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Discussion Starter #1
Came out the other day to my trolling batteries near dead. I plugged in the charger and charges it for 2 days. Trolling motor battery indicator showed all 4 blocks lite up as in fully charged. I then unplugged charger to use extension to charge sons scooter. It’s been a day and a half, and now the trolling motor battery indicator shows 1 red block lite up. How did my 2 batteries (4 years old) drain themselves that quick. I’ve never had this issue, and my master power is shutoff so nothing should be utilizing battery power.
On board charger works fine, my starting battery has remained fully charged


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#1- check the water in the batteries
#2- make certain nothing is connected to the batteries and charge again (check the wires for damage)
#3- pull them out and get them tested after charging (auto zone-batteries plus-any auto shop can test them) or you could do that first then #1&2 they have to be charged to test or at least attempt to charge
You might have a bad cell in one of the batteries that’s causing issues
BOAT= bust out another thousand
4 year old tm batteries imo are on the borderline of replacement.
Hope this helps
 

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Discussion Starter #4
#1- check the water in the batteries
#2- make certain nothing is connected to the batteries and charge again (check the wires for damage)
#3- pull them out and get them tested after charging (auto zone-batteries plus-any auto shop can test them) or you could do that first then #1&2 they have to be charged to test or at least attempt to charge
You might have a bad cell in one of the batteries that’s causing issues
BOAT= bust out another thousand
4 year old tm batteries imo are on the borderline of replacement.
Hope this helps
Thanks for the response! yeah I know boats are money hungry, that’s not an issue. I’m just not super savvy with mechanical stuff, so I like to get others opinions before I make any decisions


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Recharge and disconnect the batteries completely from the wiring and see if they continue to drain. You can use a multimeter to verify voltage after disconnecting from charger (wait an hour or so for the charging voltage to settle) then retest voltage in a couple days.

You could use a multimeter to read current by disconnecting a lead, then setting your meter to DC amps, and putting the meter leads in line from battery to wire to see if there is something drawing amps even though your switch is off. Maybe there is a bare spot in the wire or something.

Or... your battery is toast.
 

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Thanks for the response! yeah I know boats are money hungry, that’s not an issue. I’m just not super savvy with mechanical stuff, so I like to get others opinions before I make any decisions


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As others have stated you probably have a bad cell, it is also a good idea to disconnect your batteries when they are not in use as sometimes even with everything powered down you can get whats called a parasitic drain, however if it has never been an issue in the past and nothing has changed it is most likely a bad cell and the battery will need to be replaced but charge it and have it checked to be sure. Also if you do not use one it is a real good idea to keep your batteries on a tender especially during the off season it will just make them last that much longer.
 

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4-year old batteries are likely bad.

Disconnect the trolling motor and anything else at the battery (shouldn't be anything else). Then charge them as normal. Wait at least 8 hours and check the batteries with a multimeter. If it is 12.6 or 12.7, then the batteries are still good and you must have a parasitic drain on the boat.

If they are 12.5 or below, then the batteries need to be replaced.

The water checking suggestion is a good one....but putting water into the batteries now won't fix them. You need to check the water at the end of each season.
 

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Some batteries will retain around 13v... so get a baseline full charge number based on your battery type. My AGM sit at 13.0 when topped off.
 

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I have a powerdrive trolling motor that I bought the I pilot conversion head for. Unlike the terrova that I had on my previous boat this motor will continue to draw my battery down if it's not unplugged because it's still trying to maintain a GPS signal.
 

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You could use a multimeter to read current by disconnecting a lead, then setting your meter to DC amps, and putting the meter leads in line from battery to wire to see if there is something drawing amps even though your switch is off. Maybe there is a bare spot in the wire or something.
Or... your battery is toast.
If your meter is not fused in the amperage portion, do not do this. A draw over 10 amps could cause the meter leads to get warm to very hot. If the leads do not open, the magic smoke in the meter could be released and the meter will quit functioning. In things electrical, the smoke needs to stay within the equipment in order for the equipment to work.

Good luck.
 

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If your meter is not fused in the amperage portion, do not do this. A draw over 10 amps could cause the meter leads to get warm to very hot. If the leads do not open, the magic smoke in the meter could be released and the meter will quit functioning. In things electrical, the smoke needs to stay within the equipment in order for the equipment to work.

Good luck.
True story!

Yes, it is never good to let the magic smoke out of electronics. It's what makes them work :)
 

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If your meter is not fused in the amperage portion, do not do this. A draw over 10 amps could cause the meter leads to get warm to very hot. If the leads do not open, the magic smoke in the meter could be released and the meter will quit functioning. In things electrical, the smoke needs to stay within the equipment in order for the equipment to work.

Good luck.
:D:D:D:D:D:D:D
 

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Discussion Starter #14
Took them up to AutoZone and their battery checker said the batteries are good but only at 17% charge I went back and looked at my onboard battery charger connection to the battery and they are very loose, so I think they split.


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I have a powerdrive trolling motor that I bought the I pilot conversion head for. Unlike the terrova that I had on my previous boat this motor will continue to draw my battery down if it's not unplugged because it's still trying to maintain a GPS signal.
That’s exactly what I have to but I’ve never done anything with any GPS portion of it


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That’s exactly what I have to but I’ve never done anything with any GPS portion of it


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Does it have spot lock or anything like that?? If so, he had a really good point - if you leave it plugged in. I always unplug mine.
 

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Discussion Starter #17
Does it have spot lock or anything like that?? If so, he had a really good point - if you leave it plugged in. I always unplug mine.
It does have the anchor button for spot lock, i’ve only used it two or three times on inland lakes. Never even crossed my mind that would pull battery when not in use


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