BaitMonkey1984 Posted July 23, 2015 Posted July 23, 2015 I have a dual pro 3 bank charger for my Ranger. I always read to keep the batteries charged. I bought three new batteries last year so I am doing my best to maintain them properly. After a full day on the lake it takes several hours to get all batteries to full charge. Today, I was out for about two hours and it was calm so I would estimate used my 2 deep cycle batteries less than 10%. My question is, I leave my batteries charging till morning even if they only discharged 10%. Is this recommended, or is the charger over-charging the battery. Quote
BKeith Posted July 23, 2015 Posted July 23, 2015 There is a little window you are playing with. It's not recommended to charge a battery that's at 90% or greater charge. At the same time, a battery left uncharged that's at or below 80% will start to sulfate within 12-24 hours. If I only use mine a little and plan on going back that afternoon or the next morning, I typically do not charge them, unless I know for sure I'm going to be using them hard and heavy the next trip, like when feel we will be chasing schooling fish. I also have a Curtis charge level meter mounted in my boat so I know exactly what level of charge they are at. However, if I only use it a little and done for the next few days or the week, the charger gets plugged in, even if they are at 95% charge, because I know if I don't, I will forget to later. Quote
scbassin Posted July 23, 2015 Posted July 23, 2015 I have a Minn Kota 4 bank on board charger & leave my Interstate batteries on the charger 24/7 when not on the water. Read the instructions on your charger to see if it floats your batteries when fully charged. Quote
no39 Posted July 23, 2015 Posted July 23, 2015 I have a Minn Kota 4 bank on board charger & leave my Interstate batteries on the charger 24/7 when not on the water. Read the instructions on your charger to see if it floats your batteries when fully charged. +1 I use a minn kota 3 bank precision and do the same. Most chargers these days have some sort of multiple phase charging. The batteries are close to six years old and load test the same year after year. Quote
Super User WIGuide Posted July 23, 2015 Super User Posted July 23, 2015 The Dual Pro's won't overcharge your battery. Plug them in and you'll be good! 1 Quote
Super User iabass8 Posted July 23, 2015 Super User Posted July 23, 2015 I also have a dual pro 3 bank chatger . I leave my batteries plugged in all the time. Read your manual. It will charge (these numbers arent exact but close) to i think 90%. (4-5 red lights i dont recall) then it will trickle charge to full (flashing green) and then maintenace mode (solid green). Im pretty sure thats how it works with dual pros at least. Quote
BKeith Posted July 23, 2015 Posted July 23, 2015 His question was, should he plug the charger in if the batteries are only down by 10%, if he plans to go out again the next morning, not if he should leave his charger on them 24/7. Most manufactures do not recommend charging one that has only been discharged less than 10%. However, for me, on those rare occasions mine is at 90% or more and I'm not going back out soon, I plug the charger in just so I don't forget to later. Most all name brand on board chargers can and should be left on them 24/7 and keep the batteries maintained and will not over charge them. The last Dual Pro I had did not have a float mode, it turned off and then back on when the battery self discharged to a set point. This is also the same way most of the MinnKota chargers work. I haven't checked the details on their Precision series, since they have a high frequency mode to help desulfate a battery, they may be using the float method with those. One difference between a charge mode and a maintenance mode is the charge mode in most quality chargers over charges the battery by approximately 10% for about 20 minutes, this is to equalize the cells to insure they are all fully charged. Then if goes into the maintenance mode, which does not do that 10% overcharge, it just brings them back to it's set level. This overcharge is also why most of those cheap chargers cause a battery to die a slow death, they are not capable of providing that equalization charge. They reach a certain level of charge when the current slows down to a certain point and shut off. Repeatedly connecting one to charge that is only down by 10% is subjecting the battery to that initial overcharge every time and is what they are trying to avoid. Technically, it only needs that equalization charge (10% over charge) about every fifth time charging them but that would be kinda hard for the charger to keep track of. Industrial chargers have a button you are suppose to push about once a week to equalize the cells. Quote
Super User Further North Posted July 23, 2015 Super User Posted July 23, 2015 I have a Minn Kota 4 bank on board charger & leave my Interstate batteries on the charger 24/7 when not on the water. Read the instructions on your charger to see if it floats your batteries when fully charged. I do exactly the same with the same equipment...in fact I leave my batteries in the boat on on the charger during the winter. My last set of Interstates (I have 4, 3 for the trolling motor, one for the main motor and electronics) lasted 5 seasons. Quote
5 Dollar Fishing Game Posted July 24, 2015 Posted July 24, 2015 I have three batteries. One for electronics, one for trolling, and one for cranking. All three get the trickle charge after a day on the water. No issues at all. Quote
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