Bad AGMs? Bad Charger? Bad Luck?

jhorta

So, I arrived at my 05 290 today to find that the batteries were not fully  charged.  I currently have 3 DieHard Platinum Marine Batteries (AGM Group 31 1150CCAs).  The charger is a ProMariner Pronautic 1250P 3 stage charger (New for 2015).  The charger was in fault mode, with the temperature control light blinking.  When I reset it, what I discovered is that the STB Battery AND House Battery were getting HOT when charging.  The charger has a line that runs to one of the batteries to monitor temperature, and in this case, it was the HOUSE battery that the line was run to.  The port battery stayed cool during charging.  Do you think the batteries could have gone bad so soon.  I just put them in for the 2015 season.  

Black_Diamond

A hot battery usually means over charged. I'd suspect the charger, batteries are probably toast though b

Mightys4

I had terrible luck with those Die Hard AGM batteries and they wouldn't warranty them.  Went back to lead acid.

Charger needs to be set for AGM as well. 

Hope you have better luck with Sears than I did.

Black_Diamond

I was talking with the parts guy at my marina, he said they are not really seeing longer life with the AGM batteries. The real kicker with AGM is if you run them dead, like dead dead, you can ruin them. 

That said, I'll be switching to them as I have a charger that can handle them and my starting batteries have to be 'almost' horizontal to remove/install due to the locatation. So no spilling worries with AGM. 

Michael T

Probably bad charger, poor cables (internally corroded or poor connections), or improperly wired batteries. IMO some third party reason. 

Soon old technology, fragile, poor performing, somewhat dangerous and environmentally questionable lead acids will be dodos. IMO they are right now, for most of the applications on this forum (except maybe small run abouts - where you don't have a house battery need and can easily use a less expensive LA that has lots of CCA))

For house batteries AGMs have out performed LAs in every way. In the last few years "normal" AGMs are even able to out perform LAs for straight cranking power.

But first - let's define the reference terms for "dead" as there is IMO a lot of misunderstanding and misuse of that term.

The only battery chemistry available to normal boaters that can be run truly "dead" (100% discharge) are Lithium NMCs. They will take that +/- 800 times. Thin Plate Pure Lead AGMs can be run down to 80% of discharge about +/- 400 times, Normal Series 31 AGMs can be run down to 50% discharge (maybe a bit more) +/- 300 times. Gel can be run down 50% (maybe a bit more) +/-1000 times, Most Deep Cycle Flooded can be run down 50% (maybe a bit more) +/- 200 times.

Soon AGMs (and maybe some Gels) will be the normal battery of choice, AGM Thin Plate Pure Leads will be the up-grade and exotic L - Ions will be the newer frontier.

BTW a Series 31 AGM that has 1150 CCA (COLD cranking amps not MCA, marine cranking amps) is a BEAST and would last a long time (I'd say at least 5 years in your 290) unless it is screwed-up by something or in a rare case is factory bad.

Of course money will dictate your choice. When I outfitted my 2014 EC 360 I chose 5 Series 31 AGMs. They outperformed my friends LAs like - well, to be honest they just put them to shame. One on my AGMs did fail and it was replaced. Factory duds do happen.

If I were to purchase a new Rinker 370EX I would install Series 31AGM Thin Plate Pure Lead.

As for most techs knowing the performance characteristics of AGMs, TPPLs or L-Ions, really? That hasn't been my experience. I have found most shops don't even know the proper way to connect house batteries. I had to show my shop and three other local marinas how to do it. They had been wiring ALL the house batteries in the less performing manner - as we discussed at length (with diagrams) on here.

BTW I have seen posts on here of cruisers with the lower performing way to wire their house bank (if 2 or more batteries)

BTW#2. Have your cables ever been lying on the bottom of the bilge or submerged to any degree? If they have been they are probably performing poorly and will only get worse. If water penetrates the cable jacket or gets in either end of a cable the electrical current draws it along the length of the cable corroding it as it goes. I recommend only Marine battery cables, most of which have been "tinned" and have proper cable ends suited for Marine use.