Sealed batteries don't have to be AGMs. I use sealed marine deep cycles in both my Class A and my Class B. But for sure sealed batteries are best for confined spaces with poor ventilation.
I thought those wet sealed were starting batteries. Do you have a link to those batteries so I can review the specs? My details are in my profile.
The AGMs are hybrids with both starting and deep cycle service specs.
I used an inverter to run a 900W electric 120V kettle with my 79AH AGM for 7 min to boil a quart of water. Would an equivalent AH wet sealed do that without exploding?
AGM batteries were a godsend for me. In my case, the AGMs made my system possible.
I have living space issues because there is not enough outside space for the AHs I need.
There are no batteries on the tongue. I use that space for other cargo.
The AGMs are inside the van and under the bed/dinette in the TT. Some have suggested that they could have been wets if I bought a sealed container and then drilled holes for vents in the van and TT. That only makes maintenance more difficult and dangerous. Nogo for me as I put the AGMs in somewhat inaccessible locations where an acid spill could occur during water maintenance. There goes any cost savings.
I also believe I need fewer AHs than wets would have required. That saves space and $.
Coat the roof with Herculiner.
Then install the new battery bank at the rear bumper on a rack welded to the frame. Run #6 wire to the OEM connection or to the power center which ever is easier.
I assume you are messing with me now. Herculiner the black truck bed coating does not seem like a good plan.
Wow really? I read a few threads about how it was a very bad idea to install batteries on the rear bumper. I had had that thought too, but most of the threads said that is one of the bounciest spots on the trailer and would damage the batts over time. Also if you were to back into anything or to be rear ended in a wreck battery acid could be all over.
I can assure you PT is not messing with you. He just forgot you have a TT. That often happens when you don't have a sig or profile and also when the topic is in a general forum.
You may be interested to know that I switched to AGMs and now store the TT bank inside and under the dinette seat. The bank is now adjacent to the power center. This keeps charge wiring very short.
Take a look at my profile.
I have two DieHard Platinum Marine Group 31 AGM batteries.
Question is, what should be my cut off voltage charge setting in my solar controller?
From what I have gleaned off the Internet, I have it currently set at 14.2 volts.
Sears Platinum batteries are mfgrd by Enersys which also is sold under the Oddyssey brand name.
Here is the Odyssey Technical Manual.
Start reading at page 15.
Ask more questions. :)
I was seeking, from that northstar PDF, the initial charging current as it relates to battery capacity. Most of what my concerns in this entire thread is being able to meet the minimum recommended bulk current with my main recharging source, which is solar.
The initial/minimum charge current is related to the time to recharge or catch up.
Can solar return ~110% of missing AHs. If you have days of inclement weather, can solar catch up for the days there was a % shortfall?
If not, you need more initial current and this translates into solar array sizing. I cannot, so I carry a genny.
14.8V charging here but now that I think about, my real secret just might be only one cycle a month tops.
Let's see. 500 cycle life expectancy at 12 cycles per year. That is 41+ years. You better put those in your will. :)
Let them float. The controller brings the batteries up to 14.3+ volts for at least few minutes every day yes?
I do agree. The Rogue manual states that the controller resets after dark and repeats the bulk,Abs and float the next day. Perhaps over time the battery will improve.
My Morningstars cycle like that as well so that is to be expected. Due to parasitic draws, that lightly cycles the bank daily.
Are you planning to keep updating us as you go?
What tells you that they are not performing?
2)Battery: AGM 100 AH by UPG aka Universal Battery. I have 3 of them, they survived Mexican heat, losing 25% in 8 months, Voc=12.45, put one on charging. Shortly after hooking up it went into Abs, so much for 490W system. I set I abs=1A min, since it's 100AH, and Abs time to 4 hours - pure charging, no loads. Some clouds on the first day, current never went over 7A, - well, it's Abs. Had to reset the Abs timer a few times, and by the end of the NEXT day it was still at 1.5A. So I gave up and put darn AGM on 8A load - 12V 100W bulb.
3) Testing AGM 100 AH. Like I said, it spend more than 8 hours in Abs. Next day battery Voc=13.05. Surprise #3: V on load = 12.45. This is 83%. What the heck? It was 75% before 2 days of charging. Alright, let the real SOC test commence. V load dropped from 12.45 to 12.0 (=50% SOC under load) after 4.75 hours. This is 38 AH. So it was 76% full after it has been charged to 1.5A min. Does that look normal to you? Man, I REALLY wish I had some you guys money I'd would've gotten some Rolls Surrette AGMs, 1000W of solar, Victron 5kVA inverter/charger, and paid AM Solar to install it all. Then I would've cracked open a beer and just sat there observing it all.
I could have misread, but I believe Almot later posted that he found a problem with shading with his array, and that that battery was now going to float along with the other 2. I read that to mean they were in service since he has begun to use them.
I do appreciate your prompt attempt to correct me. I sure don't intend to misinform.
