Starting Battery Issue

[Skincheese]

Hoping to get some input from someone on this board about a dead starting battery. First some background on what is attached to my starting battery

1. 2016 Mercury Pro XS (2 stroke)
2. 3 Humminbird Solix Units, 2-10" units and 1 12" unit
3. Mega 360
4. 2 Power Pole Pumps
5. Live well pumps
6. Sea Clear wiring harness
7. Power Pole Charging System
7. Interstate AGM 31 series AGM7 with 925 CCA 200 RC 200 100ah. Battery is less than 2 years old.

Had boat out this past weekend. PP charge showed starting battery fully charged before launch. Fished about 3 hours with all 3 graphs running...went to start big motor and had trouble starting but did turn over but all electronics shut off. Ran about 5 minutes to next stop...fished for about 2 hours and went to start outboard...dead.

This is the 2nd AGM battery that has lasted less than 2 years. My previous battery was also a 31 series AGM. My Power Pole charge app shows starting battery fully charged this morning but am taking it to be load tested this afternoon. Will provide update once that is completed.

Any ideas what may be causing this issue? Very frustrating.....and expensive. Thinking about going to a Lithium starting battery but dont want to spend any more money until I can identify the issue.

[DQM]

What is the priority on your PP Charge set to? Engine, Shared or Trolling?

What do you have for trolling motor batteries and how much were you using them? What was the state of charge on them? With the PP Charge, you have to look at everything, including them.

You are using I would guess about 9 amps total with everything on. That should get you 7+ hours on that battery if it is good condition at at 100% effectiveness not taking the PP Charge in to account. The Charge will also draw up to 15+ amps from it for your trolling motors if it thinks they need some juice as well. It will It can also put about 15amps of juice (from a 36 volt system) to the starting battery if the trolling batteries have quite a bit more juice in them that the starting battery.

But the Charge unit does not know capacity, just an estimate of state of charge based on voltage.

[CatFan]

Have you checked voltage at the battery with the engine running?

[CJ1]

It sounds like you are pulling way too much from 1 battery and like Cat is saying nothing going back in. I don't think I would like a unit that could pull juice from my starting battery to power my trollers. I think sometimes we are overcomplicating things anymore! CJ

[Jig_Man]

I had the same issue and solved it with a house battery for my Solix units.

[billnorman1]

Looks like a pretty stout battery. Also looks like one cannot check the level of the electrolyte. I would think if you can't find any thing wrong elsewhere you might look at the charger to see if it goes to a maintenance voltage level after it does the fast charge cycle. Cancel that, I see you have a Power Pole charger, and that's Black Magic to me.
When your main goes dead, does the PP system take from your trolling batteries and get you started again? Is that automatic? How can you tell?

I used to go to Deale and play payoff pinball at Smoky's Happy Harbor bar in my drinking days. I don't see how my wife ever put up with me.

[DQM]

If the main starting battery is low and there is enough juice in the trolling motor batteries, the PP Charge will definitely pull from the trolling motor batteries to charge up the starting battery.

They won't give you much, if any, details on the specifics on when or how it decides this. But if you set the priority to Engine, versus Shared or Trolling, it will not draw as much from the starting battery overall.

Charge does have an emergency start feature. You can force it to pull power from the trolling bank to the starting battery if the starting battery drained very low.

But if you have an undersized starting battery to begin with, or a bad starting battery, Charge will not really make it any better. You need to make sure you have a starting battery that is capable of handling all of your stuff and not discharging significantly faster than your trolling bank.

It is not a solution for not having properly sized and good working batteries.

The problem is, Charge was designed around the idea that your trolling motor batteries take the most abuse and discharge the most. And that has typically been the case for most people. But now, with all of the stuff (toys) we are cramming on out boats, the issue has flipped and people are pounding their starting batteries in to submission with multiple large graphs, pumps, LiveScope/Active Target, networking, Mega 360, etc.

People will spend $450+ on a big bad X2 or Northstar or whatever, when they could get a 125ah Ionic for $750 or so and not deal with worrying about reduced capacity from running it to low, or the diminishing returns of a lead acid or AGM battery as it goes below 40% charge, or under 12 volts. And given that there are really no reports of issues with properly designed lithium starting batteries causing any problems, other than the occasional bad battery (which happens from anyone, lithium or lead), it really is a no brainer in my opinion.

I cannot speak for othe brands, but I can say without hesitation my Solix units and Ulterra really do not like going below 12 volts :).

[lmoore]

With that much going on, I would go to a larger battery. The Interstate AGMs technically meet the minimum requirements for your motor, but there isn’t a lot of room for additional hookups. I believe the recommendation on the 3L forum is that battery only be used on Mercury motors smaller than 150 hp. A battery from the top list in this link would probably perform better for what you have. House battery would be a decent option also, if you wanted to go that route.

https://www.bbcboards.net/showthread...batteries+meet