Anybody having issues with minn Kota chargers ?

[riverrat29]

I recently purchased a new precision 10a 4 bank charger and it seemed to work great the first time I used it. My batteries were charged from previous trip out and when I installed the charger they all went green into maintenance mode as expected. I haven't used the boat at all this weekend and I plugged back in this eve and they all hovered around 75% for at least a hour or so and when I went into the garage I could smell battery acid. Bank 2 was boiling the battery. I thought this chargers technology should not allow that to happen and I find it odd that they had not gone green within reason since they were charged. Now the boat was outside today and it did get hot under the cover for a while. Would that have anything to do with it or is there an issue with the charger ? My batteries are all good.

[billproxs]

Which model unit. The 460 has had some known issues

[catdude28]

Are you using the correct gauge extension cord as recommended in the manual?

[riverrat29]

You know.. I had not thought about that. I was using a lighter cord last night like a short outdoor Christmas light cord which is by far not high end or heavy guage. I think they want 12 gauge right? I spoke to tech support this morning and she stated for me to check voltage again tonight when at 75% to make sure it is in 14.4-14.6 range before it goes to maint. mode. She stated anything over 15 is bad news bears. But I did find it odd that all banks were not going green and I know that they were up just that week prior and this charger was doing fine in maint mode. I did not fish this weekend either. I wonder if that cord did something to the way it is was sensing and charging?

[riverrat29]

But I would think that cord is at least 16 guage? I just checked the manual. I will get a new short heavy duty cord today and try it again.

[billproxs]

I think its like 16ga for 25feet
12ga for 50 feet
10ga for anything farther

[riverrat29]

I think its like 16ga for 25feet
12ga for 50 feet
10ga for anything farther

Yeah. after looking at that this cord it was 15 foot long and probably at least 16 gauge. I think I will find this charger has an issue just my luck. Dang shame its brand new and I have had dual pro and noco my whole life. just read the new nocos have issues with charging some batteries and the pulses it sends damaging connected electronics. Everyone you ask says MK is the only one out there worth a dang anymore.Not a good way to start out this purchase.

[billproxs]

Which model number is yours?

[riverrat29]

Which model number is yours?

MK-440 PC

[billproxs]

mk 440 pc is same one i'm using with no issues. new batteries?
i was using all spring and till 2 weeks ago a 16gs 100 ft cord and my plug in was 75 feet away with no issues at all. just bought a new 12ga cord tho. i used same 16ga 100 ft cord plugged in at 75ft with a duel pro with 3 everstart maxx 31s and a blue top 31 for 7 years without any issues.
minn kota does recommend the 12 and 10 ga tho.

[riverrat29]

mk 440 pc is same one i'm using with no issues. new batteries?
i was using all spring and till 2 weeks ago a 16gs 100 ft cord and my plug in was 75 feet away with no issues at all. just bought a new 12ga cord tho. i used same 16ga 100 ft cord plugged in at 75ft with a duel pro with 3 everstart maxx 31s and a blue top 31 for 7 years without any issues.
minn kota does recommend the 12 and 10 ga tho.

I don't think the cord is the issue. Batteries have been tested and are a year old. Within 5 minutes all 4 are at 75% and charging voltage goes to 15.2 all the way to 15.8v Dc and the batteries start boiling.

[Lou r Pitcher]

I only have a very basic diagram of the MK PC's charging algorithm.

Some of our better chargers may reach (peak) ~15.8volts while applying their equalization stage. It typically is a temp compensated voltage so its exact value varies a bit. The time period of its application is very controlled being limited to not produce excessive loss of electrolytes or too high of buildup of internal pressures if it were applied to a sealed AGM. If flooded lead acid, a slight odor would not necessarily be unexpected.

Charging a battery and disconnecting the charger, then again reconnecting the charger to apply yet a subsequent full charge cycle can have unintended consequences. Charging algorithms often are setup to auto apply the full charge cycle only once and then monitor the battery waiting ~30 days before going through a followup charge cycle. This allows the charger to be AC powered 24/7 with no buldup of internal pressure and minimal loss of electrolyte.

Are you running flooded lead acids with caps and experiencing any unusual reductions of electrolyte levels requiring frequent water replacements?

[riverrat29]

Thanks for the insight. This is the first charger I have ever seen boil them bad enough to produce a strong odor in the garage and I put nearly a half gallon of distilled water in all four today. I would think the algorithm should recognize they are fully charged and go to maintenance mode The water levels were fine two weeks ago. The mk rep stated that greater 14.8 upwards of 15 vdc was not something this charger should do. I placed a stand alone charger and all were at 95% or greater on initial hook up. I will report back to mk tomorrow and see what they say. Something just doesn't seem right. It didn't do this on initial use after install.

[Lou r Pitcher]

Does appear that the charger is suspect if it is not being confused by a left on parasitic load on the affected batteries.

[riverrat29]

Does appear that the charger is suspect if it is not being confused by a left on parasitic load on the affected batteries.

By left on parasitic load you mean a draw of some sort correct ? Main power is off hds units off and trolling motor is unplugged as I always do before charging.

[Larry3215]

No matter what, they should never boil the batteries. A low input voltage from too small a cord should not trigger that situation. On-board chargers need to be able to deal with low voltage situations. Its very common to have low voltages at marina docks and they need to be able to compensate or just turn off - not boil the batteries.

Id be asking MK for warranty replacements.

[riverrat29]

No matter what, they should never boil the batteries. A low input voltage from too small a cord should not trigger that situation. On-board chargers need to be able to deal with low voltage situations. Its very common to have low voltages at marina docks and they need to be able to compensate or just turn off - not boil the batteries.

Id be asking MK for warranty replacements.

Spoke with tech service this morning and reported back the voltage being applied after 5 minutes of charging on batteries that were just in maintenance mode two days earlier with no parasitic loads on the batteries. Charger was putting out 15.3-15.8VDC on all four banks and you can hear the electrolyte bubbling and sizzling. She stated it should not produce that high a charging voltage irregardless (should peak at no more than 14.8VDC) and should recognize (couldn't give me specifics) as to time it will go to maintenance mode, but said either way the charger was defective. They are sending me a new one. Well this one lasted less than 1 week out the box, but maybe it was just a dud. I hope this new one does what it should do considering I did quite a bit of research before committing to this brand.

[billnorman1]

Hooking up, powering up and turning on and off of a "smart" charger can have unintended negative outcomes. Even though the batteries are as fully charged as they can be, exploratory voltages sent to them can confuse the charger into cycling a charge sequence through them again. Wet cell batteries outgas at high rates and at the end of their charging cycles.
Anyhow, if your batteries are getting hot, outgasing excesssively, using water or eminating odors it is something that merits looking after.
My cheapo Walmart Neverstart trolling motor batteries are over 2 years old, and I haven't added a drop yet, but once they show green, I don't futz with them until after the next tournament.

[riverrat29]

Hooking up, powering up and turning on and off of a "smart" charger can have unintended negative outcomes. Even though the batteries are as fully charged as they can be, exploratory voltages sent to them can confuse the charger into cycling a charge sequence through them again. Wet cell batteries outgas at high rates and at the end of their charging cycles.
Anyhow, if your batteries are getting hot, outgasing excesssively, using water or eminating odors it is something that merits looking after.
My cheapo Walmart Neverstart trolling motor batteries are over 2 years old, and I haven't added a drop yet, but once they show green, I don't futz with them until after the next tournament.

Although I have never experienced it, I asked her about that. She stated that it should not matter. The trouble is MK won't give you any good info on the charging algorithms so there is no way to know what is "normal" for this case. She was more concerned about the >15VDC output at the state of charging. I am almost tempted to try again and see once they go down after fishing Saturday, see what it does and return the warranty replacement if it acts normally. I would hate to go through changing it out again for no reason. I agree with you, if the batteries are charged there really should not be any reason to plug back in, I just used to do it the night before or shortly before a tourney to make sure they are all up good before going even if I had charged them right after fishing the week prior. Maybe this is not a good practice with this charger ?

[cmb]

You mentioned having Dual Pro chargers in the past, what were your issues with them?