Bringing an 12 V SLA back to life from 9V

I’ve spent the last four hours or so – in between other tasks – nursing an almost expired 12 V SLA. The charger usually has the green LED glowing to indicate a charge, but not so with this battery – a Power-Sonic PS1229A 12V 2.9Ah SLA which has been a little neglected over the last 6 or more months.

It was registering 9V and was still very low after an hour of charging at 500mA so I feared the worst. About 3 hours later the battery is showing about 10.9V and rising. It may need more than one re-charge though to get it back to something near normal.

While it retails for US$20 in the US or about US$31 from Mouser, here in Australia I’ve seen it selling for about A$29 plus A$11 shipping from a Melbourne dealer or A$50 (free shipping) from an Adelaide one. So it’s a relief that it may not be completely dead.

It sits inside a K2. I’m preparing to drill a hole in the back of the K2 to accommodate a power connector with a direct connection to the SLA for float charging it.

I am amazed how much time you can spend finding out about the care and maintenance of SLA batteries to enable you to operate, time I can’t help feeling would be more enjoyably spent, well operating.