Do AGM's charge quicker?

Can't seem to nail this all down apples to apples when the goal posts keep shifting. :(

What's the story on this battery EG?

http://www.wegosolar.com/products.php?product=S6%252d460AGM-Surrette-AGM-Sealed-Battery-6V-400AHR-%40-20hr

It is 6v, 415AH (on its label), has a recommended 80amps and a max amps 140a on its label at about 14.6 when paired as 12v. Note that there IS a max amps.

So if that means the same at 12v using two of these ? does it?
then 80/415 = 19.3% charging rate, and 140/415 = 33.7% charging rate.(same as Prosine 2.0 says for deep cycle Floodeds)

My ugly graph was using 70 on 220 = 31.8% and could have been higher on those two 110AH Wet 27s.

I don't believe that it would be faster at a 33% rate to charge that pair of AGM 6s than on the same AH worth of Floodeds.

How can you speed up the time without increasing the charger amps?

Perhaps by extending the time in Bulk? But the examples seen show they are similar SOCs for when Bulk ends. So faster Absorption time after Bulk ends? Could be--I don't have any time numbers for how long it takes to get from 90-100 for either type of battery.

Mex wants to do "saturation charging" for fastest time. That means no Bulk, all Absorption with its tapering amps. If AGMs do absorption faster (maybe they do) he would see a faster AGM time there than with Wets. Maybe.

the issue is then how fast will amps taper to a lower amp and less costly charger size that can be run on a lower VA size generator and how many minutes of gen time will you save between saturation amps and getting down to the lower amps? Is that going to be worth it?

What does "worth it" mean? Mex wants to save Gen fuel because it is a hassle to get more fuel. I don't care about the fuel, cost or ease of getting more, but care about gen time to fit into "gen hours" as set by campground rules. Scenario is everything.

• Run point to point vf drop + then the same -.
• Then an accurate meter millivolts across the shunt to confirm and agree
• Starting at 12.23 volts my 31, accepts 104 amperes which a remaining profile close to your's.

An -accurate- amp hour meter can reflect charging acceptance via ampere hours total count. But the meter must be dead-on accurate. Most aren't.

A rig that has dual alternators (Ford) the 2nd being a hairpin 275 ampere would be a blessing for multiple AGM recharging. Charge with the alternator until absorbsion voltage is equal to or less than the potential of the charger or converter, then switch.

With my rig the Niehoff 400 amp alternator works at 260 amperes max charge with the 4 L-16 Rolls batteries. There is absolutely no question in my personal battery realm that the AGM batteries charge substantially faster. Enough to make a major dent is generator run time.

But that advantage disappears if a wimpy charger is used. I would like to see at least 50% of bank amp hour capacity for maximum reduction of gen run time.

One of the big boo boos, is to try and cook a dinner for 12 in a one quart sauce pan. The generator and charger has to be sized for the task.

Skid Row Joe wrote:

MrWizard wrote:
I go AGM
got my first AGM set in 2012
changed RV's last year, and recently put a 200AmpHr 4D AGM in this RV.

AGM. Got it. Now, might I have a brand name and size (12V?) to go with that description please? I don't follow the technicals on batteries beyond AGM. Thank you!

Deka MK 8A4D
specs currently listed are 25"*12"*12" 139# 198AmpHrs 12v sealed Valve relived AGM

don't know if this will fit your batteries are

BFL13 wrote:

EDIT--read the 3012 manual on charging. So the BMK is the monitor with the shunt. In your case the Bulk stage was at constant amps of about 105 amps. 105/220 = 48% charging rate.
-------------

What is Inverter amps vs BMK amps? Important to use the actual amps to the battery for this calculation.

That would be the amps on the charger to battery wires, where the voltage will be higher at the charger end due to voltage drop.

You have the BMK voltage higher but the BMK amps lower (amps would be the same on those wires, so what's with that?). Please explain.

Yes BMK is battery monitor kit, it's the shunt and a voltage sense that goes to the battery, so it gives very accurate amps and volts.

Yes I quickly wrote the previous post and forgot about the inverter amps vs shunt amps. So the inverter tops out at 125 amps, but only 105 to the battery due to wiring losses (3-4 feet of 4/0 wiring) and a few amps to the loads, which should just be my computer equipment and maybe a led light or to at the time. Magnum inverter amps is derived from the AC amps if I remember right and not a true measurement of the DC side, thats why it has no decimal places so that would include conversion losses too.

The BMK voltage was slightly lower when topped out at bulk, but also the voltage reading is more accurate from the BMK vs the inverter which is only one decimal. Would be nice to get a good multimeter on both sides while running to really see accurate drop.

Bottom line the BMK measurements are the most accurate as far as what the batteries are getting, the Lifelines are very impressive AGM batteries none the less.

SFVdave wrote:
All these numbers look good, but how would they correspond to the 60 amp converter charger I have if I bought 2 Lifeline 12v group 27’s AGM 100 ah each? My charging system would not put out like those shown.

