Originally Posted by camaraderie
OK...none of the above sources require temp compensated charging. That was my point. If they mention it, it is only as a good practice and then only do so in terms of ambient temperature adjustments.
Cam- Regarding the use of the word "require" I think that we are arguing about how many angels can dance on the head
of a pin
When you purchase
a piece of equipment
, that piece of equipment
usually comes with an installation/owner's/technical manual. That publication provides the installer and end user with instructions for installing, operating and maintaining the equipment. And, generally speaking, warranty claims are based on the proper installation
, operation and maintenance
of the equipment. Operate the equipment outside of the parameters spelled out in the documentation
may very well negate a warranty claim.
Do the manufacturers that I cited "require" temperature compensated battery charging sources; I say yes. They provide tables, graphs and text to guide the installer and end user in how the product is expected to be installed, operated and maintained. If it wasn't an important factor, they would not include the temperature compensation information in their technical documents. And AGMs are more susceptible to high voltage charging then flooded batteries and not quite as susceptible as Gels.
As I have stated in other posts on AGMs, battery temperature is made up of two components: the ambient temperature of the area where the battery bank is installed and the temperature increase that is a result of the electrochemical reaction taking place during the charging process. One of the main virtues of AGMs, and especially TPPL AGMs, is that the charging rate can be as high as C (C is defined as the amp-hr capacity of a battery; thus, a 200 amp-hr battery can accept a 200 amp temperature compensated
charging rate). These two damaging components can be mitigated, to a large extent, by using a temperature compensated charging source. (And there is the specter of thermal runaway that we can get into at a later time.)
Regarding your statement, "I am not aware then of any non compensated 3 stage charger made by any of the common marine
store brands which could damage your ultimate battery life from ANY ambient temperature up to 100 degrees." here is an excerpt from the Xantrex TrueCharge 2 technical manual (the successor to the venerable TrueCharge 20+/40+ chargers):
Xantrex strongly recommends that you install the optional
Battery Temperature Sensor (BTS) to protect your battery
and improve charging accuracy. If no BTS is connected, the
charger defaults to the charging temperature settings (Cold,
Warm, or Hot).
And, again, it is not ambient temperature that is of concern. It is the temperature of the battery that will prematurely age it when exposed to excessive charging voltage.
Finally, AGMs are expensive and their care and feeding is more sophisticated then most people know about. They are sensitive to high charging voltage, which is a function of temperature, but they are also sensitive to under voltage. For instance; the charging profile for the TrueCharge2 battery charger is not nearly agressive enough for AGMs in general and TPPL AGMs in particular. The 25C absorption value is 14.3 VDC and the float voltage is 13.4 VDC. The Northstar TPPL AGMs, and others, require a nominal 14.7 VDC and 13.6 VDC respectively. Using the AGM profile on this particular charger will chronically undercharge the batteries which will ultimately lead to sulfation and premature failure.
In the early days of AGM initiation into the marine industry, we did not understand the affects of temperature and charging voltage. I have a very good friend that we cruised with in the Eastern Caribbean
. He went through three sets of AGMs before we began to understand what was going on. Installed the fourth set and temperature compensated his charging sources and all was right with the world