On Sun, 24 Dec 2017 20:59:54 +0000 (GMT+00:00), TheChief wrote:

I did see a serial type number on the battery top.
Next time I open the panel I'll check.

Is there an age at which I should be returning this? E. G. Older
than a year?

That's the sort of age I'd be wary of buying and would take back if
it didn't perform as expected. Take a volt meter with you off load
terminal voltage should be over 12 V, less than 12.5 V might be OK, a
good fresh battery probably over 13 V.

--
Cheers
Dave.