That has been answered about 14 times already in this thread and in the other thread on the same topic you must have somehow missed at the same time you started this one.

https://forums.trailerlife.com/index.cfm/fuseaction/thread/tid/29795454.cfm

All these numbers look good, but how would they correspond to the 60 amp converter charger I have if I bought 2 Lifeline 12v group 27’s AGM 100 ah each? My charging system would not put out like those shown.

I read the 3012 manual on charging. So the BMK is the monitor with the shunt. In your case the Bulk stage was at constant amps of about 105 amps. 105/220 = 48% charging rate.

That boat guy's test
"this battery, when charged at .4C from 49.3% SOC, stayed in BULK/CC for 19 minutes and entered ABSORPTION/CV charging, where current begins declining, at 63.3% SOC"

Your charging rate was higher than 0.4C, so Bulk would end at more like 60%, not in the low 70s like you show.

Please explain.

EDIT--Ok your figures show 67% end Bulk. That comes out about right between 737 and 800 where 105 x 23/60 = 40AH and 110+40 =150/220= 68%

jharrell wrote:
Here is my two Lifeline GPL-4CT's with my Magnum 3012 that can charge at 125 amps.

Ran the batteries down to 50% SOC then let it rip:

Time Inverter-V BMK-V BMK-Ah BMK-SOC Inverter-A BMK-A BMK-T
9:50am 12.5v 12.70v -5Ah 97%
7:35pm 12.2v 12.32v -113Ah 49%
7:37pm 13.5v 13.44v -110Ah 50% 125A 104.0A 77F Bulk
7:52pm 13.8v 13.79v -87Ah 60% 125A 105.6A 82F
8:00pm 14.1v 14.08v -73Ah 67% 125A 105.2A 86F Absorb
8:04pm 14.1v 14.14v -66Ah 70% 111A 95.8A 88F
8:12pm 14.1v 14.18v -55Ah 75% 85A 77.2A 88F
8:22pm 14.1v 14.20v -44Ah 80% 70A 60.8A 88F
8:34pm 14.1v 14.22v -34Ah 85% 51A 45.8A 86F
9:06pm 14.2v 14.32v -15Ah 93% 30A 25.8A 84F
9:25pm 14.2v 14.36v -8Ah 96% 20A 17.2A 82F
9:45pm 14.2v 14.34v -4Ah 98% 15A 11.2A 82F
10:23pm Float

As you can see the two Lifelines will accept 125 amps for about a half hour going from 50 to 70% SOC, they
will accept 50 amps up to 85%. 98% charge in two hours, full float transition in 3 hours.

EDIT--read the 3012 manual on charging. So the BMK is the monitor with the shunt. In your case the Bulk stage was at constant amps of about 105 amps. 105/220 = 48% charging rate.
-------------

What is Inverter amps vs BMK amps? Important to use the actual amps to the battery for this calculation.

That would be the amps on the charger to battery wires, where the voltage will be higher at the charger end due to voltage drop.

You have the BMK voltage higher but the BMK amps lower (amps would be the same on those wires, so what's with that?). Please explain.

Here is my two Lifeline GPL-4CT's with my Magnum 3012 that can charge at 125 amps.

Ran the batteries down to 50% SOC then let it rip:

Time Inverter-V BMK-V BMK-Ah BMK-SOC Inverter-A BMK-A BMK-T
9:50am 12.5v 12.70v -5Ah 97%
7:35pm 12.2v 12.32v -113Ah 49%
7:37pm 13.5v 13.44v -110Ah 50% 125A 104.0A 77F Bulk
7:52pm 13.8v 13.79v -87Ah 60% 125A 105.6A 82F
8:00pm 14.1v 14.08v -73Ah 67% 125A 105.2A 86F Absorb
8:04pm 14.1v 14.14v -66Ah 70% 111A 95.8A 88F
8:12pm 14.1v 14.18v -55Ah 75% 85A 77.2A 88F
8:22pm 14.1v 14.20v -44Ah 80% 70A 60.8A 88F
8:34pm 14.1v 14.22v -34Ah 85% 51A 45.8A 86F
9:06pm 14.2v 14.32v -15Ah 93% 30A 25.8A 84F
9:25pm 14.2v 14.36v -8Ah 96% 20A 17.2A 82F
9:45pm 14.2v 14.34v -4Ah 98% 15A 11.2A 82F
10:23pm Float

As you can see the two Lifelines will accept 125 amps for about a half hour going from 50 to 70% SOC, they
will accept 50 amps up to 85%. 98% charge in two hours, full float transition in 3 hours.

MEXICOWANDERER wrote:
Which AGM

Which Flooded

Can you set the Regressive Dynamics converter to put out a steady 14.4 volts? If it's anything like a WFCO it'd drop charging time from five years to three (yes it is sarcastic as hell but the WFCO deserves it).

This is far more biased for discussing converter types than it is about battery chemistry. Someone will have to speak up about your charger type and it's options before an accurate answer can be construed.

Duracell Group 27 92ah AGM vs Exide flooded Group 27 Natilus 100ah
PD Intelli-power converter charger has a max of 14.4 but it usually is charging 13.9 slowly going up to 14.4