Over the years I have purchased a number of Lloytron D1002GR Rechargeable LED Emergency Lanterns. They are permanently fixed to the walls in each room. I have had a couple that have gone faulty and have now got two spare 6v SLA batteries. I was wondering if it would be possible to each of these batteries in parallel with the battery inside the lantern to give extra time if the mains power fails.

Any advice gratefully received.
Gerald

 

Welcome to AAC!

It's best to use well matched batteries when connecting in parallel, or series.

http://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

 

Over the years I have purchased a number of Lloytron D1002GR Rechargeable LED Emergency Lanterns. They are permanently fixed to the walls in each room. I have had a couple that have gone faulty and have now got two spare 6v SLA batteries. I was wondering if it would be possible to each of these batteries in parallel with the battery inside the lantern to give extra time if the mains power fails.

Any advice gratefully received.
Gerald

Don't forget to balance them - initially connect them in parallel via a current limiting resistor.

Not as important as with some other battery types, but might as well limit any risk.

 

Welcome to AAC!

It's best to use well matched batteries when connecting in parallel, or series.

http://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

I disagree with figure 5 in the link.
"A weak cell will not affect the voltage but provide a low runtime due to reduced capacity. A shorted cell could cause excessive heat and become a fire hazard. On larger packs a fuse prevents high current by isolating the cell."
In my experience a low cell in parallel with others will drag them all down to the voltage of that low cell.