Battery Woes

Batteries, Generators, Solar, Wind and Electronics
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bobr
Posts: 97
Joined: Wed Jul 22, 2009 5:05 pm

Battery Woes

Post by bobr »

I have room for 2 group 31 batteries in my house bank (without ripping out an accumulator tank for my fresh water and losing some important storage space).

I'm currently using Sportsman deep cycle 31's, if memory serves they are rated at 120 ah. Three years old. Before that it was Intestate.

These batteries have never held a charge very well, and it gets worse over time. They will drop down to 12.4 volts shortly after running the engine for an extended period of time and I'm often below 12 volts, which I know isn't good for them. The boat lives on a mooring, and in a week they will self discharge down to about 12.2 volts.

My big draw is the refrigerator. I converted the lights to LED and use them sparingly. I don't mind running the engine once a day at anchor as I have to heat up hot water anyway, but I'm not willing to do it twice a day, which is what it currently takes to keep them above 12 volts.

I have babied these babies, they only get used 4-5 months of the year and I keep them topped off at home all winter. They are under 100 cycles but failing fast.

I don't think I have an alternator problem, as my starting battery (an ancient Optima Blue top) comes right back up and stays there. Of course I don't punish it like the house bank. I'd buy 3 of these if I could fit them, but 2 won't do the job as they are only 75 ah.

So my question is what else is out there in flooded 31's? I see the Rolls brand which costs quite a bit more than most others, but if I knew they would be better I'd gladly buy them.
Bob R.
1995 Freedom 35 (Pedrick)
"Liberty"
Old Saybrook, CT

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newt2u
Posts: 93
Joined: Wed Sep 11, 2019 11:24 am
Location: UK

Re: Battery Woes

Post by newt2u »

On my Coaster 33, which I just sold I had two Crown deep cycle batteries in my house bank (120Ah 20 hours/105Ah 5 hours). I bought these in 2017 and sold the boat recently. I have never had a problem with them, they always kept their charge well. I have moved to a pair of 50Ah LifePO4 on my Freedom 21 but these were quite a bit more expensive but are a good choice for me in that they do not self-discharge. However, on both setups I have the facility for regular charging, wind/solar on the Coaster and just solar on the F21. I am not sure what output your alternator gives but I suspect that your batteries are rarely brought up to full charge. A 50A output would require in excess of 5hrs of engine run to bring them up to full charge. My advice would be to add some wind or solar to your boat. On the F21 I have two small 50W panels in series and an MPPT charge controller. I typically get around 3Amps in full sunshine and even 1Amp in cloud. Its enough to keep my batteries full whenever I go onboard.
Rockin - F21 twin drop keels - located Milford Haven
Wintered in Shropshire where I am when I’m not sailing

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GeoffSchultz
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Re: Battery Woes

Post by GeoffSchultz »

I agree with newtu2. You need to fully charge your batteries, and being on a mooring and just running the motor a few hours a day won't do that. A key question is how many Ah is your refrig drawing per day?
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

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bobr
Posts: 97
Joined: Wed Jul 22, 2009 5:05 pm

Re: Battery Woes

Post by bobr »

Thanks for your suggestions, guys. I hadn’t considered that I wasn’t bringing the batteries back up to full charge. But that makes some sense because they come down quickly even without a load. I do have an aftermarket oversized alternator but as Geoff says that hour or so I run it at anchor is likely insufficient. I suppose I may also have a voltage leak somewhere that isn’t helping. Looks like I need to consider solar panels or a wind generator. Not quite sure where to put the solar panels on my boat. I do have a radar pole that theoretically could serve as a mount for panels or a generator.
Bob R.
1995 Freedom 35 (Pedrick)
"Liberty"
Old Saybrook, CT

Sailing-61-North
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Joined: Thu Jun 04, 2020 8:17 pm
Location: Valdez - AK
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Re: Battery Woes

Post by Sailing-61-North »

I'm running two Trojan 27 TMX batteries. 105-am each placed in parallel. Rolls are also very good batteries. I have T-105's in my RV and wanted to go that route yet height was an issue (Moved the house batteries to the holding tank location). Lithium was on the list but cost has not dropped enough yet - plus I need new sails....

