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Old 07-07-2019, 09:33   #1
KTP
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Lifeline equalization

Hey, so want opinions please (guess I could contact Lifeline but it is Sunday)

We currently have eight Lifeline GPL-31XT 12V 125AH batteries in our sailboat, wired up 4s2p for a 48V at 250AH bank. We use a Magnum 48V inverter/charger which can charge at 60amps for the 48V bank (about 3kW).

I am wiring in another four batteries to give us a total of 375AH at 48V but was debating if I should equalize our existing eight batteries first. They are about 9 months old now and have pretty much seen minimal use, always connected to shore power and the Magnum inverter/charger. At 65 degrees F they usually sit at around 52 volts after the float turns off and the float comes back on at about 51.2 volts, charging them at around 54 to 54.2 volts.

Would it hurt to give them a equalizing charge before connecting in the new series string? It would have to be a series equalizing charge meaning the Magnum would be putting out about 62 volts.
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Old 07-07-2019, 09:41   #2
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Lifeline equalization

It doesnít hurt to equalize a Lifeline battery at least once a month, it may not be necessary always though.
If in doubt call them, they are helpful people.
I would equalize them, unless you have spent those months on float plugged in, Iíd still just to be sure, but likely not necessary
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Old 07-07-2019, 10:33   #3
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Re: Lifeline equalization

Yes you should be equalizing when possible to extend longevity.

But make sure to follow Concorde's protocol, not something generic.

And to each battery unit individually at a time.

As a side note, going to three strings rather than two increases the odds of balancing issues,

doing regular equalizing as above should help prevent problems, and

when it comes time to replace that bank, look at doing so with larger Ah units, likely in lower-voltage units in series, maybe two strings if you feel you need redundancy.

But hopefully that will not be for a long time.
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Old 07-07-2019, 10:46   #4
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Lifeline equalization

Equalizing individual batteries isnít in my opinion very logical, it would be next to impossible for someone who is Cruising.
I have two banks, ganged into one, I have only equalized the whole bank, and even doing that when cruising means hours of generator time, cause step one is to be fully, 100% charged of course, then hours spent at equalization voltage.
Being hooked to shore power makes it much, much easier of course, and better, you can then be sure your both 100% charged and your bank has had hours to cool down and equalize temps.

But to equalize each battery individually is way more work than Iím willing to do, I obsess over my bank yes, but not to that point
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Old 07-07-2019, 12:52   #5
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Re: Lifeline equalization

Yes such maintenance protocols are best performed on shore power.

And yes setting up so they are easy to perform while keeping the batteries physically in place requires designing the wiring with that in mind.

Most boats require compromises away from the ideal for bank care, but what is "obsession" and "impractical" is a subjective judgment call.

Especially with three strings, there may in future be imbalance problems that significantly affect bank longevity.

Besides combatting sulphation, balancing issues are one of the goals of equalizing, and doing the bank as a whole may well exacerbate those rather than prevent them.

But then many (most) owners are happy to just replace the bank more frequently.
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Old 07-07-2019, 14:38   #6
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Re: Lifeline equalization

Shore power is ideal, but equalize mine on solar while out cruising. Makes a noticeable difference in their performance.
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Old 07-07-2019, 15:39   #7
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Re: Lifeline equalization

Well I already encountered an issue which does seem to indicate my lightly used banks have gone out of whack (at least one series string has).

Voltage on the banks was 51.2 when I arrived this morning, battery temp 66 degrees F. Charger was off (it would cut on at 51 volts to go into float for 4 hours as per Magnum specs).

I measured one series string and the batteries were somewhat close, within 50 millivolts. On the other series string one battery was 12.86 volts while the others were 12.7 to 12.78 volts. After floating them I kicked on equalize for 62 volts and the battery that had been 12.86 volts was 16.2 volts while the other batteries were in the 14 volt area. Seriously out of whack.

I dropped equalize down to 58 volts and saw 15.6 volts across the "hot" battery in the series string and 13.6 to 14.2 volts across the others.

Evidently of the eight Lifelines I purchased at the exact same time direct shipped from Lifeline, one of them has a much lower internal resistance than the others, or something has happened to make it different.

I can either wait a month until I can get my equipment here so I can equalize each battery individually or I could put a load across the "hot" battery to shunt some current around it during the 62 volt equalization. Maybe a light bulb or something that would draw a few amps at 15 volts.
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Old 07-07-2019, 16:47   #8
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Re: Lifeline equalization

Just thought of a dummy load I have on hand...a cheap $9 AC hotplate. I'll measure the resistance but it should be about right to shunt across the 12V battery and deliver the equalizing charge better to the other batteries.
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Old 07-07-2019, 17:21   #9
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Re: Lifeline equalization

Before you do anything call Lifeline.
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Old 07-07-2019, 17:40   #10
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Re: Lifeline equalization

I stumbled across one of my old posts from 2014 on another forum where I had had a similar issue with two 12V Lifelines in series in our RV. I had half forgotten about this (must be getting old...about to turn 49!).

