If it were me, (and it was back in the spring), I'd make sure they have taken all the charge they can, and take them to a parts house and ask them to load test them. (Auto Zone has one). It's a neat little device you hook up to both posts, and it shorts a 10 second load on the battery, at which point shows you on a meter whether it's still good, or on it's way out. If it has one or more dead cells, you may as well givem' up!!!. It will fail you when it's needed most...........you can bet the bank!!!!