Battery/Charger Question

[JusDreaming]

While in a marina for long periods, is it better to just leave the charger on continuously or is it better to top off the batteries (agm batteries), then let then cycle down and then recharge. It is a new charger so I am sure it reads voltage ands reduces voltage

[Paul Elliott]

It depends on the charger. If it has a true "float" mode, then keeping it connected is probably best. Otherwise letting them run down a *little* bit and recharging will be fine. You don't want to cook the batteries, nor do you want them to self-discharge too much.

One reason you might want to keep the charger (usually) disconnected is to reduce the electrolysis you might get from your shore-power connection. This also depends on your boat wiring, the marina wiring, and the boats nearby.

I have solar panels that keep the batteries topped-off, which I think is the best arrangement. Removing the shore-power cord did reduce the rate at which I had to replace zincs. I could have added an isolator or transformer to the shore-power connection, but since I needed the solar panels anyway, this was easiest and it works well.

[Alan Wheeler]

I very strongly recomend you get a "true" 3 or 4 step charger. What I mean by "true" is, there are many chargers that say they are multi stage chargers. But the one you want, is one that goes into an automatic bulk charge ones a week or so. Just because a battery suggests to a charger that is trickle charging it, that the batt is fully charged, maynot be the case.
A cheap charger with a trickle charge only facility can do as much harm to your battery as can be done if you left the battery off the charger.

[forsailbyowner]

I usually let the converter do the house power at dock and just switch the battery banks on once in a while(once a week) to keep them topped off

[Alan Wheeler]

As soon as a battery(flooded lead acid) is disconnected, it goes into a self discharge. A float or trickle charge is essential to maintain the life of the battery.
However, every now and then, I get people that don't follow the rules and still get unbelievable amounts of time from their battery. Eh Seafox. Darryl compleatly "abuses" his battery and still got 10yrs from the thing. So sometimes the arguments of correct maintenance get blown out the window.