It seems back then I was concerned that my two 12V batteries wired in series would charge differently when in absorption. One battery would read something around 13.9 volts and the other would read 15.2 volts (while in absorption). From what I wrote back then, it was very easy to flip which battery was so much higher in absorption by very slightly changing the state of charge (just a tiny load for a few minutes would flip which battery had over a volt higher absorption charge).

The thread tapered off but it seems the resolution I got from Lifeline back then was this was normal.

Still, I don't like to see 16.2 volts on a battery during an equalizing charge which is supposed to be 15.6 volts. It is almost like I need a BMS.....for lead acid!
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Old 08-07-2019, 17:26   #11
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Re: Lifeline equalization

Yes absolutely BMS done right greatly extend lead bank life.

Just that they are considered **absolutely required** for (non-LFP) LI banks in cars, for safety reasons as well as longevity.

For LFP banks in low C-rate House use, they aren't so critical, but do make life easier for owners.

Setting aside the protective functionality, for just balancing purposes, dealing with 12V units, these have a great rep

ZHC battery equalizer balancer

Shenzhen Huaxiao Technology Co., Ltd
HA03 for 8 units, 2xHA02
HA02 4x batteries

detects mV level difference between two 12V batteries


20mV level triggers shunt current from higher voltage battery
to the lower voltage one, at 5A

LVC @10V

HA01 2 batts, has LED's (BT01 a knockoff?)

2 pieces for 36V system; 3 pieces for 48V system

https://huaxiaotech.m.ec21.com/mobil..._id=GC10246048

https://zhcsolar.com/product/24v-battery-equalizer/

https://wap.china.cn/Switching-Power...?t=description

https://wap.china.cn/Switching-Power...?t=description

Also other variants

-----
Victron, Battery Balancer the same but 50mV difference trigger, 200mV alarm, balance current under 1A, only for 24V units, operates while charging, over 27.3V - 26.6V LVC
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Old 09-07-2019, 07:47   #12
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Lifeline equalization

Quote:
Originally Posted by john61ct View Post
Besides combatting sulphation, balancing issues are one of the goals of equalizing, and doing the bank as a whole may well exacerbate those rather than prevent them.

Why should equalising the whole bank exacerbate an imbalance?
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Old 09-07-2019, 08:01   #13
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Re: Lifeline equalization

Quote:
Originally Posted by DefinitelyMe View Post
Why should equalising the whole bank exacerbate an imbalance?
I will take a stab at a guess.

In my case at the recommended 2.58V per cell (about 62 volts across my 48 volt bank at 70 degrees F), one battery was getting 16.2 volts while another battery was getting only 14 volts. Thus one battery was getting seriously equalized, almost over equalized while the other battery voltage was too low to really help dissolve any sulfation. This means the "hot" battery got even better (less sulphation) while the sulfated batteries didn't even get a good equalizing charge.

I could be wrong here but that is what I would guess.
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Old 09-07-2019, 08:17   #14
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Lifeline equalization

Quote:
Originally Posted by DefinitelyMe View Post
Why should equalising the whole bank exacerbate an imbalance?


I donít think it will. I believe that over the 5 hour interval that all batteries will come up to the correct voltage and maintain it long enough to be equalized.
The Godberís arenít stupid people, they know more about batteries Iím sure than me for example and wouldnít recommend a procedure that would harm their batteries.

Iíve never measured individual battery voltages, but I think I may just to see what they are, and then run a short equalization to see what happens.
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Old 09-07-2019, 08:28   #15
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Re: Lifeline equalization

Yes, although the main issue is simpler.

Just the fact that pack-charging "masks" the actual voltage each string/cell is getting.

If charging each unit separately, that faster one would not be getting such harmful overcharge,

with FLA less critical, long as you keep adding water. Sealed, the lost electrolyte can't be restored, and lifespan is shortened.

And the slower one would be getting its treatment.

Such a conditioning process is called Equalization, because one of its more important goals is to get the individual units back to being at a similar voltage vs bank SoC correspondence.

That can only happen when it is applied to each unit separately.

Yes, that requirement may simply be impractical in some scenarios, just as many owners "simply can't" get their bank to 100% Full very often, or even ever.

The result, a bank needing replacement more often, is not necessarily a major problem, the point is to be aware.
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