time to replace battery?

[Megunticook]

Before the 2018 season I bought a Rolls-Surette 12V flooded lead-acid battery (https://rollsbattery.com/battery/s12-24/) to run the modest electrical system on my TySenior. Loads are just the running lights, GPS, depthfinder, interior light, charging phones, etc. A 40W solar panel and a Morningstar charge controller (https://www.morningstarcorp.com/products/sunsaver/) keeps the battery topped off while the boat sits on its mooring.

Normally when I check my voltage meter when coming aboard it reads 13.7 (unless I happen to catch it during absorb or equalization, when voltage is even higher).

Battery is fully charged at the end of the season and stored disconnected. In April I checked the water level, specific gravity, put it on the bench charger, everything seemed normal. Same on the boat. Now this week suddenly it's only reading 12.6V when I come aboard. The Morningstar indicates it's charging. I know batteries wear out and one sign of that is when it won't rise above a certain voltage.

Think it's time to replace? Was hoping to get more than 5 seasons out of it but maybe that's not realistic. And it can get recycled so I'm not worried about contributing yet more toxic materials to our waste stream.

Should I go with AGM this time instead of flooded? Slightly more expensive but probably a better product for a boat application.

I could try finishing the season with this one and it would probably be fine but when a fogbank rolls in off the Gulf of Maine sometime when I'm threading the needle at Lime Island bar I don't want to have to worry about whether my GPS might go out on me.

[Jim Walsh]

Peace of mind has value, thus I’d replace it. My buddy just replaced his Rolls battery for the same reason after five seasons use. I’ve had flooded and AGM’s over the years. Other than the additional maintenance required I see no real difference in longevity between the two. Currently I’m an AGM guy and happy with East Penn manufactured batteries. They come in myriad name brands, just pop a label on that says West Marine, or anything else, and you’re in business. If you read the label it will specify that it was manufactured by East Penn.
Four to five years is normal before replacement is necessary. Anything more than that and luck is shining down on you. Like anything else boat related, exceptions are the rule.

[gonesail]

you can always have it tested at an auto parts store or by your own test instrument. everybody i know says the AGM are better than the flooded. however .. 12.6 volts is a good reading for a battery.

[wikakaru]

Those resistance load testers are cheap compared to the cost of a battery--only $20 to $30. Definitely test the battery before you replace it. The testers are designed for starter battery testing--high load over a short duration--but the specs you linked to show a CCA rating of 550 amps, so a resistance tester should provide a good idea of the battery's health.

It's possible you can revive the battery with an equalization charge. According to Trojan's page (https://www.trojanbattery.com/resources ... aintenance) the equalization voltage is 2.70 volts per cell, or 16.20 volts for your 6-cell battery. I don't know about the Morningstar controller, but my Victron allows me to change the charging voltage. Remember to do this ONCE at the beginning of the season, then switch back to the normal charging voltage, which for this battery should be 14.70 volts for absorption and 13.50 for float.

At the end of the season when you lay up the boat, make sure you store the battery properly. Clean the battery's exterior at the end of the season--accumulated dirt will increase the self-discharge rate. Store the battery in a clean, dry place that won't freeze. I think I remember reading somewhere that batteries shouldn't be stored on concrete to minimize self-discharge; instead they should be up on wooden blocks. I clean out my plastic battery box at the end of the season and keep the battery in the clean plastic battery box over winter. I also keep my battery on a trickle charge all winter. You want to avoid the battery discharging completely over the winter, as that will kill a battery more quickly, though Roll's specs on that battery show you should get more than 500 cycles at 100% discharge. This may be a warranty issue.

Good luck and smooth sailing,

Jim

[Megunticook]

False alarm--even though charge controller was indicating it was charging, I tested the PV output when disconnected from the charge controller and there was no voltage. Turns out one of the wire splices on the PV leads failed. I redid the splices, reinstalled the panel, and battery voltage started climbing again. I figured a quality battery like the Rolls with good TLC would last more than 5 years.

The 12.6V I was getting makes perfect sense now and is what you'd expect a full healthy battery to show. Interesting that several hours of instrument use and phone charging loads don't put much of a dent in the battery's state of charge.

Anyway thanks for all tips and advice. Couple of comments--since auto battery chargers test cold cranking amps, and this battery is designed/used instead for deep cycling, it's not the best indicator. Measuring specific gravity in each cell is probably the best way to test health. I did that in April, they all looked fine.

The adage about not storing batteries on concrete is no longer true I hear from pros, but I do the same as Wikakaru and store it in the cleaned plastic box over winter. Don't leave it on the charger but put it on for a few days each month just to be sure it's topped off.

Cleaning the battery after the season is definitely a good idea.

Be happy to get a couple more seasons at least out of the Rolls, will probably go to an AGM next, looks like their 85AH version (https://rollsbattery.com/battery/s12-95agm-re/ runs $350 or so. Not the cheapest battery manufacturer but they make quality stuff.

[Steve Laume]

I find that having a battery monitor gives me a lot of information and peace of mind.

If you had one in your system, you would have been able to see that the panels were not charging the battery. It will tell you how many amps are going in or out of the battery at any given time and how many or what percentage of your total amp hours have been used. It is very hard to know the state of a battery with a voltage meter alone.

A battery monitor is much cheaper than new batteries, Steve.

[John Stone]

I have a victron battery monitor and it works well telling me what's going on with the battery.

BTW, I had a Lifeline AGM and I switched to Trojan T 105s lead acid. Simple, inexpensive, reliable. I have two 45 watt panels each running through its own MPPT controller because often only one panel is charging while the other is shaded. No desire to change. T105s are more amps than you probably need, but you seem to have a similar simple system.

My recommendation is to keep it simple as possible.

[Megunticook]

I have a victron battery monitor and it works great telling me what's going on with the battery.

BTW, I had a Lifeline AGM and I switched to Trojan T 105s lead acid. Simple, inexpensive, reliable. I have two 45 watt panels each running through its own MPPT controller because often only one panel is charging. Works perfectly. No desire to change. T105s are more amps than you. I think you have a similar simple system.

My recommendation is to keep it simple as possible.

Interesting you went the opposite way from AGM to FLA. I'll take a look at battery monitors, more data is always a plus. My system is definitely simple but has been very reliable (except for the failed wire splice which was easily spotted and fixed). I would've thought that the heat shrink tubing would've protected it from corrosion but I think the real issue is that the wire got strained occasionally, putting stress on the connection.