SLA Batteries on their sides?

[corrado33]

Hi all,
I've recently scavenged some SLA batteries from our E-waste and was debating putting them into use for an application where they would be mounted horizontally.

The batteries say "Valve regulated maintenance free battery."

I want to use them as a power supply for my pedal bike (for lights and heated gloves, I'm too cheap to buy a dynamo) but seeing as how they are taller than they are wide, so it's be more convenient to mount them horizontally.

Is this ok? I'm getting mixed reports online.

[potatogun96]

Because the batteries are sealed, their orientation does not matter. I have a few projects powered by SLA's, and have noticed no negative side effects from being on their side.

[Fraser]

+1

SLA batteries are designed to be orientation insensitive and may be used mounted in any plane.

Aurora

[corrado33]

Great, thanks for the info guys.

[Fraser]

The biggest problem with using salvaged SLA batteries is finding ones that have not sulphated. If an SLA battery is left in a discharged state for more than a few days, sulphation within the plate mats begins. Once the sulphation has reached a serious level, the battery capacity is seriously compromised. Eventually the battery cannot be charged and draws no current. Even if a battery presents 12V across its terminals, it can still be beyond recovery and not charge correctly.

I once placed over 200V dc across a sulphated SLA battery and still could not get it to draw any current ! It was just like a capacitor to the supply.

Testing SLA batteries is usually done by either an internal impedance test (ESR) or a discharge test into a known constant current load. A very crude test may be done with a load resistor of suitable value.

[mtdoc]

Because SLA (usually AGM) batteries cannot be equalized which helps prevent sulphation in FLA batteries by mixing (via bubbling) the electrolyte, there is some thinking that SLA actually benefit from periodic changes in their orientation relative to gravity.

I have 8  12V  218AH  AGM batteries for my PV backup system. They each weigh 132 pounds (about 60kg).  So I have yet to test out this theory...