Lifeline AGM and extreme temperatures?

Your hair-splitting scalpel needs a tune-up.
Porosity of active plate material accounts for a significant static level of charge.
The THINNESS of plates, the porosity of plates, plus construction for chemistry determines the characteristics of a flooded battery.

I went toe-to-toe with the phone answering "Applications Engineer" at Lifeline. He too suggested a high voltage, maybe "13.8 volts" would cause loss of water if present year after year. Why the exaggeration? I did not say 13.8, I spelled it out, THIRTEEN POINT SIX VOLTS.

It boiled down to this...read carefully...

"Our engineers feel a float voltage of thirteen point four volts will offer the maximum possible lifespan on a battery at float"

This isn't wrong. But the age advantage is almost asinine. Maybe a year IF THE BATTERY IS UNDERGOING UPS DUTY and total lifespan is in excess of twelve to fifteen years.

Don't spin the steering wheel when the front tires are stationary and enjoy added tire life (200 miles on a 40,000 mile tire).

And please don't throw Rolls and Surrette recommended flooded float voltages at me as a challenge. Rolls is right on the dot with their voltages.

I have a 50Kg gram scale here. Measures resolution to .1 gram. A 5-1/2 digit bench meter, and thermocouple that defines Fahrenheit to .1 degree. Ya think just maybe I have the ability to measure resolution of .001 ampere? Ya think a weight loss of a 35 kg battery of .1 GRAM (not ounce - GRAM) would not be detected? How much H2O in one tenth of a gram?

I doubt I REALLY doubt even Concorde goes to such elaborate steps to determine limits of suitability of a particular float voltage correlated to temperature. I do it for FUN. I have caught so many application engineers telling ridiculous fairy tales that I refuse to talk with them unless really forced to. The hidden design engineers espouse facts and by god they HATE to be challenged. They adopt ROTE replies to a majority of issues and stick by ROTE. When pressed to defend ROTE they get veins sticking out of their neck and temples. I have done this for many decades and as Larry D'Aquino at Ramcar told me. "Of course you are correct. But don't make a habit of embarrassing engineers - some of them might have a .45 in a desk drawer".

The validity of abandoning a Lifeline for a .2 float voltage disparity is sad. I tried every example I know, explaining the ridiculous contradiction of imposing a fixed .2 volt differential across a temperature range of ONE HUNDRED DEGREES FAHRENHEIT. That didn't work. Neither did explaining the contradiction of using a Lifeline at underhood temperatures at automotive charging system voltage values.

You are entitled to do as you wish. I have presented my side of the issue with a plethora of easy-to-understand examples. I must now abandon this issue as there is nothing to be gained by head butting. Hopefully enough folks have read this to arrive at a common sense deduction and conclusion.

Saludos! pnichols :)

Efficiency of recombinant properties is temperature dependent. Recovery is compromised when internal temperature raises to the point that venting valves open to relieve pressure. This opens the door for loss of electrolycized water vapor loss. Water vapor loss CANNOT HAPPEN with relief valves intact. This is the principle behind recombinant technology. OEM considers this level of technical information to beyond the scope of the average consumer. Temperature DIFFERENTIAL as well as ultimate battery temperature are the keys to successful AGM management under highly stressed conditions. Lifeline mentions a C10 charge rate is appropriate. Under extreme elevated battery, ambient or Delta T (differential) temperature, full capacity charge acceptance must be avoided. This is true of any Valve Regulated Battery. Compromising VRB sealing integrity is not intelligent. Period. No exceptions. No hair-splitting.

Well two of them are above 13v, the other at 12.88v and I'm sitting here wondering what the heck did I just do. I'm reading Lifelines manual and see I need a better charger than the good ol 2/12/70. I'm pretty sure the TS-MPPT-60 can handle a conditioning charge but not a deep discharge recovery. That is of course when it is set up and the sun shines, neither has been often lately.

Tomorrow is sunny so I will set up the system and hit the lower voltage one first. I want to see how each does alone before hooking them together. One is lower in voltage, I don't have any lugs yet and I'm not sure my system has the power needed to slap all three of them around at once.

As for the weight, any batteries were going to add weight. These are going over the axles opposite of the kitchen. That will let me put the controller in the rear compartment and have shorter runs of wire everywhere. The rear hold is accessible thru the bunk so the controller will be mounted on a board that can be lifted up to working level. Not having the batteries on the tongue will allow me to upgrade to a 50 gallon fresh water tank.

Got the solar, controller, inverter, wire and batteries. Time to work out the switching, fusing and layout. I might even get to see it all work this season.