Battery/FF Question

hey all,
heres the scenario:
I have a dedicated battery (mfr date of 5/08) for my 998. I charge my batteries with this type charger ( Minn Kota - MK105PA ) after every use and have had no problems.

I Its been cold here in NE arkansas but I store my boat in my garage. I charged my batteries after last use ( bout month ago), then since I was fishing saturday, put charger back on friday night to "make sure they were fully charged". When doing this to my batteries this time, my dedicated battery wouldnt accept charge from above charger. The charger said "check connection" which I did, and cleaned terminals as well as posts. No identifieable connectivity issue, I tried again and it read the same- check connection.

off to lake to fish, start motoring out, push to turn on 998 and NOTHING. Check those connections, try to turn on again, and I could barely see the home screen then off again. So I fish and come home not using unit.

Once home I try above charger, it acts correctly and starts charging. Charges for about 5 minutes and says "charging complete". So I start getting fishy about the battery. So I take it to autozone, he checks it and says, " its okay, just low on charge". So I go get distilled water and add very little to battery since i could see fluid in cells. put my regular charger on 2amp setting and begin charging using different charger. I let it set bout 3hrs, check battery with volt meter and it says 12.8 volts. So I put FF back on and power up, it comes on. I begin to do playback and it begind shutting down. I go look at battery with volt meter and it reads 12.3 volts. SO i put charger back on.
So what do yall think, bad battery or just need good long charge?

Tom

May have dead cell in battery.

Battery is shot. You got your money's worth out of that one.

I'd say at almost 5 years, your battery is shot. Right after charging, you should see 13.3V or more. I'd suspect if you let that battery sit for 24 hours you'll see a reading somewhere around 10V.

If you have a conventional charger, I'd take the whole works outside and let it charge for several hours at a 10A rate and see what it does. You might see some improvement.

okay so I put battery on slow charge this morning for bout 4hrs then swapped to fast 10 amp charge for about 3 1/2 hrs. I let it set and then it measured only 12.5 volts. So im gonna recheck tomorrow after work and see what it reads.
I checked my other "good" battery after I charged it the other day after use and it read 12.3 volts. So I put it on the slower trickle charger for a while........
Am I looking at getting 2 new batteries?Both are same age........

Im pretty much sold on getting new batteries- they have done me well. So now im wondering if the minn kota charger is a good one??

Trickle charging is not good for the batteries. They need to current to circulate the electrolyte and reverse sulfation. 10A is better for them than 2A.

What charger is good?

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Quote:

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Originally Posted by muzzy125acc

What charger is good?

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Most any charger can be good, but some take a lot more operator effort than others to get good results. I'd steer clear of any charger with a timer or that is labelled just "Automatic" for routine deep cycle charging. Generally the portables that are labelled as "Smart Chargers" or "3-stage" or "4-stage" tend to be best since they monitor battery current draw and shut the charger down to a maintenance mode when the battery is fully charged.

Black and Decker makes some portables that are good, and the Schumacher Ship and Shore line are good portables as well. Any of the common onboards do a good job. Dual Pro, Guest, Minn Kota, NOCO, Pro Mariner and the Cabela's and BPS versions too.

10A is always a good charge rate for the batteries typically used in boats. 15A is fine and 5A is acceptable for routine charging too. Weight and your need to quickly recharge come into play in deciding. Some larger AGMs need more current than that to get maximum life when they are deeply discharged routinely.

Google "slow or fast charge deep cycle battery". You are going to find that slow charging is much better. Repeated fast charges may overcharge a battery and reduce service life