Second battery location and battery life

[Two89w Member Find all posts View Profile Close Two89w]

I have been reading that installing a second battery under the bonnet decreases battery life due to the amount of heat generated by the engine.

Is that true as most second batteries I see are installed under the bonnet? And if it does how much faster would engine heat kill a battery compared to if it was installed in the cargo area?

[Rdae1981 Junior Member Find all posts View Profile Close Rdae1981]

I have been reading that installing a second battery under the bonnet decreases battery life due to the amount of heat generated by the engine.

Is that true as most second batteries I see are installed under the bonnet? And if it does how much faster would engine heat kill a battery compared to if it was installed in the cargo area?

I believe it is more of an issue with AGM/lithium batteries more then lead acid or marine batteries although optima agm batteries are fine under the bonnet.