Also being a volunteer FF, I have been on several house fires involving suspect battery chargers & batteries. Now that I finally own a home that has a garage for my boat, I am cautious about leaving my boat batteries on a continuous trickle charge. I always just unplug the charger before I leave for anywhere.
So what I'm asking the forum is this; Is there a brand of charger and battery out there that any of you all would trust to leave unattended for an extensive amount of time?
I have a 10amp charger with a timer on it. I leave it connected to the battery over the winter and about once a month when think of it I crank it up to two hours and leave it. The battery is out of the boat. It holds a charge pretty well on it's own.
With chargers and timers it is important to locate them where they will not be exposed to the gasses from the battery. The arc from the switch contacts could ignite them. Also, the charger should be switched off before attempting to clamp or un clamp the leads from the battery. I guess it goes without saying the charging area must be well ventilated with no nearby ignition sources. I think in the OP situation I would buy the sealed gel cell batteries, if they are available in a deep cycle.
My main question here if you need the charger to actually charge the battery in a timely fashion or prevent self-discharge of the battery. If the boat has a charging system and you just need to hold the charge during storage, aim small. A small, current limited supply might be all that you need and would add a safety margin. Don't use a cycle charger unless it can be switched to float or switches automatically when the current drops below a threshold or over time. Joe
I've got a little 1 amp charger that works well for me. It takes awhile to charge the (large) battery, but always seems to be finished before there's another chance to take the boat back out again.
I've got no battery switch, so always have to disconnect the battery cables after each use and flushout anyway. It's usually just go ahead and pull the battery, box and all, right out. It saved my tail once when my truck battery died, so is just kept in the truck as a spare when not in use.
Use a low current option if you want to keep the charger on permanently.
Or if you good in electronics set up a LM 317 for say 200 mA trickle and let that do the job or buy one.
Always have a proper rated fuse in the DC line and of course on the AC side as well.
These simple safety devices seem to be omitted in the cheaper chargers but can be easily fitted for additional safety.
I got 4 x 100 Ah 12 Volts, back up accu banks at home, for my 24 volts master clock, 12 Volts burglar alarm and 12 Volts emergency lighting. These are all on trickle charge 24/7 at around 150 mA. feed from 4 different chargers.
The product of rotation, excitation and flux produces electricty.