Lifeline equalization

[KTP]

I did find this tidbit in the Lifeline technical manual:

"(2) A large variation of individual float voltages in a new battery system is normal because of variations in oxygen recombination efficiency due to slight variations of acid saturation within the AGM. As the battery ages, the variation should drop to lower values. Excessive variation of float voltages after the first 1-2 months is an indication that the batteries may be out of balance. If individual battery voltage readings during float charge vary by more than 0.1
volt per cell (0.10 volt for 2V batteries, 0.30 volt for 6V batteries, and 0.6 volt for 12V batteries), then a conditioning charge per Section 5.5 is recommended."


That is really the only mention of something that could apply in this situation. They were talking about float voltages though, which are lower than equalizing voltages. It doesn't really say if a series string can be equalized or if you should equalize each battery individually. Obviously there is no way to equalize the 2V cells in a 12V battery.

[a64pilot]

OK this is what I got, first numbers are in float, a temp compensated 13.3 VDC.
Second numbers are equalization voltage, again a temp compensated 15.5 VDC.
I have been sitting at float for a month, so I’m certain they are fully, completely charged.

Now my bank is not connected like it should be, many of you would laugh, as my interconnect wires are not equal length etc. so mine isn’t by any means done “right”
I just checked one bank as the other is only two batteries and harder to get to, this is a 440 AH bank at 12 VDC.

Battery
1. 6.59
2. 6.74 total for both 13.31

Battery
3. 6.66. ( I guess this is the devil battery?)
4. 6.64 total for both 13.33

Equalizing, note amp draw for the bank is 1.8 amps at equalization voltage

Battery
1. 7.81.
2. 7.61 total for both 15.42

Battery

3. 7.70
4. 7.72. Total for both 15.42


If you noticed, battery 1 and 2 differ in which one was higher in float and equalization voltage, check again in a few minutes and which one is higher does switch back and forth, but it’s only .2VDC or so.

My bank is 5 yrs old.

[a64pilot]

Originally Posted by KTP

Obviously there is no way to equalize the 2V cells in a 12V battery.

Good point as most batteries are series connected individual cells.

If Lifeline thought that individual equalization was helpful for their batteries based on how comprehensive the manual is, they would address it, and they don’t.

[john61ct]

I've discussed this with Lifeline's engineers, and there is no question separate is better.

But no one is saying that's the only way to go, your bank your call,

certainly better to do it as a bank than not at all.

[KTP]

I managed to massage the bank by putting a small load across the hot batteries for a few minutes and now they are all floating and equalizing within 100 millivolts of each other. After 12 hours of rest they all show about 13.1 volts...they are pretty much like new in as far as that is concerned. In all probability they probably have not even been broken in yet, which is likely why I saw the differences. I bet they have only been down below 90% of full maybe five times in the past 9 months.

[a64pilot]

Originally Posted by john61ct

I've discussed this with Lifeline's engineers, and there is no question separate is better.

But no one is saying that's the only way to go, your bank your call,

certainly better to do it as a bank than not at all.

You need to consider the reality of what your suggesting on the average cruiser.
To begin with if your cruising and don’t get to an honest 100% but a few times a week, you need to equalize monthly. Not my opinion, that’s Lifelines suggestion.
I have 6, 6V batteries in my bank, which I think is real common, so to equalize them one at a time. I’d first have to disassemble my bank and shut down my DC system in the boat. Let the freezer and food defrost etc.
Or start juggling the remaining batteries around to keep the system operating and get by with a much reduced bank and cycle it much more deeply.
Then as they are 6V batteries, I’m not equalizing them with my chargers, I’d need a power supply to do that. I could equalize two batteries a day, by running the generator all day long. It would take 3 full days to equalize the bank, then I could reassemble it and three and a half weeks later do it all again. Or maybe carry around multiple power supplies?
That’s ridiculous, it’s not practicable, not for some one cruising.

Then as was pointed batteries are multiple cells connected in series, how are you going to individually equalize those cells?

[john61ct]

I've already addressed those concerns.

Learn what the ideal care parameters are, then do the best you're willing and able to do given your own unique setup.

Some owners have huge expensive setups running gennies many hours at a time for other reasons. Others have a panel or two, no alt at all.

Or some might want to ignore all of it, and at least you're informed rather than murdering banks out of ignorance.

Your rig, your choices.