Translations:Fonctionnement, entretien et régénération de batteries au plomb/46/en

Gel batteries are a type of sealed battery / VRLA. In a gel battery, the electrolyte is gelled by adding silicate.
View the inside of a gel battery

Advantages Disadvantages
Maintains the homogeneity of the electrolyte perfectly. Limited peak current.
Low self-discharge (1-3% per month). Slow charging and discharging. (charge current limited to 5-10% of capacity).
Cannot withstand high temperatures (loss of electrolyte in the form of gas - permanent effect).
Longer life span/shelf life. Sensitive to overload (loss of electrolyte in the form of gas).
High cost