I am going to follow the advice of Smkettner and keep the batts on Float for some time, so they would "wake up" and hopefully behave more like they should. Also, to watch the Tcomp and fine-tuning it with VRIM if necessary. Light use in daytime like charging laptop, running shaver, radio, etc with that much solar doesn't cause batts to cycle - voltage drops but they remain in Float.
IMHO, your batteries are healthy and performing per specs. I don't see any more wake-up being needed and I don't see where you did anything beyond fully charging before use as specified in the Shelf Life & Storage chart.
By no definition can it be said that you recovered/conditioned your bank.
What tells you that they are not performing?
Re the comment about nudging temp-comp Volts up to account for a difference between readings: I would hold off on that. What you are doing is using wet thinking. Wets are Volt whores, AGMs are Amp whores. Maybe that will get my point across. What is the Amp loss? :)
Also, direct your attention to having the Float Volts correct. If you nudge the temp-comp Volts, will you also be raising the Float Volts? That could cause longer term problems if you plan to use the solar during storage.
With solar Watts at 163% of bank AHs, you should be able to manage draws below average daily AH production. Will AH production usually be 110% of draws? I would like to know how many hours per day you are floating.
I have 159%, but my worst-case daily draws exceed my solar AHs. That is one reason that I have a genny.
When i turned my battery switch to both, bringing the AGM northstar into the loop, the draw from the Crown dropped to 0 and all the current was flowing from the AGM which was at ~12.9v.
I don't know who said anything about cycling a starting battery. Just because it is in my engine compartment does not mean is is a starting battery. I have not owned a pure starting battery in 12 years. My engine requires a 650 CCA battery, and I've had a 600 CCA Marine wally world -27 battery in there for the last 7 years
I guess we'll see how my strategy of less capacity works out.
Please do not keep the AGM and wet connected full time. The wet will, at a minimum, suck the Volts from the AGM until the two reach equilibrium. This leaves the AGM at about 75% SOC and will result in sulphation of the AGM due to chronic undercharging. You now have two banks, not one. Why not two matching, wet or AGM?
AGMs are hybrids. Does this read like a starting battery spec? "Cycles over 400 times to 80% depth of discharge". That equates to camping every weekend for 8 years with an 80% drawdown every time.
Yep, I also subscribe to the smaller is better for bank size and agree with your analysis. Lions and Tigers and.... :)
There is simply a curve for that. The old standby for GC2s is below.
Interesting, that chart looks exactly like this one located in a solar-electric FAQ under the paragraph Cycles vs Lifespan.
The last sentence attributes the chart to Lifeline:
The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary.
Since Land uses solar, after some "bulk" charge via an alternator, in theory the battery bank gets fully charged each day.
That is exactly how I managed 31 consecutive days without pedestal power in Corpus Christi, TX while beach camping. I used inverter genny power for bulk and part way into abs charging. I ran the genny until it idled which told me it was time to let the solar finish the job. I also used a Kill-A-Watt which confirmed when the genny was not needed. At no time did any charging Volts exceed 14.4V temp-comp.
I am going to Q-zite with a caravan of fellow campers in Jan where I plan to repeat that using the same batteries, except that they are now 2 yrs older.
Yes, John, that is essentially my charger. Except it doesn't have the "C". I purchased my charger from Sams some time in the late nineties. The manual reads almost the same, and the "Personal Precautions" reads word for word including "For Lead Acid Only". I suppose that wording is/was my concern. Since I only have one of the small AGM batteries in my possession at the current time I'm going to try a test charge to see what the results might be. Again, thanks to everyone for your interest and comments. If I blow the battery up, I will post the results.
Uhhh, AGMs are lead-acid!, as are Gels and flooded.
The difference is mainly in the acid. The cautions against high Volts are related to the sealed, or valve regulated ones.
Flooded can be open or sealed, but the acid is a free flowing liquid solution and the battery must always be upright to keep the acid in contact with the plates.
AGMs and Gels are always sealed where the acid is immobilized and they can be placed on their side or end.
This is great material. And I am considering the AGM's to replace my 4-6 volt batteries in the not too distant future. But, first...the reason for my question about using a Century 87151 automatic charger at the low 2 amp setting is....let's say you wanted to recharge a simple kids electric scooter AGM 12 volt 7 amp-hour battery. I know this is a far cry from trying to figure out how, etc, to recharge a 4 battery 800 + amp-hour system, but if we can understand a simple small battery recharge it may shed some additional light on charging the more expansive systems. and let's assume the physical makeup of the small battery is the same as the 200+ AH. This may be a mute point in that as I understand the previous discussions that my charger even at the 2 amp setting may put out too much voltage. Am I understanding this correctly, and subsequently shorten the life of any AGM?
Is this the Charger?
Is this the manual?
If so, on page 6, I recommend you:
Step1 - Normal/Automotive
Step2 - Charge
Step3 - 2A
Plug in charger
Yes, this is my battery.
