Just finished a charge that took approx. 3 hours to get my Crank battery on the charger to show green for a full charge. I connected my mulit charge for wet cell/Gell Cell/AGM batteries. It listed the battery only 90% full charge. Wondering why I am not getting the full charge?

Has anyone used batter additives to resulphate the plates to optimize charging and battery life?

Flyswatter

When the going gets tough, the tough go fishing!

Any onboard does a far better job of charging the battery than a typical portable. Most portables will overcharge a battery, so they will always continue to charge the battery after it has been on an onboard. Every charger has set charging point that may vary by a few hundredths of a volt. Comparing what one charger thinks is fully charged and what another thinks is usually going to result in a mismatch, and the bottom line is that it doesn't make enough difference in capaacity to have any effect on performance. If you wanted to, you could charge the battery at 18V, and they would hold more power, but the life would be shorter.

The additives are complete and total junk.

Removing the electrolyte from a battery is useless in all but a few fairly unusual cases, and is a very dangerous process. This stuff is sulphuric acid, and shouldn't be messed with.

What is your source or experience? Do share so we can better understand and educate ourselves.

Regarding my onboard charger (brand new boat, 2010) it only charges to about 90% capacity to my portable (NOT JUNK, very expensive) to test charge in my batteries. Is that typical for on board chargers? It Blinks green for full charge on my onboard charger but to specific percentage charge rate it only registers 90% on my portable charger. I trickle charge at 2 amps with the option to go to 2,10 and 15 amps for remaining 10% not charged. This takes additional 2 plus hours to complete but feel confident of a full charge now. From my perspective when traveling and fishing I view my onboard charge to keep my batteries from getting zapped with adequate charging vs. expecting a full charge from my experience. If I am missing something with this observation do share.

Thanks!

Flyswatter

Everything you ever wanted to know about batteries:
http://www.windsun.com/Batteries/Battery_FAQ.htm

The article references the part about never adding acid to an existing battery. Good explanation as well as to why AGM batteries are far superior to gell or wet cell batteries.

2008 Z520/Yamaha 250

About 12 years as a battery test engineer working with some of the most thoroughly tested batteries in the world.

Okay you have 12 years experience as a Battery tester engineer. I am not sure How it relates to your comment that battery additives are junk. Have you done test or have doucmentation that disproves their usefulness? If so please share.

First, the manufacturers would have to provide some evidence that they work or even propose an idea of why they might work. The burden of proof is on the one making the claim. Batteries use sulphuric acid as an electrolyte. The chemistry of how they work and how they fail is well understood and there is no evidence that any of the additives work. There isn't even a reason to believe the additives might work, so nobody is going to spend any time investigating them.

If they continue to run down quickly you might have a dead cell in the battery and should be replaced. I don't recommend adding acid to batteries either.

The life of a battery is keeping them stored fully charged and full of water. We see customers getting 5 or 6 years out of a battery and some that can't get 12 months out of the same type battery.

You didn't mention what type of trolling motor you have. But the newer digital trolling motor use less power and will last longer during a day of fishing. The older analog motors use more power.

Hope this helps

Okay, high amp charging is good info.

Please read this website on Battery Equlizing works.

http://www.batteryequaliser.co...s.htm

So this is hocus pocus and unsubstantiated?