What is the proper way to charge your batteries. I leave mine on the charger until I use my boat next. That might be one week to one month. Is that bad for the batteries? Friend of mine only charges his the day before he goes. Who's right?
A big opinion discussion often ensues when discussing battery charging as there are opinions in several camps. One thing that no battery-knowledgeable person would ever do that's quoted about the friend above is: Leave the batteries in a discharged state for any length of time.
1. Discharging a battery takes a toll on it, which is why they don't last forever.
2. The deeper a battery is discharged, the shorter its service life will be. This is why higher capacity batteries last longer, assuming all other characteristics are fairly equal.
3. The LONGER a battery stays in a discharged state, the more pronounced the impact of that discharge cycle will be.
4. You give a battery the best chance for a longer service life if you recharge it ASAP after any discharge cycle.
So, the buddy who doesn't charge his batteries until he's ready to fish again is killing those batteries faster. Today's high tech smart chargers have a microprocessor controlled profile that includes a high-frequency desulfation cycle that can help extend battery service. They also have a smart float mode that avoids evaporating excessive amounts of water from the electrolyte. This "boil-off" was a reason that chargers were once not left connected.
I vote for the following with respect to conventional lead-acid batteries:
1. Charge ASAP with a good smart charger.
2. Leave it connected, but keep an eye on it and the condition of the batteries.
3. Check electrolyte level after charging at proper intervals for your level of use; fill properly using only distilled water. You'll have to learn by experience how often your batteries need water replenished.
4. Use a battery cut-off switch for the main battery.
5. Be sure to flip the TM breaker or unplug the TM. (Read TM manual to discover you should do this.)
6. Use an AC supply surge protector with your charger. This step is cheap insurance.
I bought a small 2 outlet surge protector made as a small box. It isn't waterproof, but I can protect it under the deck in a place where rain doesn't get to it if charging outdoors on a trip. IF something funky happens on the AC line, the surge protector makes it less likely that my expensive charger will get fried.
Ever had an extension cord stolen? Use a small shackle padlock to secure the cord to a transom eye of your boat. The padlock lets the cord pass through, but the plug and receptacle on the ends are too large to do so. Stealing the cord would require cutting the lock or cutting the extension cord itself. This could be an adequate deterrent.