Don't let an AGM fool you...

For those who may not know...

On the weekend, for amusement, the "found in" 8D AGM deep cycle battery in the Roamer does a lovely job of almost immediately achieving full charge, volt meter reads a lovely 13.2 volts.

But...

Turn off the charger, put the load tester on it, click the switch and POW!

It has 4 volts.

Any boater may just turn off the charger and turn on some significant load to accomplish similar, an old fashioned automotive battery tester optional.

Off to the recycler to recoup some battery money.

HTH
RB

Really a proper electric setup yields no (very few) surprises.

IMO all boat batteries should be replaced long before their reduced AH capacity becomes apparent.

Lifecycle ratings assume 20% capacity lost = scrap lead.

Of course that means decent monitoring gear, but also some human attention: initial benchmarking, cycling logs, periodic 20-hr load testing as part of scheduled maintenance, etc.

People running engines a lot and sticking close to shore get spoiled, learn from the world of cruising sailers.

"Of course that means decent monitoring gear, but also some human attention: initial benchmarking, cycling logs, periodic 20-hr load testing as part of scheduled maintenance, etc.

People running engines a lot and sticking close to shore get spoiled, learn from the world of cruising sailers."


All useful exercises , but SEA TOW gets rid of the need for battery knowledge and discipline, at least inshore.

Exactly my point.

Just because your survival isn't as much at stake, IMO is no excuse to properly set up and care for your expensive banks of batteries.

Or periodically pay an expert to do so.

To me this is like when your teenager blows a rod from not knowing about checking the dipstick, or doesn't know how to change a blowout while off-roading.

A great opportunity to point out what needs learning.

And you my daughters included