Skip's Corner

Can AGM Batteries Suffer Thermal Runaway like Lithium Ion Batteries?

The Question –

Can AGM Batteries suffer thermal runaway like Lithium Ion Batteries: Are they safe?

The Answer –

Does everyone know that when our RG series batteries are subject to the destructive overcharge test that they do NOT thermally runaway?

They get HOT about 260F, the electrolyte boils, the water turns to steam and the excessive internal pressure opens the vent valves releasing the steam (H20) NO ACID is expelled.  This continues for about 10 minutes and as soon as the battery runs out of water the charge current stops and the battery starts to cool down to ambient.

Skip's Corner

Arcing Conditions

The Question –

We have an RG380E/44 battery, S/N: 40450578 that has slight arcing on the negative battery terminal from a loose connection at the connector. We have replaced the aircraft connector but I cannot find any information in the CMM, (5-0171, Rev P), regarding how to repair this condition. Can you advise on how to repair so that I have manufacturers data/recommendations for repair and return to service please?

The Answer –

The battery terminal pins are .375 or 3/8” in diameter. Make sure you remove any copper deposits from the plug socket terminals so the pins will have maximum contact with the airframe plug sockets.

Make a go-no-go gage from a 3/8 drill rod or bolt that you can use to check ALL YOUR AIRFRAME PLUG SOCKETS. There needs to be enough tension on each socket, so that the 3/8” diameter gage will not slip out when the airframe plug is inverted.

The battery terminal pins are silver plated, protect them from corrosion using ACF-50 in the plug sockets.