1. Consider a quality battery monitor such as Victron or BM-1. Victron is nice since it can blue-tooth to your phone.
2. Solar is nice for keeping things charged. Rule of thumb is 100 watts per 100 amp hours minimum. I live in coastal Alaska and I try to double that. I am working on a 300-watt system for the boat, I have a 300-watt system for the RV and a 5500-watt system on the house.
3. MPPT solar charge controller that is programmable for the battery specifications provided by the manufacture. Use C10% -C13% for sizing. A 200-amp system would need a 20-25 amp charge controller. If you over do it with Lead Acid it will destroy the batteries via cooking them. I like Victron due to the ability to change charge parameters. If it does not provide equalization then keep looking. With Lithium you can go way higher in the percent of charge - way higher.
4. I would, for house batteries, only ever consider true deep-cycle batteries. I have beat the heck out of my T-105's and they keep on going.
S/V Arctic Tern
Freedom 33
1981 - #37
Prince William Sound - Alaska

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newt2u
Posts: 93
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Location: UK

Re: Battery Woes

Post by newt2u »

Bob, I have my panels hanging out back, using a frame attached to the pushpit The angled brackets are adjustable so I can change the angle of the panels depending on orientation in the marina and time of year. I have 2 18V 50W panels and an Epever MPPT controller. That way I am able to put the panels in series and avoid some of the problems of partial shading. As you can see on the controller, when I took that pic I was getting 35V into the controller which then down shifts this to whatever voltage is required for given charge state. This means you are always getting the benefit of whatever voltage you are generating. For example in parallel a panel output may drop below the charge threshold, because of shading, cloud etc., whereas with MPPT, I always see some charge going in even a trickle on the cloudiest days. The Epever can be set up for different battery types, including my LifePo4s.
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Rockin - F21 twin drop keels - located Milford Haven
Wintered in Shropshire where I am when I’m not sailing

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bobr
Posts: 97
Joined: Wed Jul 22, 2009 5:05 pm

Re: Battery Woes

Post by bobr »

Thanks again, guys! You give me a lot to think about!
Bob R.
1995 Freedom 35 (Pedrick)
"Liberty"
Old Saybrook, CT

TonyB
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Joined: Tue Sep 25, 2018 2:33 pm
Location: San Francisco Bay Area, California

Re: Battery Woes

Post by TonyB »

Just a thought. If you feel you are going to abuse them (Deep dish charge them, not charge them back up properly, etc), get AGMs. They will take a lot more abuse than flooded lead acid batteries. Batteries like Lifeline of Trojan or Deka are better than Optima (look at weight, it is all about how much lead they have).
But I ran a pair of Optima blue top 31s in my Newport 30 for 10 years with no problems. And I abused the hell out of them. I had no battery monitor. Not even a volt meter on them. So my only indication they were low is when things would shut down. That is low!
AGMs can just take a lot more abuse.
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

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bobr
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Joined: Wed Jul 22, 2009 5:05 pm

Re: Battery Woes

Post by bobr »

Hi Tony,

Thanks for your suggestion. I actually have an optima blue top as my starting battery, and I agree that they are nearly indestructible. Of course I don’t draw it down as far as the House bank, but that thing comes right back up and stays there as opposed to what I’m seeing with my flooded batteries. I have no idea how old it is but it was on the boat when I bought it six years ago and it performs just as well today.

My issue is that they are only 75AH and I would really need to fit at least one more and I can’t do that without some serious reworking of my battery compartment and freshwater plumbing as I have an accumulator tank next to the battery compartment. But it is a good suggestion and one that I have not ruled out.

Thanks again!
Bob R.
1995 Freedom 35 (Pedrick)
"Liberty"
Old Saybrook, CT

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bobr
Posts: 97
Joined: Wed Jul 22, 2009 5:05 pm

Re: Battery Woes

Post by bobr »

P.S. Tony, I now see that other manufacturers make group 31 AGM‘s at 100 amp hours or more. So that does seem like something to consider.
Bob R.
1995 Freedom 35 (Pedrick)
"Liberty"
Old Saybrook, CT

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