Deep Cycle Battery Safety

[Jorrie]

Hydrogen molecules are so small that they tend to pass through almost anything given a little time. It is unlikely that there will be a buildup of gas in the vehicle. However, when the battery is contained in a typical battery box, the risk increases when the "end off charge" is reached with a lead-acid, because at this point the battery gasses freely and should therefore be well ventilated.

[Chris Skinner]

Jorrie - what does end-off-charge mean?

[Jorrie]

Chris
Chris

"End of charge" is the point where lead-acid batteries approaches their maximum voltage during the charge and where the charge current should be reduced. This is exactly what the intelligent chargers. When this stage is reached the battery starts gassing. The electrolite stats to bubble (almost like it is boiling). These bubbles are the release of hydrogen which if contain in a restricted space like a battery box can produce a dangerous build-up. It also indicates that the battery is full. In my environment we work with very large lead-acid batteries and manage this very carefully as a hydrogen explosion can be catastrophic. (I have experienced a small one, and it it not nice). Proper ventilation reduces the risk of such an explosion to a minimum.

Here are some simple guidelines for charging lead-acid batteries.

1. Charge in a well-ventilated area. Hydrogen gas generated during charging is explosive.

2. Choose the appropriate charge program for flooded, gel and AGM batteries. Check manufacturer’s specifications on recommended voltage thresholds.

3. Charge lead acid batteries after each use to prevent sulfation. Do not store on low charge.

4. The plates of flooded batteries must always be fully submerged in electrolyte. Fill battery with distilled or de-ionized water to cover the plates if low. Tap water may be acceptable in some regions. Never add electrolyte.

5. Fill water level to designated level after charging. Overfilling when the battery is empty can cause acid spillage.

6. Formation of gas bubbles in a flooded lead acid indicates that the battery is reaching full state-of-charge (hydrogen on negative plate and oxygen on positive plate).

7. Reduce float charge if the ambient temperature is higher than 29°C (85°F).

8. Do not allow a lead acid to freeze. An empty battery freezes sooner than one that is fully charged. Never charge a frozen battery.

9. Do not charge at temperatures above 49°C (120°F).

You may want to look at this link http://www.battcon.com/PapersFinal2008/ ... ROOF_6.pdf