As long as a vent is present and operating properly this should not present an issue.
Vented lead acid batteries.
Vented lead acid batteries are commonly called flooded spillable or wet cell batteries because of their conspicuous use of liquid electrolyte figure 2.
High performance batteries are designed to give long services life.
Epsom salts reduces the internal resistance in a weak or damaged battery and may allow a small amount of extended life.
Chemical additives have been used ever since the lead acid battery became a commercial item to reduce lead sulfate build up on plates and improve battery condition when added to the electrolyte of a vented lead acid battery.
Since these are stored inside your vehicle you run the risk of inhaling dangerous battery acid vapors.
They need to be enclosed and vented to the outside to prevent this gas from being trapped and creating a hazardous environment.
Flooded lead acid batteries release toxic hydrogen gas when charging.
Deteriorated old or damaged lead acid batteries should be removed from service as damaged batteries are much more likely to be associated with production of h 2 s.
Agm batteries must still be vented.
Overcharging especially if the battery is old heavily corroded or damaged can produce h 2 s.
Even though your batteries are normally sealed they actually do have a venting system integrated into the case top.
While nicd loses approximately 40 percent of their stored energy in three months lead acid self discharges the same amount in one year.
Agm batteries are a type of valve regulated lead acid battery.
Most of the battery complies with bs 6290 din40738 and iec standard.
These batteries have a negative and a positive terminal on their top or sides along with vent caps on their top.
Lead acid has a moderate life span but it is not subject to memory as nickel based systems are and the charge retention is best among rechargeable batteries.
These products are suitably used by utilities marine oil gas and petrochemical.
Vented lead acid battery.
Type pp vented pasted plate.
The short answer is your mechanic is giving you the straight story and you do need to vent these batteries.
In the event of an overcharge condition it is possible for excess pressure to build up inside your battery.
This vent is valuable because it gives a good amount of airflow to keep the battery compartment cool and vapor free.
Crown cr430 6v flooded lead acid battery.
As the name implies this type of battery vents hydrogen continuously during normal float operation.
Two compounds used for such purposes are epsom salts and edta.