It looks like Odyssey has addressed one of my concerns of using AGM VRLA batteries underhood exposed to engine compartment temperatures.. that is their tendency to enter into a thermal runaway scenario.. While I have one of our commercial 100AH VRLA batteries (i.e. free to me) in the rear of my vehicle where it is in a temperature controlled environment, I've been reluctant to use one underhood where it would be exposed to high ambient temperatures.
VRLA AGMs have historically had the tendency for thermal runaway when on charge in 95F deg and beyond temperature environments for extended periods of time. I've seen the results of one happening in an IT server farm power system.
Based on their app manual below, I see that they have tested and addressed that concern.. Interestingly, they still have the caution on high temp environments and recommend the metal jacket versions for high temp situations.
Roger, I see you have yours mounted away from the engine heat, a good idea...
http://www.odysseybattery.com/documents/US-GPL-AM-003_0906.pdf
3.2 Thermal runaway test
Thermal runaway (TR) describes a situation in which the battery is unable to maintain a steady current when connected to a CV charger. TR can also happen when the battery temperature increases rapidly due to inadequate
heat dissipation from the battery.
As the battery draws current, its internal temperature rises. If the heat generated is not dissipated, the internal reaction rate of the battery will increase, forcing the battery to draw more current. This in turn generates more heat. The increasing heat generation and attendant higher current draw feed on each other which, if allowed to escalate will trigger TR.
........... and here they have the results of their tests showing their batteries do not enter TR or, at least remain safe if it were to happen...... follow above link for further info...
4.4.1 Temperature
Avoid placing batteries in areas of high temperature or in direct sunlight. The optimal temperature range for performance and service life of the Genesis battery is 20?C (68?F) to 25?C (77?F). These batteries can, however be used at temperatures ranging from -40?C (-40?F) to 80?C (176?F) when fitted with a metal jacket.
I see the one recommended above is the metal jacket version..... <img src="/forums/images/graemlins/kewl.gif" alt="" />
