Charging the Lifelines questions

JiminDenver wrote:
. I am assuming that is the point I have the controller switch out of bulk. Correct?

Yes, bulk -> absorb -> float

Thanks.

After seeing some of the charging threads on here, 14.3v just seemed low. The conditioning/ equalization voltage is 15,6v and the recovery, that's just plain scary. lol

Charge at a constant current of 5 % of rated (20 hour)capacity until the voltage reaches 15.6 volts (7.8 volts for a 6 volt battery), then continue charging at this rate for an additional 4 hours. Note that the charging voltage may get as high as 18.0 volts (9.0 volts for a 6 volt battery)
, so the power supply must be capable of outputting this level to maintain constant current. This constant current charge may take 16 to 20 hours.

My wet cells would boiling fluids big time at that VOLTAGE and CURRENT. I'm betting your AGM's will still be venting Hydrogen Gas during this process. Definitely would keep away from open flames, sparks, and red hot elements... My wet cells will start bubbling even at 13.6VDC in the NORMAl MODE. When it drops down to 13.2VDC STORAGE MODE then the bubbling stops. If i was running 14.3VDC verses 13.6VDC in the NORMAL FLOAT MODE it would be raining battery fluids haha...

In my PD9260C charging uses the same 14.4VDC for the EQUALIZE MODE EVERY 21
HOURS FOR A PERIOD OF 15 MINUTES. This is the highest DC VOLTAGE I will see on this charger. 15.7VDC at high currents would scare me as well even for a short period of time...

I am old enough to remember the days where the automotive shops would put 50VDC on a battery with 200AMPS of DC CURRENT available to be used. This was their quick two hour charge. They also had signs around that they would be not be responsible for replacing the battery if the top blows off... I saw go over the shop roof one time... People would be lined up waiting to be next haha...

Roy Ken

jim i wouldn't charge an 8-D AGM within anything less than 50 amperes, let charging continue to 14.4 @ 25c until amperes slump to 3.0 then maintain the battery at 13.6 volts to a temp max of 28c.

This would be when the battery is seeing daily cycling duty and the values above are for a single battery.

I pondered the point of minimum acceptable charge rate and came up with a chemical deduction. Yesterday I called a friend Fred Polanski who handles the tech issues at an AGM OEM. He chuckled over the phone when he heard my assumption and replied ("your rationale is right o the mark")

"The mat absorbed 1.300 SG electrolyte demands substantial amperage which encourages it to circulate"

The result of chronic under-amperage encourages -excessive- acid starvation. Free electrolyte and soaked-mat electrolyte are two different animals.

I noted this in my era way back when, with gelled electrolyte but that critter was a literal nightmare to manage correctly. if I was home I would have benefit of a lot more instrumentation. The only reason I have that divorced platform scale is to send it to Denver for recalibration. The gel battery could not be desensitized from reluctance of acid circulation thus it makes a horrible choice for regular cycling.

One Megawatt 36-ampere power supply adjusted to 14.4 volts would make a suitable charging source for each 8-D but one of the two polarity bridges would have to be opened to isolate the circuit for the sake of the Megawatts.

When I get home I will verify my idea that minimum charging amperage is only necessary until the battery reaches 14.4 volts and amperage slumps to 10% of total amp hour capacity of the DUT. For your 8-D's this would mean something in the neighborhood of 25 amperes.

The data above is pure conjecture on my part. Ideas put to print. Proofing will involve instrumentation and forty to fifty cycles. This I have a gut feeling OEM is aware of and practices it but getting data out of them is like extracting blood from a turnip. The title of this is called THE IDEAL CHARGE PROFILE.

Making this agree with a solar system will take some work. Compromises have to be researched and selected. But the batteries have a single demand that must not be ignored = chronic undercharging, regardless of which profile you settle on.

I am pleased that I can offer this information on a level that most of you can understand (a sharp group) yet present it at a professional level.I was fooling myself that retirement meant abandoning research for a hammock. Can't train a Labrador to not whine when he smells water.

Wow

45-50a is the best my system can maintain. I suppose I can add a switch to each battery to be able to separate them if needed.

Mex

I can only speak for myself although I would imagine the feeling is shared. i really do appreciate having what I am ignorant about explained in terms I can almost understand.

I hooked up the full system to the 8-D sitting at 12.88v. Between the time I hooked up the array and got back to the controller it was already in absorb at just above 7a. I have no way of forcing the amps, so I put the Eco-w on the battery sitting at 13.01v and set it's float at 14.3v since it wont hold a absorb voltage. It is pushing a bit over 2a.

Once the absorb time is met, I will switch the Eco-W set up to the 8-D holding 13.1v and the MS and the first battery to equalize/ condition.

I'll check into the Mega watt. You can explain about the bridges when it gets here.

It sure was a lot easier with just a Eco-W and 230w panel on a Grp 27 FLA, then again so is a tent.

Roy

The old 8-D goes to the recyclers Monday. i wonder how far it would fly. lol

The TS-MPPT-60 dropped out of absorb and the acceptance on the Eco-W at absorption voltage is down to 2.5a. According to the manual having a acceptance below 5% means the battery is full. So I Switched the MS to the last 8-D and dropped the Eco-w to float.

I might get a chance to equalize Monday, at least I'll get to see how each battery rest after charging.

Those figures I submitted are for a 50% discharged AGM ready to be recharged. For regular recharging at >50% remaining, just keep the voltage limited to 14.4

The weird and wacky fetish by an AGM to eat with a ladle or suffer becomes more sensitive the lower the charge status becomes. It is less sensitive at 80% but the ability to fulfill 14.4 volts is easier to achieve. Hmmm I should put this in clearer text...

When the charger is in BULK mode, trying it's little heart out but unable to raise voltage to 14.4 then the 50 amp minimum applies. Per battery. Weird capillary circulation. Yet another point about Lifeline, they use proprietary glass mat with much finer fibers than run-of-the-mill AGMs. The enhanced circulation is yet another reason why that battery can be charged at such a high rate. And for general message - no that does not affect charging or float voltages, only receptivity.

As far as conditioning is concerned, it is absolutely not de riguer to massage these critters with extremely high voltages. Period. The battery has to be PROVEN to have lost capacity before extremes are employed.***

At conditioning values, the AGM will vent. No question. Use a SIX HUNDRED WATT rated DROK DC to DC booster as found on Amazon. Set the voltage while booster is connected to the Megawatt. The booster must have a fan played across the heatsink to endure this power level.

I would ALWAYS first try using an amp hour meter, a Megawatt and timer to recover a sulfated AGM. Set the Mega on 15.0 volts, note the amperage and when amperage decreases to 1% or around 2.5 amperes, terminate the desulfation. Wait 24 hours and repeat. Note accumulated ampere hours. The second time around accumulated amp hours should be half or less than what was recorded in the first session.

I cannot even BEGIN to tell you how important it is to establish your own written baseline of amperes, amp hours, and voltage Trends & Tendencies when the battery is brand new. This baseline saves you from pulling your hair out trying to calcu-guess the state of the battery later on in it's life.

Even such mundane testing as fully charging the battery, waiting 48-hours and taking a standing at rest voltage reading has meaning. A battery impedance meter like Sold at Harbor Fright, is also a useful management tool. Take a new battery baseline reading. Then compare it to subsequent tests.

Now you see why I still am fond of flooded batteries, and a hydrometer. Can't have your cake and eat it too.


***The gentle renovation should be termed CONDITIONING
The hard core high voltage repair should be termed RECOVERY

Lifeline Charging from the Lifeline Technical Manual

The Bulk stage charging current should be set as high as practical resulting in faster charging time. For example charging a 100Ah battery at 50% DOD with a 25A charger would take ((50/100) x 100 / 25) + 2 = 4 hours to reach full charge and a 10A charger would take 7 hours . Charging continues until the battery reaches 14.3V +- 0.1V when the Absorption stage begins.

In Absorption charging the voltage is held to 14.3V until the current drops below 0.5% of the battery’s rated capacity (0.5A for a 100Ah battery) when the Float stage begins.

In the Float stage the charging voltage is reduced to 13.3V +- 0.1V while maintaining the battery at 100% state of charge.

For repetitive deep cycling (deeper than 50% DOD) chargers should have an output current of at least 0.2C (20A for a 100Ah battery.

The above values are for a battery at 77F and the manual has a table for different temperatures. Plus there is a lot of other technical information. Click here to download the manual.

The above makes me wonder how many RV chargers and solar chargers charge Lifelines correctly as they need to be constant current in bulk, constant voltage in absorption and then the float stage.

As I said, what have I gotten myself into here.

I do have a Radio Shack 10 amp 13.8v regulated power supply, not even worth getting a booster for I would imagine. Sighhhh Another $70 bucks for the Megawatt.


I don't know that the last 8-D will make it to float by night fall but it had 3-4 hours in absorb and was down to 3a. I'll let them sit until Monday to get a resting voltage. I am keeping a log on them but if I buy anymore fancy toys I am sure Honey will just about pop.