There are various reasons for this, including how the battery is constructed internally - some may not be appropriately braced internally to be able to be installed on their sides (ie after years of use and vibration, components in a horizontal position that were designed for a vertical position may become loose) as well as heat dissipation conc.
However, manufacturers of batteries state the battery can be positioned vertically or horizontally or sideways, but there is no mention of upside down: With isolated seal, it is not limited to direction, position in place. It can be put in horizontal way, vertical way and side way, its safely and functions totally will not be affected.
The internal design of AGM batteries relies on gravity to maintain optimal electrolyte distribution. If the battery is on its side, it can cause uneven distribution of the electrolyte, leading to diminished capacity and increased internal resistance. Warranty issues arise if the battery is used outside the manufacturer's specified conditions.
No, it is not true that all batteries can be laid on their sides. Some battery types, particularly sealed lead-acid (SLA) and absorbent glass mat (AGM) batteries, can be positioned horizontally without issue. However, other battery types, such as standard lead-acid batteries, should remain upright to prevent leakage.
Why are batteries arranged in opposite directions?
Batteries are typically aligned in opposite directions and next to one another so the current can flow smoothly with a minimal need for additional hardware. When batteries are arranged in a series, the (+) and (-) terminals must be connected; an alternating orientation makes this more efficient and easier to design.
According to Exide, a leading battery manufacturer, upright installation allows the internal components to function optimally. The battery's internal structure is designed to support a specific orientation, which can prevent damage occurring from side positioning.
Should batteries be aligned in opposite directions?
However, one thing you undoubtedly noticed, and have seen hundreds of times since, is that the visual instructions for the batteries explicitly told you to align the batteries in opposite directions. You would meticulously match the nub side of the battery to the (+) sign and the flat side of the battery to the (-) symbol.