OK, it's time to forget all those voltage charts created for FLA. I thought 12.45 rested = 75%.
Nice battery. I had them on my radar for replacements until the Sam's Club nearby began stocking Johnson Controls AGMs for a comparable price. I am still using my first three AGMs; a Deka and 2 x Optimas, totalling 189AH.
Do you have a link to the Rogue manual?
Those wet battery voltage/SOC table values will continue to show up in the strangest places. Many battery monitors with LEDs are calibrated for wets where a full LED may only be 75% for your AGM. I use a Turnigy with real digital values.
It is a wet world out there. :)
I am concerned about the 12.45V = 75% SOC.
Here is a Deka Manual pdf. On page 2 they show 12.60V = 75% SOC. That would put your 14.45V halfway between 75 and 50 for 62.5%.
Is this 45978.pdf the battery?
Looking at the chart Shelf Life & Storage you can see the 60% line and how you may have crossed the line. What if the battery was two months older or only 90% charged when put in storage?
That 62.5% estimate is dangerously close to the 60% charge may fail... threshold and likely explains why 1 AGM is not charging to float. I wish I could help more, but I have not been there with my AGMs.
P.S. I just saw your amended post and await your report that all three AGMs are ready for service. :)
I have to believe that folks are not going to wake up at dawn on 4 July in Bad Water Death Valley and run outside and charge their batteries. "Yeah I found out the hard way that 13.6 was too high a float voltage at 50C"
Most folks are definitely not happy camping where battery temperatures start out at 35C.
So I abbreviated my answer. For 90% of campers 14.7 is fine.
If I must I'll repeat it again:
If time is not an issue, limit the charging voltage down from 14.7. When I discharge a flooded battery 20% in less than 24 hours and then connect to public power to recharge, I will limit charge rate to FIVE PERCENT of A/H capacity until 15.0 is reached then reduce to float. Of course I adjust for temperature if I see camels or penguins outside.
It's when the aggregate total price, the total cost of "babying" batteries with a reduced voltage limit threatens to cost more than the purchase price of the batteries is when I crank the voltage up to 14.7 It doesn't take long for the price of fuel, generator wear out, and GOING TO GET MORE FUEL adds up to more than purchase price the batteries.
Yes, good stuff!
But, when I say I use 13.5V on 110F AGMs and 15V on cold AGMs it doesn't mean I do it myself. The Temp-comp chargers do it for me while I sit back and enjoy the R in RV.
When I do get out the genny, it is for bulk and some Abs charging while I go back to the R in RV until the genny idles down. Then I shut the genny down and let the solar finish the job. Many penguins and camels, however, I don't need to take notice as the temp-comp automatically deals with that.
Are you saying I should go out of my way and override my setup to use 14.7V on my AGMs when they are 110F? This is a normal, daily condition right in my driveway as I have AGMs in the van in the summer sun. I just let the solar charger take care of this.
Was just on lifeline's page and am impressed with its depth
They say 14.3v max +/- 0.1v acceptance
and 13.3v +/- 0.1 floatI saw that also. The following information is on my battery label. Of course the actual label is half for the 6V battery. So I assume that both sets of numbers are correct.
For 2 GPL-4CT Lifeline AGM batteries in series the charging voltage is bulk 14.2-14.4 and float 13.2-13.4.
14.3v +/- 0.1v = 14.2-14.4V, or Abs
13.3v +/- 0.1V = 13.2-13.4V, or Float
As to rate/current/Amps:
...The charging current during the Bulk stage should be set as high as practical; higher current levels mean faster recharge time.
For repetitive deep cycling, chargers should have an output current of at least 0.2C (20 Amps for a 100 Ah battery). If the output current is less than this value, the cycle life of the battery may be negatively affected.
Due to the low impedance design, Lifeline® batteries can tolerate in-rush current levels as high as 5C (500A for a 100Ah battery).
They say bulk, but I believe they mean to include Abs in the 14.3TCV(temp-comp-Volts) spec.
Doesn't this say that regular temp-comp charging hard-limits Volts, but encourages higher Amps?
I know but in this case I know he's mentioned it a few times so it's safe. I think. :)
Yes, I am sure Mex means temp-comp. However, many readers do not understand or choose to ignore temp-comp. So, yes, I do harp on that! :)
All too often the chargers like PD, IOTA, HF, etc. are recommended without any consideration being given to temp-comp. I have two banks and four chargers, 2 x solar, one portable with an AGM button, and the semi-smart WFCO 8735 conver/charger. The WFCO, which never sees more that 13.6V, is the only one without temp-comp.
I do practice temp-comp charging and I have never felt the need to condition/recover my AGMs.
Plus, I tend towards the lower end of the Volts range when charging. Too many people use high-Volts/wet-battery thinking when choosing to boost Volts. AGMs want Amps, not Volts for regular charging. Wets are Volt whores.