Robot Battery Placement

[Cothron Theiss]

Originally Posted by Kevin Sevcik

The only time orientation matters is charging. You shouldn't charge the batteries upside down, as overcharging can generate hydrogen, and the vents at the top of the battery need to release said hydrogen.

Huh. I've never heard that. Is charging batteries on their side still ok? Is the hydrogen still able to vent in that orientation?

[Kevin Sevcik]

Originally Posted by Cothron Theiss

Huh. I've never heard that. Is charging batteries on their side still ok? Is the hydrogen still able to vent in that orientation?

Most of the stuff I see says anything but upside down is fine. The issue is that when you're charging lead acid batteries the charging voltage is causing water electrolysis at the same time as the normal charging chemical reaction. A slow charge lets the H and O recombine at the same rate it's generated. Extremely rapid charging and overcharging create H and O faster than it can recombine, so pressure builds up and has to be vented through a pressure regulated valve. There shouldn't be much or any liquid electrolyte in an SLA battery, but charging it upside down would concentrate it at the valve, where it could leak if the valve ever has to release pressure.

So it's an unlikely problem, but completely avoidable by just not charging them upside down.