AGM Batteries

The problem with the Excide is that it is not a deep discharge battery it is a starting battery and if you look at their litterateur http://www.exide.com/Media/files/Downloads/TransAmer/Products/Edge%204%20page%20booklet%20non%20spread.pdf they are not going for 50% SOC as the standard.

Just installed AGMs last year ,no more checking water level with a mirror in hard to reach places.

I will take those one at a time.

"Do Not leak acid and corrode my battery tray ."
This is true, but the same is true of Maintenence free

"Do charge faster than conventional batts"
Only LIFELINE recommends that fast charge from what I have found.
Other brands the recommended max charge rate is the same as for Wet Cells

"Are more tolerant to deeper discharges than conventional batts ."
I have not seen evidence of this, And I tried AGM's

"Do Not give off gases in the way that conventional batts do"
Again true of most MAINTENANCE free designs, that is part of how they make 'em maintenance free... By re-combining the vapors and dripping them back into the cell.


"AGM batteries have come down in price because they are becoming mainstream in new cars ."
This is true in part (They are coming down in price due to more sales reducing the unit cost. But if you want a WAY lower price, try Golf Car batteries. Same argument times 10

"At BiMart in Oregon I paid $ 140 each for exide edge agm batteries in a size group 78 ( GM side post )"

Can not argue with this but the group 78 is a small battery Roughly equal to a Group 24 which only holds about 75 amp hours. 150 amp hours if paired, 75 safely usable. (This is the starting battery on my Motor Home which is why I researched it)

I paid just over 300 for a pair of US made DEKA 230 amp hour six volt batteries, (in short about the same price) 115 amp hours usable (nearly twice the power)

My MK AGM's lasted 5 years (Both MK and Deka are products of East Penn Battery Company by the way) they were Group 31's 130 amp hours each.

My Interstate Golf Car batteries (OEM) lasted nearly 9 years FROM DELIVERY of the motor home (Next month is 9 years I replaced the Interstates last month.

If not for small batteries like the 12 volt AGM I use as a paper weight and to charge some smaller batteries and for other portable power uses, and the Jump Start pack I have which is also 12 volt AGM.. I would say "I've bought my last AGM".. Very good for hand held portable power.. Not so much for house power.

I have three- nine year old Deka 8D - 12 volt AGMs, 250 AH each. Love them.

Yes lifeline it'd the only one that says you can use a rely high rate of charge
That does not mean exactly the same thing as "charge faster"

I have four large AGM batteries in my drivers side bank
From my experience, when disconnected and charged as a separate bank, using the same 40 amp vector charger, they come to full charge faster than the equal amount of flooded batteries, there charging is more efficient

No I don't preform discharge~ recharge cycle tests
This is simply an observation from daily use, with periodic individual bank maintenance

It is not hard to find other AGMs with fast charge specs.

Per the Enersys(Odyssey) Technical Manual:

On page 17, please observe 'Table 6: fast charge capability' where it can be seen that an Odyssey can be charged to 100% in 30min at a charge rate of 3.1c10.

For example, the ODYSSEY ® 31-PC2150 battery is rated at 92Ah when discharged at the 10-hour rate (9.2A for 10 hours).

Using the above spec, this battery can be 100% charged in 30min at 3.1 x 92 = 285A at 14.7V with temperature compensation.

Another mfgr is Optima which has a temp comp fast charge spec of 15.6V at unlimited Amps so long as battery temp is under 125F, switch to float when accepance current reaches 1A.

HTH;
John

Optimas have more exposure to air (So they cool faster) and less capacity than other batteries.

Still, in the larger scheme of things, that is not a big difference in charge speed.

PLUS, imaging a 700 amp charger.. WOW. That is like 9 times the converter I have here. AND it would total my 30 amp shore line. It would major damage to the remaining power on my 50 amp cord in fact. Any converter over 100 amps is actually impractical on a 30 amp rig, or 200 on a 50. You simply do not have that much INCOMING power.

The $ 20 rebate for the Exide Edge AGM makes a great deal on those AGM construction.
For us pickup drivers the AGM battery is the way to go .
We use jumper cables in the campsite to run from the 2 tow vehicle batteries to the RV batteries .
The quicker charging time for the 2 Edge AGM is a bonus .
We do not have to charge our batteries other than just letting them equalize after driving our pickup .
The AGM batteries are definitely cleaner .
The corrosion of trays and terminals has stopped by switching to AGM .
The 6 volt GC2 is probably better for the motorhomer .
But the complete maintenance free AGM makes for a very good solution .
The AGM batts will outlast the conventional .

I disagree. Flooded lead acid type are better in situations where the battery is not fully recharged before it again has to provide current than the AGM type. This is a common situation for most RV's.

I use an AGM battery where there is no venting or where the battery needs to lay on its side. For this I pay extra but I have no illusions that I get a "better" battery than the flooded lead acid type.

If AGM were that great they would be used in golf carts and forklifts instead of flooded lead acid type. Same applies to industry in general where there are very few applications where AGM batteries are used.

You can say anything you want about AGM and flooded cells I'm sold on my Optima Blue Tops. Two months into the 12th year on the same set is hard to beat.

Denny