AGM batteries are a type of sealed lead-acid battery using "Absorbed Glass Mats" between the plates. This is a very fine fibre boron-silicate glass matting. Electrolyte (acid) is fully contained in the glass matting and will not spill, even if broken. The result is a deep cycle battery which is considered non-hazardous for transport.
Traditional flooded lead-acid deep cycle batteries off-gas hydrogen during charging. This is avoided when using a sealed AGM battery. No off-gassing occurs under normal charging and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in an AGM battery are tightly packed and rigidly mounted and typically withstand shock and vibration better than traditional flooded lead-acid batteries.
Nearly all AGM batteries are "recombinant", meaning oxygen and hydrogen generated during charging recombines inside the battery case. The recombining process is typically 99+% efficient, so almost no water is lost.
Internal resistance is lower in sealed AGM batteries than traditional flooded models, allowing more efficient charging. AGM batteries have a very low self-discharge rate of 1% to 3% per month on average at 25°C (77°F).
Was this article helpful?
That’s Great!
Thank you for your feedback
Sorry! We couldn't be helpful
Thank you for your feedback
Feedback sent
We appreciate your effort and will try to fix the article