Batteries

[muskyjim]

Do deep cycle batteries have a memory? If I don't run it down completely and keep recharging it, will it die an early death?
Do things like automatic bilge pumps constantly draw power from a battery?
I'm asking all of these questions because based on this forum it seems that running my accessories off of a battery other than my starting battery is the best way to go.
Thanks,
Jim

 

[Barnacle_Bill]

Re: Batteries

Your batteries will last longer if you recharge immediately after use.

 

[drewpster]

Re: Batteries

Battery Memory, also called voltage depression, interestingly is not caused by the amount of discharge of a battery. It is caused by overcharging. Overcharging creates electrolyte crystals to form on the battery plates causing resistance and loss of battery efficiency. It is not as common in wet cell batteries as it is in NiCad batteries.

It is important to recharge wet cell batteries quickly after they are used because a low battery will form rust, or lead sulfates, on the battery plates due to an imbalance in the electrolyte. This also causes internal resistance and loss of battery efficiency.

Overcharging causes 'memory', undercharging causes sulfating. These conditions are easily confused.

Overcharging is common among boaters who use trickle chargers to slow charge their batteries. Inexpensive plug-in chargers will overcharge if left connected too long. Undercharging is most common in battery systems that are inadequate for loads over time. If you deeply discharge your batteries and depend on you engine's alternator to recharge them, it typically takes running the engine for a long time to completely top them off.

The holy grail in battery systems is balancing cycles of discharge and charge.

 

[muskyjim]

Re: Batteries

Regardless of the amount of discharge, the battery should always be topped off, correct?
If an accessory is not wired to an on/off switch, will it draw power from a battery?

 

[drewpster]

Re: Batteries

Yes it is best to fully recharge a wet cell battery after use. I my case I use an automatic charger onboard that takes care of my batteries while connected to shore power. I also have an automatic charger I use while the batteries are on the bench. The key here is not to overcharge or undercharge. Hence the use of a automatic charger. It is also important to use a charger that has settings for a particular battery type.

I always use, and recommend using, a main battery switch to isolate the batteries. It is not as important what kind of switch you use (1-2-both, single pole ect.) as it is using one that isolates the batteries from the electrical system and each battery bank from each other. There are allot of good reasons for doing this not the least of which is preventing unintended battery discharge. All systems have battery draw. Using high quality marine components and conductors help combat this, however they do not eliminate it. It especially important to turn the batts off during extended periods of storage.

 

[tashasdaddy]

Re: Batteries

i have 8 of these, great for maintaining the battery, when not in use. recharge after use, then connect these and it's ready when you are.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42292

 

[muskyjim]

Re: Batteries

I use a 10 amp Ship to Shore charger for recharging my batteries. Two float chargers for maintaining the charge in between trips and through out the winter. I think I will get more float chargers for on board. Great idea.

 

[drewpster]

Re: Batteries

musky, It may be a good idea to check your onboard charger to see if it already has 'float' features already built in. Many onboard chargers have an automatic float feature that is done automatically for storage.
Mine is an older charger and it has this feature. After staying on the batteries for a period of time at full charge the charger goes into a storage mode automatically. It maintains the batts and does an automatic saturation charged every 21 days (if memory serves) You may be flaotin' when there's no need to.

 

[muskyjim]

Re: Batteries

I don't have an on board charger. If I'm not going to use the boat for a while I'll pull the batteries and recharge them. Then attach my float chargers in the garage to maintain. It's kind of a pain pulling the batteries, but until I decide to spend the $$ for an on board charger that's how it goes.

 

[tashasdaddy]

Re: Batteries

jim i just run an extention cord to the boat with a double plug, for my float chargers.

 

[muskyjim]

Re: Batteries

I sometimes just pull the batteries out from under their storage area and will charge them, so that there is separation between the charging batteries and my gas tanks. My gas tanks share the same storage area in the aft section of the boat. That is just the way the boat is designed. I try to make sure there is plenty of ventilation in that area. I still get a little nervous about that setup, so I try to take precautions when I can.

 

[I/O WALDO]

Re: Batteries

Try not to run your deeps down under 11 volts.

 

[Silvertip]

Re: Batteries

Here's the answer your question about whether a device draws current if its's not connected to an on/off switch. It depends on the type of accessory you are talking about. An automatic bilge pump for example is activated by a float switch which is nothing more than another on/off switch (although there are some electronic versions). If water rises in the bilge the float switch turns on, the pump runs until the water drops and float switch turns off. So in that case the answer is no -- it doesn't draw current unless turned on. Accessories like a stereo system is a different story. The station memory and clock both require a constant source of +12 volts. If that line was turned off you lose stored stations and the clock stops. That current draw however is very low and a decent battery would run it for weeks without going dead.

 

[drewpster]

Re: Batteries

All true. The amp draw I am referring to is the tiny amount of draw on a battery when its posts are connected to anything. Even with everything turned off there is still a tiny amount of draw. Moist air can even cause it. Most of the time it goes unnoticed except during storage. Ever turn everything off store the boat with a topped off battery and find the battery dead in the spring? Even battery suppliers at retail stores rotate batteries on the shelf from time to time.

 

[cbavier]

Re: Batteries

Does anybody know is an " AUTOMATIC BATTERY FLOAT CHARGER "
solar powered? Or are Solar powered or are "AUTOMATIC BATTERY FLOAT CHARGERS" Available?

If so does harbor Freight carry them or where can I get one besides West marine?