Bad Battery or Bad on-board charger?

Woke up to a terrible sulfur smell coming from my battery compartment this past week and two of my three trolling batteries were boiling and making a hissing sound. Now I’m not sure if my minnkota onboard charger over charged them or if the batteries are just shot and that’s what caused the problem. I had checked all 3 batteries at the begit of the season and all had correct water levels but now the two are bone dry. I’ve added distilled water and I’m gonna throw a trickle charger on them to see what happens but if they’re shot I’m a little hesitant to just buy new batteries fearing that my charger caused the problem. Anybody know how to diagnose the issue a little better to figure out if the batteries are just bad or if my charger is overcharging? Batteries (interstate) and charger are 3yrs old.

Thanks

I would still guess that your water levels had gotten low somehow. Had that happen to me too. I bought new batteries and everything is working fine now.

I have a MK460 PC.

I’d take your batteries into interstate after a full charge and have them load test them.

take them back for a refund if you can.I had an interstate battery do the same thing less than a month old. Before I retired my State issued vehicle was equipped with an interstate battery. I needed a replacement every 2-6 months. After the last one that only lasted 1 month. I paid for my own battery not with the state’s/government money to buy a different brand.Problem resolved.The majority of car batteries are created by 3 manufacturers – Delphi, Exide and Johnson Controls Industries. And they sell them to other retailers so they can put their own brand name on them.
Posted something like this on another thread regarding battery charging.
I have used a few battery charges. Best ones IMO that I personally own:for automobile Batteryminder.com, https://www.batteryminders.com/why-batteryminders/
and for Boat Minnkota MK series Precision Chargers. https://www.minnkotamotors.com/learn/buying-guide/battery-chargers
Good luck Good fishin

If there is a bad cell and the battery doesn’t charge, the battery tends to heat up and boil off the water. I think the resistance of the bad cell creates the heat.

Just because different brands of batteries are manufactured under the same roof doesn’t mean they are the same battery with a different sticker.

biggill youre right,I’m not an expert on car batteries by any means but I did find some additional information that might be used to make a good choice.

The different brands/products coming out of the same factory may differ in any of these respects, to list just a few:

raw material specifications
individual component design and tolerance requirements
quality control requirements and inspection processes
warranty duration and coverage

So, I guess it could come down to at least some of this criteria plus intended use,durability,reputation and warranty not in that order necessarily.
thanks

edge175 wrote:

The different brands/products coming out of the same factory may differ in any of these respects, to list just a few:

raw material specifications
individual component design and tolerance requirements
quality control requirements and inspection processes
warranty duration and coverage

So, I guess it could come down to at least some of this criteria plus intended use,durability,reputation and warranty not in that order necessarily.
thanks

Thanks for looking into it. Those differences can have huge impacts on the functionality of the product. I work in manufacturing and see this first hand. We make products for different customers that are used in the exact same application, but they want different specs. It results in a different cost and ultimately a different level of overall quality.

If they were slapping different labels on the same battery there would be no need for interstate or others to employ engineers. They would simply be marketing companies.

biggill wrote:

Just because different brands of batteries are manufactured under the same roof doesn’t mean they are the same battery with a different sticker.

If the specs are different, you are correct.
If the specs are the same, there are many batteries on the market with the only difference being the store label.
I worked in a battery distribution warehouse while in college. While the labels may brand them differently (Walmart, Cenex, Sears, etc.), the batteries are many times EXACTLY the same.
The batteries came to the warehouse unlabeled by the pallet loads(according to specs) and depending upon how many each store had ordered, we’d put that particular stores label on x number of batteries, load them on other pallets, load them on trucks and deliver them directly to individual stores. Even though they are exactly the same batteries, prices and warranties varied considerably from store brand to store brand.

Karry Kyllo wrote:

If the specs are different, you are correct.
If the specs are the same, there are many batteries on the market with the only difference being the store label.
I worked in a battery distribution warehouse while in college. While the labels may brand them differently (Walmart, Cenex, Sears, etc.), the batteries are many times EXACTLY the same.
The batteries came to the warehouse unlabeled by the pallet loads(according to specs) and depending upon how many each store had ordered, we’d put that particular stores label on x number of batteries, load them on other pallets, load them on trucks and deliver them directly to individual stores. Even though they are exactly the same batteries, prices and warranties varied considerably from store brand to store brand.

That’s all I’m saying. Like any consumer product, some stuff is simply rebranded under a different name. The problem is there is this myth that all batteries are the same because they’re made in the same place.