lifeline agm batteries

Has anybody here had a good experience with a lifeline battery and some partial state of charge time? I ask because I have one thats about 1.5 years old that is done and I can get a good deal on a replacement, but I'm hesitant to buy another one. Only about 60% capacity and it takes a long time to charge up at the proper absorption voltage.
This is in a camper van with 210W solar and a 60 amp xantrex charger. I've taken really good care of it the last 14 mo, but I may have stressed it last year on a trip when it was fairly cloudy and I typically didn't drive the 6 hours or so that it took to get it 100% I think I went about 2 -3 weeks without getting to 100%, but it never got below 50% and got to 95% several times. I thought I got it back with a conditioning cycle and lots of time at float, resting voltage was 12.85. Then for the last 5 mo I've been in the van 95% of the time and I've been keeping it topped up pretty well, maybe a week with out a full charge, but 98% in that week, never below 70%. It's taking long and longer to get a full charge so at lifeline tech support's suggestion I tried a couple of conditioning and discharge cycles. During the 21 amp discharge test down to 11.3V, I only got 84 ah out of the 150 aH battery. I could probably live with the lower capacity, but it takes forever to charge up. On a recent test, using the xantrex charger, from only 18 aH down it took 8 hours to charge up.
This is in a camper van with 210W solar and a 60 amp xantrex charger. I've taken really good care of it the last 14 mo, but I may have stressed it last year on a trip when it was fairly cloudy and I typically didn't drive the 6 hours or so that it took to get it 100% I think I went about 2 -3 weeks without getting to 100%, but it never got below 50% and got to 95% several times. I thought I got it back with a conditioning cycle and lots of time at float, resting voltage was 12.85. Then for the last 5 mo I've been in the van 95% of the time and I've been keeping it topped up pretty well, maybe a week with out a full charge, but 98% in that week, never below 70%. It's taking long and longer to get a full charge so at lifeline tech support's suggestion I tried a couple of conditioning and discharge cycles. During the 21 amp discharge test down to 11.3V, I only got 84 ah out of the 150 aH battery. I could probably live with the lower capacity, but it takes forever to charge up. On a recent test, using the xantrex charger, from only 18 aH down it took 8 hours to charge up.
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This time of year the sun is at it's lowest point in the sky. Is your panel mounted flat on top of your camper? if so it isn't getting much insolation and would struggle to create any substantial amperage thus taking a really long time to bring up your battery.
AGM batteries have a pretty long shelf life as long as they don't sit too long in a substantially discharged state.
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
What are the measured absorption and float voltages on the Xantrex charger? (actually check them)
What is the output voltage of your alternator regulator?
Are you using temperature compensation?
What is the date code (small round white sticker) or serial number on the battery?
How did you perform the conditioning cycles?
Why did you use 11.3v as a cutoff for the capacity test?
What was the approximate current draw shown on the charger when recharging from 11.3v? (Assuming a Truecharge 2?)
How are you determining that it took 8 hours to fully charge with the Xantrex 60a charger?
The GPL-30H is well known to be a very good battery. I can give you a lot of history of them by the hundreds.
Marc
I have a trimetric bat monitor and solar charge controller (pwm)
I have 160W on the roof, 50W portable. Not much this time of year, about 7 amps, but I'm usually only down 15%
Exloring with the numbers for "sanity check":
- Inverters are continuous wattage devices, so as the battery voltage drops, the current climbs. How did you hold the steady 21 amps?
- If you got 84 ah on the test, then you ran right at 4 hours. Is that right?
- A continuous 21 amp load represents about a 6.2 hour rate on that battery, with a storage capacity of roughly 130 ah at 77-80 degrees F. At 40F, you have a 110 ah battery when discharged at a 21 amp rate. And it goes lower there, when colder.
- Running the capacity test to 11.3v in lieu of 10.5v, represents roughly an 87% to 90% depth of discharge. Which means that the actual storage capacity is higher than 84 ah.
If the battery was warm, then 10%-13% remaining capacity would equate to something like another 13 ah to 15 ah. If so, then 84+13 = 97 ah against a 130 ah battery capacity at that rate = 75% capacity.
If the battery was 40 degrees for example, it would have a capacity of about 110 ah at the 6 hour rate. So 84+12 = 96 ah against a battery capacity of 110 ah = 87% of rated capacity.
I do not know what the battery temperature was during your test, but your capacity deficit may not be as radical as you thought. Check my numbers to see if I missed something major! (There was a lot of IPA consumption last night :-))
Marc
The PWM solar is not accurate at keeping the voltage below the damage points on an AGM. I am amazed they still sell that beast.
I would really make sure that it is not over voltaging the AGM. I would use their mppt or another make if I had AGMS.
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Yep, 4.05 hrs for the discharge test. The fridge was coming on and off so it was a constant 21 amps.
The charger is plugged into the inverter, the van 12V system can supply the inverter.
When I did the discharge test it was at 59F. I could probably live with the lower capacity since I rarely go down more than 35 ah, but since it's taking so long to charge I know it will only get worse since I won't be able to charge it back up everyday.
Dave, Why do you say the PWM is not accurate? How much more would I really get from an mppt CC? 10%?
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IF you "work" the pot and make sure it is repeatable you probably are OK. An mppt will probably not help you other than what I said about the voltage.
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2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
I may be missing an important point here, so I want to verify:. Is your Xantrex charger a 120v 60a Truecharge 2? (I think so because of the every hour baby sitting required like mine!)
I am not comfortable that your battery is taking so darned long to reach full charge. At 14.2v to 14.6v, how long would you say that it takes to get down to an amp or two?
Please note that I am not challenging your knowledge - you have very obviously done your homework x 2! I do a lot of trouble shooting on Lifelines and I am just trying to get a handle on what is happening. (Ask anyone at Lifeline about me when you call them next time)
That model just doesn't do that, unless it's really abused - is what I keep saying to myself. But what you have described doesn't sound abused at all. BTW, out of the last 4,000 of their batteries that I have dealt with, exactly two had a bonafide defect.Neither was the 30H.
I don't suppose that you are planning to be anywhere near Austin, TX?
Yes its a 60 amp truecharge2. They recommend that it is charged when the current drops to 0.5% of C, or .75 amps in my case. For the test I did a couple of weeks ago, after 3 conditioning cycles it took 7.25 hrs to get to 0.8 amps. Unfortunately, I'm not going to be anywhere near Austin.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
I didn't realize that you were fighting the final few tenths of an amp of charging current. The 0.5%C (0.75 a in your case) end amps is the spec for a brand new battery in perfect condition. It will climb a bit as a battery ages. Your battery is likely coming up on two years old, so I would use a higher number in my charge planning.
Remember that we are talking about fairly small values here. If your amperage measurement is off by a a tenth or two in the 0-1 amp range, or there was some small parasitic load - the whole picture changes.
I am left wondering something: If the refrigerator kept turning on/off while the battery voltage was continually, gradually falling, how did you keep the current draw constant at 21 amps on the battery for the test?
Based on your measurements and my assumptions, it would appear that your battery has 80% to 85% of original rated capacity. But if you were nearby, I would run a controlled discharge test to 10.5v for you, just to verify.
Marc
For the discharge, there was some variation with the fridge cycling, but the aH was measured with the TM.
I agree with your estimate of 80-85% capacity after correcting for the 4 hr discharge rate, 11.3V and temperature.
I am always cautious regarding the calibration/accuracy of devices and methods being used to verify capacity. I am NOT saying that you are doing something wrong - only that I have been doing this for a long time and I am big on "verify" before deciding what is right or wrong!
Marc
I'm using a decent qualtiy DVM and a while back I compared a volt reading with someone else's and they were spot on. Next time I find someone else with one I'll check again.
Softdown, the data I posted in #14 was using a xantrex trucharge, not solar.
Is the charge time equation that lifeline gives, time = (aH discharged)/(charger output) + 2 hours, close to accurate?
Can a lifeline battery last 5 years (the warranty) if it doesn't get fully charged everyday?
6-9 years if fully charged each cycle
4-6 years if recharged each week and EQ'ed every month
2-4 years if recharged to 85% and EQ'ed once a month
1 year if charged to only 85% and never EQ'ed.
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Every battery design has its own strengths and weakness that must be weighed against long term owning cost. Are AGM's perfect, or the best battery for every app? Oh, Hell no.
Have you explored going FLA?
It would seem like lithium would be a good answer for you?
If you know that your operational needs do not include what a Concorde battery "needs".......but if you need an AGM, seriously consider buying a much cheaper battery that will be replaced more often!
Marc
Marc: I agree with you completely - while I *prefer* AGM, one always has to take into account ALL the other variables. There are many ways to go, including manufacturer and chemistry. There is no one-shoe-fits-all battery made to my knowledge, so your outlook is refreshing.
I have flooded in the companionway of my sailboat, and while they've worked okay I will be seriously considering AGM replacements when the time comes.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter