent partially discharged.

 

[dLj]

The types of battery applications IEEE and DOE are talking about are probably different than what sailboats need. For example, batteries used for “Backup Power Sources for DOE Facilities” probably don’t get cycled very often, but rather sit on a maintenance charger for months or years before being called into service. To be effective in our use case requires all of the same considerations as the DOE case, but deep cycling itself puts additional wear on the batteries. The effects of that additional wear will be greater or less depending on how effectively the boat’s systems address additional considerations that the DOE might not list, like depth of discharge, recharge rates, and time spent partially discharged.

Time spent partially discharged I'm sure is one major problem. However, every other point you mention is directly addressed.

The types of batteries are exactly the same - the application may be somewhat different. But not hugely different such that use of IEEE 450 would be negated. While it is true the DOE application does not cycle their batteries as often as we do, they do cycle them in a much more frequent time frame than you are suggesting. At least at Hoover dam they did. That was part of the maintenance schedule where the batteries had to be cycled as part of the maintenance schedule. I don't recall the frequency, But it was every few months or something like that. I'm trying to recall a conversation I had decades ago so the details, especially of details I didn't really care about, are definitely fuzzy.

My main point, is we seem to spend a lot of time throwing marketing type information back and forth rather than actual technical data. And there are sources of technical data that we are not tapping into.

For example, how does one know when an equalization phase has gone to completion? How do we know if that charger that has some proprietary program that claims to perform equalization is actually doing so, and doing so in a way that is truly beneficial to our batteries? We seem to simply get marketing answers, not solid technical answers.

What are the specifics on how long one can be at what % state of discharge before you get serious damage to your batteries? And how does one define serious damage? Where are the curves that talk about this? As I'm sure they indeed are complex functions that depend upon % discharge, temperature and time... We tend to spend a lot of time not really talking to these specifics.

Just my 2 cents worth.

dj

 

[Davidasailor26]

While it is true the DOE application does not cycle their batteries as often as we do, they do cycle them in a much more frequent time frame than you are suggesting. At least at Hoover dam they did. That was part of the maintenance schedule where the batteries had to be cycled as part of the maintenance schedule. I don't recall the frequency, But it was every few months or something like that. I'm trying to recall a conversation I had decades ago so the details, especially of details I didn't really care about, are definitely fuzzy.

Still, a cruiser cycles their batteries every day, and even a weekend sailor does it once or twice a week for at least half the year. That’s still a lot more cycles than a monthly or every few months test. That cycling might be a big part of the difference between the 6-8 years we hope for and the 10+ years they expect. Or maybe it doesn’t. But that brings me to my agreement with the main part of your point -

My main point, is we seem to spend a lot of time throwing marketing type information back and forth rather than actual technical data. And there are sources of technical data that we are not tapping into.

For example, how does one know when an equalization phase has gone to completion? How do we know if that charger that has some proprietary program that claims to perform equalization is actually doing so, and doing so in a way that is truly beneficial to our batteries? We seem to simply get marketing answers, not solid technical answers.

What are the specifics on how long one can be at what % state of discharge before you get serious damage to your batteries? And how does one define serious damage? Where are the curves that talk about this? As I'm sure they indeed are complex functions that depend upon % discharge, temperature and time... We tend to spend a lot of time not really talking to these specifics.

Absolutely! I’ve been frustrated by the same lack of data for my batteries. The manufacturers are in a position to only publish cherry picked metrics that show off the best characteristics of their models. There seems to be little standardization about how to quantify durability over time under varying conditions. And it’s hard to do independent research into that because of the variety of batteries, variations within a single line, different usage conditions, and the time it takes to see effects of different processes. The downside is that by not publishing that data the manufacturers limit our ability not just to pick the best batteries, but also to best maintain the batteries we have.