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Off topic Battery question...

S

slauder

Regular Contributor
I left my two deep cycle (12v 105 amp hours) batteries in the boat this winter. I had them on trickle charge and they showed 12.8 6 weeks ago. I also have my large cranking battery on board too, also trickle charged 6 weeks ago.

Yesterday I tested them with a volt meter and the house batteries were 6.8 volts so I pulled them off and brought them to my garage and put them on trickle again just to see if they a will take the charge.

The big cranking battery read 12.84 volts. I trickle change it next weekend.

I live on Long Island and we have had some days way way colder then normal with some days in teens and nights around 5 f.

why so different results?
 
A fully charged 12 volt lead/acid battery that has been at rest for 6 to 8 hours (after charging), should read between 12.6 and 12.7 volts...... if it's good!
That's based on 2.12 to 2.15 volts per cell.
(I know...... the math doesn't work out quite right! :D )

Trickle chargers (when left on for any lengthy duration) ruin batteries, because the voltage range boils the H2O from the electrolyte.
You may want to replace it with an On Board Charger using "Smart Charge" technology!


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There must be something draining the charge on those 2 deep cycle batteries. A month or more ago I had a similar problem with one of my batteries. The Safe-T-Alert fire, water, and fume system had drained it down to about 8 volts. I finally found the location of the fuse and pulled it out. Now both batteries are still at about 12.5 volts.
 
The 2 deep cycle house batteries are 4 years old. The new big cranking one is 10 months. All have no connections on terminals. I trickle charged them with 2amps for a day. I had not load tested them ever so maybe they were in bad shape from the boat being pulled and having the bilge pump (runs on timer) connected for a couple weeks before I disconnected terminals. Most years I connect ac power to boat and let the on board zantec charger handle all cells at once but I had a mystery zantec control panel fry last winter so I though I would try something different.
 
it depends on what i am using a battery for...ignition battery gets replaced in 3 years...no exception and that includes the wifes car...i have batteries that have lasted much longer in other applications and environments.. ...i have replaced both my trickle chargers on the campboat with ''Battery Tender plus'' chargers....
http://www.amazon.com/Battery-Tende...qid=1390965722&sr=8-2&keywords=battery+tender.....
i am sure there are equal or better chargers out there and i am not pushing these but i have had good results with one and they are not too expensive...i have a new one here in my office to go on the sewer treatment plant next trip..
 
To clarify a pint: "Trickle chargers" are bad news! They do not know how to maintain a battery at a proper, fully charged state. Instead--being 'stupid' chargers--they continue charging a battery until it is destroyed by over charging. What a battery needs is a maintainer charging system that 'knows' when to back off before doing damage.

I assume this is what you have (a maintainer, not a trickle charger) and you simply named them incorrectly. However, if this is NOT true, that is your problem.

Jeff

PS: Last year, one of my battery chargers turned out to be a damn trickle charger (long story) and destroyed one of my batteries.
 
you are correct Jeff on the terminology.....the so called trickle chargers have always been a problem...25 years ago a ''maintainer'' was impossible to find...and if you found one the average boater could not afford it...of course that was before the web was active to do research and shop worldwide...a local engineer designed and built a few and i got a couple at his build cost that worked well but it was a pain in the butt to use them because you had to use a regular charger to drive them....in todays micro electronic world they are available in the 50 buck range...there is a misconception with the so called maintenance free batteries...storage and the state of the charge are the two ignored things that some boaters dont consider..especially during the winter....
 
Rick mentioned something earlier that is very important.....after a charger is disconnected the charge needs to be checked later....if its not at a good charge 8 hours later there is a problem somewhere...it could be something pulling current or it could be the battery itself...any spark when connecting a battery is a dead give a way that something is pulling current....
 
I agree. A good charger needs the ability to go into "float" or "maintenance" mode. Most chargers manufactured prior to "smart charge" technology, do not have this ability.


What takes a good quality Deep Cycle wet cell battery to it's grave, would be the number of cycles, the depth of each cycle, and of greater importance....., the duration left in a SOD ( state of discharge), etc.
That shortens life span, and even kills batteries!!!!!
When we prevent these from becoming discharged below 50%, and when we bring them back quickly to a near full SOC, they should go for four or even five years......., and sometimes even longer!


Those of us who are getting long life from our "House Banks", are typically using a Shunt Resistor based Amp Hour battery monitoring system that allows for tracking AH in/out.

http://www.google.com/search?client...1c.1.32.mobile-gws-serp..2.7.2105.yImDP0-3xuk



Voltage readings alone can't offer